Study on the microstructure of the tannery sludge and solidified block

The microstructure of the tannery sludge and solidified block was investigated by scanning electron microscope and energy dispersive X-ray spectroscopy(SEM-EDS).The results showed when mixed lime,fly ash,cinder and the tannery sludge was 0.12,0.02,0.08 and 1.00kg respectively,the compressive strength and compactness of the solidified block was greatly improved when the curing time changed from 6,8,10,15 to 20d.The solidifying agents played a significant role at the later stage.The SEM test also showed that the solidified sludge block exhibited the acicular structure when the curing time was 20d and the magnification was 5000 times.The compactness of the solidified sludge mainly came from the ettringite,which was generated from the chemical reaction of lime,active silicate materials(fly ash and cinder) with water,and the longer curing time also played an important role in improving the compressive strength.