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INFLUENCE OF BASALT FIBRES ON THE PROPERTIES OF FLY ASH BASED GEOPOLYMER BINDER
Temuujin, J.,Minjigmaa, A.,Davaabal, B.,Darkhijav, B.,Ruescher, C.H. Korean Association for Particle and Aerosol Resear 2016 Particle and Aerosol Research Vol.12 No.2
The influence of basalt fibres on the compressive strength of the geopolymer type binders has been studied. For the experiments 2 types of the basalt fibres were used, namely chopped and spooled fibres. Both types of basalt fibres were 7-10 micron thick in diameter and cut into pieces of 6 mm length. The fibres were mixed with 1% weight to the fly ash powder, followed by the addition of the activator solution (8M NaOH). The pastes obtained were cured at $70^{\circ}C$ for 20 h revealing compact bodies. Compressive strength was measured after 7 days and microstructure observation performed with SEM. The cube bodies ($2{\times}2{\times}2cm$) reveal compressive strength of 47.25(4.03) MPa, while it decreased to 34.0(9.05) MPa in spooled basalt fibres and to 17.33(5.86) MPa in the chopped basalt fibres containing binder, i.e 76% and 36% of the strength without fibres, respectively. The much weaker compressive strength of the chopped fibres containing binder is related to the absence of significant adhesion between the geopolymer binder and the basalt fibres, forming voids instead. Alkali leaching effect of basalt fibres could probably explain the drop in the compressive strength with spooled and chopped fibres, respectively.
L.Telmenbayar,J. Temuujin 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.5
Mechanically milled mixtures of wolframite and coke, coking coal or thermal coal have been characterized with DTA-TG,XRD and SEM techniques. Mixtures were milled with a planetary ball mill for 4 h and heated at 1000 oC or 1100 oC for 1 hrunder argon gas. The mixtures with coke and coking coal contained WC and Fe3W3C whilst the mixture with thermal coalconsisted of only Fe3W3C phase even after 1 hr calcination at 1100 oC. The amount of WC in the product from coke was higherthan with coking coal. Thermal coal was not a suitable carbon source for forming WC by this route. Coke is considered themost preferable carbon source on preparation of WC in the carbothermic reduction of the wolframite
Nanoporous inorganic materials from mineral templates
MacKenzie,K. Okada,J. Temuujin 한국물리학회 2004 Current Applied Physics Vol.4 No.2-4
The crystal architecture of layer-lattice minerals has been used to prepare inorganic materials containing pores of closely con-trolled size and shape. The template minerals are activated, either bythermal or mechanical treatment, and selectivelyleached withacid to remove the octahedrally-coordinated component, or with alkali to remove the tetrahedral (silica) component. Some acid-leached products contain hydrophilic slit-shaped pores with narrow size distributions typically in the nanopore range, whereas thealkali-leached products contain unimodal pore distributions of larger size (23 nm). The leaching by-products have also been used toprepare combined anion and cation exchange material potentiallyuseful for simultaneous removal of PO.4 and NHþ4 from wastewaters.
V. G. Grossman,B. G. Bazarov,Ts.T.Bazarova,L. A. Glinskaya,J. G. Bazarova,J. Temuujin 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.12
Subsolidus phase relations in the Tl2MoO4-Ho2(MoO4)3-Zr(MoO4)2 system have been studied by X-ray diffraction anddifferential thermal analysis methods. The system has been shown to contain molybdates with the compositionsTl5HoZr(MoO4)6 (5 : 1 : 2) and Tl2HoZr2(MoO4)6.5 (2 : 1 : 4). A new ternary molybdate TlHoZr0.5(MoO4)3 was discovered bythe method of spontaneous solution-melt crystallization through spontaneous nucleation, and its crystal structure has beendetermined to be: sp. gr. R 3, a = b = 13.3665(2) Å, c = 11.9844(4) Å, V = 1854.31(7) Å3, Z = 6. The mixed three dimensionalframework of the crystal structure is composed of Mo tetrahedra sharing O vertices with (Ho,Zr)O6 octahedra. The thalliumatoms occupy wide channels in the framework. Crystals of binary molybdate of Ho2Zr2(MoO4)7 composition were grown bysolution-melt crystallization and their crystal structure were determined to be: sp. gr. С2/c, a = 20.6668(4), b = 9.8193(2), c =13.8187(3) Å, b = 113.678(1)о, .V = 2568.20(9)Å3, Z = 4. The crystal structure is composed of three types of polyhedra: МоО4tetrahedra, ZrO6 octahedra, and eight-vertex HoO8.
A. Minjigmaa,G. Oyun-Erdene,Ts. Zolzaya,B. Davaabal,J. Amgalan,J. Temuujin 한국자원공학회 2016 Geosystem engineering Vol.19 No.3
Phosphorus is one of the most important nutrients for plant growth. The main compounds containing phosphorus are natural phosphate minerals such as apatite. However, the solubility of apatite is low in the humic acid in soil. Therefore, phosphorus is applied as a fertilizer for plant growth. Generally, fluorapatite Ca5(PO4)3F is used for the preparation of phosphorus fertilizer such as superphosphate. Mongolia is rich in phosphorus reserves which are distributed between two phosphate basins at Khuvsgul (4.5 billion tonnes) and Zavkhan (1.2 billion tonnes). However, preparation of phosphorus fertilizer from natural fluorapatite, by a wet chemical method raises health and ecological concerns. Therefore, we have mechanically treated phosphorite from the Burenkhaan deposit in order to prepare fertilizer by a dry method. Phosphate samples were milled in a vibratory ball mill for 15–120 min. Raw and milled samples were characterized by XRD, FTIR, particle size analyzer and SEM. The efficacy of mechanical activation was determined by solubility of milled phosphate in a 2% citric acid solution. Mechanical activation results in a threefold increase in solubility of phosphorus in citric acid solution to 18%. Such solubility is comparable with the superphosphate prepared by the wet chemical method.