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Öğe An experimental study on the ultra-fine grinding of gypsum ore in a dry ball mill(ELSEVIER SCIENCE BV, 2016) Oksuzoglu, Bilge; Ucurum, MetinGypsum is a crystalline form of hydrated calcium sulfate (CaSO4 center dot 2H(2)O) generally used in cements and plasters in the construction industry, though also in paints, fertilizers, medicines, papers, and textiles. For use in these materials, gypsum must be ground finely (<100 mu m), if not ultra-finely (<10 mu m), for which ball mills are most effective. Despite gypsum's widespread use and the regular need to grind it, studies concerning the grinding of gypsum ore remain scarce. In response, in this study, we have systematically investigated how certain grinding parameters (i.e., mill speed, ball filling ratio, ball size distribution, powder filling ratio, grinding aid ratio, and grinding time) of conventional dry ball mills affect the grindability of gypsum ore. We determined the properties of the micronized gypsum products obtained in optimal grinding conditions, and the results showed that the dry ball mill grinding process can effectively produce ultra-fine gypsum products. (C) 2015 Elsevier B.V. All rights reserved.Öğe Coal flotation optimization using modified flotation parameters and combustible recovery in a Jameson cell(PERGAMON-ELSEVIER SCIENCE LTD, 2010) Vapur, Hueseyin; Bayat, Oktay; Ucurum, MetinThis study discusses a new coal flotation optimization approach. It is conducted using modified flotation parameters and combustible recovery. The experimental work was evaluated in two stages. In the first stage, recoveries (1, 2, 3, 5 and 8 min of flotation times) of Jameson flotation operating parameters were fitted to first-order kinetic model, R = R(infinity) [1 - exp (-kt)] where R was recovery at t time, R(infinity) was ultimate recovery and k was the first-order rate constant to draw the time recovery curves in the experimental study. Two parameters, the ultimate recovery (R) and first-order rate constant (k), were then obtained from the model to fit an experimental time recovery curve. A modified flotation rate constant (K(m)) defined as product of R(infinity) and k, i.e., K(m) = R(infinity) * k, and selectivity index (SI) defined as the ratio of the modified rate constant of coal to the modified rate constant of ash (SI)=K(m) of Coal/K(m) of Ash), which could be collectively called "modified flotation parameters". It was used to determine of the sub and upper values of operation variables. In the second one, combustible recovery (%) and ash content (%) were used to optimization of the Jameson flotation variables and it was found that d(80) = 0.250 mm particle size, 1/1 vegetable oil acids/kerosene ratio, 20% solids pulp density, 0.600 L/min wash water rate and 40 cm downcomer immersion dept could be used to separate efficiently coal from ash. Final concentrate was obtained with 94.83% combustible recovery and 17.86% ash content at optimum conditions after 8 min flotation time. (C) 2010 Elsevier Ltd. All rights reserved.Öğe Evaluating the grinding process of granitic rocks using the physico-mechanical and mineralogical properties(Chulalongkorn Univ, Metallurgy & Materials Science Research Inst, 2019) Kahraman, Sair; Ucurum, Metin; Yogurtcuoglu, Emine; Fener, MustafaGranitic rocks are sometimes ground for different purposes. Predicting the mean particle size (d(50)) is useful for planning and cost estimation of purposes. In order to investigate the possibility of predicting the d(50) of ground rock from the physico-mechanical rock properties, six different granites were tested in the laboratory. First, the d(50) values were correlated with the corresponding physico-mechanical properties. The simple regression analysis showed that there were no good correlations between the d(50) and the physico-mechanical properties. Then, the multiple regression analysis was carried out and strong prediction equations were developed. It was also shown that the dominant parameter in grinding was the abrasive mineral content of rock. It is concluded that the d50 of granites can be predicted from the derived multiple regression equations especially for preliminary investigations. The developed estimation equations including index test values are especially useful since they are easy to use.