SU1590135A1 - Method of dispersing kaolin - Google Patents

Abstract

This invention relates to the production of fine powders of kaolin. In order to increase the degree of dispersion and reduce the energy intensity of the process in the method, including the preparation of a suspension, hydrodynamic cavitation treatment and the impact of shock waves on the moving suspension when recirculating the latter, the pre-suspension, moving at a speed of 5-8 m / s, is degassed in the advanced cavitation mode in the range of cavitation numbers 1-6 with a supercavern length equal to 25-40 of its diameter, for 1-1.2 s, and subsequent hydrodynamic cavitation processing is carried out with cavitation numbers of 0.6-1.5, and Before the impact of shock waves, a gaseous agent inert in relation to kaolin is supplied to the suspension moving at a speed of 12–14 m / s in the amount of 10–15% of the suspension volume. In addition, in the amount of gaseous agent, a vapor-gas mixture obtained in the process of degassing the suspension, or air can be used. The specific energy consumption is 18–23 Wh / m 3, the particle size of kaolin is 0.3–0.4 µm. 1 hp ff, 2 tab.

Description

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The invention relates to the processing of non-metallic minerals, in particular to the processing of clays, and can be used to produce fine kaolin powders.

The aim of the invention is to increase the degree of dispersion and reduce the energy intensity of the process.

The method is implemented as follows.

Water and kaolin in a given ratio;, continuously flow through the porn control devices into the receiving buffer tank, from which

with the aid of the pump, they are pumped at a speed of 5-8 m / s to a degassing unit with a conical cavitator. From a nonstagardary cavity formed behind the cone with a relative length of 25-40 its diameter, with cavitation numbers 1-6, a vapor-gas mixture is taken, evaporating from the liquid-cavity cavity interface to the cavity. The residence time of the suspension in the degasser is 1.0-1.2 s.

At the same time, the gas content in the suspension is reduced to 1% by volume, which allows for more rigid

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cavitation modes with low energy consumption (i.e. cavitation numbers 0.6 -1.5) for dispersion.

From the degasser, the degassed suspension enters the chamber of the cavitational-cumulative treatment 1, which is a combination of supercavatiating working sites, in which the incoming flow is accelerated in the KOH- | Q fuzor and flows on in the narrow cylindrical the area of the supercavitating impeller with the formation of helicoidal nonstationary cavities of finite size. tS

The caverns, non-stationary closed, generate polar cavitation bubbles, which collapse to form cumulative streams of large kinetic energy. The speed of the cumulative jet reaches values up to 1500 m / s, the pressure at the collapse point is up to 100 MPa, and its dimensions are 1 - 40 µm. The relative depth of penetration of the cumulative stream into the solid particles 25 is 0.1–5.0 of its length, depending on the physicomechanical properties of the material and the stream. Kumul tivna. the stream, penetrating into the surrounding liquid-liquid and solid particles of the suspension, disperses the last

The slurry then enters the device, which is a Lawal-type nozzle used to create shock waves. Since not all cavitation chambers collapse in the chamber, the mixture entering the device is essentially three-phase, consisting of liquid, solid particles and cavitation bubbles (vapor gas), 40 uniformly distributed in the liquid is sufficient, therefore the speed of sound in such a mixture is small and is only 10 - 15 m / s, depending on the volume ratio of water to kaolin - 4 vapor gas bubbles.

A uniform flow through a perforated grid of 0.5 mm inert to the kaolin gas agent in an amount of 10-15% of the volume of the suspension at the entrance to the device reduces the threshold sound propagation rate in this new mixture in connection with the fast dissipation of energy, wave on a large amount of gas and vapor-gas.

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When the suspension moves with a speed of 12-14 m / s, the formation of shock waves. Formed. gfy

overcoming the flow of a sound barrier suspension, shock waves interact with kaolin particles and destroy them. In addition, when a suspension flow passes through the shock wave front, the bubbles of the injected vapor-gas mixture and cavitation bubbles are fragmented, conditions of their collapse and additional cavitation effect on the suspension are created, since the shock pressure of the cumulative stream at the front of the shock wave is much higher than in the suspension stream.

As a result, the suspension of hydrodynamic cavitation and shock waves, disaggregates and disperses the solid particles of kaoo vu water, which is expressed in a significant increase in the degree of dispersion of kaolin, increasing the uniformity of particle size, improving its operational characteristics - with a significant decrease in the energy intensity of the process.

