The preparation of powder includes batching, ball milling, sieving and removing iron, mud homogenization, spray drying, powder storage, stale storage and so on.
Firstly, the corresponding raw materials are weighed and proportioned according to the process recipe sheet (including the amount of water added).
Then the raw materials are added to the ball mill for grinding and pulping, and the ball mill is equipped with the grinding medium, ball stone, according to the technological requirements. The purpose is to make all kinds of lumpy, coarse and fine raw materials mix evenly after grinding and crushing. On the one hand, it can promote the physical and chemical reaction of the billet in the firing process, reduce the firing temperature, on the other hand, it is also conducive to the separation of impurities in the raw materials.
After ball milling, the slurry is put into the slurry pond according to the technological quality requirements, and iron is screened during the process. Screening is to remove the coarse particles and some impurities that are not grinded when ball milling; iron removal is because iron affects the whiteness of overland ceramics, and will form defects such as black spots, melting holes and impurities on the surface of ceramic tiles, so it must be strictly removed through multiple channels.
After iron removal through sieving, the slurry should be continuously stirred and homogenized to make the composition of the slurry more uniform, improve the fluidity performance of the slurry, increase the plasticity of the later slurry, increase the strength of the body, reduce the cracking during shaping and firing, etc.
After homogenization, the slurry is tested to meet the quality requirements. It is transported to the spray tower by high-pressure atomization, and powder particles are made by hot air drying provided by hot blast stove. In the process of spray granulation, the control of moisture content of powder is very important. The moisture content of powder and the uniformity of moisture distribution in powder will directly affect the pressing operation and the quality of brick.
The powder discharged from the spray tower, due to the difference in moisture content inside and outside the granules, and the uneven moisture content of each part of the powder, need to be conveyed to the silo to be worn out, so as to make the moisture content of the powder more uniform. Powder is obsolete in silo for 24 hours. It can be said that the preparation of ceramic tile blank has been completed. The prepared powder will be sent to the next step by conveying belt.