Öğe Investigation of the cyanide leaching optimization for ultrafine grinding gold-silver ore(TAYLOR & FRANCIS INC, 2016) Birol, Onur; Ucurum, MetinIn recent years, the ultrafine grinding (UFG) process has become increasingly important for the recovery of precious metals (especially for Au and Ag) from raw ores. It is well known that cyanide leaching of gold-silver ore has been an accepted process in the world. In the current study, UFG was proposed as a pretreatment method prior to cyanide leaching of a gold-silver ore. First, the ore was crushed and ground by jaw, cone crusher, and ring mill, respectively. Particle size of ground product was 75 mu m based d(80). Second, the fine product was subjected to the grinding process by vertical wet stirred ball mill, and the final ultrafine product was used as leach feed material. The leach feed material had about d(80)=20 mu m and d(50)=6.02 mu m particle size. Some important leaching parameters were optimized by using the ultrafine powder in the study. The final leach experiments demonstrated that the recoveries of Au and Ag were 91.92% and 82.15% under optimum leaching conditions such as 150kg/t quicklime dosage, 25% pulp density, 85 degrees C leach temperature, 500g/t cyanide concentration, and 90h leaching time.Öğe MECHANO-ACTIVATED SURFACE MODIFICATION OF CALCIUM CARBONATE IN STIRRED MILL(INT SCIENTIFIC CONFERENCE SGEM, 2010) Ucurum, Metin; Yogurtcuoglu, EmineThe industrial importance of calcium carbonate as a filler in composite materials such as plastics, textiles, rubbers, paints, pigments and paper is well recognized and the application in the polymer industry is increasing. Therefore, surface modification is a key process in functional calcium carbonate powder preperation. In this study, surface modification of calcium carbonate particles, obtained Nigde region, using sodium stearate (SDS) and sodium oleate (SO) as modification agents incorporated with the simultaneous wet ultra-fine grinding in the laboratory horizontal stirred mill was investigated. The results indicate that the hydrophilic surface of calcium carbonate is turned into hydrophobic after modification with the reagents.Öğe Recovery of Silver from Waste Radiographic Films by Chemical Leaching(ASIAN JOURNAL OF CHEMISTRY, 2011) Arslan, Volkan; Ucurum, Metin; Vapur, Huseyin; Bayat, OktayThe major sources to recover silver are photo-processing solutions, spent rinse water, scrap film and scrap printing paper. As much as 80 % of the total silver processed for black and white positives and almost 100 % of the silver processed in colour work will end up in the fixer solution. The waste radiographic films used in the experiments were taken from Cukurova University, Balcali Hospital, Adana, Turkey and cut into small pieces. The film pieces (1-9 g) were boiled with 100 mL of various quantities of oxalic acid, nitric acid and sodium hydroxide solutions for about 2.5, 5.0, 7.5 and 10 min at boiling temperature (congruent to 97 degrees C). The aim of the study is to recover silver from waste radiographic films by HNO(3) leaching. To optimize the results of the experimental work, variance analysis was used. The statistical tests (F-tests) showed that nitric acid gave the best results compared with the other agents. Under optimum leaching conditions (radiographic films quantity, 50 g/L; nitric acid concentration, 30 g/L; stirring speed, 180 rpm; leaching time, 15 min) 89 % silver recovery was obtained.Öğe Surface modification of calcite by wet-stirred ball milling and its properties(ELSEVIER SCIENCE SA, 2011) Yogurtcuoglu, Emine; Ucurum, MetinThis paper investigates the surface modification of calcite from the Nigde region of Turkey with sodium oleate (SDO) as a modification agent, which is incorporated into the calcite with wet ultra-fine grinding in a laboratory stirred ball mill. The effect of surface modification is evaluated by a floating test, which measures the active ratio (AR), fourier transform infrared spectrometry (FT/IR) and thermogravity analyses (TG-DTA). The results indicate that the hydrophilic surface of calcite becomes hydrophobic after the incorporation of SOD through wet-stirred ball milling. (c) 2011 Elsevier B.V. All rights reserved.Öğe Wet Grindability of Calcite to Ultra-Fine Sizes in Conventional Ball Mill(TAYLOR & FRANCIS INC, 2015) Ucurum, Metin; Gulec, Omer; Cingitas, MuratAn experimental practice on the ultra-fine wet grinding of calcite ore in a conventional batch ball mill is reported. In this study, the effect of wet grinding conditions on the production of fine particles was researched. The influence of operating parameters such as operation speed (% of critical speed), ball filling ratio, calcite filling ratio, pulp density, ball size distribution, and grinding time on the grindability of calcite ore was systematically examined. Experimental results were evaluated on the basis of d(80) product size. As a result of this study, optimum experimental conditions were found to be 80% of critical speed for operation speed, 35% for ball filling ratio, 15% for calcite filling ratio, 75% for pulp density, 50% (1cm) and 50% (2cm) for ball size distribution, and 60min for grinding time. It was found that the best product has d(10)=1.51, d(50)=12.53, and d(80)=30.02 mu m particle size and its steepness factor is 3.75. The outcomes indicate that the wet grinding technique in conventional ball mill for calcite ore is effective to obtain ultra-fine size products.
