论文总字数：28403字

摘 要

磷石膏是湿法生产磷酸过程中得到的副产物，属于工业废渣，磷石膏长期堆积不仅占用大量土地，还会对环境造成影响，因此磷石膏的开发利用非常重要。目前，针对磷石膏制备建筑胶凝材料的研究较多，但其大部分都对磷石膏进行了预处理，如：水洗、煅烧、石灰中和、球磨、浮选以及筛分等。这些预处理工艺不仅工艺繁琐，还增加原料成本，甚至会带来二次环境污染。本文针对以上问题，研制了一种磷石膏基复合胶凝材料，其以未经预处理的磷石膏为主要原料，复配矿渣、少量水泥和外加剂而制成，不仅为大量利用磷石膏提供了一条非常好的途径，而且具有较高的经济、社会和环境效益。本文研究了，磷石膏掺量、矿渣与水泥的比值、硅灰掺量、无机保水剂掺量以及外加剂的种类和掺量对磷石膏基复合胶凝材料水泥浆的标准稠度需水量、初终凝时间以及硬化体的干、湿抗压强度。实验结果表明，磷石膏的掺量为50%时，矿渣与水泥的比值为4:1，外掺3%的硅灰，磷石膏基复合胶凝材料浆体标准稠度需水量为30.8%，初终凝时间分别为606min和872min。硬化体7d和28d湿抗压强度能够达到25.86 MPa和38.25 MPa。由于水泥浆的析水较严重，选择加入适量无机保水剂来提高浆体的保水效果，无机保水剂掺量为2%时，标准稠度需水量为32.4%，7d和28d湿抗压强度达到28.73 MPa和42.19 MPa。不同的外加剂及掺量也影响磷石膏基复合胶凝材料的性能，掺入CaCl₂能明显提高初终凝时间，但其掺量超过1%时，硬化体7d后强度明显下降，并出现较明显的裂纹；Na₂SO₄对初终凝的影响优于CaCl₂，其掺量为3%时，3d湿抗压强度增加明显，较未掺的增加了623.27%，而7d和28d湿抗压强度增加不明显。水玻璃对初终凝的影响最大，掺量为3%时，初终凝时间分别为117min和337min，对3d湿抗压强度提高较多，对7d和28d湿抗压强度无明显影响；CaCO₃对初终凝时间影响较小，对强度影响也不明显。所以，应选择合适的外加剂及掺量。

关键词：磷石膏 外加剂 标准稠度 初终凝时间 抗压强度

ABSTRACT

Phosphogypsum is a byproduct of the wet process phosphoric acid production obtained, belonging to industrial waste, the long-term accumulation of phosphogypsum not take up a lot of land, but also impact on the environment, so the development and utilization of phosphogypsum is very important. Currently, the study of the preparation for phosphogypsum building cementitious materials is more, but most of them were pretreated for phosphogypsum, such as washing, calcined lime neutralization, milling, flotation and sieving. The pretreatment process is not only cumbersome, but also increase the cost of raw materials, or even bring secondary pollution. Aiming at these problems, a gypsum based composite cementitious materials was developed, which in non-pretreated phosphogypsum as the main raw material, complex slag, a small amount of cement and additives made, it not only provides for the extensive use of phosphogypsum a very good way, but also has high economic, social and environmental benefits. In this paper, phosphogypsum content, the ratio of slag and cement, silica fume, mineral aquasorb content and the type and dosage of admixtures affect phosphogypsum based composite cementitious material grout standard consistency water demand, the beginning and final setting time, the hardening body dry and wet compressive strength. Experimental results show that the content of phosphogypsum 50%, the ratio of slag and cement 4:1, mixed with 3% silica fume, gypsum based composite pastes standard consistency water demand was 30.8% ,initial and final setting time was 606min and 872min. Hardened 7d and 28d wet compressive strength can reach 25.86 MPa and 38.25 Mpa. Because the grout analyze water more serious, the amount of inorganic aquasorb opt to increase water retention effect, inorganic aquasorb content of 2%, standard consistency water demand is 32.4%, 7d and 28d wet compressive strength 28.73 MPa and 42.19 MPa. Different admixtures and content also affects phosphogypsum based composite cementitious material properties, the incorporation of CaCl₂ can significantly improve initial and final setting time, but its content over 1% strength after 7d hardened significantly decreased, and there was a apparent cracks; Na₂SO4 impacts on the initial and final setting time is better than CaCl2, when its content is 3%, 3d wet compressive strength increased significantly, compared to undoped increased 623.27%, while the wet 7d and 28d compressive strength increased insignificantly; sodium silicate impacts on the initial and final setting time is most, when the content is 3%, the initial and final setting time is 117min and 337min, increased the 3d wet compressive strength more, no significant effect on the wet compressive strength 7d and 28d; CaCO₃ little impacts on the initial and final setting time, and the intensity of the impact is not significant. Therefore, we should choose a suitable additives and dosage.

Keywords : phosphogypsum gypsum admixtures standard consistency initial and final setting time compressive strength

目 录

摘 要 I

ABSTRACT II

第一章 文献综述 1

1.1 前言 1

1.2 有关磷石膏的应用 2

1.2.1 磷石膏在建材方面的应用 2

1.2.2磷石膏在农业方面的应用 4

1.2.3磷石膏在水泥工业上的应用 5

1.2.4磷石膏开发利用研究的热点领域 8

1.3 磷石膏复合材料的缺点和改性 9

1.4 总结 10

第二章 实验部分 11

2.1 研究思路 11

2.1.1 研究内容 11

2.1.2 实验内容及要求 11

2.1.3 实验主要测量的数据 11

2.2 实验方案 12

2.2.1 实验原料 12

2.2.2 实验仪器 13

2.2.3 试验方法 14

第三章 实验结果与讨论 16

3.1 磷石膏掺量对磷石膏基复合胶凝材料性能的影响 16

3.1.1 磷石膏掺量对磷石膏基复合胶凝材料浆体性能的影响 16

3.1.2 磷石膏掺量对磷石膏基复合胶凝材料硬化体性能的影响 16

3.2 矿渣与水泥的比值对磷石膏基复合胶凝材料性能的影响 17

3.2.1 矿渣与水泥的比值对磷石膏基复合胶凝材料浆体性能的影响 17

3.2.2 矿渣与水泥的比值对磷石膏基复合胶凝材料硬化体性能的影响 18

3.3 硅灰掺量对磷石膏基复合胶凝材料性能的影响 18

3.3.1 硅灰掺量对磷石膏基复合胶凝材料浆体性能的影响 18

3.3.2 硅灰掺量对磷石膏基复合胶凝材料硬化体性能的影响 19

3.4 无机保水剂掺量对磷石膏基复合胶凝材料性能的影响 20

3.4.1 无机保水剂对磷石膏基复合胶凝材料浆体性能的影响 20

3.4.2 无机保水剂对磷石膏基复合胶凝材料硬化体性能的影响 21

3.5不同外加剂及掺量对磷石膏基复合胶凝材料性能的影响 21

3.5.1 不同外加剂对磷石膏基复合胶凝材料浆体性能的影响 21

3.5.2 不同外加剂对磷石膏基复合胶凝材料硬化体性能的影响 23

第四章 结论 27

参考文献 28

致谢 31

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