Effect of storage temperature on the cementitious property of hemihydrate phosphogypsum
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摘要: 半水磷石膏(HPG)长时间堆存状态下会出现固结现象,其胶凝性能也相应下降。以室内HPG结晶水检测和单轴压缩试验为基础,通过设定4种不同堆存温度,分别为20,40,60和80 ℃,探究不同堆存温度作用下HPG试样结晶水质量分数变化和堆存后制备的充填胶凝材料(HCM)抗压强度发展规律,并采用扫描电镜等微观分析手段研究堆存温度对其强度影响机制。结果表明,堆存温度对HPG胶凝性能影响显著,高的堆存温度会加快HPG试样中的自由水转变为结晶水速率,而且会抑制堆存后制备的HCM强度发展。采用数据标准化对不同堆存温度作用后的试样抗压强度作出预测,被证实与实测值较吻合。微观分析发现,堆存温度主要影响体系的过饱和度,而使不同堆存温度作用后制备的HCM微观形态表现差异。Abstract: Whether domestic or foreign, the utilization of phosphogypsum (PG) resources is not satisfactory. A chemical plant in Guizhou produces phosphoric acid through a semi-aqueous process to obtain the byproduct hemihydrate phosphogypsum (HPG), which has a certain gelling activity. If this feature of HPG can be fully utilized, it can replace cement as a cementing material to prepare mine-filling materials. Utilizing HPG for goaf filling can not only reduce the environmental protection problems caused by the surface discharge of PG but also eliminate the hidden safety hazards in the goaf. At present, when HPG is used to prepare mine-filling cementitious materials, HPG will be consolidated into a block and lose its gelling activity when it is stacked for a certain period of time. The gelling performance of the HPG in the storage state appears to decline. Based on the indoor HPG crystal water detection and uniaxial compression test and setting four different storage temperatures (20 ℃, 40 ℃, 60 ℃, and 80 ℃), this study explored the changes in the mass fraction of the crystal water of HPG samples under different storage temperatures. The compressive strength development law of HCM prepared after storage and microscopic analysis methods, such as scanning electron microscopy, were used to study the influence mechanism of the storage temperature on its strength. Results show that the stacking temperature has a significant effect on the gelling performance of HPG. A high stacking temperature will speed up the conversion of free water in the HPG sample to crystal water and inhibit the strength development of the HCM prepared after stacking. Data standardization was used to predict the compressive strength of samples after storage at different temperatures, which is confirmed to be in good agreement with the measured values. The microscopic analysis found that the storage temperature mainly affects the supersaturation of the system, and the microscopic morphology of the HCM prepared after storage at different temperatures is different.
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表 1 HPG化学成份及含水率测定结果表(质量分数)
Table 1. Hemihydrate phosphogypsum’s chemical composition and moisture content
% CaO Al2O3 SiO2 P2O5 MgO Fe2O3 SO3 SrO loss Free water Crystal water 37.86 2.46 4.20 1.37 0.28 0.45 44.82 0.36 0.20 22.10 5.40 -
参考文献
