模拟酸雨对砂浆影响的研究

Study on the influence of simulated acid rain on sand-lime slurry

建立了周期浸泡法和喷淋试验法等两种加速腐蚀试验方法，并分别研究ｐＨ为５．６、３．５和ｐＨ为１．０、ＳＯ为０、０．０６、０．１、０．２ｍｏｌ／Ｌ六种模拟酸雨对砂浆的影响。研究结果表明：砂浆受蚀后强度降低，其下降的程度与材料中ＣａＯ和ＳＯ３／ＣａＯ的比值成二元线性关系；酸雨中Ｈ＋的侵蚀将使材料中ＣａＯ、ＭｇＯ、Ａｌ２Ｏ３和Ｆｅ２Ｏ３组分流失，Ｈ＋和ＳＯ的协同作用，使材料中的ＳＯ３／ＣａＯ的比值增大；受蚀后的砂浆其物相发生较大的变化，变化趋势是原［ＣａＮａ］［ＳｉＡｌ］４Ｏ８、ＫＡｌＳｉ３Ｏ８、０．６２ＮａＡｌＳｉ２Ｏ８·０．３８ＣａＡｌ２等矿物晶体逐渐消失，而转化成ＣａＳＯ４·２Ｈ２Ｏ、ＣａＡｌ２Ｓｉ２Ｏ８、Ｃａ－Ｆｅ－Ａｌ－Ｓ－Ｓｉ－Ｏ，甚至体积更大的Ｃａ３Ａｌ６Ｏ１２·ＣａＳＯ４。因此，酸雨对砂浆的影响，主要是Ｈ＋侵蚀引起的溶解腐蚀和ＳＯ侵蚀引起的膨胀腐蚀。

Two erosion-accelerating methods(periodical immersion and periodical spraying) were established,and the influence on sand-lime slurry of simulated acid rain of different acidity and SO concentration was examined.The following results are gotten from the study:(1) the strength of sand-lime slurry reduces after erosion,and the reduction is a linear function of CaO content and the ratio of SO3 content to CaO content in the eroded test samples;(2) the erosion effect of H+ in acid rain results in the losing of CaO,MgO,Al2O3 and Fe23O in sand-lime slurry,and the 2coordinate erosion of H+ and make the ratio of SO3 content to CaO content become longer;(3) the erosion substantially changes the phase of sand-lime,that crystal structures such as[Ca Na][SiAl]4O8,KAlSi3O8 and 0.62 NaAlSi2O8·0.38 CaA12 transform to CaSO4·2 H2O,CaAl2Si2O8,Ca-Fe-Al-S-Si-O,and even more voluminous Ca3Al6O12·CaSO4. Therefore,the main cause of erosion of sand-lime slurry by acid rain is dissolving erosion by H+ and expanding erosion by SO.