Thesis (E.M.)--University of Wisconsin--Madison, 1922. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1929. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 6, 2009) Includes bibliographical references (p. 47).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains x, 89 p. : ill. Vita. Includes abstract. Includes bibliographical references (p. 62-64).

Universiẗat, Diss., 1990--Paderborn.

No description available.

Thesis (MTech (Chemistry))--Cape Technikon, Cape Town, 2002 / The aim of the study was to develop an understanding of fine coal flotation emphasizing developing methodology capable of selecting the optimum flotation reagent. A secondary aim was to use the experimental data in a statistical program to validate the findings and investigate correlations between flotation performance and coal characteristics. The predictions that were made from the coal characterisation results were confirmed. Oleic acid, iso-decanol and dodecene resulted in the best flotation performance on the coal samples that were evaluated. This is in agreement with previous research findings, that oleic acid is a good collector for coal and that branched hydrocarbons also increase flotation yields. The ability of unsaturated hydrocarbons to increase flotation yield was also confirmed. The study included 5 coal samples from different collieries - Twistdraai (Highveld seam 3 and 4), Waterberg (Zone 10 -11), Syferfontein seam 5 upper (Highveld) and Witbank seam 2 and seam 4. Twistdraai, Waterberg and Syferfontein seam 5 upper were all found to be vitrinite rich coals. The Witbank coals are both more inertinite rich. The feed ash contents determined for the flotation feed samples were 28.8% for Twistdraai coal, 13.9% for Syferfontein seam 5 upper, 28.8% for Waterberg coal, 16.1% for Witbank seam 2 coal and 33.8% for Witbank seam 4 coal. The coal characterisation study included petrographic analysis, proximate analysis, float-sink analysis, oxygen-containing functional groups, surface extraction, flotation release analysis and contact angle measurements.

Ph.D. (Chemistry) / The effect of crystal defects on the adsorption and flotation properties of zinc sulphides was examined. Flotation experiments were restricted to collectorless flotation, that is to the flotation of untreated and copper-activated samples. The effect of cyanide treatment was examined only so that an explanation could be found for the bonding characteristics of the adsorbed copper on regions where the crystallography was undisturbed and on those where it was distorted. The electrochemical method for the determination of copper permitted continuous and highly sensitive monitoring of the copper adsorption on the sphalerites. The first part of the thesis concerns the adsorption of copper on synthetic zinc sulphide crystals and natural sphalerites. It is stated that the degree of adsorption depends on the defect structure. Structure etching, gamma-ray irradiation, and selective grinding experiments are shown to justify the conclusions reached. The second part of the thesis describes the flotation of the samples. The adsorption characteristics of the samples are defined in the first part and the adsorption and flotation properties are correlated.

In this research work, three types of flotation models (discrete, mean rate and the gamma function models) are modified based on the relationship between mass recovery and recovery. The modified models can be used to calculate both the recovery and grade of concentrate. Experimental work was carried out by using three different samples, which are chalcopyrite, coal and complex sulphide. In the chalcopyrite and coal flotation, air flow rate (AFR) was varied and different size fractions were considered in coal flotation. In complex sulphide flotation, the impeller speed (IPS) and air flow rate were varied, different size fractions were also considered individually. From the experimental results, the effect of air flow rate, impeller speed and particle size on the recovery and grade of concentrate are obtained, it is shown that an increase in air flow rate does not significantly increase recovery but reduce the grade of concentrate. High impeller speed can increase the recovery of fine and medium size, but it has very little effect on the coarse size. The effect of particle is that the medium size has the highest recovery in Fe minerals but the fine has the highest recovery in Zn and Cu minerals. The air flow rate, impeller speed and particle size affect on the kinetics of flotation is discussed from the model results. Where the modified models are used, the results show that an increase in air flow rate will increase the flotation rate of all size fraction, but an increase in impeller speed can only increase the flotation rate of the fine and medium size. The medium size has the highest flotation rate in most of the case.

M.Tech. (Extraction Metallurgy) / The techniques for the flotation of mixed copper and cobalt bearing oxide ores using the sulphidization method in order to recover the oxidized copper and cobalt bearing minerals have been well documented by previous researchers. These processes have been successfully implemented in many of the metallurgical plant operations in the Democratic Republic of Congo (DRC). The mixed copper and cobalt oxidised ores from this region present significant chal-lenges to metallurgists. Ore grades and gangue mineral constituents can vary quite significantly from one mine to another. Ore grades can also change substantially on an individual mine over a relatively short time period. These rather sudden ore feed grade changes can result in reduced flotation plant efficiency and hence losses in income. The prime objective of the project, to selectively recover and concentrate cobalt oxi-dized minerals by froth flotation, was not fully achieved on the ores tested. Very ac-ceptable cobalt recoveries were however achieved on three of the ores tested but it was invariably with an accompanying high copper recovery as well. Some valuable insights into the behaviour of both the cobalt and copper oxidized minerals in the froth flotation of these oxidized ores were observed and documented.

This work constitutes a fundamental study of the interaction between soluble sulphide,copper (II) oxide and cerussite particles in the presence of Ca²⁺ ,Mg²⁺ starch , gum arabic and Triton X- IOO . A detailed investigation of the effect of pH of the system on the rate of sulphide uptake was made . In addition , the structural form of the surface precipitat.es were determined with the aid of scanning electron microscopy . On the basis of these results , it was concluded that adsorption of sulphide on cerussite in the presence or absence of Ca²⁺ starch, gum arabic and Triton X-IOO could either lead to the formation of a non-uniform or a uniform sulphide layer depending on the experimental conditions . However , the interaction of copper (II) · oxide wi th soluble sulphide in the presence or absence of the above mentioned species always led to the formation or a non-uniform sulphide layer . Preliminary experiments of the interaction between xanthate and sulphidized surface showed that oxide surface covered with metal sulphide layer reacts with less xanthate than the free oxide surface.