• 자원리싸이클링
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• 제15권4호
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• pp.27-35
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• 2006

본 연구에서는 명반석 $[K_{2}SO_{4}{\cdot}Al_{2}(SO_{4})_{3}{\cdot}4Al(OH)_{3}]$을 고로수쇄슬래그의 활성화제로서 활용하기 위하여 하소 명반석과 고로수쇄슬래그의 수화반응 특성을 연구하였다. $650{\circ}C$에서 하소시킨 명반석은 $KAl(SO_{4})_{2}$와 $Al_{2}O_{3}$로 구성되어 있으며 하소 명반석-소석회-석고 계에서 하소 명반석은 소석회 및 석고와 $2KAl(SO_{4})_{2}+2Al_{2}O_{3}+13Ca(OH)_{2}+5CaSO_{4}{\cdot}2H_{2}O+73H_{2}O{\rightarrow}3(3CaO{\cdot}Al_{2}O_{3}{\cdot}3CaSO_{4}{\cdot}32H_{2}O)+2KOH$와 같이 반응하여 ettringite($3CaO{\cdot}Al_{2}O_{3}{\cdot}3CaSO_{4}{\cdot}32H_{2}O)$를 형성한다. 하소 명반석-고로수쇄슬래그 계에서는 하소 명반석에서 용해된 황산이온($SO_{4}^{2-}$)이 소석회와 반응하여 석고를 형성시키고, 석고는 다시 고로수쇄슬래그와 반응하여 ettringite를 형성시키면서 슬래그의 수화반응을 촉진시키기 때문에 하소 명반석을 고로수쇄슬래그의 활성화제로 사용할 수 있다.

• 한국세라믹학회지
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• 제16권1호
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• pp.13-20
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• 1979

High purity alumina has been extracted form low grade Korean alunite. Alunite ore was treated by 15% $NH_4OH$ solution, followed by 10% $H_2SO_4$ leaching and metallic impurities such as Fe and Ti were removed by solvent extraction method. Alumina prepared by the extraction process was 99.9% in purity. Hot Petroleum Drying Method has been employed for the preparation of uniformly fine alumina powder, using chemical reagent aluminum sulfate and ammonium aluminum sulfate extrated from Korea alunite. The sinterability of alumina powder prepared by Hot Petroleum Drying Method was shown to be improved in comparison with the one treated by other methods such as ball milling method, but dry pressing was difficult due to the agglomeration of calcined powder. The best slip of alumina powder prepared by Hot Petroleum Drying Method contained a lower soild content than the one treated by other methods. The alumina body formed by soild and drain casting with the former alumina powder showed a higher sintered density.

• 한국세라믹학회지
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• 제31권11호
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• pp.1401-1413
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• 1994

The synthesis of kaolinite mineral from domestic diatomite for silica resource, commercial vailable gibbsite or alumina for alumina resource were made under various hydrothermal treatment, and the sythetic effect of acidic mineralizers, temperature treatment with time duration, particle size of alumina on formation of kaolinite mineral and the plastic properties of synthesized kaolinite were investigated. The various acidic mineralizers which are HCl, HNO3, H2SO4 and Oxalic acid were employed for hydrothermal reaction in the range of 0.01 mol/ι to 2 mol/ι concentration of each mineralizers. It was found that HCl in the level of 1 mol/ι solution produced highly yields of well-crystallized and platy form kaolinite mineral and gave the most effective extraction of iron oxide, compared to that of others, that HNO3 produced highly yield of kaolinite but lower extraction of iron oxide, that H2SO4 produced low yield of kaolinite and formed alunite mineral, and that oxialic acid formed spherical crystalline kaolinite and gave low extraction of iron oxide. Moreover, it showed that kaolinite minerals were well synthesized in a wide range of less than 2 mol/ι acids, but were poorly synthesized at more than 2 mol/ι acids. However, boehmite and kaolinite were coexistently formed in the temperature range of 18$0^{\circ}C$ and 20$0^{\circ}C$ when the calcined diatomite and gibbsite were involved. The well-ordered kaolinite mineral as a platy form was highly synthesized in the temperature range of 220 and 24$0^{\circ}C$, when the same marterials as above were used with treatment of 1 mol/ι HCl solution. The results also revealed that the size of crystalline platy form kaolinite, synthesized from alumina and calcined diatomite with treatment in 1 mol/ιHCl solution at 24$0^{\circ}C$, was much larger than that of gibbsite and calcined diatomite shown previously, and that kaolinite and corundum minerals were coexistently formed under any hydrothermal treatment conditions. The plasticity of synthesized kaolinite from under 2 ${\mu}{\textrm}{m}$ alumina and calcined diatomite was very poor, and that of the synthesized kaolinite from raw diatomite and gibbsite gave higher than that of calcined diatomite and gibbsite.