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Recycling method of by-products containing ferrous sulfate in the production process of titanium dioxide

A ferrous sulfate, production process technology, applied in the direction of sulfur compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of complex process, high energy consumption, limited downstream manufacturers, etc., and achieve the effect of eliminating environmental pollution

Active Publication Date: 2015-08-19
SICHUAN LOMON TITANIUM IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is simple to handle, but the downstream manufacturers are limited, and the digestion of ferrous heptahydrate is very limited; in addition, there is also a technology to prepare ferrous monohydrate by converting ferrous sulfate to crystallization. The problem with this method is that the traditional ferrous heptahydrate wet method Ferrous monohydrate is prepared by crystallization. During the crystallization, there is always ferrous mother liquor water and there is no way to fully utilize it. As a result, the theoretical yield of ferrous monohydrate is only about 50%. Other ferrous iron is discharged along with the mother liquor water neutralization.
However, this treatment method for waste acid has high energy consumption, complex process, and serious corrosion of equipment. More importantly, the ferrous slag obtained by concentrating waste acid has high impurities and is difficult to use.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1) By-products containing ferrous sulfate from the crystallization process of titanium liquid (its main components are as follows: FeSO 4. 7H 2 O: 89%; H2 O: 7.4%; H 2 SO 4： 3.0% and TiO 2： 0.6%) 10 tons, adding 16 tons of sulfur tons, in the fluidized furnace according to the roasting intensity of 10 tons / (m 2 .h) Roasting, the calcination temperature is 750°C, the oxygen content is controlled to 6%, and the primary furnace gas containing 11.6% sulfur dioxide volume fraction, 3.2% sulfur trioxide, 2.5% moisture and 2.2% dust is generated, and the outlet temperature is 450°C ;

[0031] (2) After the primary furnace gas passes through the waste heat boiler to recover heat and cyclone dust removal, the temperature drops to 220°C, the dust content drops to 0.54%, and the flow rate in the spray cooling tower is 15m 3 / h, the concentration of 23% of the waste acid countercurrent spray contact, absorb the sulfur trioxide in the primary furnace gas, to obtain the concent...

Embodiment 2

[0035] (1) Concentrated slag containing ferrous sulfate as the main component produced in the acid preparation section (the main components are as follows: FeSO 4. h 2 O 68.0%, free H 2 SO 4 16.0%, TiO 2 2.0%, Al 2 o 3 0.2%, MgO 1.8%, H 2 O 12%) 12 tons add 16 tons of sulfur, in the boiling furnace according to the roasting intensity of 10 tons / (m 2 .h) roasting, the roasting temperature is 760°C, and the oxygen content is controlled to be 6%. Generate primary furnace gas containing 12.8% sulfur dioxide, 4.8% sulfur trioxide, 3.3% moisture and 2.8% dust, with an outlet temperature of 460°C;

[0036] (2) After the primary furnace gas passes through the waste heat boiler to recover heat and cyclone dust removal, the temperature drops to 230°C, the dust content drops to 0.68%, and the flow rate in the spray cooling tower is 15m 3 / h, the concentration is 23% of the waste acid countercurrent spraying contact, absorbing the sulfur trioxide in the primary furnace gas, a...

Embodiment 3

[0040] (1) A mixture of the concentrated slag containing ferrous sulfate as the main component and the by-product of ferrous sulfate crystallized from titanium liquid produced in the acid mixing section (the main components are as follows: FeSO 4. 3H 2 O 78.65%, free H 2 SO 4 9.8%, TiO 2 1.3%, Al 2 o 3 0.15%, MgO 1.0%, H 2 O 9.1%) 14 tons add 16 tons of sulfur tons, in the improved fluidized furnace according to the roasting intensity 10 tons / (m 2 .h) roasting, the roasting temperature is 760°C, and the oxygen content is controlled to be 6%. Generate primary furnace gas containing 13.6% sulfur dioxide, 6.1% sulfur trioxide, 4.0% moisture and 2.6% dust, with an outlet temperature of 450°C;

[0041] (2) After the primary furnace gas passes through the waste heat boiler to recover heat and cyclone dust removal, the temperature drops to 230°C, the dust content drops to 0.72%, and the flow rate in the spray cooling tower is 16m 3 / h, the concentration is 24% of the waste...

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Abstract

The invention discloses a recycling method of a ferrous-sulfate-containing by-product generated in a titanium dioxide production process. The recycling method comprises the following steps: blending the ferrous-sulfate-containing by-product from a titanium liquid crystal or acid preparation section into sulfur or iron pyrite to carry out a roasting reaction with air in a furnace in a fluid bed to generate first-level furnace gas containing sulfur dioxide, sulfur trioxide and water, processing the first-level furnace gas by a waste heat boiler and then contact the first-level furnace gas with waste acid generated in a titanium dioxide preparation process to absorb the sulfur trioxide of the first-level furnace gas to obtain second-level waste acid and second-level furnace gas, cooling down the second waste acid, wherein the cooled second waste acid can be used for absorbing the first-level furnace gas circularly and a part of second-level waste acid is continuously pumped out and used for preparing 50-60% of sulfuric acid required by the titanium dioxide production by using a sulfuric acid method; and purifying the second-level furnace gas to obtain pure sulfur dioxide. The recycling method of the ferrous-sulfate-containing by-product generated in the titanium dioxide production process, disclosed by the invention, has the advantages of recycling waste materials and sulfur trioxide from the furnace gas, avoiding pollution of waste dilute acid to the environment, saving the resource and realizing purposes of circular economy, energy conservation and emission reduction.

Description

technical field [0001] The invention relates to a method for treating "three wastes" of titanium dioxide and sulfuric acid industry, in particular to a method for utilizing titanium dioxide waste acid. Background technique [0002] Titanium dioxide is produced by sulfuric acid method using titanium concentrate as raw material. There are two main ways to produce by-products containing ferrous sulfate. One is the crystallization of titanium liquid. The amount of by-product ferrous sulfate heptahydrate per ton of titanium dioxide is about 2.7 tons. Main componentFeSO 4. 7H 2 O, accounting for about 90%, the rest is 8-10% H 2 O, H 2 SO 4 and 0.4-0.8% TiO 2 The second is the acid mixing section, which is to concentrate the dilute waste acid into 50-60% waste acid, and the precipitate precipitated by the recovery of concentrated sulfuric acid is filtered to obtain the by-product containing ferrous sulfate (also called concentrated slag), per ton Waste acid produces 0.9 tons ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B17/74C01B17/50
CPCY02P20/129
Inventor 蔡平雄
Owner SICHUAN LOMON TITANIUM IND CO LTD