Concentrating and impurity removing method for dilute sulfuric acid in titanium dioxide powder production process by employing sulfuric acid process

Abstract

The invention discloses a concentration and impurity removal method of dilute sulfuric acid in producing titanium dioxide through a sulfuric acid method, which includes the following steps: first the dilute sulfuric acid is fed into a mixing acid tank; after the dilute sulfuric acid is concentrated into concentrated sulfuric acid, part of the concentrated sulfuric acid returns to the mixing acid tank to be mixed into 25 percent to 35 percent of feed acid, and fed into a steam concentration system to receive multi-effect evaporation concentration; part of the concentrated sulfate material returns to the mixing acid tank and the rest enters into a serial back-flow cooling curing crystal growth tank; in the back-flow cooling curing crystal growth tank, the sulfate material after curing crystal growth cooling is fed into a solid-liquid separator to receive solid-liquid separation, and the filtrate is a concentrated sulfuric acid product. Therefore, the invention not only can realize the long-period good operation of devices, but also is characterized by simple process, less investment, low manufacturing expense, obvious economic benefit, etc., and belongs to a novel method of energy saving and emission reduction.

Description

Technical field: [0001] The invention belongs to a method for concentrating and removing impurities with dilute sulfuric acid, in particular to a method for concentrating and removing impurities with dilute sulfuric acid in the production process of sulfuric acid titanium dioxide. Background technique: [0002] The production of titanium dioxide by sulfuric acid method will produce a large amount of dilute sulfuric acid no matter whether titanium concentrate or high-titanium slag is used as raw material. One ton of titanium dioxide by sulfuric acid method will produce 5.0-7.0 tons of dilute sulfuric acid with a concentration of about 17-25%. sulfuric acid. In 2006, the output of sulfuric acid titanium dioxide in my country reached nearly 900,000 tons, and the by-product of dilute sulfuric acid was about 5.5 million tons. [0003] The inventor once used the hot air heat exchange evaporation concentration production method in the Chinese patent ZL02113704.8 of "a dilute sulfu...

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Problems solved by technology

[0007] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide neither three-stage evaporation concentration twice solid-liquid separation and two-stage concentration three times solid-liquid separation process caused by many equipment, long process flow, high energy consumption; There is no problem of relatively high energy consumption of low-temperature hot air sensible heat loss caused by hot air heat exchange to avoid fouling; there is no problem of long process, multiple solid-liquid separations, increased equipment, and large investment; thus Concentration and impurity removal method of dilute sulfuric acid in the process of sulfuric acid production of titanium dioxide for the purpose of simplifying the process, shortening the process, reducing equipment, reducing investment, saving energy and reducing consumption, and increasing economic benefits

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