Scientific Mining Journal

ABSTRACT

Phosphate ore is one of the most critical raw materials for all living things (plant, animal, and human), according to the European Commission report which explains the importance of economical and supply risk of raw materials. Therefore, the evaluation of low-grade phosphate ore is of vital importance. In this study, the selective removal of carbonate minerals (calcite and aragonite) from phosphate ore was investigated by using calcination sucrose leaching processes. The sample used in this study was characterized by X-ray diffraction (XRD), Termogravimetric (TG), and X-ray fluorescence (XRF) spectroscopy, respectively. The effect of calcination temperature (750, 850 and 900 ˚C) and calcination duration time (15, 30, 60, 90, and 120 min) were examined. Leaching tests were performed with various sucrose concentrations (0, 0.25, 0.50, 1, 1.50, 2 M) at different stirring speed (0, 150, 300, 450 rpm) during several times (15, 30, 60, 120, 180 and 240 min). As a result, the selective removal of carbonate minerals from phosphate rock was provided although unwanted CaSiO3 mineral was formed during the calcination process due to its high quartz content.

ABSTRACT

The possibility of using metaschist as an alternative to claystone which is used as the main input in cement production has been investigated. In the experimental work, the metaschists and claystone were used to produce cement separately from the raw materials from their fields, and their qualities were determined. As a result of the tests carried out, it was understood that corrective ingredients (iron ore, bauxite etc.) would be needed in order to use the claystone because of its high SiO₂ (silicate modulus 3.97) content. On the other hand, with the metaschist sample, it has been shown that it can form a raw meal composition singularly without the need for any corrective ingredients. Although, in the raw meal composition, the silicate module was found to be low (2.07) the aluminum module was high (2.43), They were found to be within the cement quality parameters. As a result of detailed mineralogical studies, it has been determined that the metaschist has a quartz content about 13% lower than claystone. Knowing that the quartz content is considered to have adverse effects on many production processes such as grindability, burnability and abrasion, it can be argued that the use of metaschists results in the production of cement being more economical and of good quality due to its mineralogical structure.

ABSTRACT

In this study, effect of activation conditions on the recovery of aluminum (Al) obtained by acid leaching from Pütürge (Malatya) pyrophyllite ore containing 23.6% Al2O3 was investigated. In this context, the initially non-activated ore and later activated ore samples using calcining and intensive milling were leached with HCl, separately. According to the experimental results, Al-recovery in the leachate for the raw, calcined and intensively milled ore samples were found to be 10.57%, 33.63% and 86.5%, respectively. It was also found that there was not sufficient dilation between the clay layers during calcination and the porous structure could not be obtained, also the new mineral phases which resist to dissolution in acidic media were formed at high temperatures. For this reason, the aluminum recovery of thermally activated ore was relatively low. However, it was confirmed that mechanical activation by intensive milling led to amorphization of clay minerals, and thus, the mechanical activation significantly improved the dissolution behavior of aluminum. As a result of this study, it is concluded that while Al recovery is slightly increased by thermal activation, it is dramatically increased by mechanical activation.

ABSTRACT

In case the mine enterprises do not meet some legal requirements, they face a decision to stop the activity. The reasons that are effective in the decision to stop the activity vary according to the mine groups. In this study, the distribution according to the mining groups of mining enterprises operating in Eskisehir province, employee employment and the reasons of activity stopping were examined Within the scope of this study, distribution of mining enterprises operating in Eskisehir between 2014 - 2017 according to mining groups, the employee employment and reasons for stopping of operations were evaluated according to the Law on Occupational Health and Safety No. 6331 and the Mining Law No: 3213. It was determined that 78% of the reasons of activity stopping were caused by the failure to comply with legal regulations on occupational health and safety and the solution proposal was presented. In addition, the interactions between the reasons for stopping activity and mining groups were examined by using hierarchical loglinear analysis.

ABSTRACT

In this study, a brief overview of the solvent extraction (SX) application for the separation and purification of nickel and cobalt in hydrometallurgical processing of laterite nickel ores is presented. This paper consists of two parts: firstly, the SX of nickel and cobalt from sulphate leach solutions is described; and secondly, the development of hydrometallurgical plants for the processing of laterite nickel ores that involve solvent extraction technique is discussed. The most important extractants are shortly given in the first part of the study. It is seen that the extraction and separation of nickel and cobalt from the impure leach solution of laterite nickel ores can be performed by either using a single extractant system that is called as a direct solvent extraction (DSX) or a mixture of two or more extractant which is known as a synergistic solvent extraction system (SSX). Mixed sulphide precipitation (MSP) and mixed hydroxide precipitation (MHP) processes are mentioned. This paper is also addressed advantage and disadvantages of each extraction system. It is shown that capital investment expenditure, operational investment expenditure and mineralogical content are the most important factors that can affect the selection of the appropriate hydrometallurgical process for lateritic nickel ore.

ABSTRACT

Coal tends to adsorb oxygen and oxidize due to its structure. Spontaneous combustion mechanism of coal is very complicated, and still this mechanism is not completely understood. However, coaloxygen compound theory is widely accepted by researchers nowadays. According to this theory, spontaneous combustion consists of slow oxidation, accelerating oxidation and rapid oxidation stages. In these stages, the physical oxygen adsorption, chemical oxygen adsorption and free radicals reactions are the dominant mechanisms, respectively. Spontaneous combustion of coal can occur without any external impact anywhere coal and / or coal wastes exist. Nowadays, its revealed that some common thoughts about the effecting parameters on spontaneous combustion of coal are wrong. For example; spontaneous combustion of coal does not occur only in low rank coals, and high pyrite content coals may have low spontaneous combustion tendency or coal mines which were determined as not risky can unexpectedly combust. Therefore, spontaneous combustion tendencies of coals must be determined; all stages such as mining, stockpile design and transportation must be planned in detail; continuous monitoring and emergency response plans must be arranged in case a spontaneous combustion.