【作者】 高章韵；

【导师】 石宗利；

【作者基本信息】 湖南大学 ， 材料学， 2010， 硕士

【摘要】 工业副产石膏是指工业生产中由化学反应生成的以硫酸钙(含零到两个结晶水)为主要成分的副产品或废渣,因此也称化学石膏。工业副产石膏是很好的再生资源,对它们进行综合利用既有利于保护环境,又能节约能源和资源。建材行业是我国发展循环经济的重要行业,工业副产石膏可以作为生产建材产品的替代原料,有利于建设资源节约型、环境友好型的建材产业。由于工业副产石膏在生产过程中往往带有杂质,这些杂质会影响工业副产石膏的利用,并且石膏本身存在的强度不高、耐水性差等缺陷,这些都是石膏产品亟待解决的问题。本文对脱硫石膏、磷石膏的利用进行了系统的研究,力求在大量的实验基础上,获得了一些实验结果和理论,主要工作如下：(1)研究了煅烧温度对脱硫石膏和磷石膏的影响,实验发现当脱硫石膏低温煅烧(150℃左右)成半水石膏时,各项指标均达到国家标准中建筑石膏优等品的要求；磷石膏在高温煅烧(800℃左右)成Ⅱ型无水石膏时,具有较好的后期水化能力。(2)将半水石膏、无水石膏与高炉矿渣以一定比例混合后制备成石膏基复合材料,研究了氧化钙和白水泥分别作为激发剂对复合材料性能的影响。实验发现氧化钙和白水泥均能有效提高复合材料的强度和耐水性,且白水泥的激发效果要好于氧化钙。(3)通过对添加氧化钙和白水泥的复合材料的微观分析发现,两者均能使材料内部结构更加致密,从而提高材料的强度和耐水性,但添加过量氧化钙产生的凝胶状钙矾石(Ettringite)会产生裂纹,破坏体系；白水泥掺入后生成的长针状钙矾石是影响材料强度的主要因素,其对体系的作用要大于另一种水化产物C-S-H凝胶,适量的钙矾石会提高材料的强度,但过量白水泥会生成大量细针状钙矾石而导致材料体系膨胀,产生微裂纹,降低材料的力学性能。(4)将有机硅胶粉添加到石膏基复合材料体系中能提高材料的粘结强度和耐水性能,特别在养护28d后,有机硅胶粉形成的聚合物膜与材料内部晶体以及颗粒形成较致密的网络结构,能进一步填充体系中的孔隙,起到改善复合材料性能的作用。(5)将石膏基复合材料用于干粉涂料的制备工艺,实验发现聚乙烯醇和可再分散乳胶粉对涂料的性能改善都可起到重要作用,能增强涂膜的耐碱性、耐冻融循环、干擦性、耐洗刷性等性能,对于石膏基复合材料来说聚乙烯醇用量要小,且对涂膜性能的提升要优于可再分散乳胶粉。(6)通过将干粉涂料的性能与国家内墙涂料的标准进行对比,发现本实验中的干粉涂料能完全达到甚至优于国家标准,具有性能优良、价格低廉、环保节能、使用方便等优势,具有很好的市场应用潜力。更多还原

【Abstract】 Industrial by-product gypsum is also called chemical gypsum, generated by the chemical reaction in industrial production and calcium sulfated as the main component (contains 0 to 2 hydration water). It is a good renewable resource. Its utilization is conductive to protecting the environment and saving energy and resources. Building materials industry is very important in the development of recycling economy. The industrial by-product gypsum can be used as a substitute raw material and it can be contributed to building a resource conserving and environment-friendly building materials industry.However, the industrial by-product gypsum always contains impurities during the production process which have bad effects, and gypsum also has the technical choke of low strength, feeblish water-resistance and so on. These disadvantages are imperative problems of by-product gypsum. In this paper, the utilization of FGD and phosphogypsum has been investigated systematically, and attains some significant results and theories on the basis of a large number of experiments; the main tasks are as follows:(1) has studied the sintering temperature on the impact of gypsum and phosphogypsum and found that when FGD is calcined into semi-hydrated gypsum at about 150℃, the properties can achieve the national standards of GB/T 9776-88; when phospogypsum is calcined into anhydriteⅡat about 800℃, it can get good post-hydrated gypsum ability.(2) the semi-hydrated gypsum, the anhydriteⅡand the slag are prepared into gypsum-slag composite cementitious material, using CaO and white cement as activator respectively. The results show that the CaO and white cement can effectively improve the strength and water resistance of cementitious material; the white cement has better impact than CaO.(3)the microstructure analysis shows that both CaO and white cement can make the internal structure of cementitious material to be more density, so the strength and water resistance are improved, but the excessive quantity of CaO will produce gelatious ettringite which will expand the system and produce micro-cracks. The ettringite produced by white cement is the main factor of the material’s strength. It plays an important role than C-S-H gel, but excessive ettingite will also expand the system and produce micro-cracks which will reduce the mechanical properties of the cementitious material.(4) the organic silig glue powder can improve the bond strength and water resistance, particularly in the 28-days post-hydration process, the polymer film produced by organic silig glue powder with various crystals and particles can form dense network structure, then fill the small holes of the material’s interior system, improving the properties of the material.(5) has studies the preparation of powder coating by using composite cementitious material. The experiment results show that the polyvinyl alcohol and re-dispersible polymer powders both play an important role of the coating properties, they can improving the alkali resistance, freezing and thawing cycle resistance, dry rub resistance, scrubbing resistance, ect. The polyvinyl alcohol has a smaller consumption and better effects than re-dispersible powder.(6) by comparing the properties of powder coating and national standard of interior wall coating, the results show that it can be fully achieved the national standards or even better. The industrial by-product gypsum composite cementitious material based powder coating have many advantages, like excellent propeties, low price, environmental friendly, saving energy and using convenient, it’s application has great market potential.更多还原