Laboratory of Environmental Engineering, University of Rome "Tor Vergata", Via del Politecnico 1 - 00133 Rome, Italy.
Department of Civil and Environmental Engineering, University of Rome "La Sapienza", Via Eudossiana 18 - 00184 Rome, Italy.
J Hazard Mater. 2015 Apr 9;286:369-78. doi: 10.1016/j.jhazmat.2014.12.059. Epub 2014 Dec 31.
This paper discusses the effects of accelerated carbonation on the leaching behaviour of two types of stainless steel slags (electric arc furnace and argon oxygen decarburisation slag). The release of major elements and toxic metals both at the natural pH and at varying pH conditions was addressed. Geochemical modelling of the eluates was used to theoretically describe leaching and derive information about mineralogical changes induced by carbonation. Among the investigated elements, Ca and Si were most appreciably affected by carbonation. A very clear effect of carbonation on leaching was observed for silicate phases; geochemical modelling indicated that the Ca/Si ratio of Ca-controlling minerals shifted from ∼ 1 for the untreated slag to 0.5-0.67 for the carbonated samples, thus showing that the carbonation process left some residual Ca-depleted silicate phases while the extracted Ca precipitated in the form of carbonate minerals. For toxic metals the changes in leaching induced by carbonation appeared to be mainly related to the resulting pH changes, which were as high as ∼ 2 orders of magnitude upon carbonation. Depending on the specific shape of the respective solubility curves, the extent of leaching of toxic metals from the slag was differently affected by carbonation.
本文探讨了加速碳酸化对两种类型不锈钢渣（电弧炉渣和氩氧脱碳渣）浸出行为的影响。研究了在自然 pH 值和不同 pH 值条件下主要元素和有毒金属的释放情况。浸出液的地球化学模拟用于理论描述浸出过程，并获得碳酸化诱导的矿物变化信息。在所研究的元素中，钙和硅受碳酸化的影响最大。碳酸化对硅酸盐相的浸出有非常明显的影响；地球化学模拟表明，控制钙的钙硅比从未处理渣的约 1 转变为碳酸化样品的 0.5-0.67，表明碳酸化过程留下了一些残余的缺钙硅酸盐相，而提取的钙以碳酸盐矿物的形式沉淀。对于有毒金属，碳酸化引起的浸出变化似乎主要与 pH 值的变化有关，碳酸化后的 pH 值高达约 2 个数量级。根据各自溶解度曲线的具体形状，碳酸化对有毒金属从渣中浸出的程度有不同的影响。
