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Prepn of chromium subsulfate

A chromium sulfate, basic technology, applied in the direction of chromium sulfate, chemical instruments and methods, chromium compounds, etc., can solve the problems of difficult disposal of waste residue, long process flow, high cost, etc., and achieve the effect of solving serious hazards and simple process flow

Inactive Publication Date: 2006-07-19
史培阳 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, most of the chromium taken away with the slag is soluble and toxic hexavalent chromium, which causes serious harm to the environment.
This method not only has a long process flow, but also has high cost, and the waste residue is difficult to handle

Method used

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  • Prepn of chromium subsulfate
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Examples

Experimental program
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Effect test

example 1

[0010] Grinding 20g of chromite (containing 45% chromium) to a powder with a particle size of 0.05mm is put into a three-necked flask, and the concentration of 60% sulfuric acid 80g is added, the stirring rate is 60 rpm, the temperature is raised to 110°C, and heavy Sodium chromate 2g, heat up to 150°C, keep warm for 6 hours, vacuum filter to get filter residue 28c, add sodium carbonate to the filtrate to adjust free acid to 2.3%, add 7g calcium oxide, stir at 30 rpm, heat up to 185°C, The heating rate is 0.5°C / min. After 50 minutes of heat preservation, filter to obtain 200g of filtrate (containing 3.8% chromium), add sodium carbonate to adjust the alkalinity to 33.5%, and dry to obtain 33g of basic chromium sulfate, and the yield of chromium is 81%. .

example 2

[0012] Grinding 20g of chromite (containing 45% chromium) to a powder with a particle size of 0.09mm is put into a three-necked flask, and the concentration is added to 60g of 85% sulfuric acid, the stirring rate is 100 rpm, the temperature is raised to 150°C, and heavy Potassium chromate 3g, be warming up to 160 ℃ again, keep warm for 5 hours, vacuum filter, obtain filter residue 1.8g: add sodium hydroxide to filtrate and adjust free acid to 2.5%, add 6g iron oxide, stirring speed is 40 rpm, heating rate 0.9 DEG C / min, heat up to 175 DEG C, and keep warm for 120 minutes, filter to obtain filtrate 174g (containing chromium 4.2%), add sodium carbonate to adjust alkalinity to be 32.8%, obtain basic chromium sulfate 33.2g through drying, the recovery of chromium The rate is 82%.

example 3

[0014] Grinding 20g of chromite (containing 50% chromium) to a powder with a particle size of 0.06mm is put into a three-necked flask, adding 40g of sulfuric acid with a concentration of 95%, stirring at a rate of 120 rpm, heating up to 120°C, and adding heavy Ammonium chromate 1.5g, be warming up to 130 ℃ again, insulation 5 hours, vacuum filtration, obtain filter residue 1.7g; Filtrate adds potassium carbonate and adjusts free acid to 3.1%, adds 6g magnesia, and stirring speed is 60 rev / mins, is heated up to 180 DEG C, heating rate is 0.7 DEG C / min, after insulation 100 minutes, filter and obtain filtrate 187g, add sodium carbonate to adjust alkalinity to be 32.8%, obtain basic chromium sulfate 37.4g through drying, the yield of chromium is 79%.

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Abstract

The preparation process of chromium subsulfate with chromite as material includes grinding; reacting with sulfuric acid at 110-170deg.c via stirring and under the presence of catalyst for 1-8 hr; filtering to separate filtrate and slag silica; regulating the free acid value of the filtrate with alkali to 0.8-3.1 %, adding crystal seed calcium salt, magnesium salt or chromium oxide and ferric oxide under stirring at 130-190 deg.c for 30-120 min; filtering to eliminate iron-containing slag, neutralizing the filtered mother liquid with sodium carbonate to base content of 33 %, and drying the mother liquid to obtain product chromium subsulfate; with the iron-eliminating filtered slag being produced into iron oxide red via conventional technological process. The said process is short, exhausts no toxic effluent, no slag and no waste gas, and has no environmental pollution.

Description

technical field [0001] The invention relates to a preparation method of chromium salt, in particular to a preparation method of chromium sulfate. Background technique [0002] At present, most of the preparation methods of basic chromium sulfate at home and abroad are based on dichromate as raw material. There are mainly the following methods: the organic matter reduction method is to use sulfuric acid or (NaHSO 4 Solution) after acidification, it is made by reduction with organic matter reducing agents such as sucrose, maltose or sawdust: sulfur dioxide reduction method, SO2 is passed into the solution of sodium dichromate 2 Production: In addition, there are carbon ferrochrome method, neutralization method, recovery method, formaldehyde method, chromium salt preparation method from waste chromium leather slag, etc. The traditional sodium dichromate production method is to calcinate chromite, sodium carbonate and lime powder in a certain proportion, after water immersion a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G37/00C01G37/08C14C3/06
Inventor 史培阳姜茂发刘承军刘素兰
Owner 史培阳
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