Hydrochloric acid circulation method for preparing ferrous chloride tetrahydrate, iron oxide red and sulfuric acid by using ferrous sulfate septihydrate

A technology of ferrous sulfate and ferrous chloride, which is applied in the field of clean technology, can solve the problem of unsolved by-product ammonium sulfate treatment, and achieve the effects of improving competitive advantage, great social benefits, and reducing environmental pressure

Inactive Publication Date: 2014-05-07
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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  • Hydrochloric acid circulation method for preparing ferrous chloride tetrahydrate, iron oxide red and sulfuric acid by using ferrous sulfate septihydrate
  • Hydrochloric acid circulation method for preparing ferrous chloride tetrahydrate, iron oxide red and sulfuric acid by using ferrous sulfate septihydrate

Examples

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Example Embodiment

[0049] Example 1

[0050] (1) Dissolve 400g of ferrous sulfate heptahydrate in 500ml of 37% concentrated hydrochloric acid at 70°C;

[0051] (2) Under the condition of stirring at 300rpm, the solution is slowly cooled to 30℃, ferrous chloride tetrahydrate will be precipitated, and the crystallization time will be kept for 8h. After completion, the ferrous chloride tetrahydrate can be obtained by filtering, washing and drying. The product is about 100g;

[0052] (3) The obtained ferrous chloride tetrahydrate is calcined at 500°C for 1.5 hours to obtain about 40g of iron oxide red, and the HCl generated by the calcining is returned to step 1 for recycling;

[0053] (4) The filtrate is evaporated to separate HCl at 130°C, and freeze-crystallized at 10°C to separate about 250g ferrous sulfate heptahydrate to obtain 60% sulfuric acid. The separated HCl and ferrous sulfate heptahydrate are returned to step 1 for recycling.

Example Embodiment

[0054] Example 2

[0055] (1) Dissolve 300g of ferrous sulfate heptahydrate in 500ml of 37% concentrated hydrochloric acid at 80°C;

[0056] (2) Under the condition of stirring at 300rpm, the solution is slowly cooled to 20℃, ferrous chloride tetrahydrate will be precipitated, and the crystallization time will be maintained for 6h. After completion, the ferrous chloride tetrahydrate can be obtained by filtering, washing and drying. The product is about 80g;

[0057] (3) The obtained ferrous chloride tetrahydrate is calcined at 600°C for 1 hour to obtain about 30g of iron oxide red, and the HCl generated by the calcining is returned to step 1 for recycling;

[0058] (4) The filtrate was evaporated to separate HCl at 130°C, and 180g of ferrous sulfate heptahydrate was separated by freezing crystallization at 10°C to obtain sulfuric acid with a concentration of 65%. The separated HCl and ferrous sulfate heptahydrate were returned to step 1 for recycling.

Example Embodiment

[0059] Example 3

[0060] (1) Dissolve 400g of ferrous sulfate heptahydrate in 500ml of 35% concentrated hydrochloric acid at 80℃;

[0061] (2) Under the condition of stirring at 400rpm, the solution is slowly cooled to 20℃, ferrous chloride tetrahydrate will be precipitated, and the crystallization time will be maintained for 10h. After completion, the ferrous chloride tetrahydrate can be obtained by filtering, washing and drying. The product is about 90g;

[0062] (3) The obtained ferrous chloride tetrahydrate is calcined at 500°C for 0.5 hours to obtain about 35g of iron oxide red, and the HCl produced by the calcining is returned to step 1 for recycling;

[0063] (4) The filtrate was evaporated to separate HCl at 130°C, and 260g of ferrous sulfate heptahydrate was separated by freezing and crystallized at 10°C to obtain sulfuric acid with a concentration of 63%. The separated HCl and ferrous sulfate heptahydrate were returned to step 1 for recycling.

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Abstract

The invention belongs to the fields of titanium dioxide industry, wet-method metallurgical industry and inorganic chemical engineering and in particular relates to a technology for preparing ferrous chloride, iron oxide red and sulfuric acid by using ferrous sulfate septihydrate serving as a byproduct of the titanium dioxide industry. The technology comprises the steps of preparing ferrous chloride tetrahydrate by crystallizing the ferrous sulfate septihydrate serving as the byproduct during titanium dioxide production under a co-ion effect, then calcining the ferrous chloride tetrahydrate to prepare the iron oxide red; performing evaporative separation on filtrate to retain hydrochloric acid, and cooling, filtering and separating the residual ferrous sulfate septihydrate to recycle the sulfuric acid, wherein HCL produced by calcining and evaporation is recyclable. According to the method disclosed by the invention, the clean ferrous sulfate septihydrate can be prepared into ferrous chloride, the iron oxide red and 60% sulfuric acid. The pollution to the environment is alleviated, and the production cost of titanium dioxide can be reduced.

Description

technical field [0001] The invention belongs to the fields of titanium dioxide industry, hydrometallurgical industry and inorganic chemical industry, and particularly relates to a method of preparing ferrous chloride tetrahydrate, iron oxide red and Sulfuric acid cleaning process. Background technique [0002] Ferrous sulfate heptahydrate is one of the main by-products in the production of titanium dioxide by the sulfuric acid method. For every ton of titanium dioxide produced, about 4.5 tons of ferrous sulfate heptahydrate will be produced by-product. At present, the annual output of domestic titanium dioxide exceeds 1.6 million tons, and the annual by-product ferrous sulfate heptahydrate will exceed 7 million tons. If the huge amount of ferrous sulfate heptahydrate cannot be effectively treated, it will not only cause huge pressure on the environment, but also be a waste of resources. [0003] The utilization of ferrous sulfate heptahydrate in my country is mainly concen...

Claims

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Application Information

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IPC IPC(8): C01G49/10C01G49/06C01B17/74
Inventor 李志宝李赓
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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