Guidelines for the implementation of standards for recycled copper and aluminum raw materials

Recently, the National Technical Committee for Standardization of Nonferrous Metals issued a circular on the implementation of standards for recycled copper and aluminum raw materials. The three national standards of GB/T 38470-2019 "recycled Brass Raw Materials", GB/T 38471-2019 "recycled Copper Raw Materials" and GB/T 38472-2019 "recycled cast Aluminum Alloy Raw Materials" were formally implemented on July 1, 2020.

In view of the inconsistent understanding, understanding and implementation of the standards among the relevant parties in the process of implementation, the National Technical Committee for Nonferrous Metals Standardization jointly with local customs and enterprises producing and using recycled copper and aluminum raw materials, compiled the "guidelines for the implementation of recycled Copper and Aluminum Raw Materials Standards", interpreted the three key provisions of the standard from the technical level, and clarified the typical questions in the form of questions and answers.

The details are as follows:

Introduction: since the implementation of the standards of GB/T 38470-2019 "recycled Brass Raw Materials", GB/T 38471-2019 "recycled Copper Raw Materials" and GB/T 38472-2019 "recycled cast Aluminum Alloy Raw Materials", there have been some inconsistencies in the understanding of the standards among production, use, trading enterprises and regulatory departments. In response to questions, I would like to reply as follows.

1. How is the standard positioned and what is the standardized object?

Answer: "recycled copper raw materials", "recycled brass raw materials" and "recycled casting aluminum alloy raw materials" are recycled raw materials directly into the furnace for casting / smelting, and they are clean products containing copper or aluminum waste after sorting, processing and treatment. therefore, it is positioned as the raw material product standard.

2. Announcement No. 43 of 2020 of the Ministry of Ecology and Environment, the General Administration of Customs, the Ministry of Commerce and the Ministry of Industry and Information Technology on regulating the import management of recycled brass raw materials, recycled copper raw materials and recycled casting aluminum alloy raw materials. It is clear that the import does not comply with the provisions of the three standards, but it is not clear whether those who do not meet the three standards belong to solid waste. How do you understand it?

A: notice No. 43 makes it clear that imports are prohibited if they do not meet the provisions of the three standards, except for those who have obtained a license for solid waste that can be used as raw materials. According to the definitions of "recycled brass raw material", "recycled copper raw material" and "recycled cast aluminum alloy raw material" in three standards, recycled metal raw materials are products that have been effectively sorted or pretreated, and have the characteristics of direct production and utilization. Recycled materials without effective separation or pretreatment, which need further treatment in China, do not meet the definition of recycled raw materials in the three standards and are non-conforming products. Whether it belongs to solid waste should be identified in accordance with the provisions of the Law of the people's Republic of China on the Prevention and Control of Environmental pollution caused by solid waste and the guidelines of GB 34330-2017 solid waste Identification Standards-General principles.

3. There are many technical requirements and inspection items stipulated in the standards of recycled copper raw materials and recycled brass raw materials. Which are the inspection items that reflect the raw materials?

Answer: the two national standards are applicable to the recovery and sorting of domestic and foreign raw materials. The standards are compiled taking into account the international and domestic markets, the trade needs of both supply and demand, and the requirements of the users. At the same time, taking into account the requirements of customs inspection, in the process of implementation of the standard, inspection items can be divided:

-key items reflecting raw materials: apparent characteristics, inclusions, radioactive contamination, other requirements (standard 5.5 hazardous substances), amount of copper (copper alloy);

General items: total amount of metal, moisture, metal recovery rate, fracture structure, marking, packaging, transportation, storage and quality certificate, etc.

4. The three standards of GB/T 38470-2019, GB/T 38471-2019 and GB/T 38472-2019 do not specify the specific limit requirements for apparent discrepancies. If there are a small number of nonconformities, are they directly determined to be unqualified?

Answer: GB/T 38470-2019, GB/T 38471-2019 standard, 7.6.3 "apparent characteristics, radioactive pollutants, other requirements of any test results do not meet the requirements, then determine that the raw materials do not meet the provisions of this standard", "apparent characteristics" do not meet the requirements, it is directly determined to be unqualified. GB/T 38472-2019pd7.4.1 "if the appearance test results of any sample are not up to standard, double the number of samples should be taken from the batch and repeated tests shall be carried out. All the repeated test results are qualified, and the raw materials are judged to be qualified, otherwise the batch is judged to be not in conformity with the provisions of this standard.

A small number of discrepancies in apparent characteristics and how to grasp the scale shall be carried out by the Customs in accordance with the current regulations, such as from the perspective of environmental control requirements. If the visual estimation of inclusions is not up to standard, the inspection shall be carried out.

5. The three standards cannot cover all recycled copper and recycled aluminum. How to dispose of recycled copper and aluminum materials that are not within the scope of the three standards? For example, GB/T 38470-2019 is for brass alloys and GB/T 38471-2019 is for pure copper. But in addition to pure copper (copper) and brass, there are bronze alloys containing nickel and white copper alloys. For example, the old propeller imported by a company is composed of Cu1 (grade 1 manganese bronze), Cu2 (grade 2 nickel manganese bronze), Cu3 (grade 3 nickel aluminum bronze) and Cu4 (grade 4 manganese aluminum bronze). Any kind of copper alloy is bronze alloy, not brass alloy.

