Development of High Strength Materials from Steel Slags

有许多副产品没有被使用。这些材料的数量随着工业活动的增加而越来越多。从节约能源和资源的角度来看，人们希望使用这些材料。在日本，每年产生约1000万吨钢渣，由于其化学成分的多样性，它们不容易用作工业材料。人类活动引起的CO_2气体排放的调控也是保护绿色住宅效应的重要世界性问题之一。另一方面，已知含有大量CaO的化合物，如3CaOSiO_2和2CaOSiO_2，通过碳酸化可制成高强度材料。钢渣的主要成分是3CaOSiO_2和2CaOSiO_2。本课题的研究目的是利用钢渣副产物和CO_2气体固化制备高强度材料。玻璃纤维混凝土由于基体的高碱度，需要使用价格昂贵的高耐碱玻璃纤维。以碳酸化渣为基质，碱度低，所以通常用低成本的玻璃纤维代替昂贵的高碱-玻璃纤维增强混凝土可采用耐腐蚀玻璃纤维，基质pH值在10左右，普通碱性钠玻璃的耐久性比水化基质提高5倍左右，天然砂和骨料资源量减少，海砂的采集在许多地区受到抑制，日本高质量的人造砂是人们所期望的。结果表明，碳酸化渣粉可用作人造砂，用日本1/3的钢渣作原料，可减少日本1995年CO_2排放量的0.03%。

There are many by-products which has not been used. The amount of these materials become more and more with high industrial activity. The use of these materiarls has been desired on the point of view of saving energy and resourses. The steel slags are produced about 10 million tons in a year in Japan, and they are not easy to use for industrial materials because of variety in their chemical composition. The regulation of CO_2 gas emission owing to high human activity is also one of very important world wide problems for protection of Green House Effects. On the other hand, it has been known that the compounds which contains much amount of CaO such as 3CaO SiO_2 and 2CaO SiO_2 makes high strength materials by carbonation. The main components of steel slags are 3CaO SiO_2 and 2CaO SiO_2.The aim of this research project is in the development of manufacturing high strength materials with using by-product of steel slags and solidifying the CO_2 gas. It has been applied in two category as GFRC and artificial sand.Glass fiber reinforced concrete needs expensive high-alkaline-resistant glass fiber because of high alkalinity of matrix. The matrix which is made from carbonated slag has low alkalinity, so usual low-cost glass fiber instead of expensive high-alkaline-resistant glass fiber can be used for GFRC.The matrix is about 10 in pH.The usual alkaline sodium glass showed longer durability about 5 times than in hydrated matrix.The amount of resources of natural sand and aggregate becomes small and the collection of sea sand becomes to inhibit in many regions in Japan. The artificial sand with high quality is desired. It was shown that the carbonated slag is available as artificial sand, which is obtained by carbonation of granulated slag powder.When the one third of steel slags produced in Japan is used as these materials, the 0.03% of the amount of CO_2 gas emission at 1995 in Japan will be reduced.