Separating method for chromium and iron in hydrochloric acid system

A separation method and system technology, applied in the direction of chromium halide, iron oxide, iron halide, etc., can solve the problems of difficult filtration, low iron removal rate, sensitive pH value, etc., and achieve the effect of simple process, low cost and easy operation

Inactive Publication Date: 2017-05-31
中成致远有限公司
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  • Description
  • Claims
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Problems solved by technology

Although this method can realize the separation of chromium and iron, the iron removal rate can only reach about 98%, and the loss of chromium is large, and the higher reaction temperature and longer reaction time will definitely lead to the increase of cost, the most obvious The defect is that the chromium precipitation reaction is sensitive to the pH value, and a slight error will produce a composite precipitate of colloidal chromium phosphate and chromium hydroxide, making filtration very difficult
(4) Solvent extraction method. It has been reported that TBP chromium extraction or P204 iron extraction method is used to separate chromium and iron in hydrochloric acid medium. Low rate, large loss of chromium
There

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  • Separating method for chromium and iron in hydrochloric acid system

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Embodiment 1

[0015] Embodiment 1: the chromium chloride and the ferrous chloride mixed solution that leaching carbon ferrochrome gained with hydrochloric acid are raw material, Cr in the solution 3+ Concentration of 120.6g / l, Fe 2+ Concentration 56.5g / l according to Fe 2+ Add appropriate amount of hydrogen peroxide, stir at room temperature to make Fe 2+ All oxidized to Fe 3+ , and then add secondary octanol extractant for extraction, the extraction ratio O / A=2:1, after three-stage countercurrent extraction, the Cr in the obtained aqueous chromium chloride solution 3+ Concentration of 120.6g / l, Fe 2+ The concentration is 0.005g / l, the iron removal rate is 99.99%, no chromium is extracted, and the chromium chloride solution is obtained by direct crystallization method to obtain chromium chloride crystals, and the chromium hydroxide can also be obtained by adding alkali and neutralizing the precipitation method, and then the chromium hydroxide Chromium trioxide is obtained by high-temper...

Embodiment 2

[0016] Embodiment 2: With the electroplating sludge hydrochloric acid leaching solution containing chromium and iron as raw material, Cr in the solution 3+ Concentration of 18g / l, Fe 2 + Concentration 12g / l according to Fe 2+ Add appropriate amount of hydrogen peroxide, stir at room temperature to make Fe 2+ All converted to Fe 3+ , and then add secondary octanol extractant for extraction, the extraction ratio O / A=1:1, after secondary countercurrent extraction, the Cr in the obtained aqueous chromium chloride solution 3+ The concentration is 18g / l, the Fe2+ concentration is 0.002g / l, the iron removal rate is 99.98%, no chromium is extracted, and the chromium chloride solution is obtained by direct crystallization method, and hydrogen can also be obtained by adding alkali and precipitation method Chromium oxide and chromium hydroxide are then calcined at high temperature to obtain chromium trioxide; the organic phase is back-extracted with water to obtain the extractant 2-o...

Embodiment 3

[0017] Embodiment 3: the chromium chloride and the ferrous chloride mixed solution that leaching carbon ferrochrome gained with hydrochloric acid are raw material, Cr in the solution 3+ Concentration of 118g / l, Fe 2+ Concentration 55.8g / l according to Fe 2+ Add appropriate amount of hydrogen peroxide, stir at room temperature to make Fe 2+ All converted to Fe 3+ , and then add extractant for extraction, the extractant composition is a mixture of N235 and 2-octanol, sulfonated kerosene is used as a diluent, the extraction ratio O / A=1:1, after three-stage countercurrent extraction, the obtained aqueous phase chlorine Cr in chromium solution 3+ Concentration of 118g / l, Fe 2+ The concentration is 0.02g / l, the iron removal rate is 99.96%, and no chromium is extracted. The chromium chloride solution can be obtained by direct crystallization method to obtain chromium chloride crystals, and the chromium hydroxide can also be obtained by adding alkali and neutralizing the precipita...

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Abstract

The invention discloses a separating method for chromium and iron in a hydrochloric acid system. The separating method comprises the following technology steps that firstly, a chromic chloride and ferrous chloride mixed solution is obtained through carbon ferrochrome leaching via hydrochloric acid, all Fe<2+> is oxidized into Fe<3+> through hydrogen peroxide firstly, then an extraction agent is added for extraction according to the content of iron in the solution and the proper phase ratio, a water phase obtained after extraction is a chromic chloride solution, reextraction is conducted on an organic phase through water, a ferric chloride solution and an extraction agent are obtained, and the extraction agent is circularly used; secondly, chromic chloride crystals are obtained from the chromic chloride solution via a direct crystallization method, chromic hydroxide can be prepared through an alkali adding neutralization and sedimentation method as well, the chromic hydroxide is then subjected to high-temperature roasting, and chromic oxide is obtained; and thirdly, the ferric chloride solution can be directly used as a water purifying agent, ferric hydroxide can be prepared through the alkali adding neutralization and sedimentation method, the ferric hydroxide is subjected to high-temperature roasting, and iron oxide red pigment is obtained. The technology is simple, operation is easy, and the iron removal rate reaches up to 99.95% or above.

Description

technical field [0001] The invention relates to the technical field of ferrochrome acid-dissolving production of chromium salts and electroplating sludge hydrochloric acid leaching solution treatment, in particular to a method for separating chromium and iron in a hydrochloric acid system. Background technique [0002] In the field of ferrochromium acid solution production of chromium salt and electroplating sludge hydrochloric acid leaching solution treatment technology, especially in the process of carbon ferrochromium hydrochloric acid leaching to produce chromium salt, due to the similar chemical properties of chromium and iron elements, there is an adsorption-co-precipitation effect, which makes the separation Iron removal has become a difficult problem. The existing methods for the separation of chromium and iron in hydrochloric acid medium mainly include: (1) ferrous oxalate precipitation method, which utilizes the principle of low solubility product of ferrous oxalate...

Claims

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Application Information

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IPC IPC(8): C22B7/00C01G49/10C01G49/06C01G49/02C01G37/04C01G37/033
CPCC01G37/033C01G37/04C01G49/02C01G49/06C01G49/10C22B7/007Y02P10/20
Inventor 王泽斌张伟张忠
Owner 中成致远有限公司
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