镁还原渣泡沫玻璃的制备工艺及性能研究

发布时间：2018-05-14 04:31

本文选题：镁还原渣 + 制备　；参考：《太原理工大学》2017年硕士论文

【摘要】：镁还原渣是硅热还原法炼镁过程中产生的固体废弃物。镁还原渣的大量堆积,不但侵占了大面积的土地,造成资源的严重浪费,而且危害环境,造成土壤盐碱化,水源破坏,空气污染等。随着近年来全球资源短缺、能源危机及环境污染等问题的日益严重,工业废弃物的再利用已经越来越得到国内外科研工作者的关注。因此,解决镁还原渣的再利用问题不但符合我国建立资源节约型社会的基本要求,而且在保护环境以及维护生态平衡等方面均具有重大意义。本文首先分析镁还原渣的物理化学特性,探讨利用其制备泡沫玻璃的可行性;其次通过正交实验确定工艺条件,利用烧结炉制备泡沫玻璃,并采用XRD、SEM等手段对其性能进行分析;在此基础上,对影响泡沫玻璃性能的因素进行了实验验证。结果如下:(1)镁还原渣含有CaO、SiO_2和MgO等成分,能满足制备泡沫玻璃的基本要求。同时玻璃粉、助熔剂等可降低镁还原渣的软化温度和碱度,达到制备所需的工艺条件。(2)正交实验结果表明:影响镁还原渣泡沫玻璃表观密度的因素从大到小依次为镁还原渣掺量、发泡温度、发泡时间,初步确定制备工艺条件为发泡温度950℃,发泡时间30min。(3)泡沫玻璃内部均有微晶析出,其中最主要的是CaSiO_3晶体,其次是Ca_2SiO_4晶体。随着镁还原渣掺量的增大,这些晶体的尺寸逐渐增大,当镁还原渣掺量大于35%时,泡沫玻璃内部还出现Ca_2Fe_2O_5及CaAl_2Si_2O_3等晶体。(4)镁还原渣掺量较小时,泡沫玻璃的抗压强度较低,吸水率较大,对实际工程中的应用造成限制;掺量较大时,表观密度和吸水率过大,耐酸性差,不能满足应用要求;本实验中掺量为35%时泡沫玻璃性能最佳,其表观密度为598 kg/m3、吸水率为0.43%、抗压强度为5.34 MPa,孔隙率为73.78%,在酸液中质量变化率为0.78%,在50~400℃的平均热膨胀系数为9.5916×10-6/℃,且泡沫玻璃表面气孔分布较为均匀,可满足工业应用需要。(5)选泡沫玻璃性能最佳的一组工艺条件,改变不同添加剂的掺量制备泡沫玻璃,结果表明:发泡剂掺量过小时,泡沫玻璃泡孔较小,表观密度较大,掺量过大时出现连通孔,发泡不均匀,吸水率大;稳泡剂掺量过小时,有狭长的大泡形成,过大时会产生大气泡,均造成发泡不均匀,导致泡沫玻璃吸水率较大;不加助熔剂或掺量过小时,泡沫玻璃烧结度低,会产生较多开口孔,且表观密度大,掺量过大时发泡不均匀,抗压强度低且吸水率大。当发泡剂、稳泡剂、助熔剂分别为2%、3%、2%时,泡沫玻璃综合性能最好。(6)改变温度制度制备泡沫玻璃,结果表明:发泡温度过低时,泡沫玻璃烧结度很低,有大量开口孔,表观密度和吸水率都过大,过高时会造成发泡不均,导致其抗压强度降低且吸水率较大;发泡时间过短时,泡沫玻璃的气泡孔径较小,表观密度较大,过长时又会造成连通孔的增多,泡孔大小不一,导致其吸水率较大且抗压强度较低。当发泡温度为950℃,时间为30 min时,泡沫玻璃综合性能最好。
[Abstract]:Magnesium reduction slag is a solid waste produced during the process of magnesium smelting by silicon thermal reduction. A large amount of accumulation of magnesium reduction slag not only occupies large area of land, causes serious waste of resources, but also endangers the environment, causes soil salinization, water source destruction, air pollution and so on. With the shortage of global resources, energy crisis and environmental pollution in recent years, the problem of energy crisis and environmental pollution is asked. The problem is becoming more and more serious, and the reuse of industrial waste has been paid more and more attention by the researchers at home and abroad. Therefore, it is of great significance not only to solve the problem of reutilization of magnesium reduction slag, but also in protecting the environment and maintaining the balance of ecology. The physical and chemical properties of magnesium reduction slag and the feasibility of using it to prepare foam glass were discussed. Secondly, the process conditions were determined by orthogonal experiment, the foam glass was prepared by the sintering furnace, and the properties of the foam glass were analyzed by XRD and SEM. On this basis, the factors affecting the properties of the foam glass were experimentally verified. The results are as follows: (1) Magnesium reduction slag contains CaO, SiO_2 and MgO, which can meet the basic requirements for the preparation of foam glass. At the same time, glass powder, flux and so on can reduce the softening temperature and alkalinity of magnesium reduction slag. (2) the orthogonal experimental results show that the factors affecting the apparent density of magnesium reduction slag foam glass from large to small are magnesium. The amount of reducing slag, the foaming temperature and the foaming time, it is preliminarily determined that the preparation conditions are 950 degrees centigrade, and the foaming time 30min. (3) of the foam glass is microcrystalline, the most important is the CaSiO_3 crystal and the next is the Ca_2SiO_4 crystal. With the increase of the amount of magnesium reduction slag, the size of these crystals increases gradually, when the magnesium reduction slag is mixed. When the amount is greater than 35%, there are also Ca_2Fe_2O_5 and CaAl_2Si_2O_3 crystals inside the foam glass. (4) the amount of magnesium reduction slag is low, the compressive strength of the foam glass is low, the water absorption rate is large, and the application of the actual engineering is limited. When the volume is large, the apparent density and water absorption are too large and the acid resistance is poor, and it can not meet the application requirements; this experiment can not meet the requirements of the application. The properties of the foam glass are 35%, the apparent density is 598 kg/m3, the water absorption is 0.43%, the compressive strength is 5.34 MPa, the porosity is 73.78%, the mass change rate is 0.78% in the acid solution, the average thermal expansion coefficient at 50~400 C is 9.5916 x 10-6/ C, and the porosity distribution of the foam glass surface is more uniform, which can meet the needs of industrial application. (5) The foam glass was prepared by changing the addition amount of different additives. The results showed that the foam glass had a small bubble hole, a large apparent density, a large apparent density when the amount of foaming agent was overdoped. Large bubbles will produce large bubbles, which cause unevenness of foams and lead to large water absorption of foam glass. Without the aid of flux or the amount of adulterate, the sintering degree of foam glass is low, and many opening holes will be produced, and the apparent density is large, the foaming is uneven, the compressive strength is low and the water absorption rate is great. When the foaming agent, foam stabilizer, and flux are 2%, 3%, 2%, respectively, bubble Foam glass has the best comprehensive properties. (6) change the temperature system to make foam glass. The results show that when the foaming temperature is too low, the sintering degree of foam glass is very low, there are a large number of opening holes, the apparent density and water absorption are too large, too high will cause uneven foaming, which leads to the reduction of its compressive strength and the greater water absorption; foam glass is too short when the foaming time is too short. The size of the bubble is small and the apparent density is large, and the number of connected holes will increase when the bubble is too long. The size of the bubble hole is different and the water absorption rate is larger and the compressive strength is low. When the foaming temperature is 950 C and the time is 30 min, the comprehensive performance of the foam glass is the best.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ171.722

【参考文献】