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

AI Technical Summary

Problems solved by technology

But this method does not solve the processing problem of by-product ammonium sulfate equally

Method used

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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

Experimental program
Comparison scheme
Effect test

Embodiment 1

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

[0051] (2) Under the stirring condition of 300rpm, let the solution cool down slowly to 30°C, then ferrous chloride tetrahydrate will be precipitated, and the crystallization time will be maintained for 8 hours. After completion, ferrous chloride tetrahydrate can be obtained by filtering, washing and drying The product is about 100g;

[0052] (3) Calcining the obtained ferrous chloride tetrahydrate at 500°C for 1.5 hours to obtain about 40 g of iron oxide red, and return the HCl produced by calcination to step 1 for recycling;

[0053] (4) Evaporate the filtrate at 130°C to separate HCl, and freeze and crystallize at 10°C to separate about 250 g of ferrous sulfate heptahydrate to obtain sulfuric acid with a concentration of 60%. The separated HCl and ferrous sulfate heptahydrate are returned to step 1 for recycling.

Embodiment 2

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

[0056] (2) Under the stirring condition of 300rpm, let the solution cool down slowly to 20°C, then ferrous chloride tetrahydrate will be precipitated, and the crystallization time will be kept for 6 hours. After completion, ferrous chloride tetrahydrate can be obtained by filtering, washing and drying The product is about 80g;

[0057] (3) Calcining the obtained ferrous chloride tetrahydrate at 600°C for 1 hour to obtain about 30 g of iron oxide red, and return the HCl produced by calcination to step 1 for recycling;

[0058] (4) The filtrate was evaporated at 130°C to separate HCl, and 180 g of ferrous sulfate heptahydrate was separated by freezing and 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.

Embodiment 3

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

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

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

[0063] (4) Evaporate and separate HCl from the filtrate at 130°C, and separate 260 g of ferrous sulfate heptahydrate by freezing and crystallizing at 10°C to obtain sulfuric acid with a concentration of 63%. The separated HCl and ferrous sulfate heptahydrate are 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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