Production equipment and method for producing α-type hemihydrate gypsum by utilizing industrial by-product gypsum

Abstract

The invention relates to a production equipment and method for producing α-type hemihydrate gypsum from industrial by-product gypsum. The surface of the inner wall of the shell of the equipment and the surface of the stirring blade are attached with a polytetrafluoroethylene anti-sticking layer to reduce the stickiness of the gypsum cementitious material. catch. The surface of the inner wall of the shell and the surface of the stirring blade are provided with hyperbolic grooves at intervals, and the surface of the anti-sticking layer is correspondingly provided with hyperbolic protrusions; the two sides of the longitudinal section of the hyperbolic protrusions and the hyperbolic grooves conform to the hyperbola formula. When the hyperbolic shape is used for inlaying, it can be embedded smoothly and avoid deformation of the convex body due to extrusion. Using the above-mentioned production equipment, the industrial by-product gypsum with a water content of 15% to 20% is used as a raw material to produce α-hemihydrate gypsum. It can increase the proportion of solid raw materials and finished products in the "liquid phase method" production of α-type hemihydrate gypsum, reduce process links, improve product quality, effective volume and production efficiency of production equipment, and reduce production energy consumption and investment in production lines.

Description

technical field [0001] The invention relates to the technical field of plaster of paris processing, in particular to an α-type hemihydrate gypsum (α-CaSO 4 · h 2 o) Manufacturing equipment and methods. Background technique [0002] The production process of traditional α-type hemihydrate gypsum is divided into two types, one is "autoclaved method", which uses block dihydrate gypsum as raw material, autoclaves in saturated steam to remove a semi-crystal water, then dries and The α-type hemihydrate gypsum powder can be obtained by grinding. The strength of the α-type hemihydrate gypsum produced by this process is generally 25 MPa to 35 MPa, which is used for building materials and ceramic molds; the other is the "liquid phase method" Production process, it uses powdery dihydrate gypsum as raw material, heat boiling at a temperature of about 140°C (corresponding saturated vapor pressure is about 0.4MPa) in a sealed reactor water, removes a semi-crystalline water from the ra...

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Problems solved by technology

However, the biggest problem of this process is: a large amount of process water is required, that is, the weight ratio of solid raw materials (dihydrate gypsum powder) contained in the water medium in production cannot be higher than 30%, so that in one of the industrial by-product gypsum After the semi-crystalline water is removed, the weight ratio of α-type hemihydrate gypsum in the water medium is only about 24%; If the amount of α-type hemihydrate gypsum in the produced α-type hemihydrate gypsum slurry has a high concentration, the hemihydrate gypsum bonded to the stirring blade will gradually accumulate, resulting in a very large stirring resistance; When the steam pressure is reduced to normal pressure, the saturated α-type hemihydrate gypsum will quickly reduce and solidify into massive dihydrate gypsum sticking to the stirring blade and the inner wall of the reactor, so that the produced α-type hemihydrate gypsum slurry cannot be Drain into a high-speed centrifuge for primary drying

Therefore, this production process must require that the weight ratio of dihydrate gypsum contained in the water medium is not higher than 30%; while heating and drying a large amount of water as a medium requires a lot of waste of heat energy, and the effective volume ratio of the production equipment is very low. , thereby increasing equipment investment and production cost; in addition, the reaction process link and drying process link of α-type hemihydrate gypsum are respectively in different equipment, and the temperature of the material transportation link between the above-mentioned different equipment is lower than that of hemihydrate gypsum conversion. The temperature of water gypsum, thereby reducing product quality and increasing equipment investment

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