Muhlis Nezihi Saridede

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.

Investigation on microwave heating for direct leaching of chalcopyrite ores and concentrates

The use of microwave energy in materials processing is a relatively new development presenting numerous advantages because of the rapid heating feature. Microwave technology has great potential to improve the extraction efficiency of metals in terms of both a reduction in required leaching time and an increase in the recovery of valuable metals. This method is especially pertinent in view of the increased demand for environment-friendly processes. In the present study, the influence of microwave heating on the direct leaching of chalcopyrite ores and concentrates were investigated. The results of microwave leaching experiments were compared with those obtained under conventional conditions. During these processes, parameters such as leaching media, temperature, and time have been worked to determine the optimum conditions for proper copper dissolution. Experimental results show that microwave leaching is more efficient than conventional leaching. The optimum leaching conditions for microwave leaching are the solid-to-liquid ratio of 1:100 g/mL, the temperature of 140°C, the solution of 0.5 M H2SO4 + 0.05 M Fe2(SO4)3, and the time of 1 h.

The Effect of Reduction Parameters on Iron Nugget Production From Composite Pellets

Composite pellets which contain a reducing agent and are produced only by cold bonding process are improved instead of traditionally hardened pellets by sintering. The new ironmaking technologies that are able to utilize these pellets have been developed from pilot plant to commercial scale. Iron nuggets which have a similar composition to pig iron can be produced by using composite pellets at high temperatures (1350–1400°C) and in a short reduction time (15–20 min) by smelting reduction process. In this study, the effect of reduction parameters and basicity of composite pellets on the reduction properties and product quality are investigated. Composite pellets containing magnetite concentrate with a reducing agent (coke) and a flux are processed at different temperature and at times by smelting reduction process. The increasing temperature and time has a positive effect on reduction and melting of the pellets. Excessive carbon prevents the metal droplets from coalescing. The iron nugget that is produced from the sample with the basicity (CaO/SiO2) of 0.68 has the optimal physical and chemical properties. It is also determined that a decrease or increase of basicity has a negative effect on the properties of the iron nuggets.

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.

The Effect of Slag Optical Basicity on Alloying Element Losses of Steel by Electroslag Remelting (ESR)

Slag properties affect the efficiency of Electro Slag Remelting (ESR) process by removing the quality impairing elements (S, P, etc.), while avoiding valuable alloying element losses. Therefore, a relation between element losses and optical basicity of slags, which may be assumed to be an enhanced approach to basicity concept, would play a crucial role on predicting and selecting the optimum slag composition for ESR process. The primary contribution of this paper is to investigate the effect of optical basicity of various slags on the composition change of high sulphur containing AISI 12L14 (DIN11SMnPb37) free-cutting and AISI M2 (DIN HS6-5-2C) high speed steels. For this purpose steel bars were remelted under different slag compositions at constant melting conditions. According to the chemical analysis of the products, it was observed that the element losses increase related to increasing optical basicity of slags. On the other hand, these alloying element changes show variety on steel types. High speed steel shows a relatively low alloying element changes due to its high carbide content, while higher losses were discovered in free cutting steels.

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.

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.

Utilization of waste polyethylene terephthalate as a reducing agent in the reduction of iron ore composite pellets

The increasing consumption of plastics inevitably results in increasing amounts of waste plastics. Because of their long degradation periods, these wastes negatively affect the natural environment. Numerous studies have been conducted to recycle and eliminate waste plastics. The potential for recycling waste plastics in the iron and steel industry has been underestimated; the high C and H contents of plastics may make them suitable as alternative reductants in the reduction process of iron ore. This study aims to substitute plastic wastes for coal in reduction melting process and to investigate their performance during reduction at high temperature. We used a common type of waste plastic, polyethylene terephthalate (PET), because of its high carbon and hydrogen contents. Composite pellets containing PET wastes, coke, and magnetite iron ore were reduced at selected temperatures of 1400 and 1450°C for reduction time from 2 to 10 min to investigate the reduction melting behavior of these pellets. The results showed that an increased temperature and reduction time increased the reduction ratio of the pellets. The optimum experimental conditions for obtaining metallic iron (iron nuggets) were reduction at 1450°C for 10 min using composite pellets containing 60% PET and 40% coke.

Reflotation of Mt. Isa Zinc Concentrate after SO2 Leach Treatment

Laboratory flotation tests were carried out on the SO2 leaching residues of zinc concentrates of Mt. Isa lead–zinc concentrator. In the evaluation of these tests grades, recoveries and separation index values of the metallic elements are used. Separation index value of a metallic element is a new concept proposed in this paper and is useful in the evaluation of any concentration process. In the bulk concentrates obtained after flotation tests, the grades, recoveries, and separation index values of silver were around 900–1000 ppm, 18–20%, and 17–19, respectively.