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Diffuse-layer surface potentials of colemanites mined in Turkey

Senol-Arslan Dilek, Drelich Jaroslaw W.

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 5

art. no. 151933

EN

Colemanite crystal specimens were handpicked at Kestelek, Emet (Hisarcik, Espey), Bigadic mines in Turkey for characterization of their composition and surface potential. X-ray diffraction analysis revealed no differences in mineralogical makeup of the crystals, but elemental analysis indicated differences in the type of trace (<0.1 wt%) elements. Zeta potential measurements showed small differences in zeta potential values, with isoelectric points (iep) varying from about pH = 9.6 to pH = 10.2. However, no correlation was found between iep and the type of trace elements. Additionally, atomic force microscopy (AFM) was employed to measure the colloidal interactions between a silicon nitride (Si3N4) cantilever tip and colemanite crystal surfaces in 1 wt% colemanite-saturated aqueous solutions at three different pHs (8.4, 9.4 and 11). The Derjaguin-Landau-Verwey-Overbeek theory (DLVO) was applied to examine the AFM tip interactions with colemanite surfaces in an aqueous solution of colemanite saturated solutions. The results revealed attractive forces at pH = 8.4 and 9.4 and repulsive forces at pH = 11, confirming the location of an isoelectric point for colemanite specimens somewhere between pH = 9.5 and pH = 10.1. Theoretical analysis of the force curves using the DLVO theory allowed for assessment of both surface charge density and surface potential for colemanite specimens used in this study.

2

The effect of colemanite addition on the properties of mullite-zirconia composites prepared by slip casting

Aydin H., Ceylantekin R., Tokataş G.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 80, nr 1

5--10

EN

Purpose: This study deals with the effects of colemanite (Ca2B6O115H2O) on properties of slip-cast mullite–zirconia composites prepared via reaction–sintering of kaolinite, alumina and zircon powders. Design/methodology/approach: Colloidal processing (slip casting) is the route towards preparing these materials using 45 vol.% aqueous suspensions of a mixture of fine powders stabilized with polyacrylate solution as a dispersant. Findings: The influence of powder composition on physical, mineralogical properties, and microstructure of these composites after firing at 1450, 1500 and 1550°C are observed. The results show that the density of composites tends to increase with the addition of 7 wt.% colemanite. XRD analyses reveal that using colemanite during the synthesis of mullite-zirconia composites lowers the reaction temperature. All of the composites consist of irregularly shaped mullite and round-shaped zirconia grains, which are distributed homogenously. Practical implications: Mullite–zirconia composites, owing to their chemical inertness and good resistance against chemical attack-corrosion by siliceous and metallic melts, they are employed in the glass industry. Originality/value: Reaction sintering process is considered as a promising technology for preparing mullite-zirconia composites, because it has some advantages such as low cost of traditional raw materials, straightforward production technology and low manufacturing cost.

3

Characterization of espey colemanite and variation of its physical properties with temperature

Celik A. G., Cakal G. O.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

66--76

EN

It is important to characterize boron containing minerals because of their uses in a wide range of applications. The purpose of this study is to characterize Espey colemanite by minerological, petrographical and thermal means and to investigate the variation of its physical properties with temperature (up to 600 °C). Colemanite, having a non-porous crystalline structure, was found to consist of 35.8% B2O3 and 30.5% SiO2. The thermal decomposition of colemanite occurred within the temperature range of 300–600 °C. It was found that calcination, a thermal treatment method, influenced the physical properties of colemanite. The highest surface area, 131.9 m2/g, was obtained at 500 °C. The physical properties were found to have high statistical relation.

4

Mechanical properties of polymer concretes containing different amount of hematite or colemanite

Gencel O., Brostow W., Martínez-Barrera G., Gok M. S.

Polimery

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2012

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T. 57, nr 4

276-283

EN

Polymer concretes (PCs) were created by using varying concentrations of silica sand as aggregate and also hematite, colemanite and a commercial epoxy resin. Hematite is known to exhibit radiation shielding properties. Mechanical performance was evaluated including unit weight, pulse velocity, compressive strength, flexural strength, splitting tensile strength, modulus of elasticity and dynamic elastic modulus. As expected, mechanical properties depend on the resin concentration, the aggregate type and aggregate content in the mixture. Hematite particles have a larger effect than colemanite on mechanical properties of PCs. Inclusion of hematite provides significant improvement of the mechanical properties studied PCs in comparison to PC with silica sand only.

PL

Wytworzono próbki betonu polimerowego (PC) na bazie żywicy epoksydowej napełnionej różną ilością kruszywa, którym był piasek kwarcowy oraz kolemanit lub hematyt. Hematyt zastosowano ze względu na jego zdolności ochronne przed radiacją. Badano gęstość i właściwości mechaniczne otrzymanych betonów, w tym: prędkość rozchodzenia się fal ultradźwiękowych, wytrzymałość na ściskanie, wytrzymałość na zginanie, wytrzymałość na rozciąganie, moduł sprężystości oraz dynamiczny moduł sprężystości. Zgodnie z oczekiwaniami, właściwości mechaniczne zależą od zawartości żywicy w betonie oraz rodzaju i ilości kruszywa w mieszance. Większy wpływ na właściwości mechaniczne mają cząstki hematytu niż kolemanitu. Dodatek hematytu zapewnia znaczną poprawę badanych właściwości mechanicznych betonów w porównaniu z właściwościami PC napełnionego wyłącznie piaskiem kwarcowym.