Method for extracting chromium from chromite by leaching

A chromite and pressure leaching technology, applied in the direction of improving process efficiency, can solve the problems of difficulty in popularization of industrialization, serious furnace ring formation, and high chromium leaching rate, reducing equipment investment and reducing tailings emissions. , the effect of less environmental pollution

Active Publication Date: 2015-06-24
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chromium slag pollution is a long-standing environmental protection problem. The calcium-free roasting technology that optimizes the traditional process has a high chromium leaching rate and less slag discharge, but the investment in equipment is large, and the furnace body is seriously ringed during the roasting process, making it difficult to implement industrialization.
[0004] CN1418823A, CN102275992A, CN85102681, CN1579947, CN101066779, CN102643977A, CN85100396, etc. respectively optimize and improve the roasting process with calcium or without calcification, which improves the conversion rate of chromium to a certain extent and reduces the discharge of chromium slag, but the roasting principle and operation of the above process The process and operating temperature are basically the same as the traditional process, the reaction temperature is still high, the energy consumption is high, and the problem of chromium slag pollution can only be partially reduced rather than essentially solved
However, the pressure of this method is high and the investment in equipment is large

Method used

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  • Method for extracting chromium from chromite by leaching

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] 13Kg of chromite with particle size below 200 mesh and 45%wt KOH, 10%wt K 2 CO 3 , 8%wt KAlO 2 Add 140L of the mixed solution of chromite into a 200L autoclave, the ratio of alkali to mineral is 8:1, heat to 250°C, then feed oxygen into the solution, and stir evenly, so that the chromite and oxygen are fully mixed, and the total pressure of the control system is 1.5 MPa, react for 6 hours to fully react chromite with oxygen. Finally, a solid-liquid mixed slurry containing iron-rich tailings, potassium chromate, potassium hydroxide, potassium carbonate, potassium metaaluminate and other water-soluble impurity components is obtained, the temperature is lowered, the sample is diluted, and diluted into the reaction slurry for hydrogenation The potassium concentration is 300g / L, and the mixed slurry is filtered and separated at about 80°C to obtain iron-rich tailings and chromium-containing lye respectively. After repeated washing and drying of the tailings, the chromium c...

Embodiment 2

[0042] 22Kg of chromite with particle size below 200 mesh and 50%wt KOH, 10%wt K 2 CO 3 , 10%wt KAlO 2 Add 140L of the mixed solution of chromite into a 200L autoclave, the ratio of alkali to mineral is 5:1, heat to 280°C, then feed oxygen into the solution, and stir evenly, so that the chromite and oxygen are fully mixed, and the total pressure of the control system is 1MPa , to react for 4 hours to fully react the chromite with oxygen. Finally, a solid-liquid mixed slurry containing iron-rich tailings, potassium chromate, potassium hydroxide, potassium carbonate, potassium metaaluminate and other water-soluble impurity components is obtained, the temperature is lowered, the sample is diluted, and diluted into the reaction slurry for hydrogenation The potassium concentration is 300g / L, and the mixed slurry is filtered and separated at about 80°C to obtain iron-rich tailings and chromium-containing lye respectively. After repeated washing and drying of the tailings, the chro...

Embodiment 3

[0043] 36Kg of chromite with a particle size below 200 mesh and 55%wt KOH, 15%wt K 2 CO 3 , 5%wt KAlO 2 Add 140L of the mixed solution of chromite into a 200L autoclave, the ratio of alkali to mineral is 3:1, heat to 260°C, then feed oxygen into the solution, and stir evenly, so that the chromite and oxygen are fully mixed, and the total pressure of the control system is 0.2 MPa, react for 7 hours to fully react chromite with oxygen. Finally, a solid-liquid mixed slurry containing iron-rich tailings, potassium chromate, potassium hydroxide, potassium carbonate, potassium metaaluminate and other water-soluble impurity components is obtained, the temperature is lowered, the sample is diluted, and diluted into the reaction slurry for hydrogenation The potassium concentration is 300g / L, and the mixed slurry is filtered and separated at about 80°C to obtain iron-rich tailings and chromium-containing lye respectively. After repeated washing and drying of the tailings, the chromium...

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Abstract

The invention relates to a method for extracting chromium from chromite by pressure leaching, which comprises the following steps: mixing chromite and/or pretreated chromite with a potassium hydroxide water solution, a potassium carbonate water solution and a potassium metaaluminate water solution to obtain an original slurry; adding the original slurry into a high-pressure autoclave, introducing oxidizing gas, and carrying out pressure leaching oxidizing reaction to obtain a reaction slurry; and carrying out solid-liquid separation to respectively obtain iron-rich tailings and a solution containing potassium chromate, potassium hydroxide, potassium carbonate, potassium aluminate and other water-soluble impurity components. The method has the advantages of greatly lower reaction temperature and low energy consumption, and effectively lowers the production cost, and the maximum chromium extraction yield can reach 97% above. Besides, the volume of the high-pressure autoclave can be 200L, and the reaction medium has the same proportioning as the industrial circulating liquor, so that the process is very close to the industrial process and can easily implement industrialization.

Description

technical field [0001] The invention belongs to the fields of chromite hydrometallurgy and chromium chemical industry, and in particular relates to a method for extracting chromium by pressurized leaching of chromite in a mixed solution of potassium hydroxide, potassium carbonate and potassium aluminate. Background technique [0002] Chromite, a mineral in the spinel configuration, is the only chromium ore currently available for mining. The main components of chromite are oxides of iron, magnesium and chromium, and the general formula can be expressed as (Fe,Mg)Cr 2 o 4 . Chromium salt is one of the important inorganic chemical products and the basic raw material of important chemical industry-light industry-advanced alloy materials. About 10% of industrial products in China's national economy are related to chromium salt. [0003] At present, the methods for producing chromium salt products from chromite mainly include calcium roasting method and calcium-free roasting m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B3/12C22B34/32
CPCY02P10/20
Inventor 杜浩彭中刘龙杰陈刚李猛王晓辉李兰杰郑诗礼张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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