Shared by the Director of the Rare and Precious Metals Plant of Yunnan Copper Southwest Copper Industry: Current Status and Development of Selenium and Tellurium Recovery Technology [Minor Metals Conference]

On June 13, at the 2025 SMM (13th) Minor Metal Industry Conference—Rare and Dispersed Metals Forum (Indium, Germanium, Gallium, Bismuth, Selenium, Tellurium) co-hosted by Shandong Humon Smelting Co., Ltd. and SMM Information & Technology Co., Ltd. (SMM), Wang Pengcheng, Director of the Precious Metals Plant of the Southwest Copper Branch of Yunnan Copper Co., Ltd., shared insights on the topic of "Current Status and Development of Selenium and Tellurium Recovery Technology."

Introduction to Southwest Copper

He introduced the historical evolution, development milestones, achievements over the past 65 years, profound changes in production and operational performance since the 13th Five-Year Plan, and safety and environmental protection performance during the same period.

Copper Smelting Process Flow

Copper Anode Slime Treatment System

Anode Slime Treatment Scale: The treatment scale exceeds 8,000 mt.

Anode Slime Treatment Process: After relocation, the advanced Kaldo furnace process was adopted.

Comprehensive Recovery from Anode Slime: Comprehensive recovery of rare and precious metals such as selenium, tellurium, platinum, and palladium. Tellurium powder: 50 mt, crude selenium: 400 mt, sponge platinum: 100 kg, sponge palladium: 500 kg.

Current Status of Selenium and Tellurium Recovery in Rare and Dispersed Metals

Selenium

He elaborated on the selenium industry chain.

Global selenium production is mainly concentrated in China, the EU, Japan, Russia, and North America. China accounts for 33% of global selenium production, making it the largest selenium producer. Currently, the metallurgical industry remains the most extensive application field for selenium, accounting for 44% of total selenium production.

China's current selenium supply capability is 1,300 mt, while selenium market demand is 2,400 mt. From the perspective of production and sales, selenium products are in undersupply.

Price Trends of Crude and Refined Selenium: Selenium prices experienced a downward fluctuation in 2017, hit a low in 2020, and have since stabilized. Currently, the market price of crude selenium is 130,000 yuan/mt, 3N selenium is 215,000 yuan/mt, and 4N selenium is 285,000 yuan/mt.

Price Trends of 5N and 6N High-Purity Selenium: Prices for 5N and 6N selenium are relatively optimistic, being 4.7 times and 17.3 times the price of 3N selenium, respectively, reaching 600,000 yuan/mt and 2 million yuan/mt. However, the market remains relatively small.

Tellurium

He introduced the tellurium industry chain.

Currently, global tellurium production exceeds 1,000 mt, with China accounting for over 60%, making it the world's largest tellurium producer. The global new energy movement has driven cadmium telluride thin-film batteries into a new phase of expansion. Except for the US, tellurium consumption in other countries remains relatively small. Globally, tellurium production is still in a state of oversupply.

Tellurium is mainly used in the forms of tellurium dioxide, tellurium powder, refined tellurium, and high-purity tellurium. In the consumption sectors of tellurium, semiconductors account for the largest share at 39%, followed by the metallurgical industry at 26%. The consumption in ultra-high-purity applications and the PV sector is gradually increasing. From the perspective of domestic supply and demand, the consumption of tellurium still faces oversupply.

Price Trend of 4N Refined Tellurium: In 2017, the price of tellurium fluctuated, and the current market price is 740,000 yuan/t, with the price trending towards stability.

Price Trend of 5N and 7N High-Purity Tellurium: The prices of 5N and 7N tellurium are 1.3 times and 4 times that of 4N tellurium, respectively, reaching 970,000 yuan/t and 4.5 million yuan/t.

Process for Recycling Selenium and Tellurium from Anode Slime

►Kaldo Furnace Process: The Kaldo furnace process is one of the mainstream processes for treating copper anode slime, with advantages such as strong adaptability to raw materials, high automation, and good environmental protection effects. However, for selenium and tellurium recovery, the tellurium recovery rate is only around 60%, and the selenium recovery rate is 90%. The process is complex and costly.

►Semi-Wet Process: The semi-wet process is mature, with high recovery rates of valuable metals. The selenium recovery rate is over 95%, and the tellurium recovery rate is over 70%. However, the process is complex, generates a large amount of wastewater, and has poor adaptability to raw materials, limiting its further development.

