高水废弃物的固化减量及机理研究

发布时间：2018-07-25 13:13

【摘要】：随着对资源的大量开发和利用,一种具有高含水率特征的废弃泥浆在能源和环保问题上开始引起人们的重视。目前的固化技术处理成本高、处理量小及应用性差,不能满足高含水率废弃物的固化要求。高水废弃物的固化减量处理对固化体用作农用资源、填充材料、建筑材料等具有重要现实意义。生活污泥作为一种高含水率废弃物,具有含水率高、处理量大等特点,本文将高含水率生活污泥作为主要研究对象,选用磷酸镁钾水泥(MKPC)和复合水泥作为固化剂对生活污泥进行固化,以及复合水泥对高含水率金渣进行固化处理,探究固化剂的配比和掺量对固化体的抗压强度、含水率、增容比、流变性等性能影响。同时利用激光粒度分析、X射线衍射(XRD)分析、扫描电镜(SEM)分析、水化热分析等测试方法,从原料性能、物相组成、显微结构及水化进程进行分析,并探讨了固化机理。主要研究结论如下:(1)在MKPC固化高含水率污泥体系中,固化污泥的强度、流变性、含水率、体积收缩率与污泥含水率、固化剂掺量及硅灰掺量密切相关。随着MKPC掺入量增加,固化污泥的强度逐渐增加,增加的幅度(斜率)与污泥初始含水率密切相关,含水率越低,固化污泥强度越高,当污泥含水率从94%降到85%,掺加20 wt%MKPC的固化污泥3d和7d的抗压强度分别增加了0.47 MPa和2.4 MPa;适量的硅灰掺入可以提高固化污泥的强度,且强度满足填埋要求。MKPC和硅灰显著增加固化污泥的粘度和屈服应力并降低拌合物的工作性。MKPC和硅灰均可以降低污泥的含水率,含水率为94%的污泥经7d固化后,含水率均可降到30%以下,满足填埋要求(60%)。MKPC和硅灰均可降低污泥的体积,固化7d时,掺加30 wt%MKPC的固化污泥增容比为0.53;在掺加30 wt%MKPC条件下,复掺30 wt%硅灰的固化污泥增容比为0.68。随着MKPC掺量从20 wt%增加到40 wt%时,固化污泥7d的体积收缩率从40 wt%增加到62 wt%,MKPC的掺量越大,其体积收缩率越大;当30 wt%MKPC复掺硅灰时,随硅灰掺量增加,固化污泥的收缩率降低。(2)在三元复合水泥固化高含水率污泥体系中,高铝水泥(HAC)/二水石膏(C(?)H_2)和硅酸盐水泥(PC)/高铝水泥均对固化体的力学性能、流变性、矿物组成及水化速率有影响。污泥含水率为94%,固化剂掺量为30 wt%。随着HAC/C(?)H_2比例降低,固化污泥的抗压强度先增大后降低,未出现倒缩;随着HAC/C(?)H_2的降低,固化污泥的粘度和屈服应力也逐渐降低;HAC/C(?)H_2对固化污泥的水化进程有影响,当HAC/C(?)H_2由15/10降低为13/12时,延迟了硅酸盐水泥的水化时间。随着PC/HAC增大,固化污泥的抗压强度先增大后降低,未出现倒缩;且随着PC/HAC的增大,固化污泥的粘度和屈服应力逐渐降低。随着复合水泥固化剂总掺量增大,固化污泥的抗压强度也不断增大,复合水泥固化剂掺量为40 wt%时,3d、7d和28d的抗压强度分别为1.4 MPa、3 MPa和4.8 MPa;当复合水泥固化剂掺量低于20 wt%时,固化体的最高强度将低于200 k Pa,无法满足填埋要求(0.35 MPa)。(3)在复合水泥固化高含水率金渣体系中,金渣的性质、复合水泥的配比对固化金渣的强度、凝结时间、矿物组成有很大影响。其中固化剂掺量为15 wt%,水固比0.53。在HAC-PC-C(?)H_2体系中,试样(HAC:PC:C(?)H_2=15 wt%:10 wt%:75 wt%)1d,7d和28d的抗压强度分别为1.2 MPa,3.4 MPa和2.8 MPa。固化金渣中存在二水石膏的衍射峰,这可能由于金渣含有的可溶性硫酸盐,导致二水石膏在液相中的溶解度太低。在HACPC-CH体系中,试样(PC:HAC:CH=70 wt%:10 wt%:20 wt%)1d,7d和28d的抗压强度分别为1 MPa,3 MPa和5 MPa,且后期强度倒缩不大。以硅酸盐水泥为主体,掺加适量的铝酸盐水泥和少量的熟石灰可形成早期强度高,且强度较为稳定的高标号填充体。熟石灰与高铝水泥缩短固化金渣的初凝时间,获得较好的早期强度,但会引起后期强度的严重倒缩。
[Abstract]:With a large amount of exploitation and utilization of resources, a kind of waste mud with high water content characteristics has begun to pay attention to energy and environmental protection. The current curing technology has high cost, small treatment and poor application. It can not meet the curing requirements of high water cut waste. The curing reduction treatment of high water waste is cured. As a kind of high water cut waste with high water content and large amount of treatment, the living sludge as a kind of high water cut waste has the characteristics of high water content and large amount of treatment. In this paper, the high water cut sludge is used as the main research object, and the MKPC and composite cement are selected as the curing agent to the living sludge. The effects of curing agent on the compressive strength, moisture content, compatibilization ratio and rheological properties of the solidified agent are investigated by the curing and the composite cement to cure the high water content gold slag. At the same time, the laser particle size analysis, the X ray diffraction (XRD) analysis, the scanning electron microscope (SEM) analysis, the hydration heat analysis and other testing methods, from the raw material nature, are used. The main research conclusions are as follows: (1) in the MKPC solidified high water content sludge system, the strength, rheology, moisture content, volume shrinkage of the solidified sludge and the water content of the sludge are closely related to the content of the solidifying agent and the content of silica fume. With the increase of the amount of MKPC, the content of the sludge is increased. The intensities of the sludge increased gradually, the increased amplitude (slope) was closely related to the initial water content of the sludge. The lower the water content, the higher the strength of the sludge, the water content of the sludge decreased from 94% to 85%, the compressive strength of the solidified sludge 3D and 7d added 20 wt%MKPC increased by 0.47 