摘要
钢渣中较高的氧化钙含量赋予其较好的碳化能力。本文用QXRD(quantitatively X-ray diffraction analysis)分析了钢渣的主要矿相,并合成了β-C2S,γ-C2S,镁蔷薇辉石(Ca3Mg(Si O4)2),尖晶石(Ca4Si2O7F2),黑钙铁矿(Ca2Fe2O5),钙铁石(Ca4Al2OFe2O10)等矿物。将各矿物在8 MPa下压制成型制成20 mm×20 mm×20 mm的立方体,在99.9%CO2,0.2MPa压力下加速碳化2 h。通过QXRD,TGA(thermogravimetric analysis),FT-IR(fourier transform infrared spectrometer)和SEM(scanning electron microscope)对碳化产物进行分析。结果表明,氢氧化钙吸收二氧化碳的量最大;γ-C2S,β-C2S,镁黄长石,镁蔷薇辉石和尖晶石固碳量逐渐减少。抗压强度与固碳量并不呈正相关关系,因此提出了不同矿物碳化的比强度(K)来表征单位质量CO2提供的抗压强度。β-C2S的K值最大,氢氧化钙K值最小。钢渣吸收的CO2量,抗压强度和K值都介于单矿物之间。除了γ-C2S和镁黄长石分别存在少量的球霰石和文石,所有单矿和钢渣碳化的产物为方解石。用QXRD和TGA的方法对碳酸钙进行定量分析,QXRD所得结果稍小,可能是由于碳化产物中存在少量非晶相碳酸钙。不同矿物碳化后方解石的颗粒尺寸,形貌均不同,这也对抗压强度影响。
The high calcium content makes steel slag an excellent candidate industry waste for mineral carbonation. Minerals of steel slag were analyzed by QXRD. The main minerals, i. e. , β-C2S, γ-C2S, merwinite （ Ca3Mg（ SiO4 ）2 ） , cuspidine （ Ca4Si2OTF2 ） , srebrodolskite （ Ca2Fe205 ） , brownmillerite （ Ca4Al2OFe2O10 ） were synthesized. The minerals （ water/solid ratio is 0. 1 ） were compacted at 8 MPa to 20 mm x 20 mm x 20 mm and then were carbonated in a sealed chamber （ CO2 pressure is 0.2 MPa） for 2 h. The carbonated products were analyzed by QXRD, TGA, FT-IR and SEM. The results indicate that portlandite absorb the greatest amount of CO2 and the carbon sequestration of 3,-C2S, β-C2S, akermanite, merwinite and cuspidine gradually decrease. But compressive strength don＇t show positive correlation with Carbon sequestration capacity. Compressive strength to CO2 uptake （K） values of different minerals are defined. β-C2 S presents the greatest K value and portlandite show the least K value. The CO2 uptake, compressive strength and K value of steel slag are all between the minimum and maximum values of synthetic minerals. Calcite exists in all the carbonated minerals and steel slag. Small amount of vaterite and aragonite exist in carbonated β-CzS and akermanite, respectively. Calcium carbonate from QXRD analysis is less than that from TG analysis. Calcite with different morphologies and different crystal sizes formed, which also have influence on compressive strength.
出处
《电子显微学报》
CAS
CSCD
2015年第6期464-469,共6页
Journal of Chinese Electron Microscopy Society
基金
国家自然科学基金资助项目(No.51172096)
中央高校基本科研业务费专项资金资助项目
关键词
钢渣
矿物
加速碳化
比强度
QXRD
steel slag
synthetic minerals, accelerated carbonation
compressive strength to CO2 uptake value
QXRD
