【作者】 王耀城；

【导师】 马保国；

【作者基本信息】 武汉理工大学 ， 材料学， 2009， 硕士

【摘要】 本论文的研究工作来源于国家科技支撑计划项目“新型墙体材料绿色制造工艺技术与装备”（2006BAF02A29）的子课题《新型自保温承重高孔洞率制品的绿色制造技术与装备》。主要研究内容包括以下方面:1、粉煤灰烧结制品造孔基体选择及高温烧结机理（1）页岩和钠基膨润土等粘结剂掺量的增加,使粉煤灰试样在烧结过程中更加容易出现液相,试件的密实度提高,氧气难于进入试件内部,试件进行无氧烧成,影响试件的一致性。同样,烧成温度和烧成时间也会影响试样的烧成过程及制品性能。（2）使用质量比30%的页岩做粘结剂的试件（A70a30）1050℃保温2h的抗压强度为26.81MPa,明显优于使用30%钠基膨润土的试件（A70b30）的9.82MPa,气孔率为35.49%,低于A70b30试件的48.08%,体积密度为1.58g·cm^-3。与A70a30相比,A70b30试样1050℃最佳烧成保温时间为4h,烧成需要消耗更多时间和能量。（3）粉煤灰制品烧成的最佳配比及温度制度为:A70a30试样,＜400℃时,2℃/min;≥400℃时,3℃/min;1000℃时,保温烧成2h;烧成结束后,试块置于高温炉中自然冷却。（4）页岩的加入可以有效的降低粉煤灰试样的烧成温度,提高试件的耐火度。页岩的小颗粒填充了粉煤灰颗粒间的空隙,增大了试样的堆积密度。页岩中的矿物在较低的温度下形成了可以流动的液相,使烧成的第二阶段提前结束,所以,在烧结温度点时,纯粉煤灰试样的收缩大于掺加了页岩的试样。液相量的增加也加大了试样熔融状态下的粘度,更有利于试样保持原有的形状。温度继续升高使液相表现出更好的流动性,因而掺加页岩的试样在熔融时呈近似半球状塌落,试样底角部尺寸明显增加,顶端尺寸减少,纯粉煤灰表现为竖直方向的不规则膨胀。（5）粉煤灰烧结制品在高温下的主要产物为莫来石与SiO₂。粉煤灰颗粒是高温后形成的玻璃态物质,XRD图谱中各种矿物的峰形都不尖锐,表现出了其玻璃态的性质。页岩中存在Na₂CO₃,可以与莫来石在高温下发生反应,使莫来石分解生成霞石。（6）页岩填充了粉煤灰大颗粒的孔隙,增加了堆积密度,促进了固固反应的进行,增加了高温下生成的液相的数量,降低了试件的烧成温度,使试件的强度发挥的更加充分。2、不同机理的造孔剂对粉煤灰烧结制品性能的影响（1）烧成制品中掺加造孔剂可以抑制试件基体的收缩,降低试件的烧成收缩率;由于各种造孔剂的造孔原理不同,导致了试件抗压强度损失程度的不同;试件的气孔率都有不同程度的提高,体积密度降低。（2）生物质造孔剂（PF、R、S）,在减少试件的体积收缩的效果方面相差不大;由于各种造孔剂自身的体积密度和高温燃烧后的灰分不同,造成试件的质量损失率稍有不同。掺加了S造孔剂试件的抗压强度、气孔率和体积密度等性能优于其他生物质造孔剂。S10试件的强度为12.26MPa,比相同掺量的PF、R试件强度稍高;气孔率为42.43%,比其他两种生物质造孔剂试件高约2%;体积密度为1.32g·cm^-3,低于其它两组试件。（3）矿物内燃型造孔剂（M）可以降低试件的抗压强度损失率,M10试件的抗压强度仍可以达到20MPa的标准;试件的气孔率为43.1%,高于掺加了生物质造孔剂烧成的试件;烧成试样的体积密度较高,为1.38 g·cm^-3。（4）热分解造孔剂（L）控制试件的体积收缩效果较好,直径收缩和高度变化率随掺量的增加降低明显,L15试件的尺寸收缩均降低至约2%;L对抗压强度的影响效果与生物质造孔剂试件相当,L10试件强度约为12MPa;试样的气孔率提高明显,可以达到45%。（5）各种不同造孔机理、不同掺量的造孔剂在影响试件各个区间的孔径分布的规律是一致的,掺加了造孔能力强的造孔剂的试件在每个孔径分布区间的气孔数均高于掺加了相同体积掺量造孔效果弱的试件。（6）类型相近的制品的导热系数与该试件的气孔率、体积密度两因素间均近似呈线性关系。在烧结制品体系中,导热系数y（W/m·k）与气孔率x（%）之间近似的线性关系近似为y=-0.0326x+1.872;y与体积密度z(g·cm^-3)之间的线性关系近似为y=0.4999z-0.1851。更多还原

