Development Status of Sludge Ceramsite Industry in China

Ceramsite is a silicate product whose bulk density is not more than 900kg / m³ with a certain strength by granulation, pelletizing, pelletizing and pelletizing with inorganic materials such as shale, clay, gangue and fly ash. It has low density, light weight, low water absorption, good thermal insulation, seismic, frost and corrosion resistance properties, widely used in construction, environmental protection, chemical and horticultural industries. In the construction application, ceramsite is divided into ultra-light ceramic, ordinary ceramsite and high-strength ceramsite according to the density grade. The high-strength ceramsite can be used as lightweight aggregate concrete or lightweight aggregate concrete for building insulation.

Ceramic firing mechanism: at high temperature, the ball melts, resulting in the appropriate viscosity and surface tension, while the chemical reaction within the release of gas, the gas acts on the molten liquid phase, resulting in the expansion of pores and cooling the surface of dense hard glaze Layer, and the inside is a closed porous structure. The two conditions under which the ceramic particles are swollen: 1) the melt phase has an appropriate viscosity and surface tension at the expansion temperature; 2) a sufficient amount of gas can be produced simultaneously. The main phase composition of sludge is clay minerals and organic matter, clay minerals are the main mineral composition of fired ceramic, organic matter combustion will produce a lot of gas, then the sludge can be used to produce ceramsite?
The development of sludge ceramsite has gone through two stages:
First, the basic theoretical research.This stage is mainly undertaken by the environmental engineering professional institutions of higher learning, the content is mainly sludge burning mechanism, proportioning test, firing system, product performance. The research of this stage basically formed the basic theory system of adding the sludge to burn the ceramsite, draw the following conclusion:
(1) The main components of sludge is SiO2, Al2O3 and other oxides and organic matter, of which SiO2, Al2O3 and the base material sintered together provide structural strength skeleton, the decomposition of organic matter in the firing process of gas, resulting in ceramic expansion, to help to reduce the ceramic density.
(2) The firing temperature of ceramsite is about 1200 ℃, the organic matter in sludge is decomposed, the pathogen and parasite are killed by high temperature, the harmful heavy metals are fused in ceramsite at high temperature, the leaching toxicity accords with "soil Environmental quality standards "in the agricultural land of heavy metal pollutants control standard value requirements, the disposal of the sludge completely, harmless to the environment, will not affect the usage of ceramic products performance.

Second, the ceramic production process technology.Further high sodium content of sludge raw material pretreatment technology, deodorant technology, matching technology, firing technology and flue gas treatment technology and other systems and equipment research.

The two stages research, forms the basic theory of sludge production with technology theory system, and gradually promote in the industry.

Based on the promotion and application of sludge ceramsite, Henan Zhengzhou Mining Machinery Co., Ltd. developed a test line for ceramisite production. The process flow is basically the same as that of the actual ceramisite production line, which can meet the needs of raw materials, and conditions of the test requirements, coupled with the corresponding detection equipment, process parameters can be optimized to complete the set of test analysis.