Dewatering deposits formed in purifying effluent from refractory factories by vacuum filtration

Conclusions

The residue formed from effluent contaminated with chamotte dust, with coagulation and without coagulation, is thoroughly dewatered on vacuum equipment with concentrations of more than 700 kg/m³ of suspended particles in the residue.

Residues obtained from effluent contaminated with mixtures of chamotte and clay dust in the ratio 4∶1, 1∶1, and 1∶4 are dewatered less effectively than chamotte residues. The residue from a mixture of chamotte and clay 4∶1 is dewatered with a minimum concentration of 809 kg/m³; the residue from the mixture of chamotte and clay 1∶1 can be satisfactorily dewatered only with a high vacuum (640 mm Hg) and with a filter cycle time longer than that used in existing equipment. With a filter cycle of 30 min the thickness of the skin of uncoagulated residue was 13 mm. The coagulated residue from a mixture of clay and chamotte 1∶1 even after 14 days holding had too low a concentration, and in practice cannot be dewatered on a vacuum filter. The residue from mixtures of 1∶4 chamotte and clay is dewatered very ineffectively. The thickness of the cake with a filter cycle time of 20 min for uncoagulated residue was only 4 mm.