Metin Uçurum

Effects of size distribution on flotation kinetics of Turkish sphalerite

Abstract The effects of size distribution on the flotation behaviour of sphalerite have been investigated in terms of kinetic parameters. In experimental studies, subsamples of a Turkish sphalerite ore were ground for different times using a laboratory ball mill. Timed batch tests were then undertaken using a pilot flotation column and the resulting recovery/time data were used in kinetic modelling. Results indicated that sphalerite floated rapidly at a medium particle size distribution (d80 = 0·125 mm in this case). In addition, a statistical analysis of data demonstrated that the flotation rate constant corresponded to a first-order model with rectangular distribution of floatabilities given by the equation: r = R∞(1-1/k 2 t[1-exp(-k 2 t]}

ENDÜSTRİYEL TABAN KÜLÜ ATIĞI İÇEREN KİL TUĞLA ÜRETİMİ

Sanayi tesislerinde taban kulu, komurun yanmasi ile ortaya cikan endustriyel bir artiktir. Soz konusu artigin kullanim alanin cok kisitli olmasi nedeni ile cevresel bir sorun olarak guncelligini korumaktadir. Bu nedenle, komur yakan tesislerde artik miktarinin azaltilmasi ve mevcut artiklarin degerlendirilmesi icin bircok arastirma yapilmaktadir. Ozellikle soz konusu artiklarin yapi teknolojisinde kullanilabilirligi yonunde umit verici gelismelerin oldugu bilinen bir gercektir. Bu calismada; %20’ye varan oranlarda yanmamis karbon iceren, Nigde Bor Şeker Fabrikasinin taban kulunun tugla uretiminde katki maddesi olarak kullanilabilirligi arastirilmistir. Sonucta, soz konusu taban kulunun, tugla uretiminde katki malzemesi olarak kullanilabilecegi ve atigin degerlendirilmesinde iyi bir alternatif oldugu belirlenmistir.

Stearik Asit Çeşidinin Kalsit Kaplama Verimi Üzerine Etkisi

Stearik asit, CH3(CH2)16COOH formuluyle gosterilen doymus bir yag asididir. Bircok sanayi dalinda kullanilan granul formdaki stearik asit, mikronize kalsit urunlerinin kaplanmasinda da genis olarak kullanilmaktadir. Piyasada farkli kodlarla satilan stearik asitlerin kalsit kaplamadaki verimlerinin arastirildigi bu calismada, kaplama islemi dik karistirmali bilyeli degirmen kullanilarak gerceklestirilmistir. Bes farkli stearik asitle (C1865, C1852, C1843, C1839 ve C1837) kaplanan kalsit urunleri onemli kalite gostergeleri olan aktive orani, kaplama orani, renk parametreleri (L*, a*, b*) ve tap yogunluk degerleri acisindan karsilastirilmistir. Kaplama icin en uygun stearik asit tipinin ise C1865 oldugu tespit edilmistir.

Fuzzy Statistical Process Control of a Calcite Grinding Plant Using Total Color Difference Parameter (ΔE)

Statistical process control (SPC) is one of the important approaches used in quality management. SPC can be applied in plants to obtain good quality and high standard products that have become very popular in many industries. Fuzzy process capability analysis by using X-R control charts gives more realistic results, developed with fuzzy theory. Fuzzy control charts are more sensitive than SPC. Therefore, fuzzy control charts lead to producing better-quality products. In this study, total color difference parameter (ΔE) was studied using fuzzy observation on a calcite grinding plant products. For this purpose, color parameters of the grinding plant products were evaluated using triangular fuzzy number (TFN) and fuzzy process capability indices (PCIs). The results show that the mill plant seems to be under control. Therefore, on a randomly selected sample used in the fuzzy statistical process control work was chosen and other color parameters such as whiteness index (WI), saturation index (SI), hue angle (H), browning index (BI) and yellowness index (YI) and particle size properties, XRF, XRD, FTIR, TGA-DTA and SEM were then determined on the calcite sample.

Wet Grindability of Calcite to Ultra-Fine Sizes in Conventional Ball Mill

An 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 d80 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% (1 cm) and 50% (2 cm) for ball size distribution, and 60 min for grinding time. It was found that the best product has d10 = 1.51, d50 = 12.53, and d80 = 30.02 µm 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.