Synthesizing Light-weight Insulating Brick Using Waste Slag Of Aluminum Factory

A new way of comprehensive deposal and reusing the waste by using waste slag ofaluminum factory, clay and foaming plastic material or abandoned polystyrene foam asmain raw material to synthesize light-weight insulating brick was introduced in thisresearch. This research has raw material and technical innovation, and it could set upindependent property right. The phase composition of mullite solid solution wascharacterized by XRD technique, the microstructure was observed by SEM, the amountof each phase was calculated by Rielveld quantification. The properties such as intensity,density, and the rate of shrinkage were tested also. Many procedures, such as surface cleaning, alkali washing, acid washing andanodizing oxidation are gone through in aluminum factory in order to improve thesurface quality of resulted products. The major phase in waste slag is γ-AlOOH, partlyin crystalline and partly in amorphous form. The waste slag was calcined at differenttemperature to study its phase transformation. The results show that ?-AlOOH willchange to ?-Al2O3 during 500-1050℃, and ?-Al2O3 will change to a-Al2O3 during1050-1200℃. The optimal sintering temperature of waste slag was above 1300℃, atwhich temperature ?-Al2O3 was completely changed to a-Al2O3. a-Al2O3 posses goodproperties and lower shrinkage rate, thus can be used as main raw materials forlight-weight insulating brick. Waste slag of aluminum factorywas calcined at different temperatures at first, andthe crystal conversion laws of waste slag of aluminum factory at different temperature can provide ussuitable data for its reusing. Light-weight insulating brick was synthesized from two ways inthis study. One is using waste slag of aluminum factory, clay and foaming plastic materialas starting materials, and the other is using waste slag of aluminum factory, clay andabandoned polystyrene foam as starting materials. In the first ways, the influence of sintering temperature, sintering time, the ratio ofAl2O3 /SiO2 and content of foaming plastic material on the crystalline structure andproperties was mainly discussed. The results show that there are three phases at most inthe fired specimens: mullite solid solution Al4[Si0.5Al1.5]O9.75, a- Al2O3 and SiO2. By analysisthe result, the specimen 3# was determined to be the optimal ingredient ( the content ofmullite solid solution was 75.0%, the content of a- Al2O3 was 25.0%).The results showthat the optimal sintering temperature was 1380℃ and time was 2 hours, under suchconditions, the intensityof the light-weight insulating brick was 2.25Mpa, the density was0.797g/cm2, and the rate of shrinkage was 5.70%. In the second ways the influence of sintering temperature, sintering hour ,the ratio ofAl2O3 /SiO2 and content of foaming plastic material on the crystalline structure andproperties was also discussed. The results show that the optimal content of foamingplastic material was determined to be 4.0%, the optimal sintering temperature was 1400℃ and time was 2 hours, under such conditions the content of mullite solid solution was77.5%, the content of a- Al2O3 was 22.5%, the intensity was 3.10Mpa, the density was0.868g/cm3, and the rate of shrinkage was 8.53%.