At present, there are two main methods for producing recycled copper:
- The first type is to directly smelt scrap copper into different grades of copper alloy or refined copper, so it is also called direct utilization method;
- The second type is to first cast the miscellaneous copper into anode copper through fire treatment, then electrolyze to refine it into electrolytic copper and recover other valuable elements in the electrolysis process.
When using the second method to process copper-containing waste, there are usually three different processes, namely, one-stage method, two-stage method and three-stage method.
1. One paragraph method
The method of adding the classified yellow or red copper directly into the reverberatory furnace to refine into anode copper. Its advantages are short process, simple equipment, fast plant construction, and low investment. However, when this method deals with complex copper, the smoke and dust produced are complex and difficult to handle;
The furnace time for simultaneous refining operation is long, the labor intensity is high, the production efficiency is low, and the metal recovery rate is also low.
The miscellaneous copper is first reduced and smelted in a blast furnace to obtain metallic copper. Then the metallic copper is refined into anode copper in the reverberatory furnace; or the miscellaneous copper is first blown into blister copper by the converter, and then refined into anode copper in the reverberatory furnace. Because these two methods have to go through two processes, they are called two-stage methods. The metal copper obtained by blast furnace smelting has high impurity content and is black, so it is called black copper.
The miscellaneous copper is first reduced and smelted into black copper by a blast furnace. The black copper is converted into secondary blister copper in the converter, and the secondary blister copper is refined into anode copper in the reverberatory furnace. Raw materials need to go through three processes to produce qualified anode copper, so it is called the three-stage method. The three-stage method has the advantages of good comprehensive utilization of raw materials, simple smoke and dust produced, easy to handle, high blister copper grade, easier operation of the refining furnace, and high equipment productivity. However, it also has more complex processes, more equipment, and large investment. And more fuel consumption and other advantages. Therefore, in addition to the large-scale enterprises that need to deal with some special waste slag, the general waste copper treatment process mostly adopts the two-stage method and the one-stage method.