Process for concentrating titanium white waste acid through generation of crystalline hydrate by utilizing phase equilibrium principle

A technology for crystallization of hydrate and titanium white waste acid, which is applied in the field of chemical engineering, can solve the problems of limited concentration and long time consumption, and achieve the effects of improving crystallization efficiency, less equipment investment, and improving crystallization process and phase balance

Inactive Publication Date: 2019-02-22
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method requires ferrous sulfate monohydrate slag as raw material, and the slurry ratio is limited to 1.3-1.6 mg / L, so the degree of concentration is limited; and the slurry needs to be placed for more than 24 hours, which takes a long time

Method used

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  • Process for concentrating titanium white waste acid through generation of crystalline hydrate by utilizing phase equilibrium principle
  • Process for concentrating titanium white waste acid through generation of crystalline hydrate by utilizing phase equilibrium principle
  • Process for concentrating titanium white waste acid through generation of crystalline hydrate by utilizing phase equilibrium principle

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Get 100g of dilute sulfuric acid solution containing saturated ferrous sulfate respectively (acid concentration is 15.98wt%, FeSO 4 The content is 15.77wt%. ), 34g of anhydrous ferrous sulfate in a 250ml three-necked flask, placed the three-necked flask in a constant temperature water bath, kept the temperature at 40°C for 2h to promote dissolution and hydrate formation, then crystallized at 25°C for 8h, and separated by filtration. The results showed that the concentration of sulfuric acid after separation increased to 29.45wt%. The isolated solid was identified as ferrous sulfate heptahydrate.

[0022] The principle of this embodiment is shown in image 3 The ternary phase diagram of the sulfuric acid-ferrous sulfate-water system at 25°C is shown. The state of the initial dilute acid is point A in the figure, and it is connected with the vertex B of anhydrous ferrous sulfate to form a straight line. To obtain the concentrated sulfuric acid composed of point C by c...

Embodiment 2

[0024] Take respectively 50g of dilute sulfuric acid solution containing saturated ferrous sulfate (acid concentration is 15.98wt%, FeSO 4The content is 15.77wt%. ), 220g of anhydrous ferrous sulfate in a 250ml three-neck flask, place the three-necked flask in a constant temperature water bath, keep the temperature at 40°C for 2h to promote dissolution and hydrate formation, then crystallize at 25°C for 8h, and separate by filtration. The results showed that the concentration of sulfuric acid after separation increased to 64.02wt%. The isolated solid was identified as ferrous sulfate monohydrate.

[0025] The principle of this embodiment is shown in Figure 4 The ternary phase diagram of the sulfuric acid-ferrous sulfate-water system at 25°C is shown. The state of the initial dilute acid is point A in the figure, and it is connected with the vertex B of anhydrous ferrous sulfate to form a straight line. To obtain the concentrated sulfuric acid composed of point C by crysta...

Embodiment 3

[0027] Aluminum sulfate octadecahydrate is dried to produce anhydrous aluminum sulfate. Take 100g of raw material dilute acid (acid concentration is 20.00wt%), put 70g of anhydrous aluminum sulfate in a 250ml three-necked flask, place the three-necked flask in a constant temperature water bath, raise the temperature at 40°C for 2h to promote dissolution and hydrate formation, 25 It was crystallized at ℃ for 7h and separated by filtration. The concentration of spent acid was increased to 56.10%. The separated solid is identified as aluminum sulfate hexadecahydrate, and it can be reused after drying to remove crystal water.

[0028] The principle of this embodiment is shown in Figure 5 The ternary phase diagram of the sulfuric acid-aluminum sulfate-water system at 25°C is shown. The state of the initial dilute acid is point A in the figure. Connect it with the vertex B of anhydrous aluminum sulfate to form a straight line. To obtain concentrated sulfuric acid composed of p...

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Abstract

The invention provides a process for concentrating titanium white waste acid through generation of crystalline hydrate by utilizing the phase equilibrium principle. According to the process, ferrous sulfate, copper sulfate or other sulfate capable of forming crystalline hydrates are added into titanium white waste acid, the phase equilibrium process is controlled by utilizing the equilibrium relationship among sulfuric acid, water and sulfate, moisture is brought out by generating sulfate hydrates containing different crystal water and crystallizing and separating the sulfate hydrate from diluted sulfuric acid, and the diluted sulfuric acid can be concentrated; and the separated ferrous sulfate and other crystalline hydrates can be recycled after being dried to remove crystal water; different concentration degrees can be realized by controlling the mode of generated crystalline hydrate and can be adjusted according to requirement, and a concentrated sulfuric acid product having an acidconcentration of higher than 60 percent can be obtained; and anhydrous ferrous sulfate and other sulfates capable of forming crystalline hydrate can be utilized as raw materials, and the raw materials have wide sources. The process is simple, has low operation temperature, small equipment investment and weak corrosion, moisture of waste acid is not needed to be directly evaporated, energy consumption is low, and resource utilization of titanium white waste acid can be realized.

Description

technical field [0001] The invention belongs to the field of chemical engineering, and in particular relates to a process for concentrating spent titanium white acid by generating crystal hydrates by utilizing the principle of phase equilibrium. Background technique [0002] my country's titanium dioxide production is dominated by the sulfuric acid process, accounting for more than 96% of the total output. In the production process of sulfuric acid method, about 5-8 tons of 20% titanium dioxide waste acid will be produced from 1 ton of titanium dioxide (Yang Haizhou, Qin Lingling, Chen Gang. Research progress on recovery and comprehensive utilization of titanium dioxide waste acid[J]. Guangdong Chemical Industry , 2018, 45(16):118-119.). How to economically and effectively treat waste sulfuric acid has become one of the most important issues in the production process of titanium dioxide. [0003] At present, the most commonly used method is to concentrate and recover waste...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B17/90C01B17/88
CPCC01B17/88C01B17/90
Inventor 唐盛伟庞虹因张涛陈彦逍吕莉
Owner SICHUAN UNIV
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