Ayfer Kilicarslan

The Effect of Ti Addition on the Properties of Al-B4C Interface: A Microstructural Study

In the present work, Al-B4C composites were produced by casting route at 850°C and titanium-containing flux was used to overcome the wetting problem between B4C and liquid aluminium metal. The microstructure of matrix/reinforcement interface was investigated using SEM studies with or without Ti added composites. The reaction layer was also characterized with EDS analysis and X-ray mapping. It was found from the microstructural observations by high resolution field emission gun SEM (FEG-SEM) that the wetting issue was effectively solved by the formation of very thin (80-180 nm in thickness) Ti-C and Ti-B reaction layers.

Use of ionic liquid in leaching process of brass wastes for copper and zinc recovery

Brass ash from the industrial brass manufacturer in Turkey was leached using the solutions of ionic liquid (IL) 1-butyl-3-methyl-imidazolium hydrogen sulfate ([bmim]HSO4) at ambient pressure in the presence of hydrogen peroxide (H2O2) and potassium peroxymonosulfate (oxone) as the oxidants. Parameters affecting leaching efficiency, such as dissolution time, IL concentration, and oxidizing agent addition, were investigated. The results show that [bmim]HSO4 is an efficient IL for the brass ash leaching, providing the dissolution efficiencies of 99% for Zn and 24.82% for Cu at a concentration of 50vol% [bmim]HSO4 in the aqueous solution without any oxidant. However, more than 99% of zinc and 82% of copper are leached by the addition of 50vol% H2O2 to the [bmim]HSO4 solution. Nevertheless, the oxone does not show the promising oxidant behavior in leaching using [bmim]HSO4.

Treatment of Industrial Brass Wastes for the Recovery of Copper and Zinc

A combined pyro-hydrometallurgical treatment processes involving leaching, cementation, electrowinning, and melting have been applied to industrial brass wastes, brass ash, and flue dust to recover copper and zinc. In the first stage, the effects of leach parameters on metal recovery ratio were studied. Almost all zinc was dissolved from brass wastes in conditions of 1 M H2SO4, 120 min, 60°C, 400 rpm stirring speed, and 1/10 solid liquid ratio. Negligible amount of copper was also dissolved in the same conditions and this copper could be precipitated by cementation. Pure zinc of 99.4% and 99.5% were produced by electrowinning of purified brass ash and flue dust leach solutions, respectively. Leach residue containing high amount of copper was melted with various fluxes and more than 99% of copper recovery ratio was achieved.

Application of 1-Methylimidazolium Hydrogen Sulfate Ionic Liquid to the Oxidative Leaching of Copper and Zinc in Industrial Brass Dross

In recent years, usability of ionic liquids in the extraction processes of ores and secondary raw materials has been attracted due to their promising potential as green solvents. In this study, 1-methylimidazolium hydrogen sulfate (HmimHSO4) ionic liquid and its aqueous solutions have been used as leaching media for the leaching of brass dross to recovery of copper and zinc in the presence of hydrogen peroxide (H2O2) as oxidant. The leaching experiments were carried out in the temperature range from 40 to 80°C at ambiance pressure with 100 g/L pulp density. The leaching behavior of copper and zinc has been discussed and the influences of ionic liquid concentration, leaching time and temperature on the metal recovery rate have been investigated. The results indicated that high copper and complete zinc extraction has been achieved under the optimum conditions.

Using of Boron Wastes in Red Brick Production

Large amounts of boron containing wastes are come into being during its extraction processes. The wastes consist of high amount of boron do not only cause economic loss but also serious environmental problems. Boron wastes contain boron oxide and clay can be used in the production of building materials, glass and ceramic. Utilization of boron pond waste from Eti Kırka Boron Works, Turkey in red brick manufacture was investigated. Adding different ratio of boron waste into the brick clay mixture, samples were formed. The pressed samples were fired at temperatures of 800°C and 900°C. The effects of boron waste addition on physical, mechanical and firing properties of red brick were examined by DTA-TG survey, three-point bending test, water absorption, porosity and bulk density tests. Microstructures of selected fired samples were also examined using SEM. Results shown that physical and mechanical properties of all samples were improved with boron waste addition. The best result was obtained when 20% of boron waste was used in the production.

Autocatalytic Ni-P and Ni-B Deposition on SiC Ceramic Particles

Ceramic particles like SiC have attracted great attention because of their usability as reinforcement for composite materials. Autocatalytic (electroless) nickel deposition is a unique process for the enhancement of the surface properties of ceramic particles. In this study, deposition of nickel phosphorus (Ni-P) and nickel boron (Ni-B) layer on SiC particles via autocatalytic plating in hypophosphite and borohydride baths was investigated. SiC powders were sensitized and activated respectively in order to ensure catalytic properties. Electroless nickel coating was carried from two different nickel ion sources (nickel chloride, nickel sulphate) following the pre-treatments of particle surfaces. Coated powders morphologies were characterized by transition electron microscope (SEM). X-ray diffraction and energy dispersive spectroscopy (EDS) analysis were used to investigate the chemical analysis of coating layers. The results showed that a better uniformity and bonding were obtained for Ni-P coatings with the Ni source of NiSO4.6H2+O as compared to NiCl2.6H2+O. For Ni-B coatings, the Ni2+ source of NiC12.6H2O has provided better quality and continuous coating layer on SiC surfaces.

Recovery of Metals from Waste Printed Circuit Boards by Leaching with 1-Ethyl-3-Methyl-Imidazolium Hydrogen Sulfate Ionic Liquid

The interest for the ionic liquids, which are environmentally friendly, is increasing day by day because of their high performance in recovery of metals. In this work, 1-ethyl-3methyl-imidazolium hydrogen sulfate ([Emim]HSO4) ionic liquid and its aqueous solutions were used as leaching media for dissolution of waste printed circuit boards (WPCBs) to recover of copper in the presence of hydrogen peroxide (H2O2) as oxidant. The effects of ionic liquid concentration, leaching time and temperature on the copper recovery rate were investigated. By the way dissolution behavior of iron was also determined. Leaching temperatures were selected as 25°C and 50°C. The results showed that recovery rates of copper and iron decreased with increasing ionic liquid concentration. Leaching time and temperature had positive effect on copper and iron dissolution. Higher dissolution rates were obtained with heat treated samples than not heat treated samples.