... sintering, Compared with traditional sands and coal filter material, ceramic sand filters have great advantages as follows:1. ... Shaped in sphere, the ceramic filter sand has a high void space, normally, its filtering ... about 1.2 or 1.5 times that quartz sand filter of 7.8-9 kg/m3;4. Great ... and secondary pollution may cause by the filter as quartz sand or coal filters itself. 2. Chemical ...