Ore Preparation Research Articles

Distribution of trace elements in coal and coal fly ash and their recovery with mineral processing practices: A review

Today coal is among the most important energy sources. In order to meet the world's energy demands, low-calorie lignite with a high ash content is generally used in the large capacity coal-fired thermal power plants. As a result of coal firing, wastes such as fly ash, slag, and flue gas are also produced. Subsequently, toxic trace elements within coal are transferred to wastes such as slag, fly ash, and flue gases. Large amounts of these, which are usually stored in collection ponds or stockpiles, are problematic in terms of environment. Although coal fly ash (CFA) has been utilized in construction and several other industries for decades, its current ratio of utilization is still quite limited. As an important fact, CFA also contains many valuable metals including germanium (Ge), gallium (Ga), vanadium (V), titanium (Ti), and aluminum (Al). In addtion, coal and CFA can be regarded as alternative sources of radioactive elements. Therefore, they also have a great potential in terms of the precious metals and trace elements they contain. In this study, the present literature on the distribution of trace elements in coal and coal ash during firing and ore preparation processes and their recovery possibilities with mineral processing practices are reviewed. While many research works on the subject clearly indicate that the large amounts of the ashes produced from firing of coal could be problematic in terms of environment, many studies and practices also show that coal combustion products also have a great potential in terms of the precious metals and trace elements.

Ore preparation at Talnakh Concentrator with the semi-autogeneous grinding introduction

Ore preparation at Talnakh Concentrator with the semi-autogeneous grinding introduction

Морфологічні різновиди гематиту та їх перерозподіл по продуктах збагачення відсіву дробильно-сортувальних фабрик шахт Криворізького басейну

Наведено результати вивчення петрографічного та мінерального складу відсіву дробильно-сортувальних фабрик шахт Криворізького басейну. Головні петрографічні компоненти відсіву – рядові і збагачені гематитові кварцити, багаті гематитові руди; другорядні – малорудні та безрудні кварцити, різного складу сланці, граніти, амфіболіти, жильний кварц. За даними мінералогічних досліджень, відсів має практично бімінеральний (гематит + кварц) склад. Детально досліджено особливості головного рудотвірного мінералу відсіву – гематиту. Виявлено характер перерозподілу його різних морфологічних відмін по різних продуктах рудопідготовки та збагачення. Показано, що емульсійний гематит нерудних прошарків гематитових кварцитів і дисперсний гематит «краскових» руд і малорудних гематитових кварцитів потрапляють, головним чином, до відходів збагачення. Спекулярит і мартит практично повністю потрапляють до концентрату. Наголошується на необхідності врахування одержаних результатів для мінералогічного обґрунтування оптимальної технології повторного збагачення відсіву з метою одержання високоякісного залізорудного концентрату.

Economic Effectiveness of Technogenic Mineral Formations Management as a Factor of Mineral Raw Material Basis Restoration of Kazakhmys Enterprises

The problems of the raw material base depletion, ineffective technological chain of ores mining and processing with a high loss factor require a systematic, sound approach to the future development of the Zhezkazgan region. The conducted monitoring of ore fields and tailings is represented by significant stocks of technogenic formations.
 As a methodology for research works at the mines of Kazakhmys enterprises a method of geotechnological work was chosen. Based on various physical and chemical impacts, the rocks are brought into a mobile state and receive useful components from hard-to-digest ores. In the extraction process, X-ray radiometric methods are used, which allow ore separation and mixing at the ore preparation stage, thereby reducing the yield of unpromising ores to the surface and increasing the multispectral nature of the extracted components. The created experimental furnace of chlorinating firing makes it possible to extract valuable components in the form of additional products such as rhenium, gold, iron from complex products of rough concentrate, which due to the lack of effective technology went to the tailings of enrichment. The applied geotechnology is environmentally balanced, since the waste that is not of economic value can be used as raw material in the construction industry.
 The uniqueness of the research work is in detailed spectral analysis of the physical and chemical properties of technogenic formation and poor ores of the Zhezkazgan region, using technological processes for extracting associated components from waste and decommissioned ores by the method of chlorinating roasting and obtaining an additional solution with a high content of the useful component.

