Preparation method and application of polyaluminum sulfate modified bentonite

Abstract

The invention relates to a preparation method of polyaluminum sulfate modified bentonite, and an application of the polyaluminum sulfate modified bentonite. The preparation method comprises the following steps: dissolving aluminum sulfate in water, adjusting the pH value of the obtained aluminum sulfate solution to 4.0-8.0, allowing the solution to stand, pouring out the obtained supernatant, adding bentonite to the obtained lower turbid liquid according to a mass ratio of bentonite to aluminum sulfate of 1:(1-5), stirring, allowing the obtained stirred solution to stand, pouring the obtained new supernatant, and drying the obtained new lower turbid liquid to obtain the polyaluminum sulfate modified bentonite. The preparation method has the advantages of fast reaction speed, simple operation and good modification effect. The prepared polyaluminum sulfate modified bentonite has the advantages of porous loosening, large specific surface area, easy grinding and good silicon removal effect, can be used as a green liquor silicon removal agent or for preparing green liquor silicon removal agents, and can realize silicon removal agent consumption reduction and silicon removal rate increase. Additionally, the invention provides a method for removing silicon in a green liquor by using the polyaluminum sulfate modified bentonite. The polyaluminum sulfate modified bentonite use method has the advantages of simple and convenient operation, fast reaction speed, low consumption of the polyaluminum sulfate modified bentonite, high silicon removal rate, very small change of the pH value of the green liquor, reduction of the energy consumption and cost of an enterprise, and economic benefit increase.

Description

technical field [0001] The invention belongs to the field of papermaking industry, in particular to a preparation method and application of polyaluminum sulfate modified bentonite. Background technique [0002] Bentonite is a hydrous clay mineral mainly composed of montmorillonite. In the middle of montmorillonite is alumina octahedron, and the upper and lower sides are clay minerals with a three-layer sheet structure composed of silica tetrahedron. The main element of montmorillonite is Na , Al, O, Si, etc. There are also some cations in the unit cell, such as Mg, Na, K, Cu, etc., which are not firmly interacted with the unit cell and are easily exchanged by other cations. Therefore, bentonite has excellent physical properties, including water absorption, swelling, cohesiveness, adsorption, etc. Among them, swelling and adsorption have wide application value, and it is also an important indicator to measure the quality of bentonite. [0003] The strong adsorption and high ...

AI Technical Summary

Problems solved by technology

However, due to the lack of wood resources and the abundance of non-wood resources in China, the structure of papermaking raw materials in my country has quietly changed, and the input ratio of bamboo pulp and straw pulp has begun to increase, but the silicon content of straw pulp and bamboo pulp raw materials is relatively low compared to wood raw materials. High, these silicon elements are brought into the pulping black liquor after cooking, the presence of silicon dioxide makes the viscosity of the black liquor increase rapidly with the increase of the concentration during the evaporation process, thus affecting the evaporation of the black liquor and causing scaling of the evaporation equipment , the black liquor is brought into the alkali recovery section along with the green liquor after burning, the sodium silicate in the green liquor forms calcium silicate during the causticizing process, the particles are fine and difficult to precipitate, and difficult to filter, resulting in difficulty in washing the white mud and residual alkali in the white mud The amount of alkali is high, the loss of alkali is large, and the calcining of white mud into lime requires high consumption, which eventually causes a large loss of raw materials in the entire process section, which is called "silicon interference problem".

[0004] In the traditional method of removing silicon from bentonite, when bentonite plays a role in a strong alkaline or supersaturated solution, it must be swollen with water in advance, and the swollen bentonite is in a suspended state in water to have the properties of swelling and adsorbing silicon. However, in this way It will cause the pH of green liquor to drop and the concentration to drop

In addition, the bentonite modified by aluminum salt is very hard after drying, and it is not easy to grind, which consumes a lot of energy consumption of the machine, and there are many large particles that cannot be ground, which cause waste of raw materials, increase the production cost of the enterprise, and reduce the production cost of the enterprise. economic benefits

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