Hasan Çiftçi

Biodegradation of cyanide containing effluents by Scenedesmus obliquus.

Biological degradation of cyanide has been shown a viable and robust process for degrading cyanide in mining process wastewaters. Several algal cultures can effectively degrade cyanide as carbon and/or nitrogen source for their growth. In this study, cyanide effluent degradation by Scenedesmus obliquus was examined. Gold mill effluents containing WAD cyanide concentration of 77.9mg/L was fed to batch unit to examine the ability of S. obliquus for degrading cyanide. Cyanide was reduced down to 6mg/L in 77h. Microbial growth and metal uptake of Zn, Fe and Cu was examined during cyanide degradation. The cells well adapted to high pH and the effluent contained cyanide and the metals. It is important that Zn level reduced down 50%, of the starting concentration. pH was kept at 10.3 to prevent loss of cyanide as HCN, due its volatile nature. The bio treatment process was considered to be successful in degrading cyanide in the mine process water.

Metals recovery from multimetal sulphide concentrates (CuFeS2–PbS–ZnS): combination of thermal process and pressure leaching

Abstract A laboratory-scale method for treating a bulk concentrate (CuFeS 2 –PbS–ZnS) for metals recovery was developed utilising a combination of thermal process (roasting) and pressure leaching as an alternative to conventional pyrometallurgical processing. Pyrometallurgy is becoming less acceptable from environmental standpoints for the treatment of bulk concentrates. Additionally, high capital costs make modern facilities cost prohibitive. The leaching agents employed, namely, sulphuric acid (lixivant) and ferric sulphate, are selective for metal sulphides, this coupled with the fact that they create fewer environmental problems and are economical makes this new process highly favourable. In the laboratory evaluation of this process, the metal values in the flotation concentrates were selectively recovered by combining roasting and pressure leaching. The experimental parameters studied included roasting temperature, and pressure leaching pulp density, temperature, and retention time. Laboratory results indicate that roasting followed by pressure leaching is an efficient and cost effective method of treating base metal sulphide concentrates.

Settling characteristics of coal preparation plant fine tailings using anionic polymers

The objective of solid-liquid separation in thickeners in coal preparation plants is to obtain both a clear supernatant liquid with a low turbidity for reuse and a dense slurry. It is important for the smooth operation of the plant to produce good-quality recirculation water. In this study, settling characteristics of coal tailings (d80=70 μm) taken from the thickener feed of Derekoy Coal Preparation Plant (Manisa, Turkey) were investigated with the use of anionic polymers. In the tests we determined the effects of the process parameters including polymer type, polymer dosage, temperature, suspension pH, and pulp density on the flocculation of the fine tailings of the coal preparation operation. Minefloc anionic polymer showed a better flocculation performance in comparison with other polymers. An optimum settling rate of 300 mm/min was reached at a dosage of 30 g/t-solids, a pulp density of 5%, pH 7.9, and temperature 25 °C using Minefloc polymer.

Kolemanit Artığının Mekanik Aşındırma ve Isı ile Dağıtma Yöntemleri ile Zenginleştirilmesi

This study investigates the upgrading possibilities of the tailings of Eti Maden Bigadic Boron concentration plant. Firstly, it was planned to compose a pre-concentrated product by way of clay removal from tailing in the experimental studies. The tailing samples have been tested by attrition scrubbing method in a constant stirring rate and in the several pulp densities. From these tests, a preconcentrate containing 23.78% B2O3 grade was produced. The decrepitation experiments were applied on the pre-concentrate to profit from the disintegration of colemanite minerals by heating in order to obtain a higher grade concentrate. As a result of the decrepitation tests, a concentrate containing 45.57% B2O3 grade was obtained with a recovery of 88.47% B2O3