Method for directly restoring and recovering copper iron from smelting copper slag

Abstract

The invention belongs to the field of metallurgy, and particularly relates to a method for directly restoring and recovering copper iron from smelting copper slag. The method comprises the following steps of: transferring high-temperature molten state copper slag to a high-temperature reducing furnace by a tundish, jetting oxygen to previously desulfurize, adding slagging constituent to keep temperature, jetting natural gas to carry out smelting reduction, slowly cooling to 1096 DEG C at the speed of 1.5-2 DEG C / min, and keeping the temperature for 1h to obtain 7.3at% Cu-Fe copper alloy melt and gamma pig iron, or slowly cooling to 850 DEG C at the speed of 1.5-2 DEG C / min, and keeping the temperature for 1h to obtain 2.7at% Cu-Fe copper alloy melt and gamma pig iron. According to the method provided by the invention, the total recovery use of valuable components, i.e. copper, iron and the like, can be realized, and the alloy melt obtained by the reduction smelting is slowly cooled and separated to obtain copper-rich alloy and low-sulfur gamma pig iron, so that separation of copper and iron is realized and the additional values of products can be improved.

Description

technical field [0001] The invention belongs to the field of metallurgy, in particular to a method for directly reducing and recovering copper and iron from copper smelting slag. Background technique [0002] At present, my country's copper reserves are 62.43 million tons, and 33.83 million tons have been developed. Among the remaining unused reserves, there are few rich ore, many lean ore, low grade raw ore, difficult mining and utilization. On the contrary, the copper, iron and other metal content in the smelting slag produced by copper smelting is relatively high. In 2011, the discharge of copper slag was 15-20 million t / a, and the cumulative amount of copper slag in my country has reached 200 million tons. A large amount of converter slag and wet copper leaching slag, in addition to copper, the slag also contains rich iron, the grade is as high as more than 40%, which is much higher than the mineable grade of iron ore in my country (TFe>27%), and the copper in the slag...

AI Technical Summary

Problems solved by technology

Du Qingzhi et al. used vacuum depletion technology to reduce the mass fraction of copper in the 1 / 2 to 2 / 3 slag layer of Noranda oxygen-enriched molten pool from 5wt% to below 0.5wt%. technology and shorten the processing cycle to make metal phase separation to obtain matte / metal, nickel exists with copper in copper matte or blister copper, cobalt with iron exists in converter slag, and then cobalt is recovered in the form of alloy or matte by electric furnace reduction , but there are problems such as short life of the spray gun

Pyrochemical depletion has defects such as high energy consumption and serious exhaust gas pollution, and can only recover copper, but cannot simultaneously recover copper, iron, etc., resulting in serious waste of valuable components such as iron, which does not meet the economic development requirements of modern circular industries

[0007] In summary, it is not difficult to see that the biggest difficulty in the recycling of copper slag resources is that the structure and composition of the slag are unfavorable to processing processes such as beneficiation and leaching. For example, the size of copper matte particles in Daye Noranda slag varies greatly, and it needs to be segmented The ore is ground and selected in sections; the iron element with a content of up to 46% is distributed in the two phases of olivine and magnetic iron oxide. The magnetic separation process is difficult to carry out, the yield of the obtained iron concentrate is low, the silicon content is seriously high, the cost is high, the quality is poor, and it cannot be used. The same problem also exists in the beneficiation process of converter slag. Based on the recycling of copper in copper slag, the iron in copper slag is often discarded as impurities or suppressed into the residue, and the recovery rate of copper is generally not high, and the copper content in the residue is still high

[0008] The patent application number 200910163234.7 proposes a method for direct reduction of molten copper slag to extract iron, but does not consider the recovery of copper and other valuable components; On the basis of the method, the idea of ​​direct reduction of molten copper slag to prepare low-sulfur and low-copper molten iron was proposed, but the recovery of valuable components such as copper was not considered, resulting in serious waste of resources; the patent application number 201110380257. However, the recovery of valuable components such as zinc, cobalt, and antimony has not been considered, and this method has defects such as chlorine salt pollution.