【作者】 陈湘湘；

【导师】 管宗甫；

【作者基本信息】 郑州大学 ， 材料学， 2013， 硕士

【摘要】 我国很多水泥企业,石灰石矿产资源都是含MgO较高的低品位石灰石。尽管通过生产控制迫使水泥压蒸安定性合格,但往往会给生产控制带来困难。高MgO矿带的剥离也降低了矿山收益,并可能会带来环境的影响,同时高镁熟料的后期强度也较低。因此,研究如何采用高镁石灰石生产出合格的水泥熟料对于利用低品位原料来说至关重要。本文依托于"973"项目(2009CB623101)“高介稳Alite在熟料体系中形成、结构与性质”开展研究,试图利用离子掺杂使氧化镁朝着有利的方向固溶,在定向诱导M2+固溶的同时,尽可能地促进f-CaO的吸收及硅酸相晶体的发育,改变硅酸盐的晶体结构,使阿利特水化活性提高,以达到优化高镁熟料的强度的目的,实现低品位原料的综合和高附加值利用。经过试验分析,得出以下结论：(1)当熟料中MgO固定为5%时,在SM=2.2-3.2的范围内,随着SM值的增大,熟料中MgO固溶量从2.94%降到了1.94%。低SM及低IM有利于固溶,KH则影响不大。随SM的增大,熟料的28d抗压强度从60.2Mpa增大至64.0Mpa,而90d抗压强度则从64.1Mpa逐步增大至71.8Mpa。但当SM高于3.0时,随着SM的增加,熟料28d、90d抗压强度已经接近饱和,变化不大。另外,随着KH值的增加,熟料3d、90d抗压强度不断增大,28d抗压强度基本不变。结合固溶和强度,对于高镁体系,实际生产中若要生产高阿利特熟料,可采用稍高的KH,稍低的SM和IM。(2)一定范围固定S03掺量,S03或CaF2均能有效促进熟料中MgO的固溶与吸收。且当CaF2掺量≤0.25%时,在CaF2掺量不变的情况下,MgO固溶量随S03含量增加而增加,最高固溶量为3.97%左右。但是,随着熟料中CaF2固定掺量的增加,S03含量对MgO的固溶影响越来越弱。在S03小掺量范围内(S03≤1.2%)时,CaF2掺量的增加更利于熟料中MgO的固溶。单掺S03时,熟料28天抗压强度都随着S03掺量变大而有所降低。在掺杂适量的CaF2的前提下,掺加一定量的S03有助于提高高镁熟料的抗压强度,但存在一个最佳掺量(S03=0.8%)。当生料中掺杂SO3相同时,掺杂有0.25%CaF2的样品28天强度基本上比不掺CaF2的提高大约2～6MPa左右。且熟料中CaF2的含量越高,水泥熟料的后期强度也越高。而在熟料中同时含有S03和MgO时,室温下能稳定M2-M3型的的阿利特。且在掺杂一定量的SO3时,随着熟料中CaF2含量的提高,阿利特的对称性也逐步提高。(3)单掺Ca(H2PO4)2·H2O时,随着P205含量的提高,水泥熟料28天抗压强度略有提高。单掺P205若要获得高强度的高镁熟料,需要比较高的含量(P205≥0.8%)。在F-含量相同的情况下,复合掺加Ca(H2PO4)2·H2O或CaHPO4.2H2O均有利于提高高镁熟料的后期强度,最高能达到70MPa左右。但是磷离子存在最佳掺量(0.2%～0.4%),过高或过低则作用不明显。在掺加有适量CaF2时,掺加磷酸氢钙和磷酸二氢钙均有利于熟料中MgO的固溶,最高固溶量为4.76%左右。但是掺加磷酸氢钙比磷酸二氢钙更有利于熟料中MgO的固溶。当熟料中f-MgO含量较低时(小于2%),微量的f-MgO含量的变化已经不是影响强度的主要因素。在本实验掺量范围内,单掺CaF2只能使C3S固溶体稳定在M2-M3型之间。而在此基础上,适当掺加0.2%的Ca(H2PO4)2·H2O,能使C3S固溶体稳定在M3-R型之间。但是,外掺Ca(H2PO4)2·H2O时存在最佳掺量,当其含量过高(0.80%)时,C3S固溶体的晶型又降低到M2-M3型之间。在本实验掺量范围内,C3S晶型变化是高镁熟料强度变化的主要原因。(4)采用废渣掺杂的方案不仅适用于高镁熟料,也适用于低镁的正常熟料。在低饱和比(KH=0.87)的情况下,采用PZR+F废渣方案或PG+F废渣方案都可以利用高MgO、低CaO的低品位石灰石获得强度高于57MPa的水泥熟料,但若要获得高强度(≥60Mpa)的熟料需要适当地提高KH值或提高废渣掺量。而采用F废渣+PS方案配料时,即使饱和比较低(KH=0.87),也能生产出28天抗压强度高于75MPa的高标号的水泥熟料。利用PZR+F废渣掺杂的配料方案在设备条件正常时,可以生产出28天抗压强度在68MPa以上的熟料。且该方案具有较好的易烧性和窑炉适应性,飞沙、结圈等不正常窑况较不掺废渣的生产方案好。且与实验前正常生产时相比,采用PZR+F废渣掺杂方案可以实现窑炉系统产量不降低,热耗不增加的目的。更多还原

