Dehydration method of calcium hydrogen phosphate product slurry

Abstract

The invention discloses a novel dehydration method of calcium hydrogen phosphate product slurry. The method includes the following 4 steps: material distribution, first dehydration, second material distribution and second dehydration. The four steps are mainly carried out through an adhesive tape filter, which consists of a vacuum filtration box, an adhesive tape located above the vacuum filtration box and an adhesive tape machine controlling the adhesive tape rotation. Specifically, the adhesive tape thickness is greater than or equal to 40mm, the adhesive tape moving speed is 0.08-0.1m / s; the vacuum gas pumping amount of the vacuum filtration box is set at 7-8m<3> / m<2>, the vacuum degree is 0.06MPa, and the total length of the vacuum filtration box is 6-7m. The method provided by the invention has the advantages of good dehydration effect, simple operation, high automation performance, low production and running cost, and small safety risk, etc., thus being suitable for popularization and application.

Description

technical field [0001] The invention relates to a dehydration method, in particular to a dehydration method of calcium hydrogen phosphate product slurry. Background technique [0002] Calcium hydrogen phosphate product slurry is generally made of defluorinated phosphoric acid (P 2 o 5 The concentration is about 60-80g / l) and milk of lime (the specific gravity of lime milk is 1.07-1.0) and the product slurry obtained by neutralization reaction has a high water content and can be dehydrated to obtain a semi-finished product. Due to the difference in equipment configuration, material crystallization, and operation control, the moisture content in general is controlled between 20% and 30%, and it can be dried in the furnace. [0003] The general method for dehydrating the calcium hydrogen phosphate product slurry in the industry is: use a thickener or thickener for pre-concentration, then use a centrifuge for centrifugal separation, and finally dry it. Among them, the centrif...

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Problems solved by technology

However, because the drum diameters of centrifuges are usually Ф1000, Ф1250, and Ф1350, Ф1500 is rarely used. In addition, the pre-concentration effect of the slurry is different. The processing capacity of a single machine is 1t~1.3t / h, so 100,000 tons The device needs to be equipped with more than 10 top-hung centrifuges, and more automatic flat-plate scraper centrifuges are needed. The maintenance frequency is high, and the maintenance cost is also high. At the same time, it is also necessary to consider the configuration margin

Moreover, the speed of the centrifuge is above 1000 rpm. Due to the bursting of the drum of the centrifuge, there have been more than 10 fatal accidents and countless personal injury accidents in the industry over the years, and the safety risk is great.

In addition, the mother liquor separated by the centrifuge usually contains part of the filtered material and the overflowed material when the centrifuge is clothed. It is often used for sedimentation and separation by thickeners or thickeners. At the same time, flocculants, thickened slurry and pre-concentrated The slurry is returned together and then centrifuged for dehydration. The thick slurry needs to be evenly matched, which is difficult to operate and difficult to dehydrate again.

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