[1] Cai M F, Xue D L, Ren F H. Current status and development strategy of metal mines. Chin J Eng, 2019, 41(4): 417蔡美峰, 薛鼎龙, 任奋华. 金属矿深部开采现状与发展战略. 工程科学学报, 2019, 41(4):417 [2] Wu A X, Li H, Cheng H Y, et al. Status and prospects of researches on rheology of paste backfill using unclassified-tailings (Part 1): concepts, characteristics and models. Chin J Eng, 2020, 42(7): 803吴爱祥, 李红, 程海勇, 等. 全尾砂膏体流变学研究现状与展望(上): 概念、特性与模型. 工程科学学报, 2020, 42(7):803 [3] Sun X W, Wu T J. Experimental research of alkali-activated slag cementitious material. Bull Chin Ceram Soc, 2014, 33(11): 3036孙小巍, 吴陶俊. 碱激发矿渣胶凝材料的试验研究. 硅酸盐通报, 2014, 33(11):3036 [4] Liang Z Q. Review on development and application of new type backfilling cementing materials in mining industry. Met Mine, 2015(6): 164 doi: 10.3969/j.issn.1001-1250.2015.06.035梁志强. 新型矿山充填胶凝材料的研究与应用综述. 金属矿山, 2015(6):164 doi: 10.3969/j.issn.1001-1250.2015.06.035 [5] Zhang G C, Yang Z Q, Gao Q, et al. Development of early strength filling cementing material with phosphogypsum as substitute of traditional cement. Met Mine, 2015(3): 194张光存, 杨志强, 高谦, 等. 利用磷石膏开发替代水泥的早强充填胶凝材料. 金属矿山, 2015(3):194 [6] Li J Q, Li Z J, Wang J C, et al. Development status and prospect of phosphogypsum filling material and technique. Mod Min, 2018(10): 1 doi: 10.3969/j.issn.1674-6082.2018.10.001李剑秋, 李子军, 王佳才, 等. 磷石膏充填材料与技术发展现状及展望. 现代矿业, 2018(10):1 doi: 10.3969/j.issn.1674-6082.2018.10.001 [7] Wang Y M, Wang Z K, Wu A X, et al. Preparation of new cementitious backfilling material and its curing mechanism analysis. Met Mine, 2018(6): 20王贻明, 王志凯, 吴爱祥, 等. 新型胶凝充填材料制备及固化机理分析. 金属矿山, 2018(6):20 [8] Lan W T, Wu A X, Wang Y M, et al. Optimization of filling ratio of hemihydrate phosphogypsum based on orthogonal test. Chin J Nonferrous Met, 2019, 29(5): 1083兰文涛, 吴爱祥, 王贻明, 等. 基于正交试验的半水磷石膏充填配比优化. 中国有色金属学报, 2019, 29(5):1083 [9] Lan W T, Wu A X, Wang Y M. Formulation optimization and formation mechanism of condensate expansion and filling composites. Acta Mater Compos Sin, 2019, 36(6): 1536兰文涛, 吴爱祥, 王贻明. 凝水膨胀充填复合材料的配比优化与形成机制. 复合材料学报, 2019, 36(6):1536 [10] Jiang G Z, Wu A X, Wang Y M, et al. Effect of lime on properties of filling cementitious material prepared by hemihydrate phosphogypsum. J Chin Ceram Soc, 2020, 48(1): 86姜关照, 吴爱祥, 王贻明, 等. 生石灰对半水磷石膏充填胶凝材料性能影响. 硅酸盐学报, 2020, 48(1):86 [11] Lan W T, Wu A X, Wang Y M, et al. Ionic solidification and size effect of hemihydrate phosphogypsum backfill. China Environ Sci, 2019, 39(1): 210 doi: 10.3969/j.issn.1000-6923.2019.01.024兰文涛, 吴爱祥, 王贻明, 等. 半水磷石膏充填体离子固化与尺寸效应. 中国环境科学, 2019, 39(1):210 doi: 10.3969/j.issn.1000-6923.2019.01.024 [12] Yang B. Study on the Process of Hydrothermal Treatment of Phosphogypsum [Dissertation]. Kunming: Kunming University of Science and Technology, 2006杨斌. 水热法处理磷石膏过程研究[学位论文]. 昆明: 昆明理工大学, 2006 [13] Lan W T, Wu A X, Wang Y M, et al. Experimental study on influencing factors of the filling strength of hemihydrate phosphogypsum. J Harbin Inst Technol, 2019, 51(8): 128 doi: 10.11918/j.issn.0367-6234.201804082兰文涛, 吴爱祥, 王贻明, 等. 