Causticizing method alkali preparation technology

Abstract

The invention discloses a causticizing method alkali preparation technology adopting a membrane filtration apparatus. The technology comprises the following steps: carrying out preliminary solid-liquid separation of a causticizing liquid subjected to a causticizing reaction, and carrying out precise membrane filtration of the causticizing liquid subjected to the preliminary solid-liquid separation, wherein the membrane filtration apparatus comprises a filter assembly positioned on a circulating flow path, the filter assembly comprises a shell and at least one membrane filter core installed in the shell, having two open ends and realizing filtration in an inside-feeding outside-discharge form, the shell is provided with a second port as a concentrated liquid output end, and the second port is connected with the circulating flow path through an operation mode switching control valve. When the filter assembly is in a filter state of a period, the operation mode switching control valve is in a closed state firstly, and the filter assembly runs in a first filter mode; and after the first filter mode is operated for a period of time, the mode switching control valve is triggered by a preset threshold value and is started, and the filter assembly continuously runs in a second filter mode.

Description

technical field [0001] The invention relates to a causticizing soda production process. Background technique [0002] The causticizing method is one of the main methods for producing caustic soda (sodium hydroxide). The current general process is to mix alkaline water (sodium carbonate solution) with milk of lime, and then carry out causticizing reaction in the causticizing tank, and then from the causticizing The causticizing solution is discharged from the tank. At this time, the causticizing solution is relatively turbid and contains a large amount of insoluble matter (mainly calcium carbonate). Because these solid particles are small and difficult to filter, it is necessary to use a clarification tank for clarification. After clarification Finally, light caustic lye is obtained by overflowing from the upper part of the clarifier, and the light caustic lye is concentrated to obtain solid concentrated caustic lye or caustic soda. In this process, the effect of solid-liqui...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved in this application is to provide a caustic soda production process using a membrane filtration device, the membrane filtration device has a high filtration efficiency and can improve the filter element pollution problem

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