Utilize ferrochromium to prepare the method for chromic anhydride

A technology of chromic anhydride and ferrochrome, applied in the field of development and utilization of chromite ore, to achieve the effect of simplifying process equipment

Active Publication Date: 2019-06-14
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] Various methods of 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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  • Utilize ferrochromium to prepare the method for chromic anhydride
  • Utilize ferrochromium to prepare the method for chromic anhydride

Examples

Experimental program
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Effect test

Embodiment 1

[0089] The sodium chromate solution obtained by the electrolysis method is passed through an ion membrane electrolysis device to obtain a sodium dichromate solution. Take 28.54 kg of sodium dichromate solution, adjust its concentration to a sodium dichromate content of 27% (calculated as sodium dichromate dihydrate, the same below), and the atomic ratio of sodium to chromium is 1:1. Then send to the first-stage anode chamber of the four-stage serial ion-exchange membrane electrolyzer, and the cathode chamber is fed with a concentration of 30% sodium hydroxide solution. Control the circulation flow rate of the anode chamber and the cathode chamber at 680 mL / min, the feed flow rate of the anode chamber at 2.03 mL / min, and the current density at 2 kA / m 2 , the reaction temperature was 75.5 ℃, the voltage was 4.58 V, and the reaction was carried out for 170 h. Obtaining 25.33kg sodium dichromate content is 29.9%, and the sodium chromate atomic ratio is the sodium dichromate+chrom...

Embodiment 2

[0091] The sodium chromate solution obtained by the electrolysis method is passed through an ion membrane electrolysis device to obtain a sodium dichromate solution. Take 1.07 kg of sodium dichromate solution, adjust its concentration to 73% sodium dichromate content (calculated as sodium dichromate dihydrate), and the atomic ratio of sodium to chromium is 1:1. Then send to the anode chamber of the ion-exchange membrane electrolyzer, and the cathode chamber leads into the sodium hydroxide solution that concentration is 30%. Control the circulation flow rate of the anode chamber and the cathode chamber at 1020 mL / min, and the current density at 2.88 kA / m 2 , the reaction temperature was 74.9 ℃, the voltage was 2.89 V, and the reaction was carried out for 7 h. Obtaining 0.90 kg dihydrate sodium dichromate content is 83%, and the sodium chromate atomic ratio is 0.35 sodium dichromate+chromic acid mixed solution. The solution was evaporated and crystallized at 105 °C, aged for 4...

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Abstract

The invention relates to a method for preparing chromic anhydride by using ferrochromium, wherein the method comprises the steps: carrying out an electrolytic reaction by a self circulating mode, controlling the circulating reaction time according to the formula described in the specification, to obtain a high-concentration chromate solution, and carrying out a hydrothermal reaction, to obtain a high-purity chromate purification solution; preparing a chromate solution with the mass concentration of 20%-40% with the high-purity chromate purification solution, mixing the chromate solution with adichromate solution with the mass concentration of 23%-50% to prepare an anode mixed feed liquid, and carrying out an electrolytic reaction to obtain a dichromate solution; and adjusting the concentration of the obtained dichromate solution to 27%-73%, taking the obtained dichromate solution as a raw material, carrying out an electrocatalytic synthesis reaction to obtain a mixed solution of chromic acid and dichromate, and carrying out crystallization separation to obtain chromic anhydride.

Description

technical field [0001] The invention relates to the development and utilization technology of chromite ore, in particular to a method for preparing chromic anhydride 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. The 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 th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25B1/00C25B9/18C25B15/08C25B15/02
Inventor 冯海涛董亚萍李波李武梁建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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