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Method for preparing high-purity chromate by using ferrochromium

A technology of pure chromate and chromate, applied in the direction of cells, electrolysis process, electrolysis components, etc., to achieve the effect of simplifying process equipment

Active Publication Date: 2018-01-16
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

[0009] The current various methods of preparing chromate in the industry have reduced or reduced the amount of Cr in chromium slag to a certain extent. 6+ emissions, but cannot completely avoid the presence of hexavalent chromium in the slag

Method used

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  • Method for preparing high-purity chromate by using ferrochromium
  • Method for preparing high-purity chromate by using ferrochromium
  • Method for preparing high-purity chromate by using ferrochromium

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preparation example Construction

[0085] Preparation of high-concentration sodium chromate solution: insert a titanium mesh with an outer diameter of 280 mm and an inner diameter of 80 mm, and a stainless steel mesh with an outer diameter of 70 mm in a stainless steel hollow cylinder with an inner diameter of 300 mm. Hollow plastic partitions are used to insulate the titanium mesh and stainless steel. An electrolysis device with double anode and double cathode is formed. Fill the titanium mesh with 100 kg of ferrochrome with a particle size of <100 mm, and fill the electrolytic cell with 44 L of sodium hydroxide solution with a concentration of 260 g / L. The titanium mesh of the electrolytic cell is electrically connected with the positive pole of the power supply, and the stainless steel is electrically connected with the negative pole of the power supply. Turn on the power supply, adjust the output current to 100A, and the cell voltage <2.42V. After 610 hours of continuous electrolytic reaction, the temperat...

Embodiment 1

[0088] Take 500mL of high-concentration sodium chromate solution with a sodium chromate concentration of 530g / L and a carbon content of 5g / L and pass it into the hydrothermal reaction kettle, set the reaction temperature at 280°C, the reaction time for 12h, and the reaction pressure at 8MPa. After the reaction, a solid-liquid mixed slurry was obtained, and the slurry was filtered and separated to obtain 29 g of chromium hydroxide in the solid phase and 470 mL of sodium chromate solution in the liquid phase. The liquid phase was evaporated and concentrated to obtain a sodium chromate product with a purity of 99.1%.

Embodiment 2

[0090] Take sodium chromate concentration and be 260g / L, carbon content is that 500mL of the high-concentration sodium chromate solution of 2.5g / L is passed in the hydrothermal reaction kettle. Set the reaction temperature to 220°C, the reaction time to 2h, and the reaction pressure to 3MPa. After the reaction, a solid-liquid mixed slurry was obtained, and the slurry was filtered and separated to obtain 14 g of chromium hydroxide in the solid phase and 480 mL of sodium chromate solution in the liquid phase. The liquid phase was evaporated and concentrated to obtain a sodium chromate product with a purity of 99.2%.

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Abstract

The invention relates to a method for preparing high-purity chromate by using ferrochromium, wherein the method comprises the steps: providing an electrolytic device including an electrolytic tank, adouble-cathode device, a double-anode device, an insulating partition plate, a plurality of settling tanks and an electrode; carrying out an electrolytic reaction by a self circulating mode, automatically controlling the temperature at 20 DEG C-60 DEG C, and controlling the electrolyte solution circulating reaction time according to the formula 1 described in the specification, to obtain a high-concentration chromate solution; and inducing the high-concentration chromate solution into a reaction kettle, carrying out a hydrothermal reaction, under the pressure of 2 MPa-10 MPa, heating to the temperature of 180 DEG C-300 DEG C, carrying out a reaction for 2 h-12 h to obtain a hydrothermal reaction slurry, carrying out solid-liquid separation to obtain the high-purity chromate purification solution, and carrying out evaporation concentration, cooling crystallization and filtration separation to obtain the high-purity chromate product.

Description

technical field [0001] The invention relates to the development and utilization technology of chromite, in particular to a method for preparing high-purity chromate 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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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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