贝利特—硫铝酸钡钙水泥熟料形成机制及形成动力学

发布时间：2018-01-16 16:16

本文关键词：贝利特—硫铝酸钡钙水泥熟料形成机制及形成动力学　出处：《济南大学》2014年硕士论文　论文类型：学位论文

【摘要】：贝利特-硫铝酸钡钙水泥是一种新型胶凝材料。与传统硅酸盐水泥相比，水化产物中Ca(OH)2含成量低，耐久性好；体积稳定性好；长期稳定增长；水泥水化热较低；同时该水泥烧成温度低，能耗低，可使用热值低的燃料；水泥熟料的石灰饱和系数低，可使用低品质石灰石。为了有效控制该新型水泥熟料的生产工艺，调控熟料体系的矿相组成和性能，必须研究该新型水泥熟料体系中熟料矿相的形成机制及形成动力学。本文系统研究和分析了该水泥熟料矿相形成机制，建立该水泥熟料体系的形成动力学模型，为工程应用提供理论和技术指导。主要结论如下： BaO、BaSO4和CaF2均能够促进贝利特矿物的形成，其晶型主要为β-C2S和γ-C2S，对稳定β-C2S有重要作用；当BaSO4和BaO掺量分别为3.0%和5.0%时，还能形成少量高水化活性α'-C2S；纯贝利特矿物的形成活化能为206kJ·mol-1，掺杂0.6%CaF2后形成活化能降为164kJ·mol-1，因此，少量CaF2可降低贝利特矿物形成势垒。当煅烧温度为1450℃时，掺杂BaSO4后阿利特主要晶型为M3-C3S，且存在少量的T3-C3S、R3-C3S和T1-C3S；随着BaSO4掺量的增加，试样中阿利特矿物含量降低，表明BaSO4不利于阿利特矿物形成。CaF2能够促进阿利特矿物的形成，当煅烧温度为1380℃时，阿利特主要晶型为M3-C3S、T3-C3S和R3-C3S；随着CaF2掺量的增加，M3-C3S含量增加，T3-C3S和R3-C3S含量变化不大。 C2.75B1.25A3S矿物开始形成的温度为1100℃，大量形成温度为1350℃，分解温度为1370℃。其形成的化学反应方程为： 11/4CA+BaSO4+1/4Al2O3+1/4BaO→C2.75B1.25A3S 11/48C12A7+BaSO4+67/48Al2O3+1/4BaO→C2.75B1.25A3S 1/4CaO+BaSO4+3Al2O3+1/4BaO→C2.75B1.25A3S 11/48C12A7+BaSO4+1/4BA+55/48Al2O3→C2.75B1.25A3SC2.75B1.25A3S矿物的形成受扩散机制的控制，符合的动力学模型为：D4=1-2α/3-(1-α)2/3。在1100-1300℃温度范围内，C2.75B1.25A3S矿物形成的反应活化能为227.5kJ·mol-1；在1300-1380℃温度范围内， C2.75B1.25A3S矿物形成的反应活化能为175.9kJ·mol-1。C2.75B1.25A3S矿物的分解受界面化学反应的控制，符合的动力学模型为：R2=1-(1-α)1/3，分解活化能为449.78kJ·mol-1；主要分解产物为C3A、BA和SO3。在C2S-C2.75B1.25A3S系统中，钡、硫元素的存在使贝利特矿物的形成得到促进，其晶型主要为β-C2S；在1300-1350℃的温度范围内，贝利特矿物的存在为C2.75B1.25A3S矿物的形成提供了表面，降低了C2.75B1.25A3S矿物的形核势垒，促进了该矿物的大量形成，而且使其在高温阶段分解受到抑制。在C3A/C4AF-C2.75B1.25A3S系统中，当煅烧温度为1350℃和1380℃时，高铁含量的中间相能够促进C2.75B1.25A3S矿物的形成，，当中间相含量为16%时，能够促进C2.75B1.25A3S矿物的形成；此外，中间相粘度和含量对C2.75B1.25A3S矿物的生长发育有重要影响。在水泥熟料中，MgO能够促进f-CaO的吸收，促进阿利特矿物和白色中间相的形成。当煅烧温度为1380℃，并且MgO掺量为1.0%时，贝利特矿物有分解的迹象，此时形成的阿利特矿物尺寸较小；当MgO掺量为3.0%-5.0%时，阿利特矿物的尺寸不均匀，且存在大尺寸矿物；当MgO掺量为7.0%时，贝利特-硫铝酸钡钙水泥熟料的安定性不良，这主要是因为形成了MgO矿巢。CaF2能够很好地促进水泥熟料形成，水泥熟料的形成符合的动力学模型为D4=1-2α/3-(1-α)2/3，掺杂0.6%CaF2的水泥熟料的形成活化能为195kJ·mol-1，比未掺水泥熟料形成活化能（250kJ·mol-1）降低了55kJ·mol-1。
[Abstract]:Baillet Calcium Barium Sulphoaluminate Cement is a new cementing material. Compared with the traditional Portland cement, hydration products Ca (OH) 2 with low amount, good durability; good volume stability; long-term stable growth; low hydration heat cement; the cement with low sintering temperature and low energy consumption and can use the low calorific value fuel; cement lime saturation coefficient is low, can use low quality limestone. In order to effectively control the production process of cement clinker, the clinker control system of mineral phase composition and properties, must study the formation mechanism and the formation of clinker mineral phases of the new cement clinker system. This paper studies and analyzes the formation mechanism of the cement clinker minerals, establish the dynamics model of formation of cement clinker system, provide theoretical and technical guidance for the engineering application. The main conclusions are as follows:
BaO, BaSO4 and CaF2 could promote the formation of Baillet minerals, the crystal type is mainly -C2S beta and gamma -C2S, has an important effect on the stability of beta -C2S; when the BaSO4 and BaO content is 3% and 5% respectively, but also the formation of a small amount of high hydration activity of alpha'-C2S; the formation of pure mineral Baillet activation energy is 206kJ mol-1, after 0.6%CaF2 doping formation activation energy reduced to 164kJ and mol-1, therefore, a small amount of CaF2 can reduce the formation of mineral Baillet barrier.
