COLLECTORLESS FLOTATION OF DEREKOY-SEBINKARAHISAR/GIRESUN LEAD AND ZINC-SULFIDE ORE WITH SODIUM SULFIDE

A study on collectorless flotation of lead and zinc sulphide present in the Derekoy ore in the presence of sodium sulphide was performed. The parameters of the process and influence of sodium sulphide, zinc sulphide, conditioning time, pH and cleaning of concentrate were investigated. The results were compared with collector added flotation using several types of collectors

Shear flocculation of chromite fines in sodium oleate solutions

In this study, chromite fines were aggregated by stirring after the particle surfaces were made hydrophobic with sodium oleate. The effects of pH, sodium oleate concentration, stirrer speed and flocculation time were examined. Electrokinetic potential and contact angle measurements were also carried out to interpret the flocculation in terms of surface charge and particle hydrophobicity

3-dimensional measurements of morphological properties of particles

Morphological properties of particles are important in mineral processing. Flotation recoveries are affected by surface roughness and acuteness of particles. A novel technique was developed to measure the morphological properties of particles 3- dimensionally. Pyrite sample ground in autogeneous and ball mill to differentiate the surface properties was used in this study

Hydrophobicity of chalcopyrite with dithiophosphate and dithiophosphinate in electrochemically controlled condition

The degree of hydrophobicity of chalcopyrite was determined by contact angle measurements on polished chalcopyrite surface in electrochemically controlled conditions. Results have shown that the increase in solution pH adversely affect hydrophobicity due to heavy surface oxidation. Maximum contact angles were measured at moderately oxidizing potentials, which proposed that slight oxidation is necessary for a hydrophobic chalcopyrite surface. Sodium diisobutyl dithiophosphinate (DTPI) displayed better results than potassium diethyl dithiophosphate (DTP): even at highly oxidizing potentials, contact angle did almost not change in the presence of DTPI as compared with the collectorless condition and in the presence of DTP

Focusing on the combustion properties of binder added coal

Coal briquettes and their binders were always tested from the view of resistivity to transportation, loading and storage by measuring the abrasion index and strength to crushing. The binders used in coal briquetting also affect to the combustion properties of coal. Tuncbilek lignite sample and Polymer Laboratories PL-TGA 1500 thermogravimetric analyzer (TG/DTG) for the determination of the combustion properties of the sample were used throughout the research. Molasses, CMC, Sulphide Liquor, Corn Starch, Crude oil, Lime and Sodium Silicate were used as binders with a ratio of 10% by weight. Molasses and CMC decreased the activation energies of the samples and the residue at the end of the combustion. Crude oil, Sulphide Liquor and Corn Starch increased the calorific value of the samples, however they also increased the activation energies. II was observed that Lime and Sodium Silicate were the most disadvantageous binders by not only increasing the activation energies and residue at the end of combustion, but also decreasing the calorific values of the samples

Selective shear flocculation of chromite from chromite-serpentine mixtures

In this study, shear flocculation of chromite from mixtures of chromite and serpentine was investigated. The effects of zeta potential, contact angle, stirrer speed, flocculation (stirring) time, settling time and concentration of sodium oleate, Na2SiO3 and Na2SiF6 were tested. Control of zeta potential was the key factor for selective aggregation. Experiments carried out at optimum conditions yielded a concentrate (settled material) assaying 44.6% Cr2O3 with a recovery of 81.0% and selectivity index of 9.70 from a mixture containing 29.4% Cr2O3. (C) 1998 Elsevier Science B.V

Improvements on combustion properties of asphaltite and correlation of activation energies with combustion results

Processing of Sirnak Asphaltite sample by gravity and flotation concentration methods was investigated to decrease its ash content. Finely disseminated inorganic constituents of asphaltite revealed the difficulty of operation. Ash content of asphaltite was reduced from 44.86% to 31.44% by gravity concentration method with a 75% combustible recovery. On the other hand, it was possible to reduce ash content to 24% by flotation with almost same combustible recovery. Combustion characterization of raw and improved asphaltites was performed by non-isothermal thermogravimetric experiments. The data obtained were analyzed for the determination of activation energy of asphaltite samples. Processing proved to improve the combustion characteristics of asphaltite where activation energies showed the same trend with ash contents of asphaltite samples and decreased from 47.75kJ/mol of raw asphaltite to 30.24kJ/mol. As a result, activation energies were correlated with ash contents, calorific values, burn-out temperatures and sulfur contents of processed samples

Demineralization of Sirnak asphaltites by flotation

Demineralization of Sirnak asphaltite by flotation method was investigated. The effect of different parameters on the process such as particle size, collector type and amount, pH, pulp density, flotation time and cleaning of rougher flotation product was studied. Treatment with collector Accoal 18 (Cytec Ind. Inc.) at natural pH gave the highest recovery of combustibles and low ash yield. Flotation at pulp density 10% solid by weight and 2-min residence time gave the best result. As a result of single-stage flotation, ash content of asphaltite was reduced from 44.86 to 24.58%, and 71% of combustibles were recovered. Total sulfur content was reduced from 5.53 to 1.89%, and activation energy from 46.76 to 29.84 kJ/mol, respectively. Calorific value of asphaltite was increased from 4,380 to 6,070 kcal/kg

Effects of the shape properties of talc and quartz particles on the wettability based separation processes

Shape properties of talc and quartz particles ground by a laboratory size ball, rod, and autogenous mills were studied using scanning electron microscope (SEM). More than 100 particles were measured to do the shape analysis of each mill product. The wettability behavior of (gamma(c)) a highly hydrophobic of talc mineral was determined by contact angle measurements and microflotation tests using a contact angle goniometer and EMDEE MicroFLOT test tube, respectively. On the other hand, wettability (gamma(c)) of quartz, which is a highly hydrophilic mineral, was determined by the micro-flotation method only. The results showed that the particles ground by rod mill gave higher flatness and elongation ratio, which meant higher hydrophobicity with lower gamma(c) values in the separations by flotation method