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Abstract

The worldwide consumption of wollastonite has been increasing from day to day. It is a calcium metasilicate with the chemical formula CaSiO3. Wollastonite is the only naturally occurring, nonmetallic, white mineral that is needle-shaped in a crystal habit. Due to its high chemical and thermal resistance and nontoxic properties, wollastonite replaces asbestos. Apart from this, the acicular property of wollastonite allow it to compete with other acicular materials where improvements in dimensional stability, flexural modulus and heat deflection are sought. Due to its unique properties such as: its high brightness and whiteness, low moisture and oil absorption, low volatile content, and acicular properties, it is used also as a filling material for ceramics, plastics and paints, thermal and electrical insulator, wetting agent and smelter for glaze. Three methods are used for the beneficiation of wollastonite: mechanical sorting, dry or wet magnetic separation and flotation. Magnetic separation and flotation can be applied together in some cases. In this study, flotation has been investigated for the selective separation of calcite-rich wollastonite ores from the Buzlukdağ deposit, in the Kırşehir-Akpınar region, in the middle of Anatolia. The mineralogical analysis of the sample used in the study shows that the ore sample contains 60–62% wollastonite (CaSiO3), 4–5% augite (Ca,Na)(Mg,Fe,Al)(Si,Al)2O6, 30–32% calcite (CaCO3) and minor amount of other minerals. As a result of this study, the wollastonite concentrate which contains 0.44% Fe2O3, 52.71% SiO2, 87.85% wollastonite with 0.60% loss on ignition (using 1500 g/t potassium oleate) was obtained. The ultimate grade concentrates of calcite that can also be obtained as by-products are with 99.80% calcite content and 85.4% recovery.
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Abstract

“Wartowice” tailings pond was closed in 1989, resulting in 232,4 ha tailings pile requiring reclamation. The major problem is heavy metals presence and poor nutrient conditions and physicochemical structure of soil which disturbs the plants development. In order to assess the real condition of studied area the complete biological characteristic has been done. The physicochemical conditions were assessed altogether with phytosociological, microbiological and toxicological studies of deposits. We recorded only 27 species of vascular plants belonging to 15 families on the tailings pond of which 5 belong to Rosaceae, 4 to Asteraceae and 3 to Poaceae and Saliceae. Species inhabiting the tailings depended on their dispersal capacity, metal tolerance and rhizome strategy. Microbiological analyses revealed the low number of bacteria and fungi on the tailings pond, apart from the small uplift area where the plants were indentified. Bacteria identified on the tailings pond were classified to 8 genera. The low number of bacteria suggests the lack of nutrients which affects the development of soil microflora. Toxicity tests showed that post-flotation sludge is not toxic to microorganisms because of its high pH. Some plants, such as lucerne could even influence positively the microorganisms development what has been proved in our studies. The tailings toxicity was higher towards producers, where Secale cereale appeared to be the most sensitive species. Amendment with topsoil from adjacent areas can influence positively the phytotoxic properties of tailings and enrich them into native seeds.
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Abstract

The article presents the results of plasma vitrification of solid remnants from thermal waste treatment with and without the addition of a carbonate fraction obtained from lead-zinc ore flotation. The substrates used in the research were slags and ashes from medical waste treatment, incineration of municipal waste, sewage sludge as well as hazardous and industrial wastes. The plasma treatment resulted in acquiring products of different quality depending on the processed substrate. Most of the obtained products were of vitreous and homogenic build. Treatment of remnants from incineration of hazardous and industrial wastes resulted in obtaining heterogeneous and rough surfaced products. A 20% share of the carbonate fraction enabled the obtaining of a vitrified product with a glassy surface and fracture. Hardness of the obtained products was rated in Mohs scale and ranged from 6 to 6,5. Leaching tests showed a decrease in heavy metal concentration in the leachates from vitrificates with the addition of carbonate fraction compared to the ones with it.
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Abstract

Fresh bituminous coal was stored in air-/water-oxidation conditions after 20 and 80 days, respectively. FTIR results show that the Hydrophilicity Index (HI) value of air-oxidized coal is higher than that of water-oxidized coal. SEM results show that the surface roughness of water-oxidized coal is higher than that of air-oxidized coal and water-oxidized coal surface has more holes and chips than air-oxidized coal surface. Flotation results show that the floatability of water-oxidized coal is worse than that of air-oxidized coal. The flotation performance of both air-/water-oxidized coals can be improved at larger collector dosages. The air-oxidation processes changed the HI value of coal greater than the water-oxidation processes while the water-oxidation processes changed the surface morphology of coal greater than the air-oxidation processes. Both the changes in HI value and surface roughness of coal determine the flotation behavior of oxidized coal. The changes in the surface morphology of coal particles after oxidation processes may be the primary factor determining the floatability of coal particles while the changes in the HI value of coal particles may be the inferior factor.
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Abstract

In this study, emulsified kerosene was investigated to improve the flotation performance of ultrafine coal. For this purpose, NP-10 surfactant was used to form the emulsified kerosene. Results showed that the emulsified kerosene increased the recovery of ultrafine coal compared to kerosene. This study also revealed the effect of independent variables (emulsified collector dosage (ECD), frother dosage (FD) and impeller speed (IS)) on the responses (concentrate yield (γC %), concentrate ash content ( %) and combustible matter recovery (ε %)) based on Random Forest (RF) model and Genetic Algorithm (GA). The proposed models for γC %, % and ε% showed satisfactory results with R2. The optimal values of three test variables were computed as ECD = 330.39 g/t, FD = 75.50 g/t and IS = 1644 rpm by using GA. Responses at these experimental optimal conditions were γC % = 58.51%,  % = 21.7% and ε % = 82.83%. The results indicated that GA was a beneficial method to obtain the best values of the operating parameters. According to results obtained from optimal flotation conditions, kerosene consumption was reduced at the rate of about 20% with using the emulsified kerosene.
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Abstract

Five cosmetics wastewater samples were treated by Dissolved Air Flotation (DAF) assisted by coagulation. Different aluminum based coagulants were used: (Al2(SO4)3, Al 1019, Al 3010, Al 3030, Al 3035, PAX 16 and PAX 19). The raw wastewater COD values were in the range 285-2124 mg/l. The efficiency of DAF depended on different coagulants and production profi le of factory. COD removal was varied from 11.1 to 77.7%. The efficiency of coagulants was similar during treatment of particular sample. The best results were obtained with Al2(SO4)3 and for sample 5 - lotions and shampoos production. The wastewater from UV fi lter creams production (sample 4) was resistant to treatment by DAF regardless of used coagulant. HS-SPME-GC-MS analysis can be a confirmation of DAF effectiveness
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