RU2328347C2 - Method of separation of thermal power plants fly ashes cenospheres - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: invention is related to classification of powdery materials and may be used in processing of anthropogenic waste, mostly cenospheres of thermal power plants fly ashes, for preparation of wide assortment of hollow silica-alumina microspheres with preset properties. Method for separation of thermal power plants fly ashes includes gravitation separation of cenospheres in descending flow of water medium with isolation of dust, fragments, perforated cenospheres and non-perforated cenospheres of different apparent density. Non-perforated cenospheres are successively run through columnar devices towards water flow with preparation of heavy fraction with apparent density of 0.42-0.46 g/cm³, medium fraction with apparent density of 0.35-0.41 g/cm³ and light fraction with apparent density of 0.28-0.35 g/cm³ by means of product sampling from top and bottom parts of devices. At that in every successive device water supply rate is increased compared to the previous value.

EFFECT: increase of hydrodynamic separation degree and preparation of fractions of cenospheres with different apparent density.

1 dwg, 1 tbl

Description

The claimed technical solution relates to the classification of powder materials and can be used in the processing of industrial waste, mainly the cenospheres of the fly ash of thermal power plants, to obtain a wide range of hollow aluminosilicate microspheres with desired properties.

A known method of separating the cenospheres of fly ash of thermal power plants [Pat. RF №2212276, V03V 7/00], in which, in order to increase the degree of separation and reduce the fire hazard of the process, the separation of cenospheres is carried out by granulometric classification and gravitational separation in the aquatic environment into products of various sizes and densities. Granulometric classification is carried out by sieving on sieves, and gravitational separation is carried out in a downward flow of an aqueous medium at a flow rate of 50-80 m / h with obtaining a light product with a bulk density of 0.3-0.35 g / cm ³ , a heavy product with a bulk weight of 0, 35-0.45 g / cm ³ and perforated cenospheres. Additionally, aerodynamic separation of the product with a bulk density of 0.3-0.35 g / cm ³ in an upward flow of air at a flow rate of 0.1-0.4 m / s with obtaining a light product with a bulk density of 0.1-0.3 g / cm ³ and a heavy product with a bulk density of more than 0.3 g / cm ³ . Preliminarily, dust and destroyed cenospheres are extracted from the starting material by hydroseparation of the starting material to obtain light and heavy products and the withdrawal of a heavy product. To isolate the perforated cenospheres, a light hydroseparation product is degassed, followed by filling the perforated cenospheres with water and precipitating them in the form of a heavy product. Perforated cenospheres are subjected to gravitational separation, and to obtain products of a given content of the magnetic component, the starting material or final products are subjected to magnetic separation.

In this method, to obtain light fractions of the cenospheres with a bulk density of less than 0.3 g / cm ³ , aerodynamic separation of hydrodynamic separation products is additionally used, which is most advisable only in the case of obtaining light fractions with a bulk density of less than 0.25 g / cm ³ . The use of aerodynamic separation necessitates additional drying of the products of the hydrodynamic stage and makes the process of gravitational separation multistage. The disadvantages of this method are the multi-stage separation of cenospheres by density and the low degree of separation of cenospheres at the stage of hydrodynamic separation. The method selected for the prototype.

The aim of the proposed technical solution is to increase the degree of hydrodynamic separation of the cenospheres and obtain at this stage fractions of cenospheres with a bulk density of less than 0.3 g / cm ³ .

This goal is achieved by the fact that the gravitational separation of the cenospheres is carried out in a downward flow of the aquatic environment with the release of: dust, fragments, perforated cenospheres and non-perforated cenospheres of different bulk density, while non-perforated cenospheres are sequentially passed through three columned apparatus towards a water stream moving at a speed of 5- 30 cm / min, with obtaining a heavy fraction of bulk density of 0.42-0.46 g / cm ³ , an average fraction of bulk density of 0.35-0.41 g / cm ³ and a light fraction of bulk density of 0.28-0.35 g / cm ³ by selecting products from the lower and upper parts of the apparatus, while in each subsequent apparatus, the water flow rate is increased relative to the previous value.

The drawing shows a schematic diagram of the hydrodynamic separation of the cenospheres of energy ashes, including: 1 - dispenser cenospheres; 2 - loading funnel; 3 - waste collection; 4 - pulp heater; 5.1-5.3 - separation columns; 6 - electric mixer; 7.1-7.5 - filters.

The essence of the claimed technical solution is illustrated by the diagram shown in the drawing, and consists in regulating the linear velocity of the downstream water flow (V _i , cm / min) supplied to the separation columns, which is defined as the ratio of the flow rate of water from the column discharge (Q _in , cm ³ / min) to the cross-sectional area of the column (S _to , cm ² ). The initial concentrate of cenospheres through a dispenser (1) and a loading funnel (2) together with water in the form of a pulp with a speed V _{0 is} continuously supplied to the lower part of the tank (3) equipped with a mixer (6). The heaviest fraction, mainly fragments (product "waste"), is deposited on the bottom of the tank and continuously or periodically displayed on the filter (7-1). Water containing fine dust suspensions is drained into the sewer or, after additional cleaning, can be returned to the process.