【Abstract】 For many cement enterprises in China, the limestone mineral resources are low grade limestone with high MgO. Although the autoclave soundness qualified through cement production control, but often will bring difficulties to the production control. The belts with high MgO are stripped also will reduce the mining income, and may bring about the environmental impact, and the late strength of high magnesium clinker is lower. Therefore, to study how to use high magnesium limestone to produce qualified cement is of vital importance.This article rely on the "973" project (2009CB623101):The Formation, Structure and the Properties of the High Metastable Alite in the Clinker System. Attempt was made to use the ion doping make magnesium oxide solid solution in a favorable direction. With the directional solid solution of Mg2+caused by chemical doping, as far as possible to promote the absorption of the f-CaO and the development of silicate phase. And, try to change the crystal structure of the silicate and increase the hydration activity of Alite. Ultimately achieve the goal of optimization of the strength of the magnesia clinker and realize the comprehensive and high value-added utilization of low grade raw materials. After the test analysis, several conclusions could be obtained:(1) With the increasing of SM, the concentration f-MgO presents an obvious increasing process within the scope of the SM=2.2～3.2when the total MgO in clinker was5%. The solid solution of MgO is decreaseing from2.94%to1.94%. Low SM and IM are conducive to the solid solution of MgO, but KH has little effect on it. Along with the increase of SM, the28d compressive strength of clinker increases from60.2Mpa to64.0Mpa and the90d compressive strength gradually increases from64.1Mpa to71.8Mpa.However, when the SM is higher than3.0, the28d and90d compressive strength of clinker change little with the increase of SM. In addition, with the increase of KH, the3d and28d compressive strength is increasing, but the28d compressive strength of cement basically remains unchanged. Combination of solid solution and strength, to produce high alite and high-Magnesia clinker should be used in the high KH, slightly lower SM and IM.(2) Fixed a certain amount of SO3, doping appropriate content of SO3and CaF2can effectively promote the solution of MgO in clinker. On the basis of the doping of CaF2, the solid solution of MgO show a trend of increases with the increase of SO3when CaF2<0.25%. The highest amount of solid solution is approximately3.97%. However, with the increase of CaF2is fixed in the clinker, the impact of SO3on the MgO solid solution is increasingly weak. When the content of SO3is smaller (SO3≤1.2%), the increased doping amount of CaF2is more conducive to the solid solution of MgO in the clinker. When doping with SO3independent, the28days compressive strength decrease obviously with the increase of SO3. When adding suitable amount of CaF2, adding a certain amount of SO3help improve the compressive strength of clinker, but there is a optimal amount (SO3=0.8%). When the content of SO3is equal, the strength of the samples which doped with0.25%CaF2are higher than which not about2-6MPa. And the higher content of CaF2in the clinker, later strength of cement clinker is also higher. The clinker containing with SO3and MgO, Alite can stable at M1-M3type in the room temperature. And, when mixed with a certain amount of SO3, with the improvement of content of CaF2in the clinker, the symmetry of Alite is also gradually improves.(3) When doping with Ca(H2PO4)2·H2O independent, the28days compressive strength increase slightly with the increase of P2O5. To obtain high strength magnesia clinker, single doped P2O5require higher levels. In the case of the same content of F, composite mixing Ca(H2PO4)2·H2O or CaHPO4.2H2O are conducive to high magnesium clinker late strength, and the highest strength can reach about70Mpa. But, the content of phosphorus ion exist the best dosage (0.2%-0.4%), too high or too low, effect is not obvious. When adding suitable amount of CaF2in the clinker, composite mixing CaHPO4.2H2O or Ca(H2PO4)2.H2O are conducive to the clinker in the MgO solid solution. The highest amount of solid solution is approximately4.76%. But, adding CaHPO4.2H2O is more advantageous than Ca(H2PO4)2·H2O on the solid solution of MgO in the clinker. When the content of f-MgO in clinker is low (<2%), the slightly change of content of f-MgO is not the main factor which affects the strength of clinker. In the scope of this experiment, single doped CaF2can only stable C3S at between M2and M3type. But on this basis, appropriate mixing with0.2%Ca(H2PO4)2.H2O can make the C3S solid solution stable at between M3-R type. However, the content of Ca(H2PO4)2.H2O exists the best dosage. When its content is too high (0.80%), the crystal structure of C3S solid solution reduce to between the M2and M3type.(4) Slag doped solution applies not only to the high magnesium clinker, is also applicable to the normal clinker which with low magnesium. In the case of low KH (KH=0.87), use the PZR+F slag solution or PG+F slag solution can be obtained of the cement clinker which strength is higher than57Mpa when the limestone is high magnesium and low calcium. But if you want to obtain high strength clinker (≥60Mpa), KH value or the content of slag should be improved. It is also capable of producing a clinker which compressive strength is more than75MPa even if the KH is relatively low (KH=0.87) when using the scheme of F slag+PS. And the factory can produce a clinker which compressive strength is more than68MPa under normal conditions when using the scheme of PZR+F slag. And the scheme has a good easy to burn and kiln adaptability. When using this scheme, the sand, ring and other abnormal conditions is better than the plan without slag admixture. Compared with normal production before the experiment, the plan of PZR+F slag can be accomplished by the production does not reduce and the heat consumption does not increase.更多还原