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Pyrite ash is created as waste from the roasting of pyrite ores during the production of sulphuric acid. These processes generate great amounts of pyrite ash waste that is generally land filled. This creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be utilized in the iron production industry as a blast furnace feed to process this waste and prevent environmental pollution. The essential parameters affecting the pelletization process of pyrite ash were studied using bentonite as a binder. Experiments were then carried out using bentonite and a mixture of bentonite with calcium hydroxide and calcium chloride in order to make the bentonite more effective. The metallurgical properties of pyrite ash, bentonite, calcium hydroxide, calcium chloride, a mixture of these and sintered pellets were studied using X-ray analysis. The crushing strength tests were carried out to investigate the strength of pyrite ash waste pellets. The results of these analyses showed that pyrite ash can be agglomerated to pellets and used in the iron production industry as a blast furnace feed. The crushing strength of the pellets containing calcium hydroxide and calcium chloride in addition to bentonite was better than the strength of pellets prepared using only bentonite binder.

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In this study, zinc borate (ZB) was synthesized by reacting zinc oxide and boric acid in the presence of standard ZB (w/w, in terms of boric acid) in order to promote crystallization. The effects of seed, H₃BO₃/ZnO (boric acid/zinc oxide) ratio, reaction time, water volume, reaction temperature and cooling temperature on yield were investigated for pilot-scale equipment. The results indicated that the addition of seed (w/w) to a saturated solution of reactants increased the yield of the reaction. The results of reaction yields obtained from either magnetically or mechanically stirred systems were compared. At various reaction times, the optimal yield was 86.78 % in a saturated aqueous solution. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric / Differential Thermal Analysis (TG/DTA). The results displayed that ZB was successfully produced under the optimized reaction conditions and the product synthesized had high thermal stability.

DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4432

In Turkey, pyrite ash is created as waste from the roasting of pyrite ores in the production of sulfuric acid. These processes generate great amounts of pyrite ash waste that creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be used in the iron production industry as a raw material because of its high Fe(2)O(3) concentration. The aim of this study was to investigate the reduction behaviour of pyrite ash pellets. The pyrite ashes were reduced to obtain the iron contained in pellets. Pyrite ashes samples were pelletized dried at 105 degrees C for 24 h and sintered at 1200 degrees C for 30 min. then reduced in a pressure of 4 atm. under argon gas. The mineralogical transformations that occurred during reduction were analysed by X-ray diffraction and X-ray fluorescence. The X-ray diffraction and X-ray fluorescence measurements of these samples showed that Fe(3)O(4) was successfully reduced to a metallic iron phase in a laboratory-scale electric arc furnace.

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