论文总字数：39790字

摘 要

钢渣是钢铁冶金工业排放的固体废弃物，近年来我国钢渣产生量随着钢铁工业的快速发展而迅速递增，大量钢渣堆积，不仅占用土地，而且污染环境，给人民的生活和生存带来了潜在的威胁。

本文从自然界中的生物矿化现象得到启发，利用微生物的酶化作用将钢渣组分C₂S、C₄AF和RO相水化后的活性胶凝产物进行高效固碳，可以制备微生物钢渣固碳制品，不仅可以解决钢渣的污染问题，而且可以在一定程度上缓解由CO₂所引起的温室效应。

本文以熟石灰和石膏作为激发剂，利用工业废渣钢渣微粉，采用固碳效果更显著的钢渣-熟石灰/石膏固碳体系，在微生物的酶化作用下，制备出微生物钢渣固碳制品。通过EDXRF、SEM、XRD、TG-DSC、BET等分析测试手段，验证了钢渣制品的碳化增强效应和微生物的加速矿化效应。结果表明，钢渣制品在经过碳化处理后，抗压强度从5.7MPa提高到11.0MPa，抗折强度从1.3MPa提高到2.4MPa，孔含量从0.112 cc/g降到0.093 cc/g，致密度明显提高。扫描电镜图像和能谱分析的结果则说明，微生物不仅具有加速碳化的作用，而且还能使碳化生成的碳酸钙具有胶凝性，进一步提高制品强度，抗折强度和抗压强度最高分别可达4.6MPa和32.0MPa。

本文在激发剂/钢渣质量比为0.3的基础上对微生物钢渣固碳制品进行配比和工艺的优化设计，并通过多种分析手段加以验证。最终确定最佳石膏掺量为20%，微生物宜选用活性为1.0×10¹¹cell/g的菌粉，水灰比仍取0.50但可适当减小以调控强度。采用先将激发剂制成溶液再加入搅拌锅的方式，确定最佳静停时间为3d，最佳碳化压力为0.4MPa，最佳碳化时间为6h，3d内可以完成钢渣固碳砖的制备。综合优化后配比和工艺制备的标准砖体各项性能良好，比强度达到0.012，是普通砖的两倍，吸水率仅为7.5%，安定性合格，符合MU10级建筑砖的要求。

关键词：钢渣，二氧化碳，碱激发，固碳，微生物

Study on the preparation of carbonated steel slag bricks under the microbial enzyme action

Abstract

Slag is a metallurgical industrial emissions of solid waste in recent years,with the rapid development of the steel industry,more and more slag generated and accumulated, not only occupy the land, but also pollute the environment, brought the threat to people’s survival.

In this paper,inspired by the biological mineralization in nature,using microbial enzyme action to carbonate the activated cementitious products after hydration of C₂S,C₄AF and RO phase which steel slag contains,prepare microbial carbonated bricks of steel slag.It cannot only solve the pollution of steel slag, but also relieve the greenhouse effect caused by CO₂ to some extent.

In this paper,lime and gypsum as alkali activators,industrial waste-steel slag as powder,prepare microbial carbonated bricks of steel slag under the the microbial enzyme action with the slag-lime/gypsum system of which carbonation effect is more remarkable.By EDXRF,SEM,XRD,TG-DSC,BET and other analytical means,the carbonation enhancement effect of steel slag and the accelerated mineralization effect of microorganisms are verified.Results show that the compressive strength of the products increased from 5.7MPa to 11.0MPa, its flexural strength increased from 1.30MPa to 2.40MPa and pore content decreased from 0.112 cc/g to 0.093 cc/g which means induced density increased obviously after carbonation.SEM images and EDS analyses show that the microorganisms not only have the function of accelerating the carbonation, but also make the calcium carbonate cementitious,further improving the strength of the products.The flexural strength and compressive strength were up to 4.60MPa and 32.0MPa respectively.

In this paper,optimally design the mix proportion and technique of the microbial carbonated bricks of steel slag based on which mass ratio of alkali activators and steel slag,being verified through a variety of analytical means as well.Finally determine that the best gypsum content is 20%.Microorganisms which have the activity of 1.0×10¹¹cell/g should be selected.W/C ratio is still 0.50 but can be properly reduced in order to control the strength.Turning alkali activators into solution before adding them into the mixing pot,the preparation of steel slag bricks can be completed in 3 days while determining that the optimal static time is 3 days,the optimal gas pressure is 0.4MPa and the optimal carbonation time is 6 hours.The standard brick,prepared with optimized mix proportion and technique,performs well on all hands.Its specific strength reached 0.012 which was twice as that of common bricks and its water absorption rate was only 7.5%.In addition,its stability was qualified and all of the above performances meet the requirements of the MU10 level building bricks.

Key Words: Steel slag, Carbon dioxide, Alkali activation,Carbonation, Microorganism

目录

摘要 I

Abstract II

第一章 绪论 1

1.1钢渣堆置现状 1

1.2钢渣在建筑材料中的应用现状 2

1.3微生物矿化高效固碳 3

1.3.1矿物固碳 3

1.3.2微生物矿化固碳 4

1.4国内外钢渣固碳砖研究现状 6

1.4.1钢渣的安定性问题 6

1.4.2碱激发活化 7

1.4.3钢渣碳酸化制品 7

1.5本文的研究目的和主要研究思路 8

第二章 微生物提升钢渣高效固碳机制研究 10

2.1实验原材料 10

2.1.1 钢渣 10

2.1.2 激发剂 11

2.1.3 拌合用水及砂 11

2.1.4 微生物菌粉 12

2.2实验设备及方法 12

2.2.1 主要实验设备 12

2.2.2 实验工艺流程 13

2.3钢渣碳化增强效应 13

2.3.1 SEM测试分析 14

2.3.2 EDS测试分析 15

2.3.3 TG-DSC测试分析 17

2.3.4 BET孔分布测试分析 17

2.4微生物加速矿化效应 18

2.5本章小结 22

第三章 微生物钢渣固碳制品配比优化设计 23

3.1激发剂 23

3.1.1钢渣-熟石灰固碳体系 23

3.1.2钢渣-石膏固碳体系 24

3.1.3钢渣-熟石灰/石膏固碳体系 26

3.2固碳微生物 31

3.2.1对固碳效率的影响 31

3.2.2对钢渣制品强度的影响 33

3.2.3对钢渣制品微观结构的影响 34

3.3水灰比 37

3.4本章小结 39

第四章 微生物钢渣固碳制品制备工艺与养护方式 40

4.1钢渣固碳制品制备工艺 40

4.1.1激发剂的添加方式 40

4.1.2试件静停时间 40

4.2养护方式 44

4.2.1碳化压力 44

4.2.2碳化时间 46

4.3钢渣固碳标准砖的制备与性能测试 48

4.3.1制备与养护 48

4.3.2碳化增重率 49

4.3.3密度与比强度 49

4.3.4吸水率 50

4.3.5软化系数 50

4.3.6安定性 51

4.3.7微生物钢渣固碳制品与其他建筑砖的性能比较 51

4.3.8微生物钢渣固碳制品制备成本分析 52

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