No abstract

In this study, iron selectivity behaviour of copper smelter slag (CSS) flotation tailings (38.08% Fe, 0.35% Cu, 4.48% Zn, 0.16% Co, 0.37% S) having fayalite and magnetite as major minerals was investigated with hematitization baking and base metals leaching methods using mineralogical and chemical analyses. For selectivity of iron, it was baked at temperatures of 650-690-700-710-730°C. The aim of the baking is to transform the almost all of the iron in the fayalite into the oxidized (non-soluble) form and the base metals into the sulphated (soluble) form. The temperature that had the lowest hematitization rate of iron was found to be 650°C, and the highest temperature was found to be 730°C. To examine the dissolution behaviour of baked CSS flotation tailing was leached at 50°C at a 1/10 (w/v) for 1 hour by using water. After baking at 690°C calcine and leaching residue, S values were determinated to be approximately 17% and 9%, respectively. Baking made at 700⁰C, amount of sulfate also decreased to 10% and S content was measured as 4% of its leaching residue. As a result of this study, 690⁰C/700⁰C was determined as optimum conditions of hematitization baking and base metals were extracted selectively when the iron was remained at leaching residue in Fe2O3 phase. It was determined that, hematitization is high and the sulphates of the base metals are preserved at 700⁰C temperature. The fayalite phase completely decomposed into Si-O/Fe-O/Zn-S-O/Co-S-O compounds at 700⁰C baking which was the highest iron selective and base metals dissolute temperature.

Turkish metallurgical slag flotation tailing's (MSFT) that has not been evaluated yet sulphation baking phase transformations and autogenous leaching behaviour were investigated. The MSFT in the study consists of the residual fayalite (FeO•SiO2) phase from the flotation, with a copper recovery of 87%, of the slag released during the smelting of the copper sulphide mine in northern Turkey, and the non-soluble glassy/amorphous structure containing the 0.34%Cu, 4.16%Zn and 0.15%Co base metals locked and doped to this phase. The effects of temperature (350 -650°C) and sulphuric acid dosages (4-10 ml) on sulphation baking were investigated by X-ray diffraction and sulphur analyses of the baked MSFT (B-MSFT) to produce soluble base metal sulphates. Since sulphated metals are a kind of metal salt, autogenous leaching was applied to the B-MSFTs only with purified water to dissolute copper, zinc and cobalt. X-ray diffraction patterns show the transformation of fayalite to oxide and sulphate phases due to sulphation baking. All dissolution values of Co and Zn obtained by autogenous leaching of B-MSFTs produced under all determined conditions are almost the same as one another. This indicates that Co and Zn are doped to fayalite together and that part of cobalt is doped to the zincite structure and liberated and sulphated together. This study showed that MSFTs decompose leading to liberation and sulphation of the doped base metals in its structure at a rate of ≥90%, and that they autogenously dissolve under atmospheric conditions leading to recovery in a simple and economic manner.

Investigation mechanical and microstructural behavior of operated and unoperated turbine rotor discs Kullanılmış ve kullanılmamış türbin rotor disklerinin mekanik ve mikroyapısal davranışlarının incelenmesi Yazar(lar) (Author(s)

In this study, red mud was used to synthesis of calcium sulphate anhydrite (CSA) self-doped with SiO 2 for production bioceramic. The agitation sulphuric acid leaching method was used at atmospheric conditions to synthesis of CSA powder that was pressed as green body pellets for sintering procedure at a temperature varying from 800 °C to 1200 °C. After sintering, mechanical, chemical and in vitro tests were performed to determine the optimum parameters for bioceramic production. The in vitro tests were conducted to determine the biodegradability and bioactivity characteristics of sintered--CSA (S-CSA). CSA powder was synthesized at optimum leaching parameters (95 °C, 14 M H 2 SO 4 , 0.10 (w/v), 180 min.), its mineralogical composition was CSA (97.9 %) and SiO 2 (2.1 %). Density, compressive strength and hardness were reached 2.65 g•cm 114.67 MPa and 149.20 HV, respectively at 1100 °C of S-CSA pellets. As the temperature increased wollastonite/larnite phases formed. The homogenous bone-like structure hydroxyapatite phase was detected at 28 th day of the in vitro test. As a conclusion, bioactive CSA self-doped with SiO 2 could be produced directly from red mud in a single step, without using additional substances and that was obtained to ensure the use as a bioceramic.

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Bakır izabe curufu flotasyon atığına (CFA) daha önce literatürde ve endüstride hiç uygulanmamış pirit ilaveli asit kavurma işlemi sonrası liç ile baz metallerin ve liç atığı manyetik ayırma ile manyetik ürünlerin kazanımı çalışılmıştır. Çalışmadaki CFA, Türkiye’nin kuzeyinde bulunan sülfürlü bakır madeninin izabesi sırasında açığa çıkan curufun %87 bakır geri kazanılan flotasyonu sonucu kalan fayalit (FeO·SiO2) faz ve bu faza nüfuz etmiş (%0,34) Cu, (%4,16) Zn ve (%0,15) Co baz metallerini içeren çözünmeyen/refrakter camsı/amorf yapıdır. Piritli ve piritsiz asit kavurma işlemlerinin optimizasyonu için sıcaklıklar değiştirilirken (350⁰C -650 °C), asit miktarı 10ml H2SO4 olarak ve kavurma süresi 1s olarak sabit tutulmuştur. Asitsiz yapılan pirit kavurmada fayalit fazının bozunmadığı, 450⁰C’de yapılan kavurma ile 500⁰C, 550⁰C ve 650⁰C sıcaklıklarda elde edilen kalsinlerin X ışını kırınımı desenlerinin benzer olduğu tespit edien CFA için 350⁰C, 400⁰C, 450⁰C sıcaklıklarda 10 ml H2SO4 ve 1:4 pirit/CFA oranında pirit ilavesi yapılarak FeS2 ilaveli asit kavurma işlemi uygulanmıştır. Optimum piritli asit kavurma sıcaklığının tespit edilmesi için liç edilen kalsinlerin liç atıklarının X ışını kırınımı desenleri incelenmiş ve ana fazların manyetit, vustit, hematit ve fayalit olduğu görülmüştür. Liç atıklarının da değerlendirilebilmesi için gerekli olan manyetik ürünlerden vustit ve manyetit fazlarının en fazla görüldüğü koşulun 400⁰C’de yapılan piritli asit kavurmada açığa çıktığı tespit edilmiştir. Manyetik ayrımı gerçekleştirilen liç atığı ile elde edilen manyetik ürünün analizi sonucunda ana fazların manyetit olduğu görülmüştür.