A: because the standard-setting process is short of time, and some raw materials are not fully included in these three national standards due to lack of data, we are currently in the process of formulating them one after another, and we need a process. Judging from the composition of the single old propeller imported by a certain company, any kind of copper alloy in Cu1 (grade 1 manganese bronze), Cu2 (grade 2 nickel manganese bronze), Cu3 (grade 3 nickel aluminum bronze) and Cu4 (grade 4 manganese aluminum bronze) is bronze alloy, not brass alloy. Does not comply with the GB/T 38470-2019 "recycled Brass Raw material"Zinc content needs to be greater than the content of a single metal element other than copper". Therefore, the single old screw slurry is not suitable for the national standard of GB/T 38470-2019 "recycled Brass Raw Materials".

In view of the consideration of the effective use of strategic metal resources, if the port environmental protection requirements are met, it is suggested that with reference to the key projects reflecting raw materials listed in question 3, bronze and white copper alloys not covered by the standard should be inspected or declared after new codes, so as to obtain the intentional permission of the port customs first.

The next step is to revise the relevant standards in order to regulate the recycling of other recyclable copper and aluminum raw materials.

6. The application name is recycled copper, the appearance meets the requirement of No. 2 copper, and the composition is copper-tin alloy. The content of copper is 94.2% and the content of tin is 5.47%. All other items are qualified and the surface is very clean (as shown in the figure below). However, the copper content is slightly lower than the requirement of no. 3 copper not less than 96%, but greater than the requirement of no. 3 copper meters not less than 94%, how to determine?

A: judging from the composition and pictures, the raw material is tin bronze, which is the remaining material for processing. The situation is similar to question 5, and it is recommended to make a declaration after testing or adding a new code with reference to the key items that reflect the raw materials listed in question 3.

Recycled brass raw material

Recycled copper raw material

I. Standard interpretation

1. GB/T 38470-2019 "recycled Copper Raw Materials"

Apparent characteristics and sources of copper scrap not included in recycled copper raw materials:

Enamelled wire, because the surface contains organic coating, in the melting process, will volatilize the gas of environmental pollution, does not meet the requirements of raw materials, the amount of mixing should not exceed 5% of the total amount of raw materials.

Copper shavings, because there are a lot of cutting oil and cutting fluid in the processing process, will volatilize the gas of environmental pollution in the smelting process, which does not meet the requirements of raw materials and should not be mixed into any kind of raw materials.

Copper water tank, because it contains water or a large amount of sludge, or Pb, Sn and other heavy metals, and Pb has the impact of environmental pollution, does not meet the requirements of raw materials, should not be mixed into any kind of raw materials.

2. GB/T 38471-2019 "recycled Brass Raw Materials"

Apparent characteristics and sources of copper scrap not included in recycled brass raw materials:

Brass water watch case, due to a large amount of paint on the surface, will volatilize the gas of environmental pollution in the melting process, which does not meet the requirements of raw materials, and the amount mixed should not exceed 5% of the total amount of raw materials. If there is no paint on the surface, it can be classified as mixed brass.

Brass water tank, contains water or a lot of sludge, or Pb, Sn and other heavy metals, and Pb has the impact of environmental pollution, does not meet the requirements of raw materials, should not be mixed into any kind of raw materials.

3. What are the raw materials of recycled copper and recycled brass, and how did they come from?

Answer: the raw material of recycled copper (brass) is that the recycled copper (or brass) or its mixed metal is disassembled, broken, sorted and treated to meet the requirements of this standard and can be directly produced and used.

Disassembly refers to separation from the system, such as valves from buildings, wires from electricity, and copper-containing parts from electrical appliances.

Crushing refers to further crushing and separation from the disassembled copper-containing parts, such as the removal of glass and ceramics from the failed valve, the removal of surface insulation from the wire, and the removal of inclusions such as plastics, wood and ceramics from the copper parts.

Sorting refers to the separation of copper and brass components from disassembled and broken materials, because the principle of separation is based on copper components, so the physical shape and specifications of the separated materials are not consistent.

Treatment refers to the cleaning (decontamination), packaging, drying and so on of the sorted materials.

4. The relationship between "recycled copper raw materials", "recycled brass raw materials" and GB/T 13587-2020 "copper and copper alloy scrap"?

Answer: 1) "recycled copper raw materials", "recycled brass raw materials" and GB/T 13587-2020 "copper and copper alloy scrap", the three standards coordinate with each other in content and structure, without conflict, and are complementary. "recycled copper raw materials" and "recycled brass raw materials" are recycled materials that can be directly used; "copper and copper alloy scrap" are also wastes that need to be pretreated or disassembled, but the contents of inclusions, moisture, oil and non-copper metals are high, so they can not be used directly, so they basically return to the refining process.

2) the principle of distinguishing raw materials from waste materials is that: a) raw materials are obtained after pretreatment of copper-containing recycled materials by physical or chemical methods, such as bright wire peeling off the plastic insulating skin on the surface of wires and cables, and other; b) raw material standard inclusions, radioactive pollutants, total metal, metal copper and other indicators are far more strict than the waste standard; C) even after proper classification, most of the wastes still belong to mixed materials, while the raw materials show homogeneity in physical and chemical properties.

