关键词: 黄铜矿, 低温氯化, 热处置, 选择性氧化, 流化床反应器, 铜浸取

Abstract: Extraction process of copper from chalcopyrite concentrate by low-temperature chlorination and selective oxidation in fluidized-bed reactors was studied. The exhaust chlorine and S2Cl2 from the lower reactor are expended for chlorinating the concentrate in the upper one in the two-stage chlorination. The full-chlorinated products with lower sulfur contents are obtained at about 250 and 270℃ for the upper reactor and the lower one, respectively, and within 0.015% of Cl2 concentration in the effluent gases of the lower one. The chlorinated products are thermally cured only under a nitrogen atmosphere in a supplemental reactor, thus their sulfur contents are further reduced. The chlorinated products with lower sulfur contents can be oxidized at 350~360℃ in a stable fluidizing operation. The exhaust chlorine from the oxidation can be removed by chlorinating the concentrate with it in an upper reactor. The dilute hydrochloric acid is effective for leaching the oxidized products. In the range of pH 0.30~1.86 of the leaching solution, Cu is fully solubilized, while Fe dissolution is held to less than 5%. The concentration of Cu, Fe and SO42- in the solution increases linearly with the solid to liquid ratio. When the solid to liquid ratio reaches 0.5 g/mL, the Cu concentration reaches in excess of 115 g/L, while the Fe/Cu ratio remains below 0.03 and the SO42- concentration is also very low. This can meet the requirement of the Cu electrowinning step. The changes of the precious metals and minor impurities contained in the concentrate with the process were also briefly investigated.

Key words: chalcopyrite, low-temperature chlorination, thermal curing, selective oxidation, fluidized-bed reactor, copper leaching