Thermal Activation of Kaolin: Effect of Kaolin Mineralogy on the Activation Process

Kaolin is an industrial mineral used in a wide variety of applications due to its crystalline structure, mineral and elemental composition. After kaolin undergoes heat treatment in a specific temperature range, metakaolin, which exhibits a strong pozzolanic reaction, is formed. This paper examines the effects of different kaolin qualities on the thermal activation process of metakaolin production. The qualities of kaolin depend on the impurities they contain, such as mica, feldspar and quartz. In this study, four different samples of kaolin are investigated. Each sample was heat treated in a lab-scale rotary kiln in order to study the chemical, structural and morphological changes that occurred and their influence on pozzolanic activity. The parameters being considered in the experimental process were the temperature and the duration of the treatment. Thus, the calcination process for each of the four kaolin types was carried out at 600, 650 and 700 °C for 3 h. The occurred changes were monitored using XRD, FTIR and DTA analysis. Additionally, the reactivity of all thermally treated samples was evaluated based on the Chapelle test. The results showed that the fewer the impurities, the easier the transformation of the material to metakaolin. The optimum result was the metakaolin, which originated from the purest quality of kaolin and was comparable to the commercial product. Finally, the pozzolanic activity of the thermally activated samples also depended on the purity of the kaolin.

INFLUENCE OF THE CHEMICAL COMPOSITION OF LIMESTONE ON THE DEVELOPMENT OF MINING WORKS IN QUARRY

There are only a few limestone mines in Bosnia and Herzegovina that provide the mineral raw material for industrial production. As a result, the experience in planning and designing such quarries is lesser than in designing the quarries for construction. Limestone from "Vijenac" deposit is an industrial mineral raw material, which is used for the production of soda (light, heavy and bicarbonate), cement, nitrogen fertilizer named "KAN", and is also used in construction and road construction. The use of limestone as a mineral raw material in industrial production requires more attention to the chemical composition of limestone than to the physical-mechanical characteristics. The paper presents a solution to this problem by creating a block of models of exploitation reserves of limestone, which enables foresight of the chemical composition of limestone, both in each floor partially and during the period of exploitation. The block model was created on the basis of the updated state of works, the projected contour of limestone surface mine and the exploration works' database. The block model uses the following: CaCO3, CaO, SiO2, Al2O3, Fe2O3, bulk density, category of reserves and the purpose of the mineral raw material, i.e. for industry or construction. The block model analysis has determined that the northern part of the mine, from the floor E-612.5 to E-525 meters a.s.l., does not meet industrial requirements in terms of chemical composition of limestone. Therefore, limestone from this part of the surface mine will be used for construction purposes. These quantities of limestone are about 2.6x106 m3. Limestone from the southern part of the surface mine meets the industry requirements. Its quantities are about 8.47x106 m3.

Creation of Backfill Materials Based on Industrial Waste

The possibility of replacing the traditional components of the filling mass with man-made waste and the need for the use of mechanical activation of the components of the filling composite in order to improve its rheological characteristics and the strength of the mass after solidification are proved. The demand for resource-reproducing technologies that allow the most complete use of the industrial mineral resource potential of the mining and processing enterprise, which will lead to a multiplicative ecological and economic effect, is confirmed. It is necessary to introduce the re-processing of man-made waste in order to further extract the useful component to a level that meets the standards of environmental safety and economic feasibility, which would create conditions for the actual sustainable development and give some perspectives for extending the operating time of mining regions. It is established that the sustainable development of the mining and processing region is impossible without a highly efficient exploitation of natural deposits and man-made georesources in combination with an integrated approach to the development of subsurface resources.

Python-based Fuzzy Control of Ore Feeding System

Using Python as a programming language, this study investigates the problem of controlling the ore amount in the field of mineral processing. First, data on the influencing factors collected from a certain beneficiation mill in Yuanyang are quantitatively analyzed using the NumPy module library. Factors having a greater influence are screened out and then selected as the input while the motor frequency is generated as the output by the fuzzy control algorithm developed using the SciKit Fuzzy module library. The range of values of the fuzzy control variable is defined, the fuzzy membership function is generated, and the fuzzy control rule is established. Finally, the fuzzy controller is activated to realize fuzzy control of the mine. The NumPy algorithm can be effectively applied to the quantitative analysis of data, and the calculation results are reasonable and interpretable. The simulation results are as follows: the hardness of the raw ore and the weight of the belt scale are the key factors for controlling the ore amount, and they can be used as the input variables of the fuzzy control system. The fuzzy controller developed using the SciKit Fuzzy module library can be effectively applied to the field of mineral processing, and it overcomes the limitations of current computer technology in industrial mineral processing.

Control of properties and structure of steel vessels by cooling in various media at the outlet of rolling and pressing lines

When controlling the mechanical properties and structure of vessels made of carbon structural steels manufactured by hot deformation on rolling and pressing lines (PPL) of machine-building enterprises of Russia, such cooling media as water, I20 industrial mineral oil, air are used. The applied cooling media are able to provide the workpieces with a given structure with a wide range of mechanical properties. However, the cooling media have a number of technological limitations and conditions of the use, non-compliance with which leads to reject. When cooled in oil, the probability of ignition is high; when cooled in water, hardening cracks may form, and air is not always able to provide the required rate and uniformity of heat transfer to the environment. The efficiency of control of physical and mechanical properties and structure of deformed vessels made of 50 steel by cooling in TERMAT polymer aqueous solutions in different concentrations on PPL of the plant of JSC NPO Pribor was studied. The effect of varying the concentration from 2 to 9% of TERMAT polymer on the formation of metal structure, as well as physical and mechanical properties of hot-deformed vessels was studied. The results of testing the strength and plastic characteristics of vessels by destructive and non-destructive control methods are presented. According to the results of physical and mechanical properties, regression equations were obtained with at least 95% reliability of R2, which establish the relationship between the controlled plastic and strength parameters of the vessel metal`s properties. The conducted researches allowed to compare the indicators of the main physical and mechanical properties of steel vessels at the PPL outlet and to propose methods of inhomogeneity control that reduce time and material costs by 5–10% during the tests.

LARGE MINERAL ACTIVITY: A SOCIAL, ECONOMIC AND ENVIRONMENTAL APPROACH THROUGH GEOTECHNOLOGIES

Mining is one of the most important economic activities in Goiás, and it is necessary for the municipalities. The abundance of some mineral substances in the state makes Goiás a desirable location for large extraction companies. This research paper outlines that landscape alteration is inevitable, as it is necessary to remove natural areas for the exploitation of minerals. Agricultural areas could be effected by this process. This paper is discussing a evolution of mining activity that was done with the corporation of Alto Horizonte between 1985 and 2015, observing intervals of a decade, and relating this change to the socio-economic data of the municipality. Remote sensing techniques were used in conjunction with Geographic Information System (GIS), two such techniques include: satellite, image classification and data from socioeconomic surveys. Which provided the basis for relating them to the information generated by the mappings. Through quantitative analysis and visual observations of the mappings of the enterprise and its surroundings, it was possible to notice the modification of the landscape. In addition, socioeconomic data could indicate the influence that mining has had on Alto Horizonte. Although the enterprise has a high industrial mineral production and raise the city's GDP, it is not invested in better wages for the population, ie, workers' income does not keep up with the minimum wage increase.