Manufacture method of polysulfuric acid aluminium for wastewater treatment using waste sulfuric acid generated in semiconductor process

摘要

The present invention relates to a method for preparing polyaluminum sulfate for wastewater treatment using waste sulfate generated in a semiconductor process, which is to prevent generation of an environmental pollution by preparing polyaluminum sulfate for wastewater treatment using hydrogen peroxide-containing waste sulfate which is a byproduct difficult to be treated. To this end, the method of the present invention comprises: a mixing step (ST 1) of mixing aluminum hydroxide with process water; a waste sulfate insertion step (ST 2) of inserting hydrogen peroxide-containing waste sulfate after a mixture is inserted into a primary reactor; a normal sulfate insertion step (ST 3) of inserting normal sulfate into the primary reactor; an aluminum sulfate preparing step (ST 4) of preparing aluminum sulfate by mixing the mixture inserted into the primary reactor at a temperature condition of 80 to 130°C for 1 to 3 hours; an aqueous solution mixing step (ST 5) of mixing the prepared aluminum sulfate with sodium aluminate (SA) and a sodium carbonate aqueous solution (Na_2CO_3) through a high-speed emulsifier; and a thermal polymerization reaction step (ST 6) of aging the mixture in a second low-temperature thermal polymerization reactor.