Sludge ceramsite is an artificial lightweight coarse aggregate. Due to its light weight, high strength and thermal insulation properties, it is a new type of building material with development potential. The modified sludge can be made into ceramsite as a building material. The preparation of sludge ceramsite is the use of clay and slag as auxiliary materials, sludge as the main raw material, and the filter material with certain hardness and adsorption capacity formed by roasting and forming into balls, which can be applied to sewage treatment. Sludge ceramsite has also been successfully developed using sludge, clay and a certain amount of fuel. Sludge ceramsite is an important member of lightweight aggregates and is currently the most widely used form. Sludge ceramsite firing is generally carried out by rotary kiln incineration process, matching raw material preparation, sludge dewatering, drying, grinding, kiln ball formation, kiln ball formation, firing thermal engineering, screening grading, raw material testing Control, finished product inspection and its appropriate firing technology, equipment support, automatic control.
The technology of making ceramsite from sludge in the 1980s has matured abroad. At present, there are mature processes in China. However, the technical process needs to establish an independent incinerator in the construction, the investment operation cost is large, the organic components of the sludge cannot be completely decomposed and utilized, and even some of the finished ceramics have insufficient swelling property. It can be used for reference to foreign crafts, fine-tuning the process, and testing the physical properties and leaching solution of the sludge ceramsite after the finished product to reach the standard of ceramics as building materials.
There are three kinds of substances in the process of forming ceramics. One type of materials are: SiO2, Al2O3 and Fe2O3, which account for a large proportion of sludge raw materials. In addition, the flux oxides that act as fluxing are: Na2O, K2O. , FeO, MgO, the third is a gas-generating substance, which generates gas when the material reaches a high temperature, such as water vapor, carbon dioxide, oxygen, carbon monoxide, hydrogen, etc., when the sludge is calcined, gas is generated, and the corresponding process flow is combined with the auxiliary agent. It is technically feasible to inflate the ball to achieve the ceramsite requirements, but it is necessary to find the best sintering plan for the sludge making and control the process parameters.