Study On Extracting Nickel From Laterite Nickel Ore By Atmospheric Sulfuric Acid Leaching

As the demand for nickel in the world is increasing continuously,In the recent years,Nickel production still relies on the traditional metallurgical technology of pyrometallurgical and hydrometallurgical nickel.For instance,The leaching process of atmospheric sulfuric acid has the advantages of low energy consumption and high leaching rate.This article consider pressure acid leaching of laterite nickel ore?including nickel,manganese,iron,aluminum?experiment using sulfuric acid as the leaching agent under the normal pressure?atmospheric pressure?,the research discusses the influence of some factors in the leaching rate,such as sulfuric acid concentration,leaching temperature,solid-liquid ratio,stirring speed,leaching time,and reductant species.The results indicate that the optimum leaching conditions were as follow:temperature of 90°C,leaching time of 120 min,stirring speed of 400 r/min,sulfuric acid concentration of 24%,liquid-solid ratio of 5 to1 ml/g.Under these conditions,the leaching rates of aluminum,manganese,iron and nickel reached 70.67%,82.50%,54.66%and 68.90%,respectively.In this paper,some iron trivalent in laterite nickel ore was reduced to divalent by adding reducing agent to destroy the structure of laterite nickel ore and promoted the leaching rate of nickel plasma.The analysis of the types and dosage of reductants of sodium sulfite?Na₂SO₃?,ferrous sulfate?Fe SO₄?and ferrous sulfide?Fe S?showed that sodium sulfite promoted the leaching of manganese and nickel ions more than that of aluminum and iron.Ferrous sulfide had the best effect on nickel leaching and had the better effect on aluminum leaching.The effects of temperature,amount of catalyst,amount of ethanol,and acidity on the crystallization were studied.The results showed that the crystal recovery rate of nickel salt increased with the increase of catalyst and anhydrous ethanol dosage.As the acidity of the system increased,the crystal recovery of nickel salt was firstly reduced and then increased.At a temperature of 25?,catalyst dosage of 0.008g,ratio of anhydrous ethanol to water of 5:1,and 1ml3mol/L sulfuric acid were found to be the optimal crystallization condition.