Method for producing chromium sesquioxide through chromium-rich sludge

A technology of chromium trioxide and sludge, which is applied in the direction of chromium trioxide, chromium oxide/hydrate, etc., can solve the problems of secondary pollution and low purity of chromium trioxide products, and achieve the effect of good quality and high purity

Inactive Publication Date: 2018-07-13
SHANDONG HUASHENG CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Though above-mentioned technical scheme has obtained dichromium trioxide to a certain extent, the purity of the dichromium trioxide product that it obtains is not high, and contains a large amount of calcium, iron-magnesium-aluminum silt in the reclaimed chromium sludge, easily causes dichromium trioxide secondary pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1, present embodiment provides a kind of method utilizing chromium-rich sludge to produce dichromium trioxide

[0022] First, wash and dry the chromium-containing sludge. The drying temperature is controlled at 200°C. This temperature can satisfy the drying of the sludge without changing the sludge. In this step, the main purpose of washing is to Large impurities in the sludge are washed out, for example, soluble salts.

[0023] Grind the dried sludge evenly, transfer it to a rotary calciner, use gas (mainly CO, H2) to directly heat it, and raise it to 530-570°C within 1.5-2 hours, then maintain the temperature for 1-1.5 hours, and then heat up The main purpose is to dehydrate the chromium hydroxide in the chromium-rich sludge to produce dichromium trioxide.

[0024] Then transfer to the cooling kiln to cool down to 60-90°C, add a certain amount of hydrochloric acid and water and stir for about 0.5 hours, add hydrochloric acid and water according to the rati...

Embodiment 2

[0030] Embodiment 2, present embodiment provides a kind of method utilizing chromium-rich sludge to produce dichromium trioxide

[0031] First, wash and dry the chromium-containing sludge. The drying temperature is controlled at 250°C. This temperature can satisfy the sludge drying without changing the sludge. In this step, the main purpose of water washing is to Large impurities in the sludge are washed out, for example, soluble salts.

[0032] Grind the dried sludge evenly, transfer it to a rotary calciner, use gas (mainly CO, H2) to directly heat it, and raise it to 530-570°C within 1.5-2 hours, then maintain the temperature for 1-1.5 hours, and then heat up The main purpose is to dehydrate the chromium hydroxide in the chromium-rich sludge to produce dichromium trioxide.

[0033] Then transfer to the cooling kiln to cool down to 60-90°C, add a certain amount of hydrochloric acid and water and stir for about 0.5 hours, add hydrochloric acid and water according to the ratio...

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Abstract

The invention belongs to the technical field of environmental protection, and relates to the recycling of chromium-rich sludge, in particular to a method for producing chromium sesquioxide through chromium-rich sludge. The method comprises the following effective steps: a, firstly, washing and drying chromium-containing sludge; b, then, evenly grinding the dried chromium-containing sludge, transferring the chromium-containing sludge into a calcining kiln to directly heat the chromium-containing sludge, increasing the temperature of the chromium-containing sludge to 530 to 570 DEG C within 1.5to 2 hours, and then maintaining the temperature for 1 to 1.5 hours; c, transferring the chromium-containing sludge into a cooling kiln after heating is accomplished, reducing the temperature of the chromium-containing sludge to 60 to 90 DEG C, adding hydrochloric acid and water at the end of cooling, and uniformly stirring; d, transferring the uniformly stirred chromium-containing sludge into a filter press to perform filter pressing on the chromium-containing sludge, and washing filter residue to be neutral; e, adding water and hydrofluoric acid to the washed filter residue, stirring for 0.5hour, then transferring the filter residue into a filter press to perform filter pressing on the filter residue, and washing the filter residue to be neutral; f, then transferring the filter residueinto a high-temperature calcining kiln, performing burning and heating on the filter residue through coal gas, increasing the temperature of the filter residue to 1320 to 1400 within 2 hours, maintaining the temperature for 50 to 80 minutes, and then transferring the filter residue into the cooling kiln to reduce the temperature of the filter residue to below 40 DEG C, so as to obtain a finished product namely the chromium sesquioxide.

Description

technical field [0001] The invention belongs to the technical field of environmental protection and relates to the reuse of chromium-rich sludge, in particular to a method for producing chromium trioxide from chromium-rich sludge. Background technique [0002] Tanning refers to the process of tanning raw hides and skins into leather. Remove hair and non-collagen fibers, etc., make the collagen fibers in the dermis moderately loose, fix and strengthen, and then add a series of chemical (including biochemical) and mechanical treatments such as finishing (management). The tanning process is usually divided into three stages: preparation, tanning and finishing (reasoning). The drum is the most used equipment in the tanning process. The processes of immersion, liming, depilation, softening, pickling, tanning, dyeing, emulsion oiling and other processes must be completed in the drum. Through the mechanical action of the drum, various chemical industries are promoted. The uniform...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/033
CPCC01G37/033C01P2006/80
Inventor 谢瑞兴孙新科
Owner SHANDONG HUASHENG CHEM TECH
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