赤泥⁃电石渣⁃磷石膏固化铜污染土性能

Performance of red mud⁃calcium carbide residue⁃phosphogypsum solidified copper contaminated soil

为了研究在浸泡条件下赤泥⁃电石渣⁃磷石膏3种固废物混合料对铜污染土的固化效果,本文对其混合料固化土的无侧限抗压强度、应力⁃应变、重金属形态、浸出毒性及微观结构进行了检测.结果表明,固化土强度随养护龄期的增加而增大,且掺加固废物对其强度有明显改善作用.混合料固化土中铜的存在形式以铁锰氧化态为主,其浸出毒性随龄期增加而降低,且其浓度值均低于水泥固化土.此外,混合料固化土中水化产物以水化硅酸钙/水化硅铝酸钙和钙矾石为代表.水化产物对固化土内部结构起填充作用,可改善固化土强度.同时,水化硅酸钙/水化硅铝酸钙对铜离子有吸附作用,钙矾石可与铜离子发生阳离子置换作用.因此,固废物的添加可对铜离子产生固化作用.

To study the solidification effect of the solid waste mixture of red mud,calcium carbide residue,and phosphogypsum on copper contaminated soil under the soaking condition,the unconfined compressive strength,stress⁃strain,heavy metal forms,leaching toxicity,and microstructure of the solidified soil were tested.The strength of solidified soil increases with the increase of curing age,and the strength of solidified soil can be significantly improved by adding solid waste.The copper in the mixture solidified soil is mainly in the form of iron⁃manganese oxidation,and its leaching toxicity decreases with the increase of curing age,and its concentration is lower than that of cement solidified soil.Additionally,the hydrated products of the mixture solidified soils are represented by calcium silicate hydrate/calcium silicate hydrate and ettringite.The hydration products can fill the internal structure of the solidified soil,and improve the strength of the solidified soil.Meanwhile,calcium silicate hydrate/calcium silicate aluminate has an adsorption effect on copper ions,and ettringite can exchange cations with copper ions.Therefore,the addition of solid waste can solidify copper ions.