论文总字数：36659字

摘 要

碱激发胶凝材料是一种先进的固化剂，能够固定稳定重金属污染土中的有毒重金属，有效修复重金属污染场地。其具有工艺简单、成本低廉、节能环保等优点，是一种具有巨大潜力的绿色材料。目前我国对石灰基碱激发胶凝材料的研究相对较少，本文结合碱激发胶凝材料固化剂的研究现状，开展关于使用氧化钙激发的工业废渣对甘肃省白银市的重金属Pb、Zn、Cd污染黏土固化稳定化效果的研究，通过毒性浸出试验、电导率EC测试、pH测试和无侧限抗压强度试验，分析固化土体的浸出毒性、物理化学指标和力学指标，明确了石灰基碱激发胶凝材料中各组分的质量配比，优选出了价格低廉、效果优异的石灰基碱激发胶凝材料固化剂。主要结论如下：

（1）通过预备试验，对固化剂材料进行了初步筛选。研究表明，在使用氧化钙作为碱激发剂时，添加粉煤灰可以使固化剂效果大幅度上升。

（2）研究了氧化钙含量对固化剂固化稳定化效果的影响。试验结果表明，氧化钙含量为30%时试样的无侧限抗压强度最强，浸出液重金属浓度最低。可推测在一定的数值范围内，随着氧化钙含量的增加，固化剂固化稳定化的效果呈现上升趋势。

（3）研究了粉煤灰与钢渣的质量比对固化剂效果的影响。试验结果表明，随着粉煤灰质量的增加，试样的无侧限抗压强度会上升，然而浸出液中的重金属浓度会上升。由于固化剂的首要任务为降低试样的浸出毒性，故相比之下，应优先使用固化稳定化效果好的固化剂，即确定粉煤灰与钢渣质量比为2:8。

（4）研究了GGBS对固化剂效果的影响。试验结果表明，使用GGBS的试样的无侧限抗压强度与使用钢渣的试样相差无几，而两者浸出液中的重金属浓度却相差甚远，以GGBS为组分的固化剂的固化稳定化效果要远差于以钢渣为组分的固化剂。

通过各项对比，在本试验设计的固化剂配方中，氧化钙质量所占比为固化剂总质量的30%，粉煤灰与钢渣的质量比为2:8时，固化剂的效果最好，然而其对Cd 的固化稳定化效果仍未达标，还需开展后续研究。同时，本文还通过重金属吸附试验，对可能存在的未反应的工业废渣的吸附性进行了研究。数据表明在未经激发的情况下，GGBS的吸附性最强。

关键词：重金属污染土，碱激发胶凝材料，工业废渣，固化稳定化，浸出毒性

Solidification and Stabilization of Heavy Metal Contaminated Clay with Lime-activated Cementitious Materials and the Adsorbability of Industrial Residues

Abstract

Alkali-activated cementitious materials is an advanced curing agent, which has the advantages of simple process, low cost, energy saving, etc. It can solidify and stabilize the heavy metal in the contaminated soil. There are relatively few researches on lime-activated cementitious materials in China. Based on the existing research of the alkali-activated cementitious materials， this paper focus on the effect of the lime-activated industrial residues on the solidification and stabilization of heavy metals Pb, Zn, and Cd contaminated clay in Baiyin City, Gansu Province. Through toxic leaching test, conductivity EC test, pH test and the unconfined compressive strength test, this article analyzes the leaching toxicity, physical and chemical indicators and mechanical indicators of the solidified soil, clarifying the mass ratio of each component in lime-activated cementitious materials. Finally, the lime-activated cementitious material with low cost and excellent effect is found. The

(1) Through preliminary test, it is determined that which materials can be used. It is shown that when calcium oxide is used as an alkali activator, addition of fly ash can significantly increase the effectiveness of the curing agent.

(2) The influence of calcium oxide content on the effect of curing agent is tested. The test results show that when the content of calcium oxide is 30%, the unconfined compressive strength of the sample is the strongest, and the concentration of heavy metal in the leachate is the lowest. It can be speculated that within a certain range of values, as the content of calcium oxide increases, the effect of curing agent tends to increase.

(3) The influence of the mass ratio of fly ash and steel slag on the effect of curing agent is studied. The test results show that with the increase of the fly ash mass, the unconfined compressive strength of the sample will increase, but the concentration of heavy metals in the leachate will also increase. As the primary task of the curing agent is to reduce the leaching toxicity, it is certain that the curing agent with good curing and stabilization effect should be used preferentially, which means the mass ratio of fly ash to steel slag should be determined to be 2:8.

(4) The influence of GGBS on the effect of curing agent is studied. The test results show that the unconfined compressive strength of samples with GGBS is almost the same as that of samples with steel slag. However, the concentration of heavy metals in the leachate is quite different, which means the curing agent with GGBS is far less effective than the curing agent with steel slag.

At last the formula—the proportion of calcium oxide is 30% and the mass ratio of fly ash to steel slag is 2:8—is found to be the most effective. However, the effect of solidification and stabilization of Cd is still not up to standard, and follow-up studies are needed. At the same time, heavy metal adsorption tests are carried out to study the adsorbability of the excess industrial residues. The data indicates that GGBS has the strongest adsorption capacity without being alkali-activated.

KEY WORDS: Heavy Metal Contaminated Soil, Alkali-activated Cementitious Materials, Industrial Residue, Stabilization and Solidification, Leaching Toxicity

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1 研究背景与意义 1

1.2 国内外研究现状 1

1.2.1 固化稳定化技术 1

1.2.2 水泥固化机理及传统水泥基材料的局限性 2

1.2.3 碱激发胶凝材料 2

1.3 本文研究内容与技术路线 4

1.3.1 本文研究内容 4

1.3.2 本文的技术路线 5

第二章 试验基础依托及前期筛选 6

2.1 试验概述 6

2.2 试验材料与设备条件 6

2.2.1 甘肃省白银市污染土 6

2.2.2 固化剂组分 7

2.2.3 试验设备 7

2.3 试样制备与养护 7

2.4 预备试验 7

2.4.1 预备试验概述 7

2.4.2 SPLP硫酸硝酸法 8

2.4.3 浸出毒性结果分析 9

2.5 本章小结 11

第三章 石灰基碱激发胶凝材料固化剂的试验研究 12

3.1 概述 12

3.2 试验材料及试验方案 12

3.2.1 试验材料 12

3.2.2 试验方案 13

3.3 固化土体理化特性及无侧限抗压强度 13

3.3.1 固化土体浸出液的pH和电导率EC值 13

3.3.2 无侧限抗压强度 17

3.4 浸出毒性结果分析 19

3.5 本章小结 23

第四章 重金属吸附试验 24

4.1 概述 24

4.2 试验材料及试验方案 24

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