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Method for removing hexavalent chromium in process of preparing cobalt nickel hydroxide from laterite-nickel ore

A technology of nickel cobalt hydroxide and laterite nickel ore, which is applied in the field of metallurgy and can solve problems such as unqualified products

Active Publication Date: 2020-08-07
CHINA ENFI ENGINEERING CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The main purpose of the present invention is to provide a method for removing hexavalent chromium in the process of preparing nickel-cobalt hydroxide from laterite nickel ore, so as to solve the problem of nickel-cobalt hydroxide produced by the high-pressure acid leaching process in the prior art due to the hexavalent chromium content. Too high and the product is unqualified

Method used

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  • Method for removing hexavalent chromium in process of preparing cobalt nickel hydroxide from laterite-nickel ore
  • Method for removing hexavalent chromium in process of preparing cobalt nickel hydroxide from laterite-nickel ore

Examples

Experimental program
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Effect test

Embodiment 1

[0054] Taking a laterite nickel mine in Indonesia as the implementation object, the chromium content in the laterite nickel mine is 1.37%. The laterite nickel ore is made into a slurry with a concentration of 28wt%, and the first reducing agent is added to the laterite nickel ore slurry, specifically a composite agent with a ratio of sulfur to pyrite of 1:1, which is mixed with the total amount of the laterite nickel ore. The mass ratio of chromium is 1:1. Preheat to 200°C, then heat up, and carry out high-pressure acid leaching under the conditions of reaction temperature 250°C, acid ore ratio 200Kg / t, and reaction time 1h. After high-pressure leaching, the concentration of hexavalent chromium is less than 0.5mg / L. The leaching rates were 95.25% and 91.04%, respectively.

Embodiment 2

[0056] The difference from Example 1 is only that the chromium content in the laterite nickel ore is 2.14%, the first reducing agent is sulfur alone, the mass ratio of the first reducing agent to the total chromium in the laterite nickel ore is 1:3, and the content of Ni and Co The leaching rates are 95.81% and 91.45% respectively; the concentration of hexavalent chromium after high pressure leaching is less than 0.5mg / L.

Embodiment 3

[0058] The difference from Example 1 is only that the chromium content in the laterite nickel ore is 2.42%, the ratio of sulfur to pyrite is 4:1, the reaction temperature is 250°C, and the leaching rates of Ni and Co are 97.14% and 96.45% respectively; After high pressure leaching, the concentration of hexavalent chromium is <0.5mg / L.

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Abstract

The invention provides a method for removing hexavalent chromium in the process of preparing cobalt nickel hydroxide from laterite-nickel ore. The method comprises the steps that before the high-pressure acid leaching step, laterite-nickel ore pulp is preheated, before the preheating step, a first reducing agent is added into the laterite-nickel ore pulp, and then the laterite-nickel ore pulp added with the first reducing agent is made to enter the high-pressure acid leaching step; wherein the first reducing agent is one or more of pyrite, sulfur and chromite, or organic wastewater; or, a second reducing agent is added into the leachate obtained in the cyclic leaching step, and then the residual ore neutralization step is executed; and the second reducing agent is one or more of sulfite, pyrosulfite, ferrite, thiosulfate, sulfide salt and bisulfite of alkali metal or alkaline-earth metal. By utilizing the method provided by the invention, hexavalent chromium can be removed from the source on the basis of not changing the high-pressure leaching procedure of the laterite-nickel ore, so that the nickel-cobalt hydroxide product is prevented from being carried out, and the original steps are not influenced.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a method for removing hexavalent chromium in the process of preparing nickel-cobalt hydroxide from laterite nickel ore. Background technique [0002] The preparation of nickel and cobalt hydroxide from laterite nickel ore usually adopts high-pressure acid leaching process, which mainly includes high-pressure acid leaching, circular leaching, residual ore neutralization, pre-neutralization, CCD countercurrent washing, one-stage iron and aluminum removal, two-stage iron and aluminum removal, one-stage Composed of nickel-cobalt immersion, two-stage nickel-cobalt immersion and other processes. Some lateritic nickel ores will produce hexavalent chromium in the high-pressure acid leaching process, and finally produce nickel-cobalt hydroxide products containing hexavalent chromium, and the presence of hexavalent chromium will affect the performance of nickel-cobalt hydroxide products...

Claims

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Application Information

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IPC IPC(8): C01G53/00C01G53/04C22B3/00C22B3/06C22B3/44
CPCC01G53/00C01G53/04C22B3/06C22B3/44C22B23/0415C22B23/0461
Inventor 李勇孙宁磊丁剑刘苏宁林洁媛曹敏彭建华
Owner CHINA ENFI ENGINEERING CORPORATION
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