Ash reactivity characteristics of diopside powder
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摘要: 透輝石作為矽卡巖型尾礦中的重要組成部分,研究其火山灰反應活性對于該類型尾礦的綜合利用具有重要意義,但是目前還未見到相關報道.以透輝石、天然石膏和氫氧化鈣為原料制備凈漿試塊,研究了磨細透輝石的火山灰反應活性,并利用X射線衍射、掃描電鏡、傅里葉紅外光譜、差示掃描量熱法和核磁共振對凈漿試塊的水化產物進行分析,為初步判斷矽卡巖型尾礦是否具有火山灰反應活性提供重要依據.結果表明,磨細的透輝石凈漿試塊抗壓強度在3、7和28 d齡期時分別為9.83、12.79和18.87 MPa,顯示出磨細的透輝石具有火山灰反應活性.磨細透輝石的水化產物以C-S-H凝膠為主.核磁共振結果顯示,隨著水化反應的不斷加深,處于Q2結構狀態的硅原子比例有所減少,生成的C-S-H凝膠的鋁/硅比低于原始結構的透輝石.隨著養護齡期的增加,僅有少量石膏參與反應,Ca(OH)2會被大量消耗,水化產物逐漸增多.未參與反應的石膏顆粒起到填充作用,也有助于促進體系強度的持續增長.Abstract: Diopside[CaMg(SiO3)2] is a common mineral form of calcium magnesium silicate. Apart from dioside quarries, diopside also appears in skarn tailings. Diopside is a novel energy-saving raw material, mainly used in the ceramics industry. Glazed tiles prepared with diopside have the characteristics of low-temperature fast curing, which offers significant advantages to the building materials industry. The results reported in this paper show that the silicate and quartz composition in skarn lead and zinc tailings are likely to participate in the generation of ettringite and C-S-H gel in hydration reactions, respectively. Therefore, lead/zinc tailings can be used as concrete admixtures. As an important component of skarn tailings, the study of the ash reactivity of this type of tailings has great significance for comprehensive utilization in industry, but the relevant literature is incomplete. Paste samples were prepared with diopside, gypsum, and calcium hydroxide in this paper. The ash reactivity of fine-ground diopside was studied and hydration products were investigated using X-ray diffraction, scanning electron microscopy, fourier transform infrared spectroscopy, differential scanning calorimeter and nuclear magnetic resonance. The results show that the compressive strength of the paste prepared from fine-ground diopside can reach 9.83, 12.79, and 18.87 MPa at curing ages of 3, 7, and 28 d, suggesting that fine-ground diopside has good ash reactivity. The hydration products of cement prepared with fine-ground diopside are mainly accounted for by the C-S-H gel. Nuclear magnetic resonance results show that with the deepening of the hydration reaction, the percentage of silicon atoms in the Q2 structure state reduces and the Al/Si ratio in the C-S-H gel is lower than that in the original diopside material. With an increasing curing age, a small amount of gypsum and a large amount of Ca(OH)2 participate in the reaction. The amount of C-S-H gel hydration products increases gradually. The filling effect of the gypsum particles promotes the growth of the tructure's strength with an increasing curing time, although this effect does not alter the chemical reactions. These results will provide sufficient evidence for preliminary judgments of whether skarn tailings possess ash reactivity.
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Key words:
- diopside /
- ash reactivity /
- compressive strength /
- hydration products /
- C-S-H gel
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參考文獻
[5] Sathiyakumar M, Gnanam F D. Role of wollastonite additive on density, microstructure and mechanical properties of alumina. Ceram Int, 2003, 29(8):869 [6] Geng B Y, Ni W, Wang J J, et al. An initiative investigation of the pozzolanic reaction of ground lead-zinc ore tailings. Int J Earth Sci Eng, 2015, 8(3):1271 [8] Gomes S, Francois M, Pellissier C, et al. Characterization and comparative study of coal combustion residues from a primary and additional flue gas secondary desulfurization process. Cem Concr Res, 1998, 28(11):1605 [9] Bensted J, Barnes P. Structure and Performance of Cements. New York:CRC Press, 2014 [11] Ylmén R, Jäglid U, Steenari B M, et al. Early hydration and setting of Portland cement monitored by IR, SEM and Vicat techniques. Cem Concr Res, 2009, 39(5):433 [12] Wang Q, Yan P Y. Hydration properties of basic oxygen furnace steel slag. Constr Build Mater, 2010, 24(7):1134 [13] Silva D A, Roman H R, Gleize P J P. Evidences of chemical interaction between EVA and hydrating Portland cement. Cem Concr Res, 2002, 32(9):1383 [14] Lee T C, Wang W J, Shih P Y, et al. Enhancement in early strengths of slag-cement mortars by adjusting basicity of the slag prepared from fly-ash of MSWI. Cem Concr Res, 2009, 39(8):651 [15] Mollah M Y A, Yu W H, Schennach R, et al. A Fourier transform infrared spectroscopic investigation of the early hydration of Portland cement and the influence of sodium lignosulfonate. Cem Concr Res, 2000, 30(2):267 [16] Trezza M A, Lavat A E. Analysis of the system 3CaO·Al2O3-CaSO4·2H2O-CaCO3-H2O by FT-IR spectroscopy. Cem Concr Res, 2001, 31(6):869 [17] Carmona-Quiroga P M, Blanco-Varela M T. Ettringite decomposition in the presence of barium carbonate. Cem Concr Res, 2013, 52:140 [19] Soin A V, Catalan L J J, Kinrade S D. A combined QXRD/TG method to quantify the phase composition of hydrated Portland cements. Cem Concr Res, 2013, 48:17 [20] Yu P, Kirkpatrick R J, Poe B, et al. Structure of calcium silicate hydrate (C-S-H):near-, mid-, and far-infrared spectroscopy. J Am Ceram Soc, 1999, 82(3):742 [21] Gomes S, Francois M, Pellissier C, et al. Characterization and comparative study of coal combustion residues from a primary and additional flue gas secondary desulfurization process. Cem Concr Res, 1998, 28(11):1605 -
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