Method for preparing chromium oxide green by using ferrochrome

A technology of chromium oxide green and ferrochrome, applied in the direction of cells, electrolytic components, electrolytic process, etc., can solve the problems of environmental pollution, land occupation, etc., and achieve the effect of simplifying process equipment

Active Publication Date: 2019-03-26
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Another equally urgent problem is that a considerable part of the tens of thousands of tons of chromium oxide green produced each year is produced by calcining chromic anhydride, and the toxic solid waste generated by the workshop producing chromic anhydride is piled up, not only occupying land , and caused serious pollution to the environment
[0012] Various methods for preparing chromate in the industry can reduce or reduce the emission of Cr (Ⅵ) in chromium slag to a certain extent, but cannot completely avoid the existence of hexavalent chromium in slag.

Method used

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  • Method for preparing chromium oxide green by using ferrochrome
  • Method for preparing chromium oxide green by using ferrochrome
  • Method for preparing chromium oxide green by using ferrochrome

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0092] Embodiment 1: The high-concentration sodium chromate solution prepared by electrolysis with ferrochrome and sodium hydroxide electrolyte, separated and precipitated is the preparation raw material of chromium oxide green, and the high-concentration sodium chromate solution contains microparticle carbon, and the content of microparticle carbon About 1.0g / L~5g / L.

[0093] Take 500mL of sodium chromate with a concentration of 530g / L and a high-concentration sodium chromate electrolyte with a carbon content of about 5g / L as the raw material, react at 280°C and 8.2MPa for 6h, then terminate the hydrothermal reaction, and lower the temperature to room temperature A solid-liquid mixture slurry is obtained. It is subjected to solid-liquid separation, and the liquid phase obtains a pure chromate solution, and the solid phase obtains a solid phase of chromium hydroxide. The obtained chromium hydroxide solid phase was calcined at 1000°C for 2 hours in an air atmosphere, and then ...

Embodiment 2

[0094] Example 2: The preparation of chromium oxide green by the hydrothermal method is illustrated by taking ferrochromium and sodium hydroxide electrolyte electrolytically prepared high-concentration sodium chromate solution containing microparticle carbon as raw material and adding citric acid as reducing agent.

[0095](1) Take 61mL of sodium chromate electrolyte with a sodium chromate concentration of 263g / L as a raw material, add 8.4g of citric acid, and react at 200°C for 3 hours to terminate the hydrothermal reaction. When the temperature drops to room temperature, the solid-liquid Mix slurry. It is subjected to solid-liquid separation, and the liquid phase obtains a pure chromate solution, and the solid phase obtains a solid phase of chromium hydroxide. The obtained chromium hydroxide solid phase was calcined at 1000°C for 2 hours in an air atmosphere, and then the calcining reaction was terminated. After the temperature dropped to room temperature, the obtained solid...

Embodiment 3

[0097] Example 3: The preparation of chromium oxide green by hydrothermal method is illustrated by taking ferrochromium and sodium hydroxide electrolyte electrolytically prepared high-concentration sodium chromate solution containing microparticle carbon as raw material and adding carbon powder as reducing agent.

[0098] (1) Take 300mL of sodium chromate electrolyte with a concentration of 390g / L of sodium chromate as raw material, add 3.25g of carbon powder, react at 280°C for 3 hours, then terminate the hydrothermal reaction, and obtain a solid-liquid mixture when the temperature drops to room temperature Slurry. It is subjected to solid-liquid separation, and the liquid phase obtains a pure chromate solution, and the solid phase obtains a solid phase of chromium hydroxide. The obtained chromium hydroxide solid phase was calcined at 1000°C for 2 hours in an air atmosphere, and then the calcining reaction was terminated. After the temperature dropped to room temperature, the...

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Abstract

The invention relates to a method for preparing chromium oxide green by using ferrochrome, comprising the steps of: providing an electrolysis device, including an electrolysis cell, a double cathode device, a double anode device, an insulating partition, a plurality of settling tanks and electrodes; adopting a self-circulation method to carry out The electrolysis reaction is automatically controlled at 20°C to 60°C, and the electrolyte cycle reaction time is controlled according to formula 1. After solid-liquid separation, a high-concentration chromate solution is obtained; the high-concentration chromate solution is introduced into the reactor for hydrothermal reaction , under the pressure of 2MPa~10MPa, heated to 180℃~280℃, reacted for 2h~12h to obtain hydrothermal reaction slurry, filtered and separated to obtain chromium hydroxide solid; calcined chromium hydroxide solid to obtain chromium oxide green.

Description

technical field [0001] The invention relates to the development and utilization technology of chromite, in particular to a method for preparing chromium oxide green by using ferrochrome. Background technique [0002] Chromium salt products play a very important and irreplaceable role in the national economy and people's lives, and the chromium salt industry is one of the most competitive resource raw material industries in the world. As the parent product of chromium salt, chromate is an indispensable and important chemical raw material in the development of national economy. Chromium salt products based on chromate include: dichromate, chromic anhydride, chromium oxide, chrome yellow and chromium salt essence (basic chromium sulfate), etc. These products are widely used in metallurgy, pigments, tanning, dyes, spices, metal surface treatment, welding electrodes, coinage, catalysts, printing and dyeing, medicine and other industries. According to statistics, 10% of the commo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25B1/00C25B9/06C25B9/18C25B15/08C25B15/02C25B9/17
CPCC25B1/00C25B15/02C25B15/08C25B9/17C25B9/70
Inventor 董亚萍冯海涛李武梁建李波张波郑竹林史建斌王永全杨维德史海琴
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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