When the calcination temperature is 1450 degrees centigrade, after doping BaSO4 Alite main crystal type is M3-C3S, and there is a small amount of T3-C3S, R3-C3S and T1-C3S; with the increase of BaSO4 content, reduce the content of mineral samples showed that BaSO4 Alite, Alite is not conducive to the formation of minerals.CaF2 can promote the formation of Alite minerals, when the calcination temperature is 1380 DEG C Alite, the main crystal type of M3-C3S, T3-C3S and R3-C3S; with the increase of CaF2 content, M3-C3S content increased, T3-C3S and R3-C3S content changes little.
The temperature of the C2.75B1.25A3S mineral is 1100 C, the temperature is 1350 C and the decomposition temperature is 1370. The chemical reaction equation of the formation is as follows:
11/4CA+BaSO4+1/4Al2O3+1/4BaO - C2.75B1.25A3S
11/48C12A7+BaSO4+67/48Al2O3+1/4BaO - C2.75B1.25A3S
1/4CaO+BaSO4+3Al2O3+1/4BaO - C2.75B1.25A3S
The formation of 11/48C12A7+BaSO4+1/4BA+55/48Al2O3 and C2.75B1.25A3SC2.75B1.25A3S minerals by diffusion mechanism control with dynamic model is: D4=1-2 /3- alpha (1- alpha) 2/3. at 1100-1300 DEG C temperature range, C2.75B1.25A3S mineral formation reaction activation energy is 227.5kJ mol-1; 1300-1380 degrees in the temperature range of C2.75B1.25A3S mineral formation reaction activation energy is controlled by interface decomposition the chemical reactions of 175.9kJ mol-1.C2.75B1.25A3S minerals, with dynamic model is: R2=1- (1-) 1/3, the decomposition activation energy of 449.78kJ - mol-1; the main decomposition products of C3A, BA and SO3.
In the C2S-C2.75B1.25A3S system, barium, sulfur elements to form Baillet minerals can promote the crystal type mainly for beta -C2S; in the temperature range of 1300-1350 DEG C, Baillet minerals provides a surface for the formation of C2.75B1.25A3S minerals, reduced C2.75B1.25A3S mineral nucleation barrier and promote a large number of the mineral formation but, in the high temperature stage decomposition was inhibited. In C3A/C4AF-C2.75B1.25A3S system, when the calcination temperature is 1350 DEG and 1380 DEG C, intermediate high iron content which can promote the formation of C2.75B1.25A3S minerals, when the mesophase content is 16%, C2.75B1.25A3S can promote the formation of minerals; in addition, the intermediate phase viscosity and content are important effect on the growth and development of C2.75B1.25A3S mineral growth.
In the cement clinker, MgO can promote the absorption of f-CaO, promote the alite and white mesophase formation. When the calcination temperature is 1380 DEG C, and the content of MgO is 1%, there are signs of Baillet mineral decomposition, alite small size formed at this time; when the dosage of MgO is 3.0%-5.0%, the size of Alite not even, and there are large size minerals; when the dosage of MgO is 7%, Baillet Calcium Barium Sulphoaluminate Cement Clinker poor stability, this is mainly because of the formation of MgO nest.CaF2 can promote the formation of cement clinker formation, clinker dynamics model with D4=1-2 /3- (alpha 1- a) 2/3, formation of cement clinker doped 0.6%CaF2 the activation energy is 195kJ - mol-1, the activation energy than those of cement clinker formation (250kJ mol-1) - mol-1. reduced 55kJ

【学位授予单位】：济南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TQ172.1

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