高MgO镍铁渣作为活性混合材使用的可行性分析

Feasibility of using ferronickel slag containing high MgO composition as an active mixed material

中国镍铁渣排放量很大,但目前尚未找到大量利用的途径。笔者在分析镍铁渣组成、性能的基础上,对镍铁渣作为活性混合材使用的可能性及效果进行了研究。结果表明:镍铁渣中非晶体矿物的含量为88.1%,含量高达27.07%的MgO主要以顽辉石和镁铁橄榄石两种晶体矿物形式存在。镍铁渣的比表面积影响其活性和在水泥中的掺量。作为活性混合材,镍铁渣比表面积需不低于454.6m^2/kg。比表面积越大,活性指数越大,掺量越大。镍铁渣水泥的压蒸安定性合格,即使在水泥中掺入50%比表面积842.9 m^2/kg的镍铁渣,水泥的压蒸膨胀率仅为0.11%,大大低于0.5%的GB750—1992要求,由此证明镍铁渣不会因为MgO含量高而影响其作为活性混合材的使用。

A large amount of ferronickel slag containing high MgO composition is discharged every year in China, but it has not found an efficient method to utilize the slag so far. We investigated the feasibility and the effect of using ferronickel slag Containing high MgO composition as an active mixed material on the basis of analyzing its composition and performance. The results show that the content of amorphous mineral in the slag is 88.1%. The content of MgO reaches 27.07% and it mainly exists as enstatite and hortonolite. The slag＇s activity and its dosage used in the cement are affected by its specific surface area. As an active mixing material, its specific surface area should be no less than 454.6 m^2/kg. The bigger the specific surface area of the slag is, the higher the active index is, and the larger the dosage in the cement is. The autoclave soundness of the cement mixed with high-MgO ferronickel slag is qualified. Even if the mixing dosage of the slag with specific surface area of 842.9 m^2/kg is up to 50%, the autoclave expansion rate of the new cement is only 0.11%, which is significantly lower than 0.5% as required by GB750- 92. Therefore, ferronickel slag containing high MgO composition can be used as an active mixed material.