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Abstract
This study focuses on the recovery of ilmenite and rutile from low-grade beach sand using a combination of gravity separation, “high-tension separation”, and magnetic separation techniques. The analysis shows that the feed sample contains a total of 4.72% heavy minerals, with ilmenite constituting 1.56% and rutile 0.52%. A series of continuous experiments were carried out using various separation methods to effectively isolate ilmenite and rutile. Mineralogical modal analysis was performed to establish a flowsheet for the recovery of ilmenite and rutile. The results showed that ilmenite achieved a purity of 95.02%, whereas rutile achieved a grade of 82.9%
Key words: placer sand, titaniferous minerals, beneficiation, process mineralogy
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Abstract
The present research work discusses the advantages of using seawater to recover industrial minerals present in a lean grade that occurs along the coastal stretch of the Sipasurubili beach sand deposit in Odisha, India. The bulk sample contains 4.7% total industrial minerals (TIM). The present study shows that industrial process ground/surface water could be used to produce a heavy mineral concentrate of 98.2% grade of TIM with 71% recovery could be produced, while the use of seawater produced a TIM product of 98.1% with a recovery of 85% from a gravity separator feed. Considering the industrial importance of placer minerals in modern technology and the higher consumption of process water, seawater can be an alternative for the concentration of lean-grade placer heavy minerals. Therefore, the use of mobile gravity concentrators along the coast for TIM using seawater and subsequent purification of the heavy minerals and the dewatering of saline water from the heavy minerals before sending them to the mineral separation plant is encouraged.
Key words: dune sand, industrial minerals, TIM, spiral gravity unit, saline water
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Abstract
This study investigates the grindability parameters of coal surrounding rocks (sandstone and siltstone) from the Zonguldak Basin using Hardgrove Grindability Index (HGI) and Bond Work Index (BWI) tests. Eleven different rock samples were tested to determine the relationships between grindability and mechanical properties including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), Cerchar Abrasiveness Index (CAI), Equotip hardness (ESD), and drillability parameters. Strong correlations were found between HGI and UCS (R2=0.99), HGI and BWI (R2=0.92) and HGI and drilling rate index (R2=0.90). The results show that mechanical properties significantly affect the grindability of rock, with harder and more abrasive rock requiring higher grinding energy. This research provides the first comprehensive analysis of the grindability behavior of rocks in the coal environment and creates predictive models that allow mining engineers to estimate energy consumption and equipment requirements without conducting time-consuming grindability tests. The developed correlations provide direct cost savings by enabling rapid assessment of grinding parameters at the planning stage of mining, helping to optimize energy consumption and predict equipment wear in underground coal mining
Key words: Hardgrove Grindability Index, Bond Work Index, Zonguldak Basin, coal surrounding rocks, rock mechanics.
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Abstract
In this paper, the behavior of macro and micro elements in the biomass of sorghum (Sorghum spp.) contaminated with metals was examined for the preparation of zinc extraction. The plant material, originating from the site polluted by sediment from the Begey Canal (Republic of Serbia), was subjected to thermal treatment at 400-600 °C for 120–360 minutes to analyze changes in metal concentrations. After burning, the ash was washed in distilled water in two cycles to monitor the behavior of the elements in the water environment. The results showed an average loss of biomass of about 90%, with an increase in Zn concentrations up to 19 times compared to the initial values in dry biomass. The highest concentration of Zn (≈ 1100 mg/kg) was reached at 500 °C for 360 min, while Fe and Cu reached the lowest values under the same conditions. EDS and XRD analyzes confirmed that KCl is the dominant phase in the ash, which dissolves during washing together with K2SO4. The obtained results indicate that appropriate preparations of Sorghum biomass can significantly improve the valorization process of zinc from non-hyperaccumulating plants.
