机械破碎后煤矸石在Ca(OH)_2溶液中的活性特征

Activity characteristic of mechanical crushed coal gangue in Ca(OH)_2 solution

为研究在48 h内机械破碎后的矸石粉末在不同浓度的氢氧化钙溶液中火山灰反应特性和活性离子溶出特性,采用X射线衍射仪、热场发射扫描电子显微镜和傅里叶红外光谱仪分别对矸石粉末浸入1 mol/L和0.1 mol/L Ca(OH)2溶液中不同时间段的滤渣矿物成分、微观形态和红外光谱进行分析和观测,同时运用电感耦合等离子体发射光谱仪和电导率仪分别对滤液的活性离子浓度和电导率进行测定。结果表明:机械破碎后的矸石具有火山灰活性,在两种浓度矸石-Ca(OH)2溶液中,活性离子Al3+,Fe3+,Si4+浓度均在6 h和24 h达到峰值;活性离子来源于矸石中高岭石Al—O和Si—O键能的变化,溶解时间越长,键能变化越明显;矸石在两种浓度的Ca(OH)2溶液中表面形态,都经历了片状矿物的裸露→薄片状Ca(OH)2晶体的附着→小颗粒活性物质的析出→花瓣状产物的生成向针柱状产物转变的过程;随溶解时间的增加,1 mol/L和0.1 mol/L矸石-Ca(OH)2溶液的电导率均呈下降趋势,且前者的火山灰反应程度明显高于后者。

In order to investigate the pozzolanic reaction degree and active ions dissolution of gangue powder in different concentration Ca( OH)2solutions in 48 hours dissolving time,the mineral,micromorphology and infrared spectrogram of residue in different dissolving times were analyzed by X-ray diffraction( XRD),Field Emission Transmission Electron Microscopy( FETEM) and Fourier Transform Infrared Spectrum( FT- IR),and the active ion concentration and conductivity of filtrate were measured by Inductively Coupled Plasma Optical Emission Spectrometer( ICP- OES)and conductivity meter. The results indicate that: The gangue has pozzolanic activity after grinding,the variation trend of Al3 +,Fe3 +,Si4 +ions concentration appeare similar in 1 mol / L and 0. 1 mol / L Ca( OH)2solutions with increasing dissolving time,it appeares two peaks at 6 and 24 hour; It resultes in dissolving active ions that changed the Al—O and Si—O bond energy from kaolinite in gangue,the longer time gangue dissolve,the more clearly change of bond energy appeare; The micromorphology of gangue go through from the bareness of flaky mineral,to the adhesion of lamelliform Ca( OH)2crystal,and then the precipitate of small active particle,finally the generation of petals shape productstransforming into needle-like or pillar-like products; The conductivity of 1 mol / L and 0. 1 mol / L gangue- Ca( OH)2solution appeares a decreasing tendency,the degree of pozzolanic reaction in 1 mol / L Ca( OH)2solution appeares higher than in 0. 1 mol / L Ca( OH)2solution.