Development of High Strength Materials from Steel Slags

有许多副产品没有被利用。随着工业活动的日益活跃，这些材料的用量越来越大。从节约能源和资源的角度来看，这些材料的使用是可取的。日本每年生产约1000万吨钢渣，由于其化学成分多种多样，不易用作工业材料。人类活动对co2气体排放的调控也是保护温室效应的一个非常重要的世界性问题。另一方面，已知含有大量CaO的化合物如3CaO SiO_2和2CaO SiO_2可通过碳化制备高强度材料。钢渣的主要成分是3CaO SiO_2和2CaO SiO_2。本研究项目的目的是开发利用钢渣副产物和CO_2气体固化制造高强度材料。它主要应用于gfrp和人工砂两大类。玻璃纤维增强混凝土由于基体碱度高，需要昂贵的耐高碱性玻璃纤维。碳化渣制备的基体碱度较低，因此可以用普通的低成本玻璃纤维代替昂贵的高耐碱玻璃纤维。基质ph值约为10，普通碱性钠玻璃的耐久性是水合基质的5倍左右。天然砂和骨料资源量越来越少，海砂的收集在日本许多地区受到抑制。需要高质量的人工砂。结果表明，碳化后的矿渣可作为人工砂，由粒状矿渣粉碳化而成。如果将日本生产的钢渣的三分之一用作这些材料，将使日本1995年二氧化碳排放量减少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.