Preparation Of Unfired Bricks By Industry Sludge Solidified Cement And Analysis Of Economy And Technique

As the advancing of the city industrialization,the industrial production have acquired unprecedented opportunities for development,but exposing the problems of pollution, including the problem of industrial sludge pollution paid close attention to. As everyone knows,industrial sludge contains a lot of poisonous and harmful substances.If they are piled up or landfilled for long time,they not only occupy land, they but also will pollute groundwater, soil and farmland,ulteriorly affecting human body health and ecological environment. Currenttly the means of sanitary landfill,sludge incineration,sludge agricultural and sludge compost can't effectively deal with industrial sludge,so that the treatment and disposal of industry sludge and resource utilization technology are researched for far-reaching significance.This topic is from the Angle about " Harmless,Stabilization and Recycling "of solid waste disposal,which is to the sludge derived from dyestuff-making wastewater and acid mine wastewater neutralization as the research object,which is based on the research of sludge components characteristics,physical and chemical properties and characterization of the leaching toxicity.The sludge solidified by three typical cements including alumina cement,Portland cement (32.5R and 42.5R) is prepared the high-strenght,wearable and ecological unfired bricks,exploring the best process route,the formula,condition of maintenance and other process parameters, testing the compression strength,the leaching-out toxicity and freeze-thaw cycle of standard specimens;Through the test means of the X-ray diffraction and thermal analysis, this paper probes into the action mechanism of the main components of sludge and gelled material, and studies preliminary analysis of economic benefits for sludge reuse.Through the research and analysis, the paper has got the following conclusion:(1) Under the condition of the room temperature, standard specimens are maintained in water for 3～7 days and on the air.28 days later, the condition of the same dosage of cement, compressive strength order:alumina cement> Portland cement (42.5 R)> Portland cement (32.5 R); Especially the compressive strengths of the alumina cement solidified dye sludge overpass 40 MPa at a cement/dry sludge/water ratio of 1:0.5:0.5.;(2) Dye sludge contains zinc on heavy metal, but the zinc has not detected by dye sludge solidified cement,and the curing effect is obvious;Another sludge about acid mine wastewater neutralization,The heavy metal is well solidified which are Ni, Zn, Pb.The concentrations of these maters in the leachates were below the limited values of the Chinese standards for hazardous waste materials. Its utilization of resource-oriented can't cause secondary pollution to the environment;(3) After the standard specimens of unfired bricks are freezed thawing for 25 times, compressive strength and quality are reduced correspondingly.Obviously unfired bricks by two sludge respectively solidified alumina cement are in an acceptable level range for compressive strength loss< 15% and mass loss< 5%;(4) Through analysis of XRD and TG/DTG curve, the unfired bricks produced similar inorganic composition which are prepared by two sludge solidified Portland cement, such as calcium hydroxide, calcium silicate, calcium stone and calcite; Differently the unfired bricks by sludge of dye wastewater solidified alumina cement produce mineral substance that is mostly gypsum,calcium stone (AFt), AFm (C4ASH12), and curing of acid mine wastewater neutralization gain the main mineral that is gypsum, quartz and calcite.Content of calcium hydroxide is about 8.2% and content of calcite is about 18.2% in the unfired bricks by sludge of dye wastewater solidified Portland cement (32.5R),and in the curing of acid mine wastewater neutralization content of calcite is about 13.2%;Under this circumstance of Portland cement (42.5 R) curing dye sludge,the content of calcium hydroxide and calcite are approximately 12.3% and 6.82%, and the content of calcium hydroxide and calcite are respectively about 4.52% and 7.27% in the stabilizing of acid mine wastewater neutralization.The study showed that preparation of unfired bricks by the sludge derived from dyestuff-making wastewater and acid mine wastewater neutralization solidified cement can realize reuse of the sludge. It is expected that unfired bricks won't produce the secondary pollution to the environment in the process of using.