5. The chemical composition detection methods of GB/T 38470-2019 and GB/T 38471-2019 standards. According to the standard, GB/T 5121.1 "determination of copper content in copper and copper alloys-part 1 determination of copper content" was selected as the arbitration method, and YS/T 482 (direct reading spectrometry) and YS/T 483 (X-ray fluorescence spectrometry) as screening methods. GB/T 5121.1 includes three methods for the determination of copper content: all of them involve the use of electrolyzer devices, which cause inconvenience to some laboratories in testing equipment and take a long time. YS/T 482 (direct reading spectrometry) and YS/T 483( X-ray fluorescence spectrometry) are relatively fast, but the accuracy is not good. Is it possible to choose from other measurement methods?

A: impurity elements can be measured by GB/T 5121.27-2008 "methods for Chemical Analysis of Copper and Copper Alloys-part 27: inductively coupled Plasma Atomic Emission Spectrometry", and then the copper content can be obtained by calculating the margin. YS/T 521.1 "methods for chemical analysis of crude copper-part 1: determination of copper content-iodometric method" can also be used for the determination of copper content by chemical titration. Some applicable method standards can be added in the next revision of the standard.

6. The copper content and copper content in GB/T 38470-2019 and GB/T 38471-2019 standards and the lead content in GB/T 38470-2019 standard are difficult to obtain sample data directly in the field. How to operate in practice?

Answer: the amount of metal copper is obtained by weighing method on the spot, and the method is simple. The contents of copper and lead, that is, the chemical composition of the raw materials, are tested in the laboratory. On-site can be carried out with the help of portable XRF or portable spectrometer, if there is any problem, and then sent to the laboratory to determine.

7. for the determination of copper content, it is necessary to select metal copper and copper alloy by hand, but it is difficult to distinguish copper or copper alloy from other metals in appearance, so it is difficult to realize manual selection, and there are also some problems in the determination of metal copper content. How to solve it?

Answer: the determination of copper content requires sampling, melting to prepare samples, pretreatment of the samples before melting, picking out inclusions and non-copper metals as far as possible, and even if not, slag removal should be carried out in the melting process, which has no effect on the determination of copper content.

In addition, if the testing laboratory does not have the melting sample for high-quality samples in accordance with the standard, the sample quality can be reduced to a degree acceptable to the laboratory and then the melting sample testing can be carried out.

8. With regard to the issue of group batches, at present, enterprises and customs have different understandings of group batches. How should we determine the grouping batches?

Answer: the "group batch" in the three national standards refers to the "group inspection batch", which is suitable for the inspection of raw material recovery and sorting at home and abroad. The customs conducts on-site inspection of the attributes of solid waste from the point of view of the customs by citing the environmental protection provisions applicable to port supervision, and if there is any objection in the investigation, it will be identified. Considering the existence of the split of the waybill, there are problems in the actual operation. It is suggested that the customs should organize batch sampling and identification according to the existing customs rules.

9. Does the same batch accept partial transportation? Does the definition of "different types of bulk materials should not be mixed" mean that the objects should not be mixed only refer to different types of bulk materials?

A: raw materials of the same batch should be transported in the same batch. Should not be mixed only refers to different types of bulk raw materials, does not include independent packaging of raw materials, but mixed packaging is not allowed in the same independent packaging unit.

10. In practice, some of the recycled metal raw materials coming into the port are a mixture of a variety of components and materials, appearance differences, how to declare? How to judge?

Answer: the customs conducts on-site inspection of the attributes of solid waste from the perspective of customs by citing the environmental protection provisions applicable to port supervision. For recycled raw materials that meet the requirements of environmental protection, the requirements of "each batch shall be composed of raw materials of the same name or code name" according to three standards (GB/T 38470-2019 7.3,7.3 of GB/T 38471-2019 and 7.2 of GB/T 38472-2019) are strictly enforced.

For example, when recycled copper raw materials are imported, they are declared according to the standard name of "apparent characteristics and sources of raw materials in Table 2" in GB/T 38471-2019, and the apparent characteristics of the goods are tested in accordance with their requirements. If "the composition, specification and source of the same container of goods obviously come from different raw materials" depends on whether it conforms to "mixed brass" or "copper processed material", follow-up treatment shall be carried out in accordance with Article 7.3 of GB/T 38470-2019 and Article 7.3 of GB/T 38471-2019 combined with the provisions of Table 2 in the standard.

11. The standard requires that the powder (dust, sludge, crystalline salt, metal oxide, fiber powder, etc.) with a particle size not larger than 2mm should not be more than 0.1%; non-metallic inclusions should be less than 1%. In practice, it is difficult to detect inclusions and powders, how to solve them?

Answer: this inspection refers to SN/T 1791.9-2018 "Inspection and Quarantine regulations for imported solid wastes that can be used as Raw Materials, part 9: scrap Nonferrous Metals". The standard has been in operation for more than 20 years from promulgation to revision. In the actual inspection, the customs can first judge the content of inclusions on the spot by means of visual inspection and touch; if it is suspected that the inclusions are unqualified, they should be sent for screening, inspection and identification, and if there is any objection to the appraisal results, they shall be submitted to arbitration.

