Method and technique for preparing Nano type sol of polyaluminium chloride in high purity

Abstract

This invention describes a process for preparing high-purity nanoscale polyalumina sols. This invention uses active aluminum hydroxide and industrial hydrochloric acid as raw materials, and adopts a two-stage reverse stripping process to produce a solution of polyaluminum chloride with an alkalinity higher than 50%, which is then increased to 70% or higher using high-purity calcium aluminate as the alkalizer. The process ensures complete stripping of the aluminum hydroxide raw material at normal atmosphere and a low temperature, thus obtaining a high-purity product. In addition, in the produced polyaluminum chloride sols the total content of nanoscale Al13 and Al30 having Keggin structure is higher than 70%, the alkalinity is 70-85% and the aluminum concentration is 10-19% (measured as Al2O3). The product is widely used as raw material for modern fine chemical binders, gluing agent for neutral paper manufacturing, intermediate or additive for modern pharmaceutical technology, coupling agent and catalyst for chemical production and flocculant for water treatment, and has potential applications in such emerging fields as inorganic nanocomposites and inorganic membrane materials.

Description

technical field [0001] The present invention relates to the preparation method and technology of inorganic macromolecule polyaluminum chloride sol, especially a kind of Al with high degree of alkalization and nano Keggin structure 13 and Al 30 The preparation method and process of high-purity nano-type polyaluminum chloride sol with high morphological content, the product is widely used as raw material for fine chemical adhesives, neutral paper sizing agent, pharmaceutical and cosmetic intermediates or additives, chemical production coupling Agents and catalysts, as well as water treatment flocculants. In addition, it has more potential application value in the fields of inorganic nanocomposite materials and inorganic membrane materials that have emerged in recent years. Background technique [0002] Polyaluminum chloride sol is a sol product obtained by hydrolysis and polymerization of high-concentration aluminum chloride solution (>2mol / L) under artificial forced hydr...

AI Technical Summary

Problems solved by technology

[0003] In the 20th century, the accuracy limited to the resolution of the NMR spectrometer ( 27 Al NMR), unable to decipher the sol form in the high-concentration polymerized aluminum solution, it has always been considered that the Al with Keggin structure 13 The hydrolyzed aggregated form is the dominant form in polyaluminum chloride solution, ignoring the Al 13 The shape of the sol formed by aggregation is important, thus limiting the application range of high-concentration aluminum sol products

[0005] Affect the nano-morphology of Al in polyaluminum solution 13 and Al 30 The main factors of the content are alkalization degree, preparation temperature, alkali addition rate, etc., and its optimal alkalization degree is about 75%, and the lower the preparation temperature is, the more beneficial it is to prevent Al 13 and Al 30 Equal to high polymerization form conversion, slow addition of alkali is beneficial to Al 13 and Al 30 generation, but too slow alkali addition rate will reduce equipment capacity and increase production cost

[0006] At present, high-purity polyaluminum chloride sol is mainly prepared by refluxing metal aluminum with hydrochloric acid or aluminum trichloride solution for a long time at high temperature (USP3535268, USP3340205). However, due to uncontrollable reaction rate and long heating time in this production method, the The prepared polyaluminum chloride sol has high polymer content, and the nano-sized Al 13 and Al 30 The content is low, and the production cost of using high-purity aluminum as raw material is high

Chinese patent CN1101622A reports the use of Al 2 o 3 ·H 2 O is used as a raw material, and the polymerized aluminum sol is obtained by acidolysis and peptization of a mixture of inorganic acid, organic acid or inorganic acid and a strong acid cation exchange resin, but this preparation method takes a long time to react and the particle size distribution of the prepared product aluminum form Inhomogeneous, the particle size distribution range is 10~350nm

Chinese patent CN1445167A reports that alumina or aluminum hydroxide or boehmite is used as aluminum source to react with hydrochloric acid or aluminum trichloride solution under high temperature and high pressure to prepare aluminum sol, but this preparation needs to be reacted under high pressure, and the reaction conditions are harsh

[0007] In addition, in the production field of high-purity polyaluminum chloride flocculants, industrial aluminum hydroxide gel is generally prepared by one-step acid-dissolving method. In order to ensure the dissolution rate of aluminum hydroxide and the alkalinity of the product, the reaction must be carried out in a high-pressure reactor. The reaction temperature is above 150°C, the reaction pressure is above 0.3MPa, and the reaction time is long, which generally takes 6-8 hours to complete. The reaction conditions are harsh, and the alkalinity of the product can only reach 45-55%. Al 13 and Al 30 content of only 20 to 30%

[0008] Chinese patent CN1508292, CN1177653 have reported adopting aluminum trichloride to be electrolytic solution respectively, and aluminum plate is anode, and iron plate is cathode, prepares the aqueous solution of polyaluminium chloride by low voltage, high current electrolytic reaction, the Al of product 13 The content can reach more than 70%, but this production method needs to consume anodic aluminum plate, the product cost is high, and it is only suitable for small-scale production applications

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