A nitric acid selective leaching method for low-nickel high-iron alloy powder

Abstract

The invention discloses a method for leaching low-nickel high-iron alloy powder selectively through nitric acid. The method comprises the steps that firstly, primary leaching is conducted on the low-nickel high-iron alloy powder through the concentrated nitric acid; when total immersion is ended, magnetic separation is conducted; magnetic separation concentrate is returned for further leaching, so that after remaining ore pulp is filtered, leaching residues and a leaching solution are obtained, and the leaching solution enters a neutralization-for-iron-removal procedure; the low-nickel high-iron alloy powder is added to the leaching solution, so that neutralization for iron removal is conducted; after a neutralization-for-iron-removal reaction is ended, magnetic separation is conducted; magnetic separation concentrate is returned to the primary total immersion procedure, so that after ore pulp is filtered, neutralization iron slag and a separation and immersion solution are obtained; and the neutralization iron slag obtained after filtration is subjected to washing, drying and calcinations, so that an iron ore concentrate product with the iron content ranging from 60% to 65% is obtained. By means of the method, nickel and cobalt leaching and iron removal are completed through one step, and selective leaching of nickel, cobalt and iron is achieved; the nickel and the cobalt enter the solution, and the iron is inhibited in the slag, so that the nickel and the cobalt are effectively separated from the iron; and the leaching rate of the nickel and the cobalt is greater than 98%; the nickel content of the leaching residues is less than 0.5%, the iron content of the leaching residues is less than 10%, and the cobalt content of the leaching residues is less than 0.02%; the iron content of the neutralization iron slag is greater than 50%, and the nickel content o the neutralization iron slag is less than 0.1%; and the iron content of the separation and immersion solution is less than 3 g / L.

Description

technical field [0001] The invention belongs to the technical field of nonferrous metal hydrometallurgy, and in particular relates to a nitric acid selective leaching method for low-nickel and high-iron alloy powder. Background technique [0002] The laterite nickel ore adopts the crude ferronickel produced by the RKEF smelting process, which is low-nickel and high-iron alloy powder, and the composition is 2%-8%Ni, 50%-68%Fe, 0.08%-0.3%Co, 0.1%-0.6%Mn , 3%-10%Mg, 0.3%-1.0%Al, 1.0%-2.8%Cr, 3%-10%Si. The ferronickel powder is mainly directly used in the production of stainless steel, in which nickel can only be used as a low-end product, and cobalt enters the stainless steel with nickel, causing a large loss of cobalt, which does not reflect the value of cobalt. The metals in the coarse nickel-iron powder mainly exist in the form of simple substances or alloys. Using traditional sulfuric acid leaching, the leaching rate of nickel and cobalt is below 50%, and a large amount of...

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Problems solved by technology

The ferronickel powder is mainly directly used in the production of stainless steel, in which nickel can only be used as a low-end product, and cobalt enters the stainless steel with nickel, causing a large loss of cobalt, which does not reflect the value of cobalt

The metals in the coarse nickel-iron powder mainly exist in the form of simple substances or alloys. Using traditional sulfuric acid leaching, the leaching rate of nickel and cobalt is below 50%, and a large amount of iron enters the solution in the form of divalent iron, which makes it difficult to remove iron in the next step; chlorine The leaching rate of nickel, iron and cobalt in chemical leaching can reach about 95%, but the cost of iron removal is high

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