Special features of constructing systems for underground leaching of metals

The relevance of the work is attributed to the possibility of engaging stocks of low-grade ores in mining, which is prevented by insufficient knowledge of the leaching process. Preparation of ores is carried out without accounting for all properties of minerals and modes of solution movement, which increases the cost of mining, increases the loss of useful components and degrades the technicaleconomic criteria. The aim of this work is to systematize the theory and practice of using leaching technology with optimization of the mineral resources utilization criterion, accumulated in the uranium-mining industry of the USSR. The article contains the description of the processes carried out in mining practice for the first time. Results. The fundamental distinction of the technology of leaching metals from ores as changing phase of metal explicitly in-situ is formulated. The features of layout design and the use of preparatory and development workings on the conditions of their reuse in the process, crushing by condition to ensure penetration of the reagent solution into the ore piece, irrigation as a process determining the economic purposefulness of the technology, collecting solutions and preventing leakage for industrial sanitation and human health are described. The features of intensification of the drill-and-blast leaching process by deformation of the volume of leachable ore with of explosive gases and stress waves are distinguished. Examples of accounting for special features of ore deposits leaching in the USSR are presented. The practice of monitoring the completeness of leaching by excavation workings on leached ore is described. A brief description of the benefits of leaching technology in cleaning up the stocks lost by the traditional technology is given. Conclusion. It is noted that underground leaching may take priority positions in mining, so development of scientific basics for its implementation is one of the most important tasks of mining production, accomplishing which affects the creation of highly productive and waste-free systems of extraction of useful minerals from the subsoil. The experience of the ISL allows to create a methodological basis for expanding the scope of metal leaching technologies. The article contains the description of the processes carried out for the first time in mining practice.

Processing of refractory gold sulphide carbonbearing ores by means of their pre-oxidation with water-and-gas emulsions prepared in electrochemical and photochemical reactors

In connection with the depletion of mineral resources base of gold, the engagement of refractory ores reserves in the processing becomes a necessary condition to stabilize gold market. Standard methods of processing of refractory sulphide carbon-bearing gold ores and float concentrates extracted from them include pressure oxidation and bacterial oxidation enabling the liberation of dispersive gold and oxidation of carbon having parasitical sorption with further cyanation. The alternative solution of the aforementioned problem is pre-oxidation of refractory ores with water-and-gas emulsions. Theoretical basis for active water-and-gas emulsions formation with the use of electrolytes solutions electrolysis in combination with ultraviolet exposure is stated in the article. Given method of water-and-gas emulsions preparation ensures the formation of active oxidants complex. Gold recovery into pregnant solutions up to 55.7 - 73.5% by chloride scheme was reached in laboratory experiments on samples of sulphide carbon-bearing ore, herewith 18% was recovered using cyanic solution. Based upon experimental findings, process scheme for combined oxidative preparation of sulphide carbon-bearing ore with dispersive deportment of gold was developed.

Reengineering of the ore preparation production process in the context of “Almalyk MMC” JSC

The review of ore crushing and grinding processes at the mining-and-processing enterprise is presented. An alternative to the standard technology of crushing ore in cone crushers is proposed after a comparative analysis of ore grinding processes.

МОДЕЛИРОВАНИЕ ОПТИМАЛЬНОЙ СХЕМЫ РУДОПОДГОТОВКИ ПРИ ОБОГАЩЕНИИ УПОРНЫХ ЗОЛОТОСОДЕРЖАЩИХ РУД

МОДЕЛИРОВАНИЕ ОПТИМАЛЬНОЙ СХЕМЫ РУДОПОДГОТОВКИ ПРИ ОБОГАЩЕНИИ УПОРНЫХ ЗОЛОТОСОДЕРЖАЩИХ РУД

The study of transient processes – a new direction in the development of a methodological approach to the solution of problems of complex development of georesources.

The article presents the stages of technology development and methodology of subsoil development in the postwar years to the modern period, taking into account the transition from planned to market economy. The necessity of new methodological approaches to solving the problems of subsoil development based on the principles of consistency, complexity, interdisciplinary orientation. The definition of the strategy for the development of deep-lying complex structural fields with the increase of geological, mining and technical and economic information in the dynamics of mining. The concept of “transient processes” is introduced, the accounting of which laws is the basis for the development of innovative technologies for the evaluation, production and ore preparation of mineral raw materials that meet the requirements of the subsequent enrichment and metallurgical processes of production of commodity products. The features of development of reserves of deposits in the Northern and equated regions, including taking into account the integrated development of territories by creating mineral resource centers. The directions of further research of transient processes, focused on the establishment of the main factors affecting the justification of methods, stages and timing of adaptation of the parameters of the main technological processes in the existing mining enterprises to changing internal and external conditions of their operation and the development of new deep-seated deposits in different climatic and mining conditions.

