Sulphate removal and an example at the facility which producing welding wire

ABSTRACT Reducing sulphate waste discharcing from the industrial facility which producing welding wire to sewage system, was observed. In this facility rolled iron wire is plated with copper in copper sulphate solution as chemically. Waste of factory consists of high concentrated sulphiric acid, copper (II), iron (II) and iron (IH) sulphates. More than half of the sulphate in the waste water comes from the sulphiric acid. In the study although it was tried to be balanced of material to reduce the waste, couldn't be succeded properly. At the end of experiments, reducing of sulphiric acid was concluded at the bath. Then it was tried to be purified the waste which consists of sulphiric acid, copper sulphate and iron sulphate. It was made waste characterization of wastewater, also precipitation was made while using composite sample. A limestone sand which is called filler, cheap and used in constructing industry was tried as an chemical precipitant. It is aimed to precipitate sulphate in calcium sulphate form, and also to precipitate metals in their hydroxide form, by using calcium carbonat as chemical agent. Instead of other chemical precipitate agent limestone was prefered, because of cheap and harmless. Being acidic of waste is suitable to use limestone. In the lab studies, the composite sample were prepared as a mixture of waste from acid bath, from copper bath, and from washing water bath in a ratio to observe the best treatment opportunities. In the frame of the thesis, treatment of sulphate was researched for solubility of calcium sulphate, but agglomeration velocity was not determined during in the study In trials, which were done with limestone, sulphate treated very well, but the effluent concentration from the reactor was higher value than the discharcing standarts. Also pH which tried in the study, was not enough to reduce metals into the wastewater. So after the chemical precipitation was made with using limestone and lime. Keywords: sulphate treatment, calcium sulphate, limestone, solubility, copper removal, waste minimization. IX