The surfaced cenosphere fraction in the form of pulp through the overflow pipe enters the heater (4) from above, heats up to 95-98 ° С and is fed to the bottom of the column (5-1), where it mixes with cold water coming from above (V ₁ ≈V ₀ ) and cooled to 30-35 ° C. At the same time, hollow perforated particles (the product “perforated cenospheres”) are cooled, filled with water and deposited at the bottom of the column, from where they are continuously discharged to the filter (7-2). Non-perforated cenospheres float up and through the overflow pipe are discharged to the bottom of the column (5-2). Due to the additional supply of water from above, the speed of the downward water flow is increased to the value of V ₂ (V ₂ > V ₁ ), which causes the deposition of part of the cenospheres as a heavy product (product of the “heavy fraction”), which is continuously discharged through the bottom of the column to the filter (7 -3) and is periodically cleaned. The lighter cenospheres float up and through the overflow pipe enter the lower part of the column (5-3), where similarly, by creating a higher water flow rate V ₃ (V ₃ > V ₂ ), the heavier cenospheres (product “middle fraction”) are discharged continuously through the bottom of the filter (7-4). The remaining light fraction (the product "light fraction") rises and through the overflow pipe with a speed of V ₄ (V ₄ ≈V ₀ = V ₁ ) is output to the filter (7-5). Thus, the fraction of perforated cenospheres, as well as the heavy, medium, and light fractions, the density of which is determined by the bulk density of the initial concentrate of cenospheres (ρ _n , g / cm ³ ) and linear velocities of the downward flow of water, are distinguished as target products.

The possibility of implementing the claimed technical solution to obtain products of different bulk density, including with ρ _n <0.3 g / cm ³ , is confirmed by examples of separation of the cenospheres of the Tom-Usinsk State District Power Station and Novosibirsk TPP-5 according to the above scheme (see table).

In the case of using raw materials with a lower density or when re-separating the products, as well as when varying the linear velocities of the water flow, it is possible to obtain fractions of cenospheres with a bulk density of less than 0.27 g / cm ³ if they are present in the feed. In the general case, from cenosphere concentrates with a bulk density of less than 0.55 g / cm, mainly 0.40-0.42 g / cm ³ , the bulk density of the three hydrodynamic separation products falls within the ranges 0.42-0.46 g / cm ³ (heavy fraction), 0.35-0.41 g / cm ³ (middle fraction) and 0.28-0.35 g / cm ³ (light fraction).

INFORMATION SOURCES

1. Pat. RF №2212276 "Method for the separation of cenospheres of fly ash of thermal power plants." IPC V03V 7/00. Op. 09/20/2003. - prototype

Table Results of hydrodynamic separation of cenosphere concentrates Example Name and characteristics of raw materials Products and parameters of hydrodynamic separation Waste Perforated cenosphere Heavy fraction Middle fraction Light fraction exit, % ρ _n , g / cm ³ V ₀ , cm / min exit, % ρ _n , g / cm ³ V ₁ , cm / min exit, % ρ _n , g / cm ³ V ₂ cm / min exit, % ρ _n , g / cm ³ V ₃ cm / min exit, % ρ _n , g / cm ³ V ₄ , cm / min one Tom-Usinsk State District Power Plant, cenosphere concentrate, ρ _n = 0.41 g / cm ³ 4.2 0.74 V ₀₁ 5.2 0.42 V ₁₁ 21 0.46 V ₂₁ 42.8 0.40 V ₃₁ 22.8 0.32 V ₄₁ 2 Also 3.9 0.75 V ₀₂ 5.9 0.41 V ₁₂ 23 0.45 V ₂₂ 43.8 0.41 V ₃₂ 21,4 0.32 V ₄₂ 3 Also 4.7 0.74 V ₀₃ 5.9 0.42 V ₁₃ 25.8 0.45 V ₂₃ 42.7 0.40 V ₃₃ twenty 0.28 V ₄₃ four Novosibirsk TPP-5, the product of sieve separation of the concentrate of cenospheres -0.17 + 0.1 mm, ρ _n = 0.40 g / cm ³ 2.2 0.75 V ₀₄ 5,4 0.42 V ₁₄ 19.3 0.45 V ₂₄ 39.1 0.41 V ₃₄ 34 0.33 V ₄₄

Claims (1)

A method for separating the cenospheres of volatile ashes of thermal power plants, including gravitational separation of cenospheres in a downward flow of water with the release of dust, fragments, perforated cenospheres and non-perforated cenospheres of different bulk density, characterized in that, in order to increase the degree of hydrodynamic separation and obtain fractions of cenospheres with bulk density less than 0.3 g / cm ^3, unperforated cenospheres successively passed through three columns unit toward the aqueous stream to give a heavy Fra tion bulk density of 0,42-0,46 g / cm ^3, the middle fraction bulk density 0,35-0,41 g / cm ³ and a light fraction bulk density 0.28-0.35 g / cm ³ by the selection of products with lower and upper parts of the apparatus, while in each subsequent apparatus increase the feed rate of water relative to the previous value.