Low-cost and low-acid-consumption laterite-nickel ore leaching method

Abstract

A low-cost and low-acid-consumption laterite-nickel ore leaching method comprises the following steps that (1) limonite type laterite-nickel ore and a sulfuric acid solution are mixed and subjected to size mixing, then the mixture is transferred into a high-pressure kettle for high-pressure acid leaching, and leaching liquid and leaching residues are obtained; (2) adjusting the pH value of the leaching solution to 3-4 by adopting modified humus soil to obtain iron-aluminum slag and a neutralized solution; the modified humus soil is obtained after humus soil type laterite-nickel ore is subjected to heat treatment; and (3) adjusting the pH value of the neutralized solution to 7.0-8.5 by using alkali, and carrying out solid-liquid separation to obtain the nickel cobalt hydroxide. According to the method, the humus soil type laterite-nickel ore with high magnesium content is subjected to heat treatment modification, the modified humus soil type laterite-nickel ore can serve as a neutralizing agent to neutralize free acid in limonite type laterite-nickel ore leaching liquid, the free acid can be effectively neutralized, and the content of magnesium in the limonite type laterite-nickel ore leaching liquid is increased; and valuable metals such as nickel and cobalt in the humus type laterite-nickel ore can be leached by fully utilizing the residual acid, so that the acid consumption of a unit nickel product is reduced.

Description

technical field [0001] The invention belongs to the field of metallurgical engineering, in particular to a low-cost, low-acid consumption leaching method for laterite nickel ore. Background technique [0002] With the rapid development of industrial society, the consumption of nickel is increasing year by year, and the nickel sulfide ore with high nickel content is increasingly exhausted, while the laterite nickel ore accounts for about 70% of the global nickel resources, and has become an important raw material for the extraction of nickel and cobalt. Effective development and utilization Laterite nickel ore has been valued by more and more countries. Laterite nickel ore is a kind of nickel oxide ore, and its surface layer is a limonite layer with high iron content. Because there are red or brown-red iron-containing oxide ores in the ore, it is called laterite nickel ore. Laterite nickel ore is a kind of loose clay ore, which is mainly composed of hydrous oxides of iron, s...

AI Technical Summary

Problems solved by technology

However, in order to achieve a higher nickel-cobalt leaching rate in the high-pressure acid leaching process, there is a certain concentration of free acid (20-50g / L) in the leach solution, which will consume a large amount of neutralizer in the process of adjusting the pH of the solution. Currently, it is commonly used in industry. Lime is used to adjust the pH, and a large amount of sulfate slag will be produced in this process, which will cause serious environmental pollution and seriously restrict the development of the industry.

The second is that the humus layer (humus type) located in the lower part of the ore deposit is characterized by high content of silicon and magnesium (30%-50% and 15%-35% by mass fraction respectively), and low content of iron and cobalt (mass fraction The fractions are 10%-25% and 0.02%-0.1%, respectively), and the nickel content is relatively high (mass fraction reaches 1.8%-3%). This ore layer is generally smelted to produce ferronickel by RKEF process, but this process cannot recover cobalt in the ore high value elements

However, studies have shown that in the process of using humus-type laterite-nickel ore to adjust the pH of limonite-type laterite-nickel ore high-pressure leaching solution, there are problems such as low neutralization efficiency, long reaction time, large amount of neutralizing agent, and harsh operating conditions.

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