半水磷石膏充填强度影响因素试验. 哈尔滨工业大学学报, 2019, 51(8):128 doi: 10.11918/j.issn.0367-6234.201804082 [14] Yang L, Cao J X, Liu Y M. Mineralogical characteristics of hemi-hydrate phosphogypsum. Acta Petrol Mineral, 2015, 34(6): 827 doi: 10.3969/j.issn.1000-6524.2015.06.005杨林, 曹建新, 刘亚明. 半水磷石膏的矿物学特征. 岩石矿物学杂志, 2015, 34(6):827 doi: 10.3969/j.issn.1000-6524.2015.06.005 [15] Chitambira B. Accelerated Ageing of Cement Stabilised/Solidified Contaminated Soils with Elevated Temperatures [Dissertation]. Cambridge: Cambridge University, 2004 [16] Zhang R J, Zheng J J, Cheng Y S, et al. Experimental investigation on effect of curing temperature on strength development of cement stabilized clay. Rock Soil Mech, 2016, 37(12): 3463章荣军, 郑俊杰, 程钰诗, 等. 养护温度对水泥固化淤泥强度影响试验研究. 岩土力学, 2016, 37(12):3463 [17] Morohoshi K, Yoshinaga K, Miyata M, et al. Design and long-term monitoring of Tokyo International Airport extension project constructed on super-soft ground. Geotech Geol Eng, 2010, 28(3): 223 doi: 10.1007/s10706-010-9312-x [18] Yao S, Han B, Wu A X, et al. The effect of temperature on strength of wet shotcrete in cold mining areas and its engineering application. J Min Saf Eng, 2017, 34(2): 384姚松, 韩斌, 吴爱祥, 等. 温度对高寒矿山湿喷混凝土强度影响规律及工程应用研究. 采矿与安全工程学报, 2017, 34(2):384 [19] Wang D X, Gao X Y, Zou W L, et al. Study on strength predication of reactive MgO-slag/fly ash stabilized clay considering high temperature effect. J Huazhong Univ Sci Technol Nat Sci Ed, 2019, 47(6): 92王东星, 高向雲, 邹维列, 等. 高温效应下MgO-矿粉/粉煤灰固化土强度预测. 华中科技大学学报(自然科学版), 2019, 47(6):92 [20] Yang C J, Yang M, Cao J X. Study on hydration and hardening of duplex gypsum binder of hemihydrite phosphogypsum and anhydrite phosphogypsum. Non-Metallic Mines, 2014(6): 22 doi: 10.3969/j.issn.1000-8098.2014.06.008杨成军, 杨敏, 曹建新. 半水/无水磷石膏复相胶凝材料水化硬化特性研究. 非金属矿, 2014(6):22 doi: 10.3969/j.issn.1000-8098.2014.06.008 [21] Zhang J L. Research on the Effects of Water-reducing Agents on the Hydration and Setting of α-Calcium Sulfate Hemihydrates [Dissertation]. Hangzhou: Zhejiang University, 2008张佳莉. 减水剂对α半水石膏水化硬化过程的影响研究[学位论文]. 杭州: 浙江大学, 2008 [22] Lin Z S. Cementitious Materials Science. Wuhan: Wuhan University of Technology Press, 2014林宗寿. 胶凝材料学. 武汉: 武汉理工大学出版社, 2014 [23] Lan W T. Research on Hemihydrate Phosphogypsum Based Mineral Filling Composites and Its Pipe Flow Performance [Dissertation]. Beijing: University of Science and Technology Beijing, 2019兰文涛. 半水磷石膏基矿用复合充填材料及其管输特性研究[学位论文]. 北京: 北京科技大学, 2019 [24] Jiang G Z, Wu A X, Wang Y M, et al. Low cost and high efficiency utilization of hemihydrate phosphogypsum: Used as binder to prepare filling material. Constr Build Mater, 2018, 167: 263 doi: 10.1016/j.conbuildmat.2018.02.022 [25] Rong K W, Lan W T, Li H Y. Industrial experiment of goaf filling using the filling materials based on hemihydrate phosphogypsum. Minerals, 2020, 10(4): 324 doi: 10.3390/min10040324 -