Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Experiments were conducted to study the rate of oxidation of pyrite under conditions of varying pH, temperature and oxygen concentration. The rate of oxidation appears to be slightly increased below pH 3.00. In the basic range the oxidation is retarded as pH 9.00 is approached. Increases in temperatures cause increases in the rate of oxidation of pyrites. Corresponding decreases in the pH values are also noted. The rate of oxidation is increased by increaseing the concentration of oxygen. From these results, the possible use of pyrite in alkaline soils in the prevention of chlorosis caused by iron deficiency seems feasible.

This work represents the study of the biological oxidation of iron pyrite, FeS_2. The chief objective of the study was to investigate the possibility of biological oxidation of iron pyrite and to determine, if possible, the physical and chemical conditions under which the oxidative process occurs. The apparatus used to study the problem consisted of an air-lift percolator containing Ottawa sand as a dispersing medium for the finely divided pyrite. A nutrient solution which would support bacterial growth was the lixiviant. The microorganisms used in the study were autotrophic, iron-oxidizing bacteria obtained from the mine waters of Bingham Canyon, Utah. Studies were made by inoculating the solutions in the percolators with actively growing bacteria and comparing the amount of iron oxidized in the inoculated percolators with the amount of iron oxidized in a sterile, control sample. The effect of autoclaving, mercuric chloride, temperature, light, and carbon dioxide on the oxidative process was studied. The acidity produced in the oxidation of the pyrite was measured. The effect on the activity of the bacteria of ammonium ion and cupric ion was studied. The results of the above studies showed that iron-oxidizing autotrophic bacteria do oxidize iron pyrite. Sterile control samples contained only five percent of the amount of iron in solution that appeared in inoculated solutions. Autoclaving and mecuric chloride killed the micro-organisms and therefore stopped the oxidative process. A reduction in temperature to 0° C. decreased the bacterial activity by an average of eighty-seven per cent. The bacterial activity was increased when the reaction vessels were placed in total darkness. The absence of carbon dioxide or oxygen in the atmosphere of the bacteria slows down the oxidative rate. Results showed that the ammonium ion or the nitrate ion is necessary for the normal growth and activity of the microorganisms. The bacteria in the problem have a tolerance for high concentration of cupric ion. They grew and were active in 500 ppm Cu^++. The possibilities in converting discarded pyrite waste to useful ferric sulfate by biological oxidation should prove to be valuable throughout the Intermountain area.

No description available.

No description available.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand Johannesburg in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2013. / Artisanal and small-scale mining (ASM) has been a crucial industry in Africa for centuries. In Burkina Faso approximately 95 kms northeast of the capital city Ouagadougou near the village of Dem and on a ferricrete capped ridge to the west of the village, it is possible to find a number of opencast workings and underground mines that show evidence of extensive artisanal mining for iron. Iron mining worked quartz-vein hosted and lateritic ore. Nearby, waste piles, processing sites and at least eleven (11) Bloomery furnaces are exposed on the alluvial plain. Petrographically the ore bearing rocks consist of goethite-hematite as the dominant oxides with silica. Geological and ethnographic studies conducted in 2011 focussed on detailing and mapping the mine site and host rocks (including ore rocks), and establishing the age of mining, processing and forging of ore. Selected charcoal samples were collected from furnaces sites. Limited AMS radiocarbon dating of six (6) samples was performed at Beta Analytic laboratory in Miami, Florida, USA and suggested that iron forging may have begun in the 15th century, which could also be the age of mining and processing of ore. The site has characteristics such as impure slag, eleven (11) large furnaces, hundreds of tuyeres, and crucibles, and clay fragments. Remnant slag samples were collected for petrographic and mineralogical study to deduce the mineral composition of the slag. The slag samples contained high concentration of fayalite, quartz, magnetite and hematite and low concentration of iron metal and ulvospinel suggesting an iron silicate slag of low melt temperature was formed in the furnaces.

Thesis (M.Phil.) - University of Queensland, 2006. / Includes bibliography.

Thesis is submitted in partial fulfilment of the requirements for the degree of Master of Science in Engineering to the Faculty of Engineering and the Built Environment, School of Mining Engineering, University of the Witwatersrand, Johannesburg, 2018 / Iron ore prices rallied from USD15/DMT during 2004 and experienced a significant drop from USD 140/DMT during the latter part of 2013. The purpose of the work is to identify the key drivers impacting on iron ore demand globally. Understanding the supply and demand balance and impact on price, is key to informed decision making relating to the iron ore business. The research methodology applied largely followed a quantitative methodology. Key drivers of iron ore demand, supply and demand balance and the impact on price were evaluated. The method applied consisted of gathering data from secondary sources and a detailed quantitative analysis on GDP, stage of economic development, steel consumption, supply and demand of iron ore and intensity of use. Approximately 98% of all iron ore is used for steel making and on that basis steel consumption is the primary driver for iron ore demand. Steel is mostly used for construction and manufacturing and is driven by emerging economies of which China is currently the largest contributor. Global GDP growth correlates well with steel consumption and is primarily driven by emerging economies. Urbanisation was and still is a key driver for construction in China, to provide housing and related infrastructure for transportation and services. Scrap steel recycling, currently at 15%, affect the demand for new steel and indirectly iron ore. Iron ore is abundant and can easily meet the demand. The significant growth from 2004/5 to 2013/14 and the unprecedented demand for steel resulted in elevated iron ore prices, introducing high cost iron ore, predominantly from Chinese State owned companies. From late 2013, the iron ore prices reduced significantly. This was mainly due to the steel consumption in China slowing down; delivering of large scale, low cost iron ore projects in Australia and Brazil and a significant reduction in oil prices. The key drivers impacting iron ore demand is: global GDP growth, industrialisation and urbanisation of emerging economies, recycling of steel, supply and demand balance of iron ore, the cost of production and the price of global iron ore. For the medium term outlook, the iron ore market will be structurally over-supplied and, as a result, the demand could be met at significantly lower cost of production levels than that seen during the period leading up to the price collapse in 2013. This is primarily because of the increase in low-cost supply from the major suppliers displacing higher cost producers. China will continue to grow and drive the global demand for steel and iron ore during the medium term albeit at much lower rates when compared to the last decade. The demand for steel will increase until 2020 according to various analyst views. The iron ore prices are expected to trade between USD50/DMT to USD70/DMT from 2016 to 2020 mainly because of the over-supply situation and demand being mostly met by large scale, low-cost producers. The decision around the continuation of high cost, state owned Chinese iron ore producers, new large-scale low cost production and the oil price will impact on the price outlook. / MT2018