Method for improving filtering performance of ferrous sulfate

Abstract

The invention discloses a method for improving filtering performance of ferrous sulfate. The method comprises the following concrete operations: taking a clear titaniferous solution obtained by a titanium dioxide production technology employing a sulfuric acid method, wherein the clear titaniferous solution contains ferrous sulfate; adding an accelerant to the clear titaniferous solution and evenly mixing; putting the clear titaniferous solution mixed with the accelerant into ice water to crystallize; keeping stirring in the crystallization process, and crystallizing until the temperature of the clear titaniferous solution is smaller than or equal to 20 DEG C, so as to obtain a crystallized titaniferous solution; taking the crystal titaniferous solution, and filtering under the condition of negative pressure, so as to obtain a filter cake of ferrous sulfate crystal containing the titaniferous solution; and washing when filtering, so as to wash out the titaniferous solution in the filter cake. By adopting the method, the accelerant is added to the clear titaniferous solution, a crystallization center is provided for crystallization of the ferrous sulfate, and generation of iron vitriol is facilitated, so that the crystallization speed of the ferrous sulfate is greatly improved, so as to shorten the crystallization time. In addition, the ferrous sulfate crystal particles are uniform in size, and large in particle size, washing of the filter cake is facilitated, the content of residue titanium in the filter cake can be reduced, and the yield of titanium is improved.

Description

technical field [0001] The invention relates to the technical field of sulfuric acid method for preparing titanium dioxide, and more specifically, relates to a method for ferrous sulfate crystallization and filtration in the sulfuric acid method for producing titanium dioxide. Background technique [0002] The sulfuric acid titanium dioxide process includes titanium ore acid hydrolysis, sedimentation, ferrous crystallization, ferrous separation, controlled filtration, concentration, hydrolysis and water washing, bleaching, salt treatment and calcination, etc. The acid-soluble impurities in the acid hydrolysis of titanium ore enter the titanium liquid, and the most soluble impurity is ferrous sulfate. To separate ferrous sulfate from the titanium liquid, crystallization and filtration are required. The solubility of ferrous sulfate is greatly affected by temperature, and the titanium solution is cooled to precipitate ferrous sulfate in the form of ferrous sulfate heptahydrate...

AI Technical Summary

Problems solved by technology

The method is easy to operate and has wide applicability, but there are shortcomings such as long crystallization time, large steam consumption, and uneven particle size of ferrous sulfate crystals. The filter cake, because the filter cake contains residual titanium solution, washing the filter cake while filtering can reduce the content of residual titanium in the filter cake, but because the particles of ferrous sulfate heptahydrate in the filter cake are not uniform, the titanium solution is easily absorbed Encapsulated in ferrous sulfate crystals, reducing the yield of total titanium