12. How to deal with the relationship between recycled copper, recycled aluminum and GB 16487.7-2017 "Environmental Protection Control Standard for solid waste that can be used as Raw Materials-waste Nonferrous Metals"?

A: GB 16487.7-2017 has been abolished and implemented in accordance with the newly established standards.

13. How to deal with the goods if they find inclusions, bullets, radiation exceeding the standard, etc.?

Answer: it is suggested that this situation should be treated as unqualified return of the goods, or be dealt with as required by the relevant regulatory departments.

14. If waste circuit boards and electronic components containing harmful substances are mixed into the goods, are they treated as general inclusions?

Answer: according to standard 5.5.2, it is forbidden to mix closed vessels, pressure vessels and hazardous substances stipulated by national laws and regulations in raw materials.

15. Can the oil mixed into the goods be treated as hazardous waste and be determined to be mixed with hazardous waste, which does not meet the requirements of the standard?

Answer: the "engine oil" mixed in the goods is a dangerous substance stipulated in national laws and regulations, which does not meet the requirements of Article 5.5.2 of the standard.

16. GB/T 38470-2019 and GB/T 38471-2019 have clear provisions on the packaging, transportation, storage and quality certificate of the goods. At present, the first-line imported products do not meet this regulation. Is it determined that the goods do not meet the requirements of GB/T 38470-2019 or GB/T 38471-2019? Or please clearly elaborate on the regulation in the industry?

Answer: the relevant provisions of "marking, packaging, transportation, storage and quality certificate" in the standard are based on the format requirements prepared by national product standards, and are applicable to both supply and demand, not necessary requirements. If the "marking, packaging, transport, storage and quality certificate" meets the environmental protection provisions of the port supervision, the project can be ignored.

II. On the issue of GB/T 38470-2019 "recycled Brass Raw Materials"

17. As shown in the picture below, for sundries that are not sorted, the Customs used to import solid waste that can be used as raw materials. How can it be judged now?

　

Description:

Performance features: it is composed of brass casting, or service failure castings, rolled pieces, steel products and so on.

Mixed brass RCuZn-4C

A: the picture is from the standard picture, which shows that the raw materials are mainly from parts that have failed in service, so they have a variety of physical shapes, but they are all brass. The composition of this kind of raw material after effective separation or pretreatment meets the requirements of the standard, and the content of copper and zinc is very high, so there is no need to add lead and other new metal raw materials directly into the furnace, so it belongs to the raw materials that meet the requirements of the standard, so it is included in the mixed brass RCuZn-4C material in GB/T 38470-2019. It is estimated that about 28% of the low-quality recycled brass materials previously imported according to "solid waste that can be used as raw materials" do not meet the requirements of the GB/T 38470-2019 standard and cannot be imported.

18. According to the provisions of "5.3 inclusion content, moisture content, total metal content and metal brass content", the raw material quality of the coating in the mixed brass should not be greater than 5% of the total raw material mass. 1) of which 5% specifically refers to the ratio of which two weights? 2) how to detect the mass proportion of raw materials with coating in practice? 3) most of the mixed brass from all kinds of valves, water meters and other dismantled parts have coating or coating, how to determine the material?

Answer: 1) 5% of the weight of the coated material means that the weight of the coated material does not exceed 5% of the total material weight. 2) the specific detection method should be tested in accordance with Article 6.3.4 of the standard; 3) most of the mixed brass from all kinds of valves, water meters and other dismantled parts have a coating or coating, and the surface of the coating is generally made of nickel, tin, zinc, aluminum and chromium metal. The subsequent utilization has no impact on the environment, but the organic coating on the surface will volatilize the gas that pollutes the environment in the melting process. In order to ensure that the raw material, if the coated raw material is more than 5% of the total quality of the raw material, it should be ruled that it does not meet the requirements not to be imported, in order to pollute the environment.

The weight of the coated material shown in the following figure is far more than 5%, so it is judged that the raw material does not meet the requirements and is not up to standard.

19. In the standard, "6.3.4 coating" is under the item "6.3 inclusions". Does the coating belong to the category of inclusions?

Answer: "coating" and "inclusion" are two inspection items. In Chapter 5 of the standard, "coating" is stipulated in the form of footnotes and is not listed separately. In Chapter 6 of the standard, "coating" is listed under the item "6.3 inclusions" in the order of inspection. The items should be adjusted when the standard is revised next time.

20. The raw material with logo color as shown in the following figure is the raw material containing coating. How to judge?

Answer: according to the standard, the weight of the coated raw material should not exceed 5% of the total weight of the raw material, and the direct judgment that the weight of the coated raw material exceeds the standard does not meet the requirements and is not qualified; those that are difficult to judge the content should be sent for screening and inspection and identification. The identification that does not meet the requirements is unqualified.

21. As shown in the figure below, some materials declared as "mixed brass" are a mixture of undismantled water, valves and other components, in which plastic parts, iron parts, etc., are not made of brass. How to judge?

Answer: according to the standard requirements should be dismantled, should be selected as much as possible. Among them, the undisassembled integral parts with plastic are judged according to the "inclusions" in the standard, and the undisassembled integral parts with iron are calculated according to the "non-copper metal" in the standard, participate in the difference reduction of "metal brass", and judge according to the requirements of GB/T 38470-2019 "recycled brass raw materials" standard.

