FLOCCULANT

摘要

Provided is a flocculant with which it is possible to prevent, without the use of an auxiliary flocculant, an increase in the BOD and SS of wastewater that has been subjected to flocculation. Kanoya soil, which is a vitreous pyroclastic material, serves as the flocculant starting material, and a flocculant is obtained by contacting this flocculant starting material with 1 N or higher sulfuric acid. However, the flocculant starting material contains at least 0.065 mol/kg of aluminum that elutes upon contacting the sulfuric acid. Moreover, the grain size of the flocculant starting material is 150 µm or smaller. In addition, the difference between the first weight when the flocculant starting material has been dried at 110ºC and the second weight when the flocculant starting material dried at 110ºC has been further heated to between 950 and 1,050ºC is between 1 and 19% of the first weight. Furthermore, the weight of the sulfuric acid that contacts the flocculant starting material is at least 30% of the weight of the flocculant starting material.