Generally speaking, the surface layer of the green silicon carbide crystal tube has low strength, and the quality of different parts of the crystal tube is also different. Generally, the less the sic content in the outer layer, the smaller the crystal size. Use a graded shovel to shovel the amorphous and secondary silicon carbide at the same time; clean up the crystal tube, and manually shovel the brown fused alumina fine crystals into a pile, lift it away with a grab, and store it in centralized storage for preparation Crushing and processing. The smoke removal method of the corundum electric furnace mainly adopts a smoke exhaust hood method.
That is, a large smoke exhaust hood is set above the furnace body. In this way, the crown cover is mainly composed of a furnace cover, a chimney and a furnace cover. The upper cover of the furnace is a double-layer structure welded with 6-8mm steel plates. The middle interlayer can pass cooling water and is provided with air vents to prevent explosion accidents caused by the expansion of superheated steam. The side wall of the furnace cover is welded by steel plates and lined Refractory brick. According to the way of dust removal, soot purification equipment can be divided into two categories: wet and dry.
The resistance value shall be kept within a certain range, and the resistance of each section shall be the same. For this reason, it is required to maintain the proper filling density of furnace core materials, keep the accuracy of furnace core size, control the foreign impurities of furnace core materials, control the brown aluminum oxide particle size of furnace core materials below 1 / 10 of the width of furnace core, the position of furnace core shall be in the center of side walls on both sides, and the connection between furnace core and electrode shall be filled with graphite in the shape of trumpet and tamped.
The amount of aluminum sulfide produced depends on the amount of pyrite added. The melting point of corundum furnace liquid decreases with the increase of aluminum sulfide content. The shape of the corundum crystal has a great relationship with the content of aluminum sulfide in the furnace liquid. When the content of aluminum sulfide in the melt is close to 4%, the corundum crystallized from the melt is mainly equiaxed crystal, and the particle shape is particularly good. When the content of aluminum sulfide in the melt is 6.5%, in addition to equiaxed crystals, there are slender particles.
The end point of smelting of brown aluminium oxide has not been based on strict judgment so far. Should gradually reduce the current, gradually reduce power, and slowly shut down the furnace. The white corundum is naturally cooled after the furnace is stopped. It is cooled slowly for a period of time to allow sufficient time for the crystallization of sodium perchlorate to segregate, and finally concentrated in the middle and upper part of the frit. Then water can be used to quickly cool the frit. White corundum quality appraisal is now commonly used by stick method.
Various compounds in alumite are combined together in particulate form. It is impossible to identify various oxides by visual inspection, and it is difficult to separate the various oxides by beneficiation. Due to the different chemical composition and different cementitious substances, the color of alumina varies greatly, mainly gray, tan and brown. For example, Guangxi apple ore deposits are dark gray, Henan and Shanxi mines are gray, Guizhou bauxite deposits are white and light gray, and Shandong Tianzhuang bauxite deposits are chlorite.
The stick method is judged from two aspects. On the one hand is the stick-like color and crystal luster. The color is white, and those with shiny crystal stars are better. The color is dark and the quality is not good. It is necessary to extend the smelting time. On the other hand, brown fused alumina price look at the stick-like thickness. A thin pass and a thick pass indicate that the hearth temperature is low and it takes some time. Before stopping the furnace, the thickness of the stick-like sample is 1.5 ~ 2.5mm. It is normal. If the thickness is more than 3mm, the sample is too thick.