22. The apparent characteristics of No. 1 brass shavings in the standard are composed of processed brass shavings, without file shavings and wear shavings. In practice, how to distinguish between file chips and abrasive chips and processed chips?

A: it can be distinguished by the size of the particles. The grain of the cutting and milling scrap is larger or the length of the strip. The particle size of the file debris is very small, the water or oil content is too large, it is not easy to clean, and the burning damage is serious when entering the furnace.

23. The definition of "No. 1 brass shavings" has not been found in the standard. What does "No. 1 brass shavings" mean?

Answer: "brass shavings" refers to the brass scraps produced by machining brass, because brass has many alloy grades and is often used as a material for processing parts, especially lead brass is an easy-to-cut copper alloy, which will produce a large amount of lead brass scraps. Therefore, the recycled materials of "brass shavings" are divided into "No. 1 brass shavings", "No. 2 brass shavings" and "No. 3 brass shavings". "No. 1 brass shavings" is a single lead brass, and "No. 2 brass shavings" is composed of a single series of brass shavings other than lead brass, such as bismuth brass shavings, antimony brass shavings and so on. "No. 3 brass shavings" is a mixture of brass shavings of two or more different alloy series. "No. 1 brass shavings" is included in the standard of GB/T 38470-2019 "recycled Brass Raw Materials" because of its single composition and no file shavings and abrasive shavings. "Brass scraps No. 2" and "Brass shavings No. 3" are included in GB/T 13587-2020 "Copper and Copper Alloy scrap".

Does "red copper" mean "red copper"? The name of the product is not included in the terminology of Copper and Copper Alloys (GB/T 11086).

Answer: red copper is not red copper. There is no definition of "red copper" in GB/T 11086-2013 "Copper and Copper Alloy terminology". It is a common name in the industry, which refers to brass with a copper content of more than 75%. Because of its high copper content, it is red, so it is called "red copper" in the industry and "Red Brass" in the world. The next revision of GB/T 38471-2019 will clearly define it.

III. The problem of "recycled Copper Raw Materials" of GB/T 38471-2019

25. How are the shavings of copper as shown in the following picture classified? Its copper content is relatively high, up to 96% more than 99%.

Answer: according to the standard, brass has scrap material, red copper has no scrap item. Although it has a high copper content, it generally contains a lot of oil and sundries, which does not meet the requirements of recycled copper raw materials, which is included in GB/T 13587-2020 "Copper and Copper Alloy scrap".

26, some recycled copper, broken copper is made of copper and other metal materials (such as aluminum, etc.) together, manual selection can not be separated, can not be broken after mechanical separation, so can not be quantified, how to determine?

Answer: for this kind of inlaid metal that cannot be separated, when testing "metal copper content", it is calculated according to "non-copper metal" as a whole.

27, 1) the No. 3 copper meter sample with metal copper content less than 98% belongs to the unqualified No. 3 copper meter according to GB/T 38471-2019, but meets the requirement of No. 3 copper metal copper content of 97%; 2) the copper content does not meet the requirement of No. 2 copper wire, but actually meets the content requirement of No. 3 copper processing material; The metal recovery project is also in a similar situation. Can copper meters and copper wires be classified as copper processing materials and judged by the indicators of copper processing materials?

Answer: there is still an essential difference between copper meters, copper wire and copper processing materials. Copper meter refers to the particles obtained after wire and cable shredding and separation and removal of insulation; copper wire mainly refers to wire and cable after stripping and removing insulation; copper processing materials mainly refer to all kinds of copper plate and bar types, etc., with different sources, copper meters and copper wire should not be classified as copper processing materials, and copper processing materials should not be classified as copper processing materials.

28. Oxidation leads to different colors and apparent colors of copper raw materials, as shown in the following figure, how to determine?

Answer: the apparent characteristic of "No. 1 copper wire" in GB/T 38471-2019 standard stipulates that "oxidation is allowed on the surface". The raw materials of oxidized copper wire have no effect on the follow-up utilization and environment.

No. 29 and No. 2 copper contains raw materials with surface coating, as shown in the following figure, how to determine?

Answer: the apparent characteristic of "No. 2 copper" in GB/T 38471-2019 standard stipulates that "surface coating is allowed". The surface coating generally includes nickel, tin, zinc, aluminum, chromium and other metals, which has no impact on subsequent utilization and environment.

4. The sensory judgment and test results of typical material legends are shown in the table below.

　　

Recycled cast aluminum alloy raw materials

Q: how to use recycled aluminum raw materials?

Answer: "recycled aluminum raw material" is mainly used in the production of liquid aluminum. According to the industrial use, liquid aluminum can be divided into three categories: cast aluminum alloy industrial liquid aluminum, wrought aluminum and aluminum alloy industrial liquid aluminum and other industrial liquid aluminum (such as aluminum powder, aluminum foam and other industries). According to chemical composition, liquid aluminum is divided into pure aluminum (high flexibility, low strength 1 series pure aluminum), high copper alloy (2 series high strength aluminum alloy), high silicon copper magnesium alloy (3 series high strength and wear resistant cast aluminum alloy), high manganese alloy (medium flexibility, low strength 3 series wrought aluminum).

