Sustainable Mining and Metallurgy

With the development of new energy, the process of preparing battery-grade nickel sulfate from low-copper and high-nickel matte has gradually become one of the current mainstream processes. The exploration of low-copper and high-nickel matte atmospheric pressure leaching process has important guiding significance for subsequent engineering applications. In this paper, the two-stage atmospheric pressure leaching process of low copper nickel matte was carried out. The effects of acid-to-ore ratio and oxygen-enriched air flow rate on the leaching effect in the first-stage atmospheric pressure leaching were investigated. The effects of total acid-to-ore ratio, leaching temperature and oxygen concentration on the total leaching effect in the second-stage atmospheric pressure leaching were investigated. The test results show that in the first stage of atmospheric pressure leaching, the acid-to-ore ratio is recommended to be controlled at 250~300kg/t, and increasing the oxygen-enriched air flow rate has little effect on the leaching rate. It is recommended to carry out leaching at low oxygen-enriched air flow rate, which is more economical. In the two-stage atmospheric pressure leaching, the increase of the total acid-to-ore ratio will reduce the end-point pH value. When the end-point pH value is within 2, the leaching rate of metal phase nickel and cobalt can reach 98%. When the leaching temperature is above 75℃, the temperature rise has little effect on the leaching of nickel matte. The increase of oxygen concentration promotes the leaching. However, considering that the leaching rate of metal phase nickel and cobalt is above 98% under the condition of 40% oxygen-enriched concentration, it is not recommended to increase the oxygen concentration to pursue better leaching effect.