►Full-Wet Process: The full-wet process has a simple flow, high automation, and a short production cycle. It has the highest selenium and tellurium recovery rates among current copper anode slime treatment processes, with a selenium recovery rate of about 96% and a tellurium recovery rate of around 75%. However, the process equipment is complex, consumes a large amount of reagents, generates a large amount of wastewater, and has high investment costs, making it difficult for large-scale industrial application.

►Combined Beneficiation and Metallurgical Process: The combined beneficiation and metallurgical process has advantages such as strong adaptability to raw materials, low production costs, and easy equipment maintenance, with a selenium recovery rate of about 85%. However, tellurium is easily dispersed in the process, with a recovery rate of only around 40%. The process is complex, has a long production cycle, and generates a large amount of wastewater and slag.

It also introduces the main process for recycling selenium and tellurium using the Kaldo furnace process at Southwest Copper Industry, the preparation of 3N selenium from crude selenium through wet purification, and the preparation of 4N selenium from crude tellurium.

Prospects for the Development of Selenium and Tellurium Recovery

"13th Five-Year Development Plan for the Non-Ferrous Metals Industry": Focus on breakthroughs in "high-purity and ultra-pure smelting technologies for non-ferrous/rare metal alloys," "ultra-pure rare metals and high-precision deep-processing materials," and "extra-large-sized high-purity metal target materials."

"Decision on Implementing Export Controls on Items Related to Tungsten, Tellurium, Bismuth, Molybdenum, and Indium": The export of metallic tellurium, cadmium telluride, cadmium zinc telluride, and cadmium mercury telluride shall require a license from the competent commerce department of the State Council in accordance with relevant regulations.

"Implementation Plan for Energy Equipment under Made in China 2025": Develop mass-producible cadmium telluride (CdTe) thin-film batteries with an efficiency of over 20% and CIGS thin-film batteries with an efficiency of over 21%.

"Action Plan for Innovative Development of the Smart PV Industry": Develop high-quality encapsulation films, PV glass, and backsheet products.

Recovery Trend of Scattered Metals Selenium and Tellurium in Copper Smelters

Jiangxi Copper Corporation is committed to becoming the strongest domestic producer of minor metals in terms of comprehensive strength, steadily developing minor metal industries such as selenium, tellurium, bismuth, platinum, palladium, molybdenum, and rhenium.

Enterprises such as Tongling Nonferrous Metals Group, Daye Nonferrous Metals Group, Zijin Mining, Jinchuan Group, and Baiyin Nonferrous Group Co., Ltd. have comprehensively recovered minor metals including selenium, tellurium, rhenium, antimony, bismuth, cadmium, and indium.

To enhance profitability, peer enterprises in the industry have focused on the comprehensive recovery of scattered metals such as selenium and tellurium.

High Purity of Selenium and Tellurium Products

It also elaborated on the compounding, high-quality upgrading, and greening of selenium and tellurium recovery processes.

Digitization and Intelligence of Selenium and Tellurium Recovery Processes

1. Automation: Highly automated recovery production lines reduce manual operations, improving production efficiency and safety. Automated equipment can accurately execute process flows, reducing human errors and ensuring stable product quality.

2. Robot Applications: Robots are applied in hazardous environments or for repetitive tasks, such as high-temperature smelting and material handling. Robots can work continuously for 24 hours, enhancing production efficiency and reducing labor intensity and costs.

3. Intelligent Warehousing and Logistics: Automated storage and management of raw materials and products improve inventory management efficiency. Intelligent logistics enable automated transportation of raw materials and products, reducing intermediate links and enhancing overall efficiency.

4. Online Analysis and Data Analysis: Online analysis systems enable precise control. By leveraging big data analysis, process parameters can be optimized.

Development Plan for Selenium and Tellurium at Southwest Copper

The selenium and tellurium recovery at Southwest Copper is guided by the "Development Plan for Minor Metal Industries of China Copper" as the top-level design, covering 11 minor metals including selenium, tellurium, and antimony.

Guided by the "3+5-Year Action Plan for Enhancing the Value of Associated Metals of China Copper", it covers 20 associated metals including gold, silver, selenium, and tellurium.

Development Path for Selenium Metal

Development Path for Tellurium Metal

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