TREATMENT OF WASTE LIQUOR PRODUCED BY PRETREATMENT OF METAL BEFORE COATING

PURPOSE:To prevent the corrosion of an equipment due to the accumulation of hydrogen fluoride by treating waste liquor contg. zinc phosphate produced by chemical treatment and waste liquor generated by washing with a ferric salt and calcium hydroxide to remove fluorine ions before the waste liquors...

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Bibliographische Detailangaben
1. Verfasser:	SHIGENAGA YUKIO
Format:	Patent
Sprache:	eng
Schlagworte:	CHEMICAL SURFACE TREATMENT CHEMISTRY COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL COATING MATERIAL WITH METALLIC MATERIAL COATING METALLIC MATERIAL DIFFUSION TREATMENT OF METALLIC MATERIAL INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL METALLURGY MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLICMATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASSC23 AND AT LEAST ONEPROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25 NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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Beschreibung
Zusammenfassung:	PURPOSE:To prevent the corrosion of an equipment due to the accumulation of hydrogen fluoride by treating waste liquor contg. zinc phosphate produced by chemical treatment and waste liquor generated by washing with a ferric salt and calcium hydroxide to remove fluorine ions before the waste liquors are concentrated by evaporation. CONSTITUTION:A metallic product is subjected to the chemical treatment with an aqueous zinc phosphate soln. and washing before a coating. Waste liquor generated by the chemical treatment and the waste liquor generated by the washing are treated with the ferric salt and calcium hydroxide to remove fluorine ions by flocculation and precipitation. The waste liquors freed of fluorine ions are fed to an evaporating concentrating device, where they are separated into concd. liquor and distillate. The concd. liquor is incinerated in an incinerator, and the distillate is used again as washing water or water for preparing a soln. for the chemical treatment.