IMMOBILIZATION OF PHOSPHATING SLUDGE IN INORGANIC MATRIXES

Abstract

Phosphating is the most widely used form of metalpretreatment. Although the process was initially developed as asimple method of preventing corrosion, the changing end usesof phosphated articles have forced the modification of theexisting processes and the development of innovative methodsto substitute the conventional ones. Almost all mass-producedarticles fabricated from sheet metal will be treated in this way.

Maintenance of the bath parameters and operatingconditions at an optimum level is a complicated process,especially in continuous and largescale phosphating. Moreover,baths that have been used for a long time are renderedineffective due to the formation of sludge. It has to be removedperiodically to assure a proper bath operation. This reviewarticle discusses the methods and possibilities of phosphatingsludge removal and inertization. The reviewed studies show apossibility to immobilize phosphating sludge, using ceramicmatrix vitrification or clinkerization processes. Heavy metalcontainingsludges have a potential to be utilized as alternativeraw materials in cement, ceramics and glass production.

http://dx.doi.org/10.5755/j01.ct.57.1-2.661