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Method for treating chromium hydroxide

A chromium hydroxide and treatment method technology, applied in the direction of chromium oxide/hydrate, can solve the problems of high energy consumption, poor washing effect of chromium hydroxide, long process flow, etc., achieve high removal rate, good washing effect, The effect of compact process

Active Publication Date: 2007-10-31
CITIC JINZHOU METAL
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0010] In order to solve the problems of long process flow, poor washing effect of chromium hydroxide, and large energy consumption in the prior art, a treatment method for chromium hydroxide is proposed, which is special in that it uses a diaphragm filter press to treat sodium chromate alkali Chromium hydroxide produced from neutral liquid and sulfur or sodium sulfide

Method used

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Embodiment 1

[0026] A treatment method for chromium hydroxide, the chromium hydroxide slurry generated by the reaction of sodium chromate alkaline liquid and sulfur is pressed into a diaphragm filter press composed of full diaphragm plates to filter, the filtration pressure is 0.35 or 0.4MPa, and the filtrate Recycle Haibo. Then wash the filter cake with water above 60°C. Carry out center washing first, that is, wash with water from the center feeding hole for 5 minutes. The washing solution with higher initial concentration is recycled for wet milling of sulfur. Then corner hole washing is carried out, that is, water enters the filter chamber from one side of the diaphragm plate, passes through the entire filter cake, and discharges the filtrate from the other side of the adjacent diaphragm filter plate. Cornerhole washing is carried out until the content of sodium thiosulfate in the washing solution is less than 0.05g / l. After washing, press the diaphragm, that is, use water as the pr...

Embodiment 2

[0028] A treatment method for chromium hydroxide, the chromium hydroxide slurry generated by the reaction of sodium chromate alkaline solution and sulfur is pressed into a membrane filter press composed of a diaphragm plate and a box plate to filter, and the filtration pressure is 0.35 or 0.4MPa, the filtrate is recovered to make hypo. Then wash the filter cake with water above 60°C. Carry out center washing first, that is, wash with water from the center feeding hole for 5 minutes. The washing solution with higher initial concentration is recycled for wet milling of sulfur. Then corner hole washing is performed, that is, water enters the filter chamber from one side of the diaphragm plate, passes through the entire filter cake, and discharges the filtrate from the other side of the box plate. Cornerhole washing is carried out until the content of sodium thiosulfate in the washing solution is less than 0.05g / l. After washing, press the diaphragm, that is, use water as the p...

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Abstract

The present invention discloses the method of treating chromium hydroxide produced with alkali solution of sodium chromate and sulfur as material, and features that diaphragm pressure filter is used in the treatment. The method includes the first filtering of chromium hydroxide slurry in a diaphragm pressure filter at 0.3-0.4 MPa pressure to form filter cake, the subsequent washing of the filter cake with water until reaching the sodium thiosulfate content in the washing solution not more than 0.05 g / L, and the final diaphragm squeezing of the filter cake with water or wind in the pressure of 1.0-1.4 MPa for 5-10 min. The method has compact and simplified technological process, short production period, raised chromium hydroxide washing effect, low power consumption and high product quality.

Description

technical field [0001] The invention belongs to chromium compounds, in particular to a method for treating chromium hydroxide produced by using sodium chromate alkaline solution and sulfur (or sodium sulfide) as raw materials. Background technique [0002] At present, the production processes of domestic manufacturers of chromium hydroxide are roughly the same. In the chromium hydroxide treatment process, tubular filters and centrifuges are generally used as the main equipment. The chromium hydroxide slurry is filtered and washed by the tubular filter, then neutralized with acid, settled and clarified, and solidified with a centrifuge. Liquid separation to obtain qualified solid chromium hydroxide. The process has the following problems: [0003] 1. The production process is long and the production cycle is long. The entire treatment process has gone through up to five processes including filtration, washing, acid neutralization, sedimentation, and centrifugal separation....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G37/02
Inventor 刘长河王志义金绍祥李福和李芳林
Owner CITIC JINZHOU METAL
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