Example. Water and kaolin, mixed to a density of 1.2 g / cm (kaolin concentration 30%), are fed to a receiving buffer tank (0.2 m cylinder) in an amount of 12.5. Using a pump with a capacity of 50 mz / h, a pressure of 0.3 MPa, water-kaolin slurry at a speed of 7 m / s with cavitation number 4 enters the shaft with a length of 2.5 m and a diameter. 0.055 m with a conical cavitator of variable diameter, behind which a supercover with a relative

- 1 - - - - 40 and a length of 1, "-50- -ZOI

pressure in the body of the cavity equal to the pressure of saturated water vapor — at 20 C. The selection of the vapor-gas mixture occurs from the body of the cavity along its horizontal axis through a perforated pipe with a relative length of 15; the dwell time of the Kaolin in the degasser is 0.25 seconds per cycle. After degassing, the suspension enters the chamber dp of hydrodynamic cavitation treatment with an average number of cavitation 1 and a residence time of 6 s.

 After hydrodynamic cavitation treatment, the three-phase suspension (liquid, cavitation bubbles, solid particles) arrives at a speed of 13 m / s device input (above the Laval-type sound nozzle), where the formula of the invention is

Claims (2)

1, A method for the dissolution of kaolin, which includes the preparation of a suspension, hydrodynamic cavitation treatment and the effect of shock waves on a moving suspension when recirculating the latter, An excipient regulating device feeds the gas agent selected from the cavity of the gas-vapor mixture in the amount of 0.0016, which is 12% of the volume of the moving suspension. At the same time the speed of sound propagation in such a mixture decreases to 10 m / s, therefore shock waves appear in the device. The average time is that, in order to increase the degree of the mixture being in the processing area of dispersion and reducing energy-consuming shock waves (in the nozzle diffuser) per cycle is 0.2 s. Then the mixture is fed through a regulating device for recirculation, J5 recirculation rate is 4, cavitation processing time 24 seconds, degassing time 1.1 seconds, residence time of the mixture in the zone of shock waves 1.0–0.8 seconds, total time processing 26.9 s. As a result of hydrodio This process, which is previously suspended at a speed of 5–8 m / s, is subjected to degassing and in the mode of development of cavitation in the range of cavitation numbers 1–6 with a supercavern length equal to 25–40 of its diameter, for 1–1.2 s , the subsequent hydrodynamic cavitation treatment is carried out at cavitation numbers 0.6–1.5, and before exposure to shock waves, a gaseous agent is inert in relation to kaolin, moving at a speed of 12–14 m / s, This process, which is preliminarily suspended at a speed of 5–8 m / s, is subjected to degassing and in the developed cavitation mode in the range of cavitation numbers 1–6 with a supercave length equal to 25–40 of its diameter, for 1–1.2 s, the subsequent hydrodynamic cavitation treatment is carried out at cavitation numbers of 0.6–1.5, and before the impact of the shock waves, the gaseous agent, inert to kaolin, is inert to the suspension moving at a speed of 12–14 m / s; kaolin 0.25 - 0.3 microns. The specific energy cost is 23 Wh / m. 25 of 10 to 15%. Of the volume of the suspension. The degree of dispersion of kaolin and the costs of energy intensity of the process, depending on the conditions of the method of dispersion of kaolin are given in Table. one. Table 2 shows comparative thirty 2. A method according to claim 1, characterized in that a vapor-gas mixture obtained during the degassing of the suspension or air is used as the gaseous agent. The results of the proposed and known methods. Invention Formula  the fact that, in order to increase the degree of dispersion and reduce energy-intensive 1, A method for the dissolution of kaolin, including the preparation of a suspension, hydrodynamic cavitation treatment and the effect of shock waves on a moving suspension when recirculating the latter, differing the fact that, in order to increase the degree of dispersion and reduce energy-intensive This process, pre-suspension, moving at a speed of 5-8 m / s, is subjected to degassing and in the mode of developed cavitation in the range of cavitation numbers 1 - 6 with a supercavern length equal to 25 - 40 of its diameter, for 1 - 1.2 s, The subsequent hydrodynamic cavitation treatment is carried out at cavitation numbers of 0.6–1.5, and before the impact of the shock waves, a gaseous agent in an amount of 10–15% is inert to the suspension moving at a speed of 12–14 m / s. volume of suspension. 2. A method according to claim 1, characterized in that the gas-vapor mixture obtained in the process of degassing the suspension or air is used as the gaseous agent. Table 1