Characterization of the Gold Ore to Acquire an Optimum Degree of Liberation

Gold ore processing is often ineffective in obtaining gold metal. Various methods have been successfully developed on an industrial scale, but small-scale gold mines are often problematic. The problem of inefficiency of processing is caused by gold ore characterization and evaluation of gold ore preparation process is not implemented. In this study, the conditions of gold ore deposits have a thin thickness (vein). These gold ore deposits have an economic value if they are developed by traditional gold mining. The objective of the research is to identify and characterize gold ore as well as to analyze the optimum condition to obtain the perfect gold mineral liberation degree. Research methods include characterization of gold ore geology, sampling for test preparation using rod mill (amalgamation), gold mineral liberation using time variables and number of rods. After the grinding process, grain size analysis is performed with various mesh sizes, and the analysis of each fraction uses a polarization microscope. The results show that goldore minerals are associated with pyrite, chalcopyrite, galena and gangue minerals. Gold minerals are fully liberated at a certain size. The results of this research are very useful for the gold ore grinding process to obtain an efficient gold processing

Sorptional dehydration and thermochemical sintering of converter sludge

Global steel output in 2016 exceeded 1.6 billion t, of which more than 1.2 billion t was produced in converters. The smelting of 1 t of steel produces up to 25 kg of fine dust, depending on various factors. This dust contains up to 65% iron, in oxide form. Recycling of the waste formed in steel production costs half or a third as much as the preparation of ore concentrates. For the recycling of converter sludge, methods of conditioning wet wastes by isothermal sorptional dehydration and subsequent thermochemical sintering have been developed. The adsorbent used in the present work is the solid residue from lignite pyrolysis: fine-grain lignite semicoke produced by a pilot plant at the Berezovskii-1 mine. The lignite-semicoke samples produced have a highly developed pore structure and correspondingly are characterized by excellent sorptional and energy properties. The granulometric composition of lignite semicoke is practically the same as that of the sludge. At the same time, the density of the lignite-semicoke particles is 2.5 times less than that of the sludge particles, even when the pores of the semicoke are completely filled with adsorbed moisture. On mixing the lignite semicoke and converter sludge, the semicoke absorbs moisture. The resulting mixture is highly friable, whereas the moisture adsorbed in the pores passes to the bound state and becomes an active participant in redox processes. As a result of the experiments, new material containing up to 39% Femet and 49% C is obtained. On that basis, an effective technology may be developed for the utilization of converter sludge to produce ferrocoke that may be employed as a fuel and reducing agent in blast furnaces and smelters. The proposed technology does not require complex mechanical and thermal dehydration and briquetting with binder.

Explosion-assisted preparation of dispersed gold-bearing different-grade ore for selective mining

It is found that there are transient zones (between quality and off-quality ore areas) with the respective content of useful component in an ore body, and a variant of explosive treatment of such zones before the selective mining is put forward. Practicability of two processing technologies is evaluated: processing of high-grade and low-grade ore from the transient zones and heap leaching of metals from the low-grade and impoverished ore. Open mining technology is conventional truck-and-shovel scheme, with distributed ore flows to processing plant and (or) to heap leaching, which generally enhances the mine efficiency.

Preparation of ore blocks for mine leaching by reagent explosion injection

The current drilling-and-blasting operations fail to prepare intact ore body underlying a production horizon for subsequent mining and leaching. It is found that the required preparation quality is possible by means of advanced implementation of ore body discontinuity and filling of the resultant system of joints with active leaching solutions.

Technologic Tests of Turkey-Gordes Zeolite Minerals

Natural zeolites are found at many points of the world in the form of minerals. As for Turkey, quite large volumes of zeolites reserves are available in the following regions: Ankara (Nallihan, Beypazari, Polatli etc.), Kutahya-Sa- phane, Manisa-Gordes, Manisa-Demirci, Izmir-Urla, Balikesir-Bigadic and Cappadocia. By means of the works carried out only at the field in Balikesir- Bigadic region, one of the detected reserves in Turkey, it was understood that an easily workable potential around 500 million ton is available. According to the very limited observations made until today, it is stated that the total reserve in our country may be around 500 billion ton. In these regions, the types of clinoptilolite, hoylandit, chabazite, analcime and erionite from the zeolite minerals exist. Zeolites are widely used in many sectors such as energy, environment, construction, detergent, chemistry, medicine, mining, agriculture and livestock. Zeolites also provide great benefits when they are used especially in agriculture and livestock for the purpose of preventing environmental pollution threatening human being. In this study, zeolite sample taken from Manisa-Gordes region was used. Following the processes of crushing and sieving, zeolite sample was subjected to chemical analyses according to their grain thickness, microscopic examination, the analyses of XRD and Technological Tests (ceramic pre-technological reviews, value of oil absorption, whiteness measurements, examination of the zeolite sample as cat litter, determination of bleaching capability, porosity values) and their ore characteristics were determined. After the analyses, ferrous oxide, biotite, quartz, muscovite, feldspar, chlorite, non-zeolite silicates and metamorphic rock fragments have been found. This zeolite mineral with high mineral purity has been suggested to clear off all impurities via ore preparation and enrichment methods.

