SU833283A1 - Auxiliary cellulose-base filtering material - Google Patents

Description

The invention relates to filtering, in particular to auxiliary filtering materials intended for the purification of low concentrated suspensions, for example sodium chloride brine from mechanical impurities. It is known to use fibrous cellulose as an auxiliary filtering substance l. The disadvantage of fibrous cellulose is the high compressibility of the sediment, the difficulty of applying a uniform filtering layer and a low filtration rate. The purpose of the invention is to increase the filtration rate and quality of the filtrate obtained. This goal is achieved by the fact that the auxiliary filtering material contains cellulose in a crystalline form, with 60-100% of particles of crystalline cellulose having a size of 10-90 µm. The layer formed by plastics is practically incompressible, which allows to obtain a high speed of the process. Moreover, a certain grain size distribution of the suspension crystals allows to obtain a high degree of purification at high speeds of the process. A layer of auxiliary filtering substance of the same thickness made of fibrous and crystalline cellulose is applied onto the filter septum. Next, a mixed filtration process is carried out through the applied layer of a mixture of glycerol and distilled water in a 1: I ratio at various pressure drops. According to a known technique, the specific volume resistance of the sediment is determined at these pressure drops. Then, at the same pressure drops, the suspension is filtered through the fibrous and crystalline cellulose. the solid phase of which is calcium carbonate. The solids content in the initial suspension and filtrate is constant in comparative experiments. In the experiments, the speed of the filtration process is recorded. The resistivity and filtration rates obtained on the fibrous and crystalline celkshose at various pressure drops are presented in Table I. As follows from Table 1, crystalline and fibrous cellulose have the same sediment resistance at the initial pressure drop of the filter. However, with an increase in pressure, the specific volume resistance of the precipitate of crystalline cellulose increases substantially less than the resistance for fibrous cellulose. With an increase in pressure drop, the resistance of the precipitate of crystalline cellulose becomes less than the resistance of the precipitate of fibrous cellulose. The speed of the process when using crystalline cellulose is higher than on fibrous cellulose. A layer of crystalline cellulose of the same thickness and of different dispersion composition is applied to the filter septum, which is determined by a known method. Through the applied layer, the salt is filtered with an initial transparency of 50% according to FEC with the same pressure drop.

Table J 83 in the course of the experiments, brine samples are taken for analysis by transparency and the process rate is recorded. The effect of crystallinity cellulose dispersity on the brine filtration efficiency is presented in Table 2, In experiments 1-3, the number of parts 10 µm is 70-50%, in Runs 9-11, the number of particles greater than 90 microns is 50-70%. As follows from Table 2, the dispersion of cellulose, in which the percentage of particles that are in the range of 10-90 µm is not lower than 60, provides the best filtration results — a high degree of purification of the brine at high speeds of the process. With such a dispersion, the required degree of brine purification is achieved (not less than 99% by FEC) at high filtration rates of 0.39-0.6 m / m-h. With a higher content of fine fractions in cellulose, although it is reached-. The degree of purification is high, but the speed of the process is low (experiments 1-3, with an increase in the percentage of coarse fractions (experiments 9-11, the process speed and transparency of the filtrate obtained are slower. Implementation of the proposed material will increase the speed and quality of filtration of less concentrated suspensions.

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Claims (1)

1. Muzhikov V.A. Filtration. M., Himi, 1971, p. 348.