Method for liquid filtration

Abstract

The invention relates to a method for liquid filtration and belongs to the field of separation. The invention aims to solve a technical problem of providing a liquid filtration method that can improve liquid filtration efficiency. The method for liquid filtration comprises the following steps: allowing raw liquid to enter a filter from a raw liquid inlet pipe of the filter to be filtered by a filter element or filter membrane and obtaining filtrate and slag liquid, wherein the filtrate is discharged from a filtrate discharge pipe, and the slag liquid is discharged from a slag liquid discharge pipe; and hermetically sealing the outlet of the slag liquid discharge pipe by using a liquid seal device and discharging the slag liquid into the liquid seal device from the slag liquid discharge pipe. The method prevents the air from entering the filter, so that the air does not undergo chemical reaction with the substances in the filter and the filtration effect is improved. The method of the invention can synchronously realize production and backwashing and avoids external power supply during backwashing. In the method of the invention, the liquid in the filter generates a concentration gradient during backwashing, so the backwashing is more complete.

Description

technical field [0001] The invention relates to a method for liquid filtration and belongs to the field of separation. Background technique [0002] TiCl 4 It is an intermediate material for the production of sponge titanium and titanium dioxide. It is mainly prepared by the method of chlorinating high-titanium slag in industry. Due to the influence of high titanium slag purity and chlorination process, the crude TiCl obtained by direct chlorination 4 The liquid usually contains a large number of solid particles containing Fe, Al and Mg salts, which will affect the quality of subsequent sponge titanium or titanium dioxide. Therefore, the need for this crude TiCl 4 The suspension was subjected to solid-liquid separation. [0003] Currently, for crude TiCl 4 The solid-liquid separation of the suspension mainly uses a cloth bag for filtration. However, the bag filter has the following defects: the filter accuracy of the bag filter is low, which affects the TiCl 4 The qua...

AI Technical Summary

Problems solved by technology

However, the bag filter has the following defects: the filter accuracy of the bag filter is low, which affects the TiCl 4 The quality of the filtrate causes high costs in the subsequent deep processing of improving the quality; the cloth bag is easy to adhere to TiCl 4 Solid particles in the suspension, and because the bag cannot be backwashed and regenerated, its filtration flux will be greatly attenuated in a short period of time and fail, which seriously affects the coarse TiCl 4 Filtration efficiency of the suspension; after the bag fails, the filter element needs to be disassembled and replaced after the production is stopped, and frequent replacement results in a large amount of TiCl 4 Hydrolysis produces a large amount of HCl gas, which leads to serious environmental pollution

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