SMM: from April 12 to 13, the "2018 (3rd) Nickel-Cobalt Lithium Industry chain Summit", hosted by Shanghai Colored Network (SMM) and exclusively named by Zhejiang Huayu Cobalt Industry, was successfully held in Quzhou, Zhejiang Province. During the meeting, SMM interviewed Mr. Lai Zuming, Technical Director of Shenzhen Yuanyu Environmental Protection Technology Co., Ltd., and had an in-depth exchange on issues related to industrial sewage treatment.
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At present, there are 110 cities in China are seriously short of water, 7 major rivers are polluted to varying degrees, water pollution and water resources and environmental shortage and other problems, affecting people's normal life. Among them, basic industry is the main cause of water pollution and shortage of water resources. in your opinion, the production of cathode materials in lithium electricity industry is not only a large user of water, but also a large user of wastewater. what are the characteristics of sewage?
Lai Zuming: the cathode material mentioned here may be mainly the sewage produced by the ternary precursor enterprise and the production link. There are mainly the following seven kinds, which are ternary concentrated water, ternary fresh water, purified extraction wastewater, nickel soap wastewater, iron washing wastewater, chlorine washing wastewater, raw material washing water and so on. The characteristics of these seven kinds of wastewater are different. But not all enterprises have these kinds of sewage. The production process is different, and some enterprises actually have only a few of them.
Three-way concentrated water: large amount of water, PH above 11, NH3-N content as high as 4000~8000mg/l, high content of heavy metal ions, far exceeding the industry sewage discharge standard, sodium sulfate content of high mass concentration of more than 6%, COD content is low, about 200 ≤ 500, It belongs to a kind of wastewater with high salt and high NH3-N biodegradability.
Ternary fresh water: the amount of water is larger than that of ternary concentrated water, PH is as high as 11, but the content of NH3-N is low, about 100 ≤ 200 mg/l, the content of heavy metal ions is low, the mass concentration of sodium sulfate is about 2%, and the content of COD is low. It belongs to cleaner salt-containing wastewater.
Purification and extraction wastewater: the amount of water is relatively small, the PH is about 4 ≤ 5, the content of heavy metal ions is low, but there is fluorine exceeding the standard, the mass concentration of sodium chloride is about 8%, which belongs to a kind of wastewater with high salt and no biodegradability.
Nickel soap wastewater: the amount of water is relatively small, PH is neutral, the content of heavy metal ions is low, can basically meet the requirements of the industry discharge standards, sodium sulfate content concentration of about 10%, is a relatively clean high salt wastewater.
Iron washing wastewater: the amount of water is relatively small, the content of heavy metal ions is high, which is much higher than the sewage discharge standard of the industry. the water contains a large amount of hydrochloric acid, and the concentration of hydrochloric acid is as high as 14%.
Chlorine washing wastewater: the amount of water is relatively small, PH is about 1, the content of heavy metal ions is low, can basically meet the requirements of the industry discharge standards, salt content is very low.
Raw material washing water: the amount of water is large, PH is basically neutral, the content of nickel-cobalt metal cations is as high as 100 ≤ 500 mg / L, and the mass concentration of sodium chloride is about 3%.
These are the main types and characteristics of sewage produced by the production of ternary precursors in lithium electricity industry.
SMM: with the pollution of water resources and the emergence of water shortage, the National Development and Reform Commission, including the State Environmental Protection Agency, the Ministry of Construction and other government level for lithium battery enterprises have some special requirements?
Lai Zuming: the lithium power industry belongs to the new energy industry. at the first session of the 13th National people's Congress, Premier Li Keqiang mentioned many times in the government work report that new energy vehicles, energy structure transformation, and other issues related to the lithium power industry. National policy is good for the lithium industry.
The environment and development of China's 13th five-year Plan put forward green development. for the lithium power industry, the state should not only support its development from a policy point of view, but also deeply promote the transformation of the energy structure, save energy and reduce emissions, and establish a sense of low-carbon green development. Optimize the design of enterprise production capacity. For example, the "three wastes" produced in the production link will require strict treatment, discharge up to the standard or recycling, and so on.
The wastewater system of lithium power industry should be reasonably divided according to the amount of water, water temperature, the nature and content of pollutants, as well as the methods of recycling or treatment of wastewater and pollutants, so as to achieve decontamination and diversion, and adopt resource recovery. In the selection of wastewater treatment process, multi-scheme comparison should be carried out in order to determine a technologically advanced, economical and reasonable process route in line with the actual situation of the enterprise.
