SiO_(2)和MgO协同改质钢渣抑制碱性物质溶出试验研究

Experimental Study on the Inhibition of Alkaline Substances Leaching from Steel Slag Modified by SiO_(2) and MgO

钢渣中的CaO等碱性物质在堆存过程遇到降水时易溶出,导致周边土壤的pH值升高,进而引发土壤污染问题。除了游离氧化钙外,2CaO·SiO_(2)-3CaO·P 2O 5是钢渣中碱性溶出的主要矿物相,为减少其生成,本文通过添加SiO 2和MgO对钢渣进行改质处理,考察SiO_(2)和MgO抑制钢渣碱性溶出的有效性。结果表明,采用SiO_(2)和MgO协同改质钢渣,能够显著减少钢渣中游离的CaO以及2CaO·SiO_(2)-3CaO·P_(2)O_(5)物相的生成;随着SiO_(2)和MgO添加量的增加,溶出液中Ca^(2+)含量逐渐减少,最大pH值明显降低;当SiO_(2)添加量为30%、MgO添加量为10%时,溶出液的最大pH值降到10.1,与CaCO_(3)浸出液的最大pH值(10.03)接近,可认为改质钢渣在实际应用中不会发生严重的溶出问题。

Alkaline substances such as CaO in steel slag react with precipitation during storage,resulting in an increase in the pH value of surrounding soil,which leads to soil pollution.In addition to free calcium oxide,2CaO·SiO_(2)-3CaO·P_(2)O_(5) is the main mineral phase of alkaline dissolution in steel slag.In order to reduce its formation,the steel slag was modified by adding SiO_(2) and MgO in this paper,and the effectiveness of SiO_(