*3.7. Industrial Application and Verification*

The commercial SKS smelting furnace in the Fangyuan 1# smelter (Dongying, China) is shown in Figure 9. In the Fangyuan 1# smelter, gold concentrates bearing arsenic are treated with copper sulfide concentrates by using the SKS smelting process. As more and more gold concentrates bearing arsenic are added to copper sulfide concentrates, the Cu content in the final mixed concentrate decreases gradually. Therefore, the composition of the final mixed concentrate should be optimized.

The impurity element As could be greatly eliminated from the matte to gas phase by adjusting the concentrate composition. In this work, the oxygen rate was 12,072 Nm3·h<sup>−</sup>1, the oxygen concentration in oxygen-enriched air was 73%, the feed rate of dry concentrate was 66 t·h<sup>−</sup>1, and the ratio of oxygen/ore was 183 Nm3·<sup>t</sup> <sup>−</sup>1. The matte grade, smelting temperature, slag type Fe/SiO2 were around 70%, 1200 ◦C and 1.7, respectively.

Through optimization, as shown in Figure 10, the concentrate composition was changed from its original proportions (Cu 24.4%, Fe 26.8%, S 28.7%, and other 20%) to optimized proportions (Cu 19%, Fe 32%, S 29%, and other 20%), and the distribution of arsenic among three phases was changed from the original (gas 82.01%, slag 12.08%, matte 5.91%) to optimized results (gas 94.37%, slag 3.45%, matte 2.18%). The mass fraction of arsenic in matte was reduced from 0.07% to 0.02%.

**Figure 9.** Commercial SKS smelting furnace in the Fangyuan 1# phase smelter.

**Figure 10.** Optimization of ore proportions for arsenic removal in the Fangyuan 1# smelter.

The research results and change rules were also confirmed by actual production at several other copper smelters, such as the Hengbang smelter, Yuguang smelter and Fangyuan 2# smelter. By decreasing the Cu content in concentrate, the arsenic removal ratio to gas increases, and residual ratios in slag and matte decrease. The change tendency is shown clearly in Table 3 and Figure 11.

**Table 3.** Main composition of concentrate and distribution ratios of arsenic.


**Figure 11.** Arsenic distribution in different copper smelters.

Therefore, the optimized result identified in this work provides direct guidance to actual production, and can reduce the load of removing impurities in the conversion, refining and electrolytic processes in SKS copper smelters.