【Abstract】 This paper is from the sub-project of the national technology support program of China（project No.2006BAF02A29,named Green Manufacturing Processing Technology and Equipment of New Style Wall Material）,Green Manufacturing Technology and Equipment of New Style Self-heat Insulation and Load-bearing Product with High Porosity.Major studying content included four parts:optimal selection of the ratio and sintering system of fly-ash product,sintering mechanism of fly-ash product at high temperature,the effect of different pore former on the characteristic of fly-ash and shale sintering product,the effect of pore former on porosity and thermal conductivity.The main achievements are listed as follows:1.Matrix selection of fly-ash sintering product for pore former and fly-ash sintering mechanism at high temperature（1） With the increasing of agglutinant,shale and sodium base bentonite,there comes out more and more liquid-phase during the procedure of sintering,and the density is much higher,which resist oxygen penetrate into interior of the specimens, so the sample is sintered without enough oxygen,which affects the coherence of the sample.On the other hand,sintering temperature and time affect the properties of the sintering product.（2） The specimens of A70a30,which take 30%of shale（by weight） as agglutinant,sintering at 1050℃for 2h,has the compress strength of 26.81MPa, higher than the sample of A70b30（take 30%sodium base bentonite as agglutinant） 9.82MPa.The porosity of A70a30 is 35.49%,lower than A70b30’s 48.08%,and its density is up to 1.58 g·cm^-3.Comparing with A70a30,the best sintering time for A70b30 is 4h,which use up more time and energy.（3） The best raw material proportion and sintering system for fly-ash system is, sample A70a30,sintered by the system of:＜400℃,2℃/min;≥400℃,3℃/min; holding at 1000℃for 2h;cooling down with the furnace.（4） Shale added into fly-ash powder can decrease the sintering temperature,and enhance the ability of fireproofness.Small particle of shale filled into the bigger gaps of fly-ash particles,which increases the bulk density.Minerals in shale turn to flowing liquid phase at a lower temperature,and make the second part of sintering procedure ended ahead of time,which make the pure fly-ash samples’ shrinkage at the sintering temperature higher than those added with shale.The increasing amount of liquid phase also increases the viscosity of the sample,which has the positive effect of making samples to maintain their appearance.The fluent of the liquid phase is increasing along with temperature’s elevation.So,samples added with shale melt with the shape of semi spherical,the diameter of the bottom increases obviously,and the top is decreases.Pure fly-ash expands irregularly along its vertical axis.（5） Mullite and SiO₂ are the main outcome of the fly-ash sintering product. Fly-ash particle is glass-state material after high temperature.In XRD pattern,the characteristic peaks of its mineral are vague,which proves its glass state.There are Na₂CO₃ in shale,which can react with mullite at high temperature and make the mullite decomposes into nepheline.（6） Shale particles fill the gaps among fly-ash,increase the bulk density,promote solide-solide reaction,increase the amount of liquid phase in high temperature, reduce the sintering temperature,and they benefit the samples’ compressive strength.2.The effect of different mechanism pore former on the characteristic of fly-ash sintering product（1） Pore former added within the sintering product can decrease the shrinkage ratio of the specimens when sintering;because of different pore former mechanism the compress strength losing ratio is distinct from each other,so are the porosity increasement and density decreasement.（2） There are no differences among biological pore formers（such as PF,R,and S） in controlling the sintering shrinkage ratio;Pore formers’ density and ash content after burning make the mass loss ratio different.Specimens added with S have the best property of compress strength,porosity and volume density than those added with other biological pore formers.The strength of specimens S10 is 12.26MPa,much higher than those added with PF10 and S10; the porosity ratio is 42.43%,2%higher than the other two samples;and the volume density is 1.32 g·cm^-3 lower than the rest samples. （3） Mineral-internal-burning pore formers（such as M） can decrease the strength losing percentage,samples M10 still get the strength of above 20MPa,with the porosity of 43.1%,which is higher than those with biologic pore former,the volume density is 1.38 g·cm^-3,higher than other specimens.（4） Thermal decomposition pore formers（such as L） have a better effect in controlling the sintering shrinkage,both diameter and height shrinkages decrease obviously along with the pore former volume increasement,and the shrinkage of L15 decreased to about 2%.L pore former has an equal affection on the compress strength with the biological pore former,sample L10’s strength is about 12MPa,with the porosity of 45%.（5） Added with pore formers of different mechanism,there is a consistency of specimens’ pore size distribution at each interval.Specimens,added with a better effect pore former can increase the number of pores much better at each interval.（6） The thermal conductivity has a nearly linear relationship between porosity and volume density in similar kind of product.In sintering products,the linear relationship between thermal conductivity y（W/m·k） and porosity x（%） is y=-0.0326x+1.872,while that between y and volume density z(g·cm^-3) is y=0.4999z-0.1851.更多还原