透辉石粉的火山灰反应特性

透辉石作为矽卡岩型尾矿中的重要组成部分,研究其火山灰反应活性对于该类型尾矿的综合利用具有重要意义,但是目前还未见到相关报道.以透辉石、天然石膏和氢氧化钙为原料制备净浆试块,研究了磨细透辉石的火山灰反应活性,并利用X射线衍射、扫描电镜、傅里叶红外光谱、差示扫描量热法和核磁共振对净浆试块的水化产物进行分析,为初步判断矽卡岩型尾矿是否具有火山灰反应活性提供重要依据.结果表明,磨细的透辉石净浆试块抗压强度在3、7和28 d龄期时分别为9.83、12.79和18.87 MPa,显示出磨细的透辉石具有火山灰反应活性.磨细透辉石的水化产物以C-S-H凝胶为主.核磁共振结果显示,随着水化反应的不断加深,处于Q²结构状态的硅原子比例有所减少,生成的C-S-H凝胶的铝/硅比低于原始结构的透辉石.随着养护龄期的增加,仅有少量石膏参与反应,Ca(OH)₂会被大量消耗,水化产物逐渐增多.未参与反应的石膏颗粒起到填充作用,也有助于促进体系强度的持续增长.

Ash reactivity characteristics of diopside powder

DiopsideCaMg(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.