Production process for preparing silica ceramic crucible by use of pressure grouting method

Abstract

The invention relates to a production process for preparing a silica ceramic crucible by use of a pressure grouting method and belongs to the technical field of high-grade refractory materials in a polycrystalline silicon industry. The pressure grouting comprises steps of preparation of pouring slurry, die assembling, molding by pouring slurry and demolding for fetching a green body, i.e., (1) ball-milling fused silica grain composition into slurry; and (2) fixing a resin die and assembling the die, grouting, pressurizing quartz slurry with the initial pressure being 0.1-0.2Mpa, enhancing the pressure to 0.3-1.5Mpa after a die cavity is filled with quartz slurry, keeping the pressure for about 5 minutes to filter water in the silica slurry by virtue of a micro-reticular resin mold to form a square crucible green body, and during demolding of the green body, and applying pressure of 0.2-0.3Mpa to the surface of the green body through the back layer of the micro-reticular resin mold by utilizing compression air. The green body of the silica ceramic crucible, prepared by the process, has high intensity, does not have residual air holes and is easy to demold, the product is good in thermal shock resistance and high in temperature resistance, and can meet the process requirements of polycrystalline silicon production; and the process has the advantages of high biscuit drying speed, small occupied area for production, shortened manufacturing period, low cost, and suitability for scale production.

Description

1. Technical field [0001] The invention relates to a production process for preparing a quartz ceramic crucible by a pressure grouting method, which belongs to the technical field of high-grade refractory materials used in the polysilicon industry, and specifically relates to a pressure grouting production process for a quartz ceramic crucible for polysilicon ingot casting. 2. Background technology [0002] At present, gypsum molds are widely used in the production of ceramics. This is because gypsum molds have good water absorption and mold release properties, and can give the desired shape. The disadvantages are low strength, poor wear resistance, and slightly soluble in water. In addition, the use of plaster molds is less, and the average use of general sanitary ware molds is only 60-70 times. In this way, a large amount of gypsum is consumed, and product defects are easily caused. For example, gypsum chips are mixed into the product to produce molten holes, and the surfa...

AI Technical Summary

Problems solved by technology

But this method has certain defects

First of all, the ceramic green body obtained by gel injection molding has the elasticity similar to rubber. Due to the large size of the green body, it is difficult to control the deformation of its own weight before it is completely dried; secondly, the quartz ceramic slurry is vacuumized. In the process of degassing, due to the rapid discharge of air, it is easy to cause the gelation of the slurry to proceed in advance, so the curing time is difficult to control; in addition, the quartz ceramic crucible is made by gel injection molding, the drying cycle is very long, and the green body Density is lower than that of the grouting method

To sum up, the two molding processes have disadvantages. The ordinary casting method is difficult to form and demould, the strength of the green body is low, and the molding yield is not high; The comprehensive cost of the process is high, so seeking new technologies for making quartz ceramic crucibles is still an important research direction in the field of solar polysilicon ingots