Key words: contaminated Sorghum, thermal analysis, Zn extraction, micro elements
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Abstract
Froth flotation is a proven and widely used method for fine particle separation in mineral processing and water treatment, but process efficiency decreases rapidly as particle size decreases. The separation of ultrafine particles, typically smaller than 10 μm, presents a significant technical challenge for mineral processing plants and environmental remediation efforts. Although various approaches can be considered (such as design, collector type, etc.), in recent years, the use of surface micro/nanobubbles in flotation has been recognized as an effective approach to increase removal efficiency and recovery. Compared to traditional macrobubble flotation processes, the unique surface and volume properties of micro/nanobubbles significantly enhance separation and treatment performance. Beyond ultrafine particle removal, dissolved air flotation systems are now being applied as a treatment and recovery methods in many sectors, including the food, pharmaceutical, paper, and chemical industries. This review provides a comprehensive overview of the current status by briefly outlining the fundamentals and applications of micro/nanobubble flotation
Key words: Water treatment, Dissolved air flotation, Sustainable water management, Micro/nanobubble.
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Abstract
This paper investigates the synthesis and mechanical properties of geopolymers obtained from industrial waste – fly ash and granulated blast furnace slag – with the aim of developing environmentally friendly and sustainable construction materials. The raw materials were activated with alkaline solutions of water glass and 12M NaOH in a 1:2 ratio. The ratio of alkali to precursor (fly ash, slag and quartz sand) was 1:1. The dependence of the compressive strength on the addition of slag was tested for geopolymer pastes (C), and geopolymer mortars (P) based on fly ash and quartz sand, both with and without granulated blast furnace slag. The results show that adding up to 20% slag does not significantly affect the compressive strength of the geopolymer. The compressive strengths of geo ratio polymer pastes are 30-50% higher than those of geopolymer mortars. However, the compressive strengths of both geopolymer pastes and mortars after 2 and 7 days are twice as high as the standard values of compressive strengths of cement mortars after 2 and 7 days according to EN 197-1. Chemical analysis (XRF) confirmed the presence of high content of SiO2, Al2O3 and CaO in the starting materials, which contributes to the formation of a strong geopolymer structure. The obtained results indicate the potential of geopolymers as a sustainable and environmentally friendly alternative to conventional binders in construction.
Key words: geopolymers, fly ash, granulated blast furnace slag, compressive strength, XRF analysis, environmental protection
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Abstract
The Timok Magmatic Complex (TMC) is part of the Apuseni–Banat–Timok–Srednogorie magmatic arc within the Tethyan metallogenic belt, hosting world-class porphyry and epithermal copper–gold deposits. In a bedrock channel of the Šarbanovac River (central part of the TMC), seasonal desiccation exposed a fracture cavity within Upper Cretaceous and esitic volcaniclastic rocks, revealing white and yellow mineral aggregates inside the cavity and green mineral aggregates in the surrounding wall rock. X-ray powder diffraction (XRPD) analyses of separated fractions show that the yellow crystals are stellerite-stilbite zeolites, while the white crystals are calcite. The surrounding green wall rock contains quartz, glauconite, clinochlore, and epistilbite. Quartz represents relict magmatic grains incorporated into the volcaniclastic deposit, while glauconite and clinochlore reflect early diagenetic to propylitic alteration. Epistilbite occurs within pores and microfractures, indicating local wall-rock zeolitization predating the main fracture mineralization. Stellerite-stilbite was first deposited along the fracture walls, followed by calcite filling the central part of the cavity, forming a characteristic layered (“sandwich”) texture. These findings document a multistage paragenetic history involving early diagenetic alteration of porous volcaniclastic material, secondary zeolitization, tectonically induced fracturing, and late-stage lowtemperature hydrothermal mineralization. This study provides a rare example of fracture-controlled zeolite-carbonate paragenesis preserved in situ within exposed volcaniclastic bedrock of the TMC
Key words: Volcaniclastite, andesite, fracture, stilbite, stellerite, calcite
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