【作者】 马先伟；

【导师】 陈胡星；

【作者基本信息】 浙江大学 ， 材料学， 2004， 硕士

【摘要】 提高C₃S含量，是获得高胶凝性硅酸盐水泥的有效途径，但熟料的烧成将同时变得困难，也即存在易烧性与胶凝性的矛盾，因此，要获得高C₃S熟料，提高相应的高钙生料的易烧性是关键。本文研究各种外掺氧化物对高钙生料易烧性的影响，旨在为寻找在能显著改善高钙生料易烧性的物质提供依据。 以高钙生料（潜在熟料矿物C₃S=75％、C₃A=8％、C₄AF=17％）为基准样，分别外掺2％TiO₂、ZrO₂、CuO等30多种氧化物，在1300℃和1400℃温度下煅烧，测定熟料的游离氧化钙。结果表明，外掺氧化物对易烧性的作用效果在高温煅烧和低温煅烧条件下有很大的差异：（1）在1400℃时，改善易烧性作用由大到小依次为：TiO₂＞ZrO₂＞WO₃＞MnO₂＞PbO＞Co₂O₃＞MgO＞基准样＞ZnO＞Cr₂O₃＞P₂O＞BaO＞CuO＞Li₂O；在1300℃时依次为：CuO＞Co₂O₃＞ZnO＞Li₂O＞Cr₂O₃＞PbO＞WO₃＞ZrO₂＞TiO₂＞MnO₂＞MgO＞P₂O₅＞BaO＞基准样。（2）各种外掺氧化物对高钙生料易烧性的作用效果可以归纳成以下几种情况：在较低温（1300℃）煅烧阶段明显改善易烧性，但在高温（1400℃）煅烧阶段则不明显或有变差的趋势；在低温煅烧阶段改善易烧性不明显，但在高温阶段效果显著；在高温阶段易烧性明显变差。 在此基础上，对TiO₂、Li₂O，BaO，CuO，Co₂O₃等几种有代表性的氧化物进行了深入的研究，包括测定不同掺量及不同煅烧温度情况下熟料的游离氧化钙，并通过XRD、SEM和DTA等手段对对熟料矿物形成、结晶和固溶等状况进行分析。结果表明：（1）TiO₂高温掺杂矿化效果显著，而低温情况较差。当TiO₂掺量大约在2％左右时，对改善高钙生料易烧性效果较佳，而且C₃S的结晶良好。TiO₂在C₃S中的固溶量大约1.7％，高于这个值时将生成TiO₂·CaO。（2）CuO表现为较好的低温掺杂矿化效果，而在高温情况较差。随CuO掺量增加，高钙生料的易烧性先变差，当超过某一掺量以后又变好，这个掺量随温度升高而变大。CuO在C₃S固溶量是1.2％，但是超过1.2％并没有发现生成新相。掺入CuO以后，促进C₃S结晶。（3）Li₂O，BaO高温掺杂矿化效果很差。LiO₂缩小碳酸钙分解的温度范围，使之在较高的温度下分解，这种作用随着掺量的增加，开始减弱。随着BaO，Li₂O掺量的增加，生料的易烧性变差。BaO，Li₂O对C₃S结晶不利。 本文还对外掺氧化物影响高钙生料易烧性的机制进行了探讨，认为外掺氧化物对高钙生料易烧性的影响，在较低的煅烧温度阶段，通过改变高温液相起主导作用，凡是对提高液相量、降低粘度和液相出现的温度效果明显的氧化物，其改善易烧性的作用就明显，如CuO；而在较高的煅烧温度下，通过离子的固溶起主导作用，在较高的温度下，液相的作用相对较为次要，其阳离子与Si⁴⁺相似，则对吸收游离氧化钙有利，如TiO₂，而阳离子与Ca²⁺相似，则对吸收氧化钙不利，如BaO。更多还原

【Abstract】 Increasing the content of C3S in cement is a best way of gaining high strength cement, but means the higher burning temperature. This paper is for finding a solution of the problem. We research the effect of foreign oxides on the burnability of high CaO cement raw mixes with the change of temperature und content of foreign oxides by XRD, SEM and DTA.According to potential mineral C3S=75% C3A=8% C4AF=17%,the based sample are mixed with chemical reagents, then added 2% oxide, and burnt at 1300℃ and 1400℃. We find the difference of the effect on burnability between lower and higher temperature by fCaO: (1) at 1300℃ CuO>Co2O3>ZnO>Li2O>Cr2O3>PbO> WO3 > ZrO2 > TiO2 > MnO2 > MgO > P2O5 > BaO > reference sample, at 1400℃ TiO2 > ZrO2 > WO3 > MnO2 > PbO > Co2O3 > MgO > reference sample > ZnO > Cr2O3 > P2O5 > BaO > CuO > Li2O. (2) the effects was concluded as following: Evidently positive in low temperature (1300℃) but no observably positive or negative in high temperature (1400℃); No markedly positive in low temperature but evidently positive in high temperature; remarkably negative in high temperature.We further study TiO2, WO3, BaO, LiO2 and CaF2 with different temperature und different contents by ethylene glycol method, XRD, SEM and DTA. We find: (1) TiO2, WO3 have good effect on burnability(1350℃), but they are bad at lower temperature (1300℃), for the TiO2 sample there is an optimal content, when the content exceed 2% the burnability go bad; Proper TiO2 contributes the formation and crystallization of C3S, but excessive TiO2 is adverse; The solubility of TiO2 is 1.7%, in excess of 1.7% TiO2 CaO appear. (2) CuO has evidently positive in lower temperature, but negative in higher temperature; With increasing of the content, for CuO the burnability become firstly bad, then better, the difference between 1350℃ and 1400℃ is that the extremum moves to the higher content; CuO favors the formation and crystallization of C3S; the solubility of CuO is 1.2%, but in excess of 1.2% no new phase appears. (3) Li2O, CaF2, BaO have evidently positive in lower temperature, but no observably positive or negative in higher temperature; for BaO and Li2O the burnability become bad with increasing of the contents; Li2O and BaO accelerate the formation of C3S at lower temperature, but at higher temperature prevent crystallization of C3S; Li2O narrows the temperature range of decomposition of calcium carbonate and make it decompose in higher temperature. The sample containing 4% Li2O shows two-step decomposition which has tendency to widen temperature range.At lower temperature foreign oxides mostly affect the property of liquid phase; at higher temperature mainly alter the structure of silicate mineral. Similar to the property of Si, foreign ions favor free CaO consumed; similar to the property of Ca, they prevent free CaO consumed.更多还原