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Physical properties of the charge, such as viscosity, basicity and melting temperature, are key factors for the reduction smelting of laterite ore. In this study, CaO is used to improve the properties of the ore. The effect of CaO on the properties before and after smleting is studied and the dosage of CaO is optimized. The results show that the properties of the smelted ore after the addition of CaO are improved as follows: the basicity of 0.55, the density of 2.86 g/cm3, the melting temperature of 1320 oC, the viscosity of 0.82 Pa•s (at 1500 oC), the specific conductivity of 0.64 Ω-1•cm-1 (at 1500 oC). The results also show that 99.87% of nickel is recovered and nickel in the alloy is concentrated to 14.82% while nickel in the slag is as lower as 0.004%.

In this paper, the removal of aluminum in leach liquor of nitric acid pressure leaching laterite was investigated, and a new method of aluminum removal by precipitation with calcium sulphide was presented. The effect of reaction temperature, pH value before ageing and ageing time on the removal of aluminum were examined in details. The optimum conditions were determined as follows: reaction temperature 40 °C, pH 3.9~4.1 (before aging) and aging time 30 min. Compared with the traditional precipitation method, the loss of nickel and cobalt was less than 1% in the obtained aluminum precipitate slag, which is 3% lower than that by the traditional method; the filtration rate of aluminum precipitate slurry was faster than the traditional method, when the filtration press was controlled at -0.04 MPa, the filtration rate of aluminum precipitate slurry could reach 0.109 m3/(h•m2), which is 6.5 times higher than that obtained by the traditional method.

The present paper reviews the situation and technology progress of lead smelting in China. According to the new lead smelting processes, this paper also presents a lead oxygen-enriched flash smelting technology, whose intellectual property rights are completely owned by China，it points out that lead smelting processes develop as follow: lower environmental pollution, higher metal recovery rate, more effective for complex low grade lead-bearing ore materials, lower energy consumption and higher automation degree.

An industrial converter slag was treated by a selective reduction-roasting process to recovery cobalt and copper in this study. To maximizing the recovery of cobalt and copper, the major process parameters such as reducing agent, curing agent and roasting temperature were investigated. Under the determined conditions, 95% cobalt and 96% copper can be recovered. According to the mineralogical analysis, it is found that cobalt in the converter slag mainly distributes in the iron-bearing minerals, which migrates with iron during the reduction-roasting process. After the reduction-roasting, most cobalt distributes in the metallic iron in the form of Co-Fe alloy.

A limonitic laterite ore from Indonesea was treated by pressure leaching in H2SO4-Mg(NO3)2 medium, using Mg(NO3)2 as an oxidant. Experiments were conducted in order to determine the optimum conditions by studying various parameters, including Mg(NO3)2/ore mass ratio, initial acidity, reaction temperature, holding time and liquid/solid ratio. Pressure leaching experiments showed that nickel, cobalt and iron extractions were 90.8 %, 91.9 % and 2.1 % after 60 min of leaching at 493 K with 0.06 g/g Mg(NO3)2/ore mass ratio, 140 g/L initial acidity and 2 mL/g liquid/solid ratio.The total decrement of acid consumption was 72 g H2SO4/kg ore in the presence of Mg(NO3)2.

The leaching behavior of battery grade lithium cobalt oxide (LiCoO2) was studied in Na2SO3-H2SO4 aqueous solutions with low H2SO4 concentration. The effects of H2SO4 concentration, leaching time, leaching temperature, and dosage of Na2SO3 on the leaching rate of LiCoO2 were investigated. The experimental results show that all the cobalt in LiCoO2 can be dissolved in the following conditions: the H2SO4 concentration of 0.4 mol/L, the leaching time of 0.5 h, the leaching temperature of 70°C and the Na2SO3 dosage being equal to the weight of LiCoO2. It is proved that the leaching of LiCoO2 in the system of Na2SO3-H2SO4 solutions is much more effective than that in other leaching systems. Moreover, the consumption of H2SO4 can be lowered greatly. Based on the leaching of pure LiCoO2, the Na2SO3-H2SO4 leaching system is further applied in the treatment of spent Li-ion battery and the leaching rate of cobalt can be achieved as higher as more than 98%.