Способ определения оптимальных параметров процессов рудоподготовки

Способ определения оптимальных параметров процессов рудоподготовки

Regional-scale screening of groundwater pollution risk induced by historical mining activities in Serbia

Europe has a long mining history, with some mining sites dating back to prehistoric times. Mining activities have boosted industrial development in many European countries; however, on the other hand, they left behind large degraded areas and polluted sites. This mining heritage, from small-scale mines to large industrial mining complexes, adversely affects natural resources and the environment. Exploration and mining of mineral ores have been quite extensive in Serbia. Most exploited were as follows: coal, copper, Pb–Zn ores, accompanying gold and silver and antimony. Groundwater resources are frequently impacted by mining operations, both during mining activities and after mine closure. For proper protection and management of groundwater resources, it is necessary to identify and characterize pollution sources within groundwater bodies. Abandoned mining sites, along with associated facilities for the preparation and processing of ores, waste rock disposal sites and tailings, constitute potential hazards and can have a negative effect on groundwater quality. This paper describes a methodology developed for regional-scale screening of the groundwater pollution risk from abandoned mining sites. As a first step, intrinsic groundwater vulnerability was assessed on the basis of readily available data. As potential polluters, 59 abandoned mining sites were included in the analysis. The hazard identification process comprised physical characterization of mining sites and hydrochemical assessment of mine water originating from those sites. A simple indexing method was developed for hazard and risk quantification. To assess the spatial distribution of the groundwater pollution risk, all data were incorporated and analyzed in a GIS environment. As a result of initial screening, several abandoned, mostly metallic mines were found to have higher-risk ratings for groundwater contamination. The methodology based on examples from Serbia can also be used in other regions for developing management strategies and directing of remediation activities.

Preparation of Carbon-Containing Iron Ore with Enhanced Crushing Strength from Limonite by Impregnation and Vapor Deposition of Tar Recovered from Coke Oven Gas

The optimum conditions for preparing carbon-containing iron ore (composites), in which coke-oven-gas-tar-derived carbonaceous materials completely filled the pores in Indonesian limonite (IL), are investigated using impregnation (IM) and vapor deposition (VD). A peak around 2 nm is observed in the pore size distribution profiles for the as-received IL and IL absolutely heated to a predetermined temperature. The intensity of the peak decreased with increasing ratio of tar to IL (tar/IL) for the IM-prepared composites, and it completely disappeared for the composites prepared with tar/IL > 1.0; the corresponding SBET and VBJH are <1 m2/g and <0.01 cm3/g, respectively. The peak at 2 nm in the pore size distribution profiles for the VD-prepared composites almost disappears for treatment times longer than 60 min for any combination of conditions for tar pyrolysis temperature (TPT) and VD temperature (VDT). The composite prepared using a combination of TPT–VDT of 700–350 °C for 60 min shows the highest carbon c...

Hydrometallurgical processes of antimony extraction from ores and concentrates

Data concerning the preparation of antimony and complex ores by pyrometallurgical and hydrometallurgical methods, as well as results on developing a procedure for the hydrometallurgical processing of slime antimony concentrates using chloride dealkalization, have been presented.

Investigation of the process of crushing solid materials in the centrifugal disintegrators

The paper represents the results of investigation of magnetite quartzite centrifugal disintegrators crushing. It is demonstrated that when crushing quartzites of ingoing size 100 mm, it is possible to obtain crushed product size – 10 mm, in so doing product classes – 10 mm depends on the disintegrator rotor rotation frequency. It is shown that in crushed products of the centrifugal disintegrator of CD-50 type there are more classes minus 10, 5, 1 and 0.074 mm by 30, 42, 32, 13,5 % respectively, than in crushed products of KMD-2200 cone-type crusher. Herewith, it was established that iron content in CD-50 crushed products is 3.3 % higher, that in KMD-2200 ones. The obtained empirical dependencies of material destruction process via stroke in the field of centrifugal forces can be applied in performance prediction of material centrifugal disintegrators crushing. The final formula for calculating the material escape speed out of the accelerated disintegrator rotor, which provides required destruction of material, was obtained by means of classical hypothesis method application. Namely, the required speed of material escape out of the operating cylinder of centrifugal disintegrator is linear to specified material reduction degree and value of admissible (critical) stress of the given material destruction, and inversely proportional to Sin of meeting angle of material with bumper plates and value of material acoustic stiffness. Carried out empirical and theoretical investigations showed the advantages of magnetite quartzite crushing in centrifugal disintegrator before comminution in cone crushers, which makes the use of disintegrators in schemes of preparation of ore for further concentration well-grounded.

Pomza Cevherinin Hazırlanması ve Zenginleştirilmesi

Pomza Cevherinin Hazırlanması ve Zenginleştirilmesi