摘 要

近年来，我国的水污染问题日益严重，生活用水、工业用水的排放使得江河湖水等富营养化，水质颜色改变，废弃物四处漂浮。城市生活用水大多取自江河湖水，生活饮用水安全问题开始受到各界人士的广泛关注。社会需要合适的吸附净化方法来解决这一问题，故吸附材料的选择与性能的研究显得尤为重要。本文着重探究水热试验前后硅藻土物相的变化，目的是使硅藻土的固化强度发生改变，期望它能被制成高强度的陶粒作为吸附材料缓解水污染问题，因此探究硅藻土的物相变化对我国研究水环境的治理有一定的指导作用。

文中采用Na₂CO₃作助熔剂，对硅藻土进行焙烧，用Ca(OH)₂对硅藻土进行改性。本文作者分别对Ca(OH)₂与天然硅藻土以及焙烧硅藻土两种进行试验研究，对水热处理改性后的硅藻土的物相进行分析，作者还进行了熟石灰-天然硅藻土、熟石灰-焙烧硅藻土对染料吸附性能影响的简单探究，以期望经过改进后的硅藻土能作为新的吸附材料为废水应用处理提供科学依据。本文主要针对产地为吉林省长春市的硅藻土精矿做了焙烧试验研究、水热处理研究以及吸附性能测试，得出了以下结论：

（1）焙烧试验研究表明：硅藻土焙烧后，孔径大小分布和结构发生变化，当助熔剂添加量为3%～8%时，焙烧样中出现了方解石物相。本文通过控制焙烧时间与焙烧温度来获得所需的焙烧硅藻土作为试验原材料，发现随着温度逐渐升高，焙烧的样品硬度与粒度有一个峰值变化，在时间条件下同样有这个趋势。经过大量的焙烧试验笔者发现：在助熔剂质量分数为5%，焙烧的时间长度控制在40min，焙烧的温度控制在800℃的条件下时能够得到符合本文要求的焙烧硅藻土。

（2）水热处理研究表明：在不同的条件下，硅藻土经过水热处理后生成硅酸钙水凝胶的含量有较大差异：当熟石灰用量增加时，XRD图中出现更强的托勃莫来石衍射峰；天然硅藻土与焙烧硅藻土在不同时间、温度处理下峰值条件不同。

（3）吸附性能测试表明：焙烧样吸附性能的强弱与其XRD衍射峰上在2θ=8°位置的托勃莫来石峰的强度有关联，通过对试验结果的分析推断出衍射峰的强度与吸附性能呈正比关系。

关键词：硅藻土，水热合成，熟石灰，托勃莫来石

Abstract

In recent years, China's water pollution problem become more and more serious. For example, domestic water, industrial water emissions make rivers, lakes and seas eutrophication. Not only the water’s color have changed, but also some waste are floating around the water areas. Most of the urban life of domestic drinking water from the rivers and lakes, So that drinking water safety issues began to be widespread concern from social attention. Society needs a suitable adsorption purification method to solve this problem, so the choice of adsorption materials and performance research is particularly important. This paper focuses on the change of the diatomite phase around the hydrothermal test. The aim is to change the curing strength of diatomite. It is expected that it can be made into high-strength ceramsite as adsorbent to alleviate water pollution. The change of soil phase has a certain guiding effect on the study of water environment in China.

In this paper, the diatomite was calcined with Na₂CO₃ as flux and Ca(OH)₂ was used to modify the diatomite. In this test, Ca(OH)₂ uses two materials respectively, one for natural diatomite and the other for calcined diatomite. The phase of diatomite after hydrothermal treatment was analyzed. The authors also carried out the analysis of hydrated lime Soil and hydrated lime - calcined diatomite on the adsorption performance of dyes. In order to provide a scientific basis for the application of diatomite as a new adsorbent for wastewater treatment. In the calcined experimental study, hydrothermal treatment and adsorption performance test of diatomite concentrate in Changchun City, Jilin Province, were carried out. The following conclusions were drawn:

(1) The calcination test showed that the pore size distribution and structure changed after calcite roasting. When the flux was added from 3% to 8%, the calcite phase appeared in the calcined sample. In this paper, by controlling the calcination time and the calcination temperature to obtain the desired calcined diatomite as the test raw material. It is found that, with the temperature increasing, the hardness and particle size of the calcined sample have a peak change, and this trend is the same under the time condition. After a large number of roasting tests, the author found that calcined diatomite can be obtained when the mass fraction of flux is 5%, the time condition of calcination is controlled at 40 min and the calcination temperature is controlled at 800℃.

(2) The hydrothermal treatment showed that the content of calcium silicate hydrogel formed by diatomite after hydrothermal treatment under different conditions was quite different. When the amount of hydrated lime increased, the XRD Mullite diffraction peak; natural diatomite and calcined diatomite at different times, the temperature treatment under the peak conditions are different.

(3) The adsorption performance test showed that the strength of the baking-like adsorption was related to the intensity of the tropicin peak at 2θ = 8° on the XRD diffraction peak. The strength of the diffraction peak was deduced from the analysis of the test results. And the adsorption performance was proportional relationship.

Key Words： Diatomite, Hydrothermal synthesis, Hydrated lime, Tobermorite

目 录

摘 要 I

Abstract II

第1章 绪论 1

1.1 硅藻土的概况 1

1.1.1 基本概况 1

1.1.2 主要分布 2

1.2 主要优点及用途 2

1.2.1 主要优点 2

1.2.2 主要用途 2

1.3 国内外研究现状 4

1.3.1 国内现状 4

1.3.2 国外现状 4

1.4 研究目的及实验设想 5

1.4.1 研究目的 5

1.4.2 实验设想 6

第2章 试验方法与材料设备 8

2.1 试验方法 8

2.1.1 焙烧试验方法 8

2.1.2 水热试验方法 8

2.1.3 吸附测试方法 8

2.2 实验材料以及设备 8

第3章 试验结果与分析 10

3.1 焙烧试验 10

3.1.1 焙烧准备阶段 10

3.1.2 硅藻土的焙烧时间和温度 10

3.2 水热处理研究 12

3.2.1 水热处理的配比条件 12

3.2.2 水热处理的时间条件 19

3.2.3 水热处理的温度条件 21

3.3 吸附性能测试 22

3.3.1 测试试验 22

3.3.2 试验结果分析 23

第4章 结论与展望 30

4.1 结论 30

4.2 展望 31

参考文献 31

致 谢 32

第1章 绪论

1.1 硅藻土的概况

1.1.1 基本概况

硅藻土属于非金属矿物质^[1]，具有无定形形式，其形成原因与珊瑚礁相似：远古时期海洋或者湖泊中硅藻残骸经过多代堆集后，通过天然成岩作用形成的微孔结构的生物硅质沉积岩，与海泡石、蛭石等同属于粘土矿物，故它具有粘土矿物的基本性质：颗粒极其细小，一般小于0.01毫米。硅藻土常见的颜色有纯白色、淡灰色以及深灰色等，它的主要构成物质为非晶体的二氧化硅，如下图1.1所示。