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Enrichment of wollastonite with high calcite content

Şavran Ceyda, Türk Tülay, Irgasheva Ganjinakhon, Kangal Murat Olgaç

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 153058

EN

Wollastonite plays a significant role as an industrial raw material in many fields; its exclusive properties mean that it is used in ceramics, paint, metallurgy and coatings. In nature, wollastonite mostly occurs with calcite. While the most common method for separating wollastonite from calcite is calcination, flotation is one of the methods for separating two minerals in a more economic, environmentally friendly way. In this study, the ore contains a large amount of calcite and augite, which is an iron bearing mineral that is subjected to magnetic separation, followed by flotation in order to obtain wollastonite and calcite concentrations individually. The SiO2, CaO and Fe2O3 contents in the ore are 28.00%, 48.20% and 0.45%, respectively. After magnetic separation has reduced the iron content, flotation experiments are carried out to find the optimum conditions. For the flotation process, the effect of particle size, pH and collector dosage are investigated. A wollastonite concentration of 84% purity is successfully achieved, with a 0.17% iron concentration under the optimal conditions of 100 micron particle size, pH 8 and 500 g/t collector dosage. The purity of the calcite is raised to 95% with the application of a cleaning stage.

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Characterization and production of Turkish nepheline syenites for industrial applications

Kangal Murat Olgaç, Bulut Gülay, Yeşilyur Zeynep, Basturkcu Huseyin, Burat Fırat

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 3

605--616

EN

Nepheline syenite, which is a silica-poor crystalline rock, competes with feldspar in applications such as glass, ceramic filler, and pigment industries. While its appearance is medium coarse granular like granite, main differences between them are nepheline syenite is silica poor, and contains high alumina and alkali content. Turkey has considerable nepheline syenite deposits in Kırşehir Region, and they contain 1.3% Fe2O3 on average, thus cannot be used unless beneficiated by flotation or/and magnetic separation. In this paper, physical and physicochemical experiments were carried out to improve the quality of nepheline syenite ore. After determinations of chemical, mineralogical, and properties of the sample, three different technologies such as flotation, magnetic separation, and leaching were applied on the ore sample, separately and combined. The obtained results showed that the magnetic separation alone could not produce a nepheline syenite concentrate assaying 0.45% Fe2O3. It was not also possible to obtain a nepheline concentrate less than 0.25% Fe2O3 adapting optimum flotation conditions. The best results were found in combination of the high intensity wet magnetic separation and flotation between -212+63 μm particle size, and a final concentrate with 0.20% Fe2O3 and 0.01% TiO2 was obtained. The leaching experiments were conducted to further decrease Fe2O3 content. Finally, a saleable nepheline syenite concentrate for tile, sanitary ware, electrode, glass, and fiberglass industries was obtained with 6.63% K2O, 9.02% Na2O, 0.15% Fe2O3, and 0.01% TiO2 by the weight of 63.9% at the end of the experiments.

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Value added industrial minerals production from calcite-rich wollastonite

Bulut Gülay, Akçin Elif Suna, Kangal Murat Olgaç

Gospodarka Surowcami Mineralnymi

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2019

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T. 35, z. 1

43--58

EN

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.

PL

Światowe zużycie wollastonitu ciągle wzrasta. Wollastonit jest metakrzemianem wapnia o wzorze chemicznym CaSiO3. Jest jedynym naturalnie występującym, niemetalicznym, białym minerałem, który ma kształt igieł o pokroju kryształu. Wollastonit ze względu na wysoką odporność chemiczną i termiczną oraz właściwości nietoksyczne zastępuje azbest. Poza tym igiełkowa właściwość wollastonitu umożliwia konkurencję z innymi igiełkowymi materiałami, w zakresie poprawy stabilności wymiarowej, modułu zginania i ugięcia pod wpływem ciepła. Ze względu na swoje unikalne właściwości, takie jak: wysoka jasność i biel, niska wilgotność i absorpcja oleju, niska zawartość części lotnych i właściwości igiełkowe, umożliwia zastosowanie jego jako: materiału wypełniającego do ceramiki, tworzyw sztucznych i farb, izolatora termicznego i elektrycznego, środka zwilżającego i pieca do glazury. Do wzbogacania wollastonitu stosowane są trzy metody: sortowanie mechaniczne, separacja magnetyczna na sucho lub mokro oraz flotacja. W niektórych przypadkach można zastosować zarówno separację magnetyczną, jak i flotację. W tym artykule zastosowano flotację w celu selektywnego oddzielania rud kalcytu i wollastonitu ze złoża Buzlukdağ w regionie Kırşehir-Akpınar w centrum Anatolii. Analiza mineralogiczna próbki użytej w badaniu pokazuje, że próba rudy zawiera 60–62% wollastonitu (CaSiO3), 4–5% augitu (Ca, Na)(Mg, Fe, Al)(Si, Al)2O6, 30–32% kalcytu (CaCO3) i niewielką ilość innych minerałów. W wyniku tych badań uzyskano koncentrat wollastonitu, który zawiera 0,44% ‒ Fe2O3, 52,71% ‒ SiO2, 87,85% wolastonitu przy stratach wynoszących 0,60% (przy użyciu 1500 g/Mg oleinianu potasu). Końcowe koncentraty kalcytu, które można również otrzymać jako produkty uboczne, zawierają 99,80% kalcytu i 85,4% odzysku.