MPa and 2.4 MPa, and a proper amount of silica fume could improve the solidified sludge. The strength of.MKPC and silica fume significantly increased the viscosity and yield stress of the solidified sludge, and reduced the working properties of the mixture.MKPC and silica fume. The water content of the sludge could be reduced. The water content of the sludge with water content 94% could be reduced to less than 30% after 7d curing, which could satisfy the requirement of the landfill (60%).MKPC and silica fume. The volume ratio of the solidified sludge with 30 wt%MKPC is 0.53 when the volume of the sludge is cured for 7d, and the volume shrinkage of the solidified sludge 7d is increased from 40 wt% to 62 wt% when the addition of 30 wt% silica fume is added to 0.68. with the addition of 30 wt%MKPC, and the larger the volume of the MKPC is, the larger the volume shrinkage of the sludge. When 30 wt%MKPC is mixed with silica fume, the shrinkage rate of solidified sludge decreases with the increase of silica fume content. (2) in the three yuan composite cement solidified high water cut sludge system, high aluminum cement (HAC) / two gypsum (C (?) H_2) and Portland cement (PC) / high alumina cement have influence on the mechanical properties, rheology, mineral composition and hydration rate of the solidified body. The moisture content is 94% and the curing agent content is 30 wt%., with the decrease of HAC/C (?) H_2 ratio, the compressive strength of the solidified sludge increases first and then decreases, and does not shrink. With the decrease of HAC/C (?) H_2, the viscosity and yield stress of the solidified sludge are gradually reduced, and HAC/C (?) H_2 has an effect on the hydration process of the solidified sludge, when HAC/C (?) H_2 is reduced from 15/10 to 13/12. The hydration time of Portland cement was delayed. The compressive strength of the solidified sludge increased first and then decreased with the increase of PC/HAC, and the viscosity and yield stress of the solidified sludge decreased gradually with the increase of PC/HAC. The compressive strength of the solidified sludge increased with the increase of the total content of the composite cement solidifying agent, and the composite cement was also increased. When the dosage of the curing agent is 40 wt%, the compressive strength of 3D, 7d and 28d are 1.4 MPa, 3 MPa and 4.8 MPa, and the maximum strength of the solidified cement solidifying agent will be lower than 200 K Pa, which can not meet the requirement of the landfill (0.35 MPa). (3) the properties of the gold slag and the ratio of the composite cement in the composite cement solidified high water content gold slag system. The strength, setting time and mineral composition of the solidified gold slag have a great influence. The dosage of the curing agent is 15 wt%, and the water to solid ratio 0.53. is in the HAC-PC-C (?) H_2 system, the sample (HAC:PC:C (?) H_2=15 wt%: 10 wt%: 75 wt%) 1D, the compressive strength of 7D and 28d is 1.2 respectively, and the diffraction peaks of two water gypsum in the 3.4 and 2.8 solidified gold slag are possible. Because of the soluble sulfate contained in the gold slag, the solubility of two water gypsum in the liquid phase is too low. In the HACPC-CH system, the specimen (PC:HAC:CH=70 wt%: 10 wt%: 20 wt%) 1D, the compressive strength of 7D and 28d are 1 MPa, 3 MPa and 5 MPa, and the later strength is not reduced. The main body of the cement is silicate cement, and a proper amount of aluminate cement and a small amount are added. The early lime and high alumina cement can shorten the initial setting time of the solidified gold slag and get better early strength, but it will cause the severe contraction of the later strength.
【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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