Method for concentrating titanium dioxide waste acid by adopting reverse osmosis process

Abstract

The invention relates to a method for concentrating titanium dioxide waste acid by adopting a reverse osmosis process. The method comprises the following steps: pressing titanium dioxide waste acid with acid concentration of about 20% in a filter to remove micro-grained suspended matters, pressurizing through a high-pressure pump, enabling a small part of titanium dioxide waste acid to penetrate through a reverse osmosis membrane through a reverse osmosis device to prepare clean fresh water, and feeding the clean fresh water to a clean fresh water storage tank for later use; reserving sulfate radicals and other impurities for a large part of titanium dioxide waste acid, feeding into a cooling crystallizing groove, stirring, fully separating out and settling the impurities, conveying concentrated waste acid into a pressure filter, and putting concentrated waste acid subjected to impurity removal into a circulating groove for reverse osmosis treatment; when the acid concentration is more than 40%, feeding titanium dioxide waste acid to a sulfuric acid production device, mixing with concentrated acid for increasing the concentration, and removing the impurities to prepare 98% concentrated sulfuric acid. According to the method, titanium dioxide waste acid is effectively concentrated until 98% concentrated sulfuric acid is prepared, so that the difficult problem of recycling of titanium dioxide waste acid is solved; and the method has the advantages of being low in process energy consumption, simple, effective, stable to perform, remarkable in economic and environmental benefits and the like.

Description

technical field [0001] The invention relates to a method for concentrating titanium white waste acid by reverse osmosis. Background technique [0002] Since the production of titanium dioxide by sulfuric acid method, the most difficult problem in environmental protection is the effective reuse of waste acid, because waste acid with an acid concentration of about 20% accounts for 70% of the treated waste. Calculated according to the F value of 1.9 in the production hydrolyzate, that is, 1 ton of titanium dioxide corresponds to 1.9 tons of sulfuric acid, about 70% of which enters the hydrolysis filtrate, that is, 100% of 1.33 tons of sulfuric acid, and the ferrous sulfate brought by the ratio of iron to titanium , the total adds up to nearly 1.7 tons of sulfate radicals, and the remaining 30% enters the dilute waste acid with washing water. Concentration and impurity removal treatment of waste acid for reuse or reuse has always been a serious problem that lingers and cannot b...

AI Technical Summary

Problems solved by technology

However, there are insurmountable problems in concentrating waste titanium dioxide acid by heating: (1) high energy consumption; (2) easy blockage of evaporation pipes and unstable operation; (3) high requirements for equipment materials and large investment; (4) operation complex, difficult to maintain

[0004] Some new methods for concentrating titanium dioxide waste acid have been reported in related open literature, for example: Inventor Liu Qianshu and others disclosed a method for concentrating titanium dioxide waste acid by solar heating in invention patent ZL201210365019. The waste acid is preheated so that the temperature of the waste titanium dioxide acid reaches 50-90°C, and then the preheated waste titanium dioxide acid is sent to a vacuum evaporation tank equipped with electric heating for concentration. This method reduces the traditional waste acid concentration. Energy consumption reduces the production cost of titanium dioxide waste acid concentration, but solar energy is not available for 365 days, so the heat generated by the solar heating device is only used as an auxiliary heat source for the vacuum evaporation tank

[0005] However, the above-mentioned literature still fails to find a method for concentrating titanium dioxide waste acid with low energy consumption, simple treatment method, and suitable for small and medium-sized sulfuric acid titanium dioxide enterprises.

Images