The Study Of Sewage Treatment System In Wet Reclamation Process Of Sodium Silicate Used Sand

Green manufacture is a developing trend in the foundry industry production of the 21st century. Among all kinds of mould sand, the sodium silicate sand is one of the most possible mould sand to realize green casting. To realize green casting based on sodium silicate sand, the key point is achieving complete reclamation of sodium silicate used sand. Currently, the common ways of sodium silicate used sand reclamation include dry reclaiming method, wet reclaiming method, chemistry reclaiming method. Wet reclaiming method is better than other reclaiming methods because of high removing rate of the remnant film, high reusing rate of the used sand etc. Wet reclamation sand can entirely substitute for new sand, so wet reclaiming method is considered to be the completely reclaiming method, but the biggest defect of wet reclaiming method is sewage and sludge treatment problem. Therefore, the study of sewage processing and recycling as well as sludge processing and reusing in wet reclamation of sodium silicate used sand is one of the crucial technologies to realize complete reclamation of sodium silicate used sand.This thesis systematically studied sewage treatment problem in wet reclamation of sodium silicate used sand and tested chemical composition of the sludge after sewage was treated. The analysis of sludge reusing was also included in this thesis. Based on the simulation experiment, the thesis designed practical sewage treatment system in wet reclamation of sodium silicate used sand.In this experiment, polymeric aluminum chloride (PAC) water solution and polyacrylamide (PAM) water solution were used as flocculants. Through systematically studying how the sewage PH value and the flocculants adding quantity affect the reclamation sewage treatment results, the experiment finally determined the optimal formula and calculated the cost of different treatment processes. The thesis tested chemical composition of the sludge after sewage was treated by using modern testing method such as X-Ray Diffraction (XRD), Atomic Absorption Spectroscopy (AAS) etc. The possibility of sludge reusing was analyzed according to the sludge chemical composition. The process of sewage treatment in wet reclamation of sodium silicate used sand was simulated in this thesis. The practical sewage treatment system in wet reclamation of sodium silicate used sand was designed on the foundation of simulation experiment, and this system comprised mixer and sewage processor. This thesis illustrated working principle and process flow of sewage treatment system according to the structures of mixer and sewage processor. The sewage flowing speed and processing time as well as the sludge falling speed and falling time of the whole sewage treatment system were calculated in this thesis. All of the drawing designs of the sewage treatment system were also included in this thesis.