Recently, Chenzhou Jingui Silver Industry Co., Ltd. and Central South University jointly developed the technology of direct extraction of lead, matte and copper cathode, which won the third prize of Hunan Science and Technology Progress Award.

Lead copper matte is a by-product of blast furnace smelting and pyrometallurgical refining of crude lead, which is generally difficult to handle. At present, lead copper matte is usually treated by pyrometallurgical method in large enterprises, and crude copper is obtained by blowing in converter, then electro-copper is obtained by further refining. However, this method has some problems, such as low metal recovery, long process flow, high operation cost and serious environmental pollution, and is difficult to miniaturize. The output of lead copper matte in general lead smelting enterprises is limited, so it can not be treated by the above method. It has to be sold as copper raw material to copper smelter for pyrometallurgical extraction of copper, but as a result, the impurities such as lead, silver and other metals with higher value can not be priced. On the contrary, the priced copper has lower valuation coefficient because of the above impurities with low economic benefits. On the other hand, long-term stockpiling of enterprises will lead to environmental pollution and capital backlog. The development of wet atmospheric leaching is limited by its low leaching rate. Therefore, it is imperative to develop a new process for comprehensive recovery and deep processing of matte.

In order to break through the bottleneck of lead copper matte treatment, the company set up a project team to research and develop pressurized oxygen wetting process for comprehensive recovery and deep processing of matte. This project can not only solve the problem of serious environmental pollution and low copper recovery in existing technology, and also can create more economic benefits.

The technology of direct extraction of cathode copper from lead copper matte is to treat lead copper matte by pressure alkali wetting process. The process leaches copper from lead copper matte by pressurized alkali. After purification, copper enters the solution, while lead, silver and other metals remain in the residue. The leaching residue is leached by dilute sulfuric acid. The copper sulfate solution can directly electrowinning qualified cathode copper products, and the residue can be returned to the pyrometallurgical lead smelting system to recover valuable elements such as lead, silver and sulfur. This process is a clean metallurgical process, with little pollution to the environment and no sewage, and can realize selective leaching of metals. It has short process flow, high comprehensive recovery rate of metals, large or small scale, strong practicability, and strong adaptability to scale and raw materials. After five years' improvement by R&D center of the company, through small-scale and pilot-scale tests, the technology of "oxygen pressure leaching-cyclone electrolysis" was finally formed to treat lead copper matte.

At present, the project has been put into full production. It can produce 5000 tons of cathode copper products annually, 1500 tons of lead metal and 10 tons of silver, which adds 50 million profits to the company. The project technology has broad application prospects and will bring billions of yuan economic benefits to the industry.