| Nickel is widely used in stainless steel, alloys, batteries, catalysts and other industrial fields. Nickel sulfide ore distribution is less than 30% in the global. The nickel sulfide resources are mainly distributed in the northwest and northeast in our country. The nickel ore in Shaanxi Jianchaling is a larger nickel resources discovered in recent years which reserves is 37353kt and has an annual output of 3000 tons of concentrate (metal amount). The concentrate gradeis is about 5.7%. Based on the requirements of recycling economy development of nonferrous metals, aimed at promoting industrial upgrading of mine production and extending industrial chain, the paper studyed the technology experiment of the preparation of nickel salt by nickel concentrate combined with the production practice.Using the technology of high temperature and oxygen pressure acid leaching of full wet sulfuric acid leaching nickel salt process, pulped with the nickel sulfide ore and acid leaching in high temperature with the condition of oxygen, then removed impurities and precipitated nickel to made crude nickel hydroxide as the raw material for preparing nickel sulfate. The paper focuses on the oxygen pressure acid leaching of nickel sulfide concentrate-remove iron-the technology of nickel hydroxide preparation process. The main contents are as follows:(1) Based on the relevant research literature of pressurized leaching of sulfide ores, the possibility of oxygen pressure acid leaching of nickel sulfide concentrate was determined by thermodynamic analysis. The experiment nickel sulfide concentrate oxygen pressure acid leaching were carried out in the autoclave. The influence of those factors including leaching time, oxygen partial pressure, the amount of lignin, leaching temperature, ratio of solid and liquid and dosage of sulfuric acid on the leaching rate of nickel was investigated. The results show that the optimum conditions of the oxidation leaching of nickel sulfide ore are leaching time of 8h, the oxygen partial pressure of 1.6Mpa, the sodium lignosulphonate dosage of 3% of the mass of nickel sulfide concentrate, leaching temperature of 150℃, liquid/solid ratio of 2:1 and acidity of 100g/L. The average leaching rate of nickel reaches 96.32%.The leaching rate of cobalt is about 40%.The leaching rate of the impurity metal iron, calcium and magnesium are about 50%. Based on the kinetic model of nickel sulfide concentrate, the kinetic process of solid film diffusion control is judged by data fitting.(2) The experiment of removal of iron from leaching solution was carried out by neutral precipitation method, jarosite process, hematite process and goethite process. Through the contrast experiment, the result shows that the goethite process is better. The optimum experimental conditions are time of 7h, temperature of 80℃ Removal rate of iron reaches 99%. The loss rate of the main metal nickel is about 5%. The loss rate of cobalt is about 1%. Calcium and magnesium are basically remained in the leaching solution.(3) Due to the fact that the solution of iron removed has a relatively high impurity content and calcium, magnesium and other impurities are difficult to remove, the separation process of main metal nickel was determined by using neutralization precipitation method. The process is simple and easy to operate, which can be used to enrich nickel effectively from the liquid removed iron, and the nickel slag precipitated can be used as the raw material for preparing nickel sulfate or sold as an intermediate product.The 40 mL NaOH aqueous solution with 5% concentration was added to the solution of iron removed. The temperature was controlled at 70℃. After 5h stirring reaction, nickel precipitation rate can reach 99.7%. Nickel content in slag is more than 40%, magnesium content in slag can be controlled at about 2%. |
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