PURPOSE: To obtain economically a low-Si iron oxide which is a raw material for high- class ferrite, by roasting or crystallizing a waste liquor obtained by ultrafiltering a waste liquor after pickling a steel material with hydrochloric acid.
CONSTITUTION: A waste liquor produced by acid washing of a steel material with hydrochloric acid such as steel plates, molds, rods, wire materials, etc. with the hydrochloric acid is ultrafiltered to reduce the SiO2 content to 2W10ppm. The resultant ultrafiltrate is then roasted and crystallized to give the aimed low-Si iron oxide. In a schematic drawing of an example, the above-mentioned waste liquor of acid washing charged into a waste liquor tank 1 is passed through a preliminary filtration apparatus 3 to a module 4 consisting of ultrafiltration membranes. The resultant ultrafiltrate obtd. in the filtration apparatus 3 is passed through a solenoid valve 5 to a filtrate tank 6. The concentrated solution is then returned to the waste liquor tank 1 and recirculated therethrough. The ultrafiltrate is suitably taken out of an extraction pipe 7, fed to a roasting apparatus and passed through a roasting stage to prepare iron oxide. The back washing necessary for the ultrafiltration is carried out by using a counterflow pump 8 and a check valve 9.
KIMURA KIYOSHI
SAITOU KIYOTAKA
MATSUMOTO KOUICHI
TETSUGEN KK
ASAHI CHEMICAL IND
| JPS5131236A | 1976-03-17 | |||
| JP44049432Y | ||||
| JPS4915359A | 1974-02-09 | |||
| JPS54120219A | 1979-09-18 |