Industrial Waste Residue Of Phosphogypsum And Red Mud In The Comprehensive Utillization Of Ceramic

Phosphogypsum(PG) is a solid waste generated in the manufacture of phosphoric acid,which contains mainly calcium sulfate and is acidic.Red mud is a solid waste generated during aluminum production from bauxite,which is the same as clay and is alkaline.The emission of two solid wastes is huge,and which pollute environment with wastes piled up for a long time.This paper utilizes the acidic PG and alkaline red mud to be mixed and make the neutralization reaction.At the same time, weigh various raw materials including PG,red mud, traditional ceramic raw materials and so on.Then take a measure of existing ceramic production technology to produce ceramics which have some properties,and achieve ceramics of burning that take the short time in the low temperature.This will provide beneficial basis with utilizing PG and red mud in ceramic industry.Meanwhile,it will promote the development of recycle economy in China.This paper invest factors of phosphogypsum's dispersity(including the proportion of phosphogypsumand red mud, the kind and content of dispersant. the kind and content of extrusion). The results indicate that the red mud can improve the paste liquidity. When slurry contain PG and red mud materials,the convent of red mud is 70%.At the moment, the slurry flowing time is 26 seconds. The dispersant of sodium hexametaphosphate has Significant influence on the slurry flowing time.When the convent of sodium hexametaphosphate is 0.3%,the slurry flowing time is the shortest,Solid content is 53.3%, and viscosity is less than 1Pa·s. The plasticity materials can improve the slurry of thixotropy.The best group of experiment is fly ash,and the convent of it is 6%, which can lay aside more than 30minutes.PG and red mud were mixed with traditional ceramic materials by a certain proportion and then sintered,and the results indicate that the amount of PG had great influence on the volume density and mechanical properties of the sample.When the PG and red mud accounted for 30%(PG:red mud=3:7),and other ceramic materials accounted for 70%.On the condition of it,we sinter them in 1150℃,and hold them about 120 minutes.We produce ceramic samples that have excellent properties,for example, water absorption of sample is 1～5%, porosity is 1～10%, volume density is 2～2.4g/cm-3, rupture strength is above 37MPa, acid-proof alkaline is above 97%.Finally, the main crystalling phase of ceramic samples are (Ca, Na) (AlSi)2O8,SiO2 and Ca0.88S0.12Al1.77Si2.23O8.The properties achieve the purpose of traditional ceramics.The ignition loss of samples is 12.68%, which are caused by decomposition of PG,fly ash and organics of raw materials.