In addition, the discharge of "three wastes" is directly related to its production process. reforming the production process, increasing the yield of products, reducing the consumption of raw materials, reducing the amount of sewage and so on are the fundamental ways of sewage treatment.
SMM: lithium power industry enterprises, now several major lithium power industry groups in China, how do they achieve the national sewage discharge targets?
Lai Zuming: generally there will be some environmental protection devices to carry out advanced treatment of wastewater to achieve the national sewage discharge targets or to achieve zero wastewater discharge. For example, in view of the ternary concentrated water in the lithium power industry, through the analysis of water quality, the zero discharge of wastewater can be realized by means of NH3 removal device, heavy metal treatment device and MVR evaporation (or multi-effect evaporation), and the useful components in the wastewater can be recovered. NH3 aquatic products can be prepared by removing NH3-N from wastewater to meet the discharge standard. Sodium sulfate in wastewater can be recovered by evaporation and sodium sulfate products can be prepared.
SMM: now the country's major lithium power industry enterprises large and small also have a lot of homes, I would like to ask, at present, we these refining and chemical enterprises generally use what kind of process to complete this target?
Lai Zuming: the original environmental protection is not so strict, the general enterprise uses chemical precipitation method to remove heavy metals, gas stripping NH3, multi-effect evaporation desalination. Now enterprises will generally increase the membrane concentration process, first concentrate the low-concentration sewage, reduce the scale of the follow-up treatment plant. In addition to heavy metals, enterprises gradually began to use ion exchange to recover nickel and cobalt.
Which of the several approaches mentioned by SMM:, physical, chemical or biological, is appropriate to the circumstances of our country?
Lai Zuming: sewage treatment, I personally think that can not be treated for the sake of treatment, should be as far as possible to achieve recycling.
For ternary concentrated water with ternary precursor enterprise, difficult to treat and large amount of water, the most suitable treatment method for this type of water is micro-negative pressure NH3, removal in physicochemical method, which is a kind of "high efficiency de-NH3 method". And our company has obtained the national invention patent. "Micro-negative pressure single-tower catalytic NH3-N wastewater treatment and high efficiency countercurrent resource recovery unit" patented technology (patent number: 201510263454.2, 201510299697.1).
At present, SMM: is the most suitable for our national conditions is the "efficient de-NH3 method", "efficient de-NH3 method" has a very good application engineering, what are the projects?
Lai Zuming: "Micro-negative pressure de-NH3 process" is mainly used in production enterprises that will produce high NH3-N wastewater. for example, we undertake Jilin Gene Nickel Industry-subsidiary Yarong Science and Technology Phase I 300t / d zero discharge project (membrane concentration, In addition to heavy metals, NH3 recovery, evaporative crystallization), the second phase of 600 tons per day, and the third phase of 1000 tons per day wastewater zero discharge project (under construction), Shandong Tianyun 1000 tons / day NH3-N wastewater recovery project, Shandong Yuhuang 600 tons / day high concentration NH3-N wastewater recovery and treatment project, Jinzhou Xinhua long-240t / day wastewater zero discharge project and so on.
How large are the SMM: projects? In addition, what are the economic and social benefits of these projects?
Lai Zuming: the several projects mentioned above, including the zero-emission project, have really realized the recovery of heavy metals, NH3-N, and salt, and basically all the water has been reused. We can see the economic benefits in this way. when it comes to environmental protection projects, they are basically money-losing projects. if we do a good job, we can also make a little profit. Social benefits to a small, the surrounding people do not complain. For the greater good, for the benefit of future generations.
What kind of technology is generally used by SMM: foreign lithium power industry enterprises?
Lai Zuming: lithium electricity industry is gradually dominated by our country, so the existing sewage treatment process of domestic enterprises is basically also a commonly used process technology abroad.
Why does SMM: choose the ternary concentrated water which is the most difficult to deal with lithium electricity industry in so many large industrial emission industries?
Lai Zuming: 1. at present, lithium power new energy is also a strong promotion and development of the industry, the choice of this kind of difficult to solve the difficult treatment of sewage, it is also a challenge to themselves! 2. respond to national policies and contribute to the environmental protection industry, especially in sewage treatment.
SMM: you are now standing at the forefront of industrial sewage treatment, so many years have been full of enthusiasm, into the most difficult to deal with lithium power industry treatment industry, the biggest feeling is what?
Lai Zuming: seeing the sewage from waste to treasure, recycling and recycling, the environmental pressure of enterprises has been reduced, there is a deep sense of social responsibility and a sense of achievement.
Shanghai Colored Network (SMM) Wan Qiong live report