And aluminum alloy) and high silicon alloy (i.e. 4 series wear resistant aluminum alloy), high magnesium alloy (i.e. 5 series corrosion resistant medium strength aluminum alloy), high magnesium high silicon alloy (i.e. 6 series wrought aluminum alloy with medium strength, easy forming and easy quenching), high zinc alloy (i.e. 7 series strong aluminum alloy) and alloys with other elements as the main alloy elements (i.e. 8 series aluminum alloy or 9 series cast aluminum alloy).

The suitable grade of liquid aluminum is selected from the above series according to the use, and the specific composition is determined, and the suitable recycled aluminum raw material is selected according to the composition. [the composition type of the raw material is inferred according to the "raw material source" (see Table 1 of the standard of recycled aluminum raw materials such as GB/T 38472-2019 "recycled cast aluminum alloy raw material"). After the recycled aluminum raw materials are melted in the furnace, the corresponding composition adjustment or microstructure adjustment materials are added, including primary aluminum ingots, magnesium, copper and other metal or semi-metal "silicon", aluminum master alloys, composition additives and other materials. after melting and refining, the liquid aluminum with chemical composition that meets the corresponding requirements can be obtained.

Liquid aluminum is used for casting aluminum alloy ingots (or castings), or casting / spray forming deformed aluminum and aluminum alloy ingots / aluminum and aluminum alloy powder, or continuous casting / rolling / extrusion into deformed aluminum and aluminum alloy products such as aluminum plate / strip / bar / tube. Casting aluminum alloy ingots are usually made into castings by remelting, casting and heat treatment, and casting aluminum alloy ingots can also be cut into shapes for direct use. Deformed aluminum and aluminum alloy ingots are usually processed by rolling, extrusion, stretching, forging, spinning and other pressure processing and heat treatment, and are transformed into aluminum plates, strips, foils, tubes, bars, shapes, lines, forgings and other product forms. The microstructure of cast aluminum alloy ingots (or castings) and wrought aluminum and aluminum alloy ingots are as-cast, with coarse grains, low toughness and fatigue resistance. The subsequent casting aluminum alloy ingots (or castings) do not need to be subjected to pressure processing deformation, and the product performance requirements are also different from those of deformed aluminum and aluminum alloy, and the control level of the content of impurity elements and other alloy elements is not as strict as that of deformed aluminum and aluminum alloy ingots. Therefore, the requirement of raw material quality of cast aluminum alloy ingots is not as strict as that of wrought aluminum and aluminum alloy ingots. It can be used as raw material for deformed aluminum and aluminum alloy ingots, as well as for casting aluminum alloy ingots. Due to the subsequent pressure processing deformation of deformed aluminum and aluminum alloy ingots, in order to prevent the formation of unfavorable plastic deformation and compounds or phase structures that affect product properties (strength, corrosion resistance, electrical conductivity, flexibility, fatigue resistance, etc.), the composition of deformed aluminum and aluminum alloy ingots is strict, the content of impurity elements must be controlled to a very low level, and the content of other alloy elements should be strictly controlled within the range. Therefore, the requirements of wrought aluminum and aluminum alloy ingots on the quality of their raw materials are extremely strict.

By adjusting the type and content of elements added to liquid aluminum and adjusting the production process, aluminum products with different properties and suitable for different application needs can be obtained. The schematic diagram of the generation and use of recycled aluminum raw materials is shown in figure 1-1.

Figure 1-1 process of generation and use of recycled aluminum raw materials

II. Analysis of the Standard of "Raw Materials of recycled cast Aluminum Alloy"

1. Q: what are the typical recycled cast aluminum alloy raw materials that meet the standard?

Answer: through actual investigation, analysis and comparison, inclusion content and metal recovery, as well as remelting slagging and exhaust gas emission, this standard defines the following after sorting, processing and pretreatment, to obtain recycled cast aluminum alloy raw materials that can be directly put into the furnace.

(1) waste aluminum alloy sheets and pure aluminum raw materials without organic coating and composite materials.

As shown in figures 2-1, 2-2 and 2-3, aluminum doors and windows without organic coating, aircraft aluminum plates, aluminum tubes and other deformed aluminum alloy products with magnesium, silicon, copper, manganese and zinc as the main alloying elements, and pure aluminum bare wire, conductive busbar, etc. after simple separation, if it meets the requirements of aluminum block material, it can be used in the production of casting aluminum alloy.

However, this kind of recycled aluminum is of high quality, which is more suitable to be used as raw material for recycled pure aluminum or recycled deformed aluminum alloy, and it is degraded for the production of cast aluminum alloy.

Figure 2-1 Aluminum alloy sheet without coating and composite material

Figure 2-2 bare wire of pure aluminum

Figure 2-3 Conductive bus

(2) Clean waste aluminum castings

Cast aluminum alloy products or products with silicon, copper, magnesium and zinc as main alloying elements can be recycled as raw materials of cast aluminum alloy as shown in figure 2-4.

Figure 2-4 Clean waste aluminum castings

(3) recycled aluminum ingots

The aluminum ingot fused and cast from recycled aluminum can be used as raw material for recycled cast aluminum alloy as shown in figure 2-5.

Figure 2-5 recycled aluminum ingots

(4) Aluminum block

Clean aluminum blocks obtained after pretreatment such as aluminum scrap, vehicle scrap, mixed metal scrap, etc., which can be used as raw materials for casting aluminum alloy, which contain silicon and other metals such as copper, magnesium, zinc, as shown in figure 2-6.

Figure 2-6 aluminum block

2. Q: there are many technical requirements of GB/T 38472-2019 standard, how to divide the requirements of key inspection items and general inspection items?

A: the technical requirements of raw materials are divided into two parts: key inspection project requirements and general inspection project requirements.

The key inspection items are applicable to the inspection of imported recycled raw materials supervised by the relevant regulatory authorities, including:

(1) appearance inspection: visual inspection of the type and quality of raw materials.

(2) fracture microstructure inspection of recycled aluminum ingots: through the detection of internal inclusions in the raw materials to prevent the mixing of recycled aluminum that does not meet the quality requirements of the raw materials (as shown in figure 2-7).

Figure 2-7 fake recycled aluminum ingots (recycled aluminum with internal non-dense casting structure)

(3) inclusion inspection: detection of non-metallic substances doped or attached to the goods, including dust, wood, textile, plastic, glass, stone, paper, sand, rubber, sludge, etc. (excluding product packaging and other substances to be used in transportation).

(4) volatile matter test: detect the content of organic matter attached to the surface of the raw material.

(5) Test of aluminum and aluminum alloy content: estimate the quality of recyclable aluminum materials.

(6) radioactivity: environmental protection requirements.

The general inspection items are related to the raw material smelting process or economic benefits, and are suitable for incoming inspection, including total metal content, metal recovery, chemical composition, etc.

In the subsequent revision, GB/T 38472-2019 will clarify the scope of each inspection item and transfer the quality indicators such as total metal content, metal recovery rate and chemical composition to the requirements of the "incoming inspection and acceptance" project.

III. Explanation of related problems in the process of standard implementation

1. Q: the source of raw materials in the standard "4 Classification" clause is not included in aluminum alloy, aluminum scrap, aluminum wire, aluminum water tank and other products?

A: GB/T 38472-2019 "recycled cast Aluminum Alloy Raw Materials" lists the types of recycled aluminum that can be used as the main "source of raw materials". Aluminum wire is more suitable to be used as the "raw material source" of recycled deformed aluminum alloy or recycled pure aluminum. Aluminum scraps and aluminum water tanks are usually rich in inclusions, easy to burn, and high volatile content, so they are not included in the "source of raw materials". If too much aluminum shavings or aluminum water tank is mixed, the volatile content and / or metal recovery index of the goods will not meet the requirements of GB/T 38472-2019, and the goods will not be up to standard.

2. Q: the standard does not specify the specific limit requirements for discrepancies in apparent characteristics, such as whether a small number of discrepancies are directly determined to be unqualified. (this is directly related to how to grasp the scale on the spot.)

Answer: the quality of raw materials can be roughly evaluated by appearance inspection. In many cases, we can rely on the long-term accumulated experience in appearance inspection to quickly determine whether the raw materials are qualified or not. If it is suspected that the inspection items are not in conformity with the quantitative provisions, the measured results of the relevant items shall be used to determine whether the goods conform to the raw material standards:

If it is suspected that the source of the raw material does not match, the instrument can be used to test the properties of the material.

It is suspected that there are too many oils and oils, and the volatiles should be carefully tested to see if they are qualified.

It is suspected that there are too many organic coatings, and whether the volatiles are qualified should be carefully tested (usually, when the ratio of the mass of the block covered with organic polymer coating to the total mass of raw materials is less than 5%, the content of volatiles will not exceed the standard).

If it is suspected that the inclusion is serious, you should carefully screen the quality of the inclusion or disconnect the internal inspection to see if the inclusion is qualified.

If it is suspected that there are too many aluminum materials from other sources (such as aluminum foil, aluminum water tank, aluminum filings), the metal recovery rate and volatile matter should be tested.

-when the surface oxidation corrosion is serious (as shown in the figure), the metal recovery rate should be tested to see if it is up to standard.

Figure 3-1 Aluminum block with severe surface corrosion

3. Q: the content of aluminum and aluminum alloy in the GB/T 38472-2019 standard stipulates that the aluminum and aluminum alloy content of the aluminum block shall not be less than 91%, but the aluminum content of the aluminum block after processing from the waste aluminum chip is about 70% Mui 92%, which is obviously different from the standard.

Answer: "aluminum" is the general name of all kinds of pure aluminum (including refined aluminum) and aluminum alloy. "however, the aluminum content of the aluminum block after processing from the waste aluminum chip is about 70%" refers to the content of aluminum element, and "the content of aluminum and aluminum alloy shall not be less than 91%" refers to the content of aluminum material, the two concepts are different.

4. Q: GB/T 38472-2019 standard "size specifications" provisions on the size of aluminum blocks (large, medium, small) have screening pass rate requirements, but if the size of aluminum blocks is mixed and slightly inconsistent with the provisions, how to determine whether it is qualified or not?

Answer: usually visual inspection of aluminum block size specifications, screening when in doubt, size specifications test results do not meet the requirements, and take double the number of samples to repeat the test. If the inspection results are still unqualified, it is recommended that both parties of the trade deal with them through consultation.

The size specification of aluminum block belongs to the general inspection item. After the future standard revision, the "aluminum block size specification" will be moved to the "classification".

5. Q: in the "5.11 other requirements" clause of the GB/T 38472-2019 standard, it is not stated whether the inclusion of circuit boards can be allowed, and there is no clear limit requirement. For the circuit board is not allowed to be mixed or included in the calculation of inclusions? The goods are mixed with circuit boards, electronic components, etc., hazardous waste is not prohibited in GB/T 38472-2019, is it treated as general inclusions?

Answer: it is suggested to refer to the standard of recycled iron and steel raw materials-"the ratio of the quality of hazardous waste to the total quality of raw materials should be less than 0.01%".

6. Q: with the mixing of deformed aluminum, most of the goods on site are a mixture of deformed aluminum and cast aluminum. Can it be determined that it has not been decomposed from the source? 100% wrought aluminum goods are also received at the site, which should not be within the scope of application of the GB/T 38472-2019 standard. How to determine? If some aluminum parts which are not recycled cast aluminum alloy raw materials are mixed into the goods, how to deal with them?

A: "Raw material source" only indicates the possible source of all kinds of recycled cast aluminum alloy raw materials, not technical requirements. The fragments of deformed aluminum alloy belong to the category of aluminum block and can be used as raw material of recycled cast aluminum alloy. However, the mixed goods of wrought aluminum and cast aluminum can not be used as raw materials of regenerated deformed aluminum alloy.

"100% wrought aluminum" can be judged according to the new standard of "recycled wrought aluminum alloy raw material", or according to GB/T 38472-2019.

When some aluminum parts which are not recycled cast aluminum alloy raw materials are mixed into the goods, if all the items inspected according to GB/T 38472-2019 are in compliance with the regulations, the raw materials are considered to be qualified.

7. Q: how to deal with thermal insulation profiles and aluminum materials with machine coating?

Answer: a small amount of mixed belt coated aluminum or thermal insulation profiles is allowed in the goods, but if the mixed belt is too much, which leads to the unqualified quality of volatiles and / or inclusions in the goods, the goods should be judged to be unqualified.

Figure 3-2 scrap alloy aluminum sheet

8. Q: how to dispose of aluminum can waste?

Answer: a small amount of coated aluminum cans are allowed in the goods, but if too much mixing leads to the unqualified quality of volatiles and / or inclusions in the goods, the goods should be judged to be unqualified.

Figure 3-3 Aluminum can scrap

9. Q: how to deal with waste aluminum castings with serious inclusions?

Answer: a small amount of waste aluminum castings with serious mixed tape is allowed in the goods, but if too much mixing leads to the unqualified quality of the volatiles and / or inclusions of the goods, the goods should be judged to be unqualified.

Figure 3-4 waste aluminum castings with serious inclusions

10. Q: how to dispose of aluminum scrap?

Answer: aluminum scraps are easy to carry inclusions in the process of production and recovery, and easy to burn and slagging in the process of remelting, which does not belong to raw materials. It includes "aluminum blocks" that add volatile adhesives to press crushed aluminum scraps into blocks, which are not raw materials. The standard standard for recycling is planned to provide a standard basis for the recycling of aluminum chips.

A small amount of aluminum shavings is allowed to be mixed in the goods, but if too much mixing leads to unqualified volatiles and / or inclusions in the goods, the goods shall be ruled unqualified.

Figure 3-5 aluminum shavings

11. Q: how to deal with wheels with coating or with iron rings, air nozzles, lead and other materials?

Answer: occasionally there are wheels with coating or inlaid with iron rings, air nozzles, lead and other materials, but if it is generally coated or undisassembled aluminum waste wheels, resulting in the overall inclusions of the goods are not up to standard, the goods should be ruled unqualified.

Figure 3-6 Aluminum waste wheel hub (with coating, etc.)

12. Q: how to deal with waste aluminum chips?

Answer: the waste aluminum chips on the recycling market (figure 3-7) are similar to garbage and should be used as raw materials after proper pretreatment such as impurity removal and screening at the request of the environmental protection department.

Figure 3-7 waste aluminum chips

13. How to deal with goods whose chemical composition does not meet the standards of recycled aluminum raw materials?

A: if the chemical composition is shown to be non-aluminum material, it is judged to be unqualified, otherwise it is recommended that the trading parties negotiate to deal with it. The chemical composition of raw materials belongs to the general inspection items. In the future, after the revision of GB/T 38472-2019 "Raw Materials of recycled cast Aluminum Alloy", the chemical composition of raw materials has been moved to "incoming inspection and acceptance" as a reference index.

14. Q: how to deal with serious flying edges and pores in recycled aluminum ingots?

Answer: there are serious flying edges and pores in the appearance quality of recycled aluminum ingots, and the internal inclusions are usually serious (the goods are actually compound ingots, not recycled aluminum ingots). If the appearance quality can not be judged, and its quality is suspected, the fracture structure of recycled aluminum ingots should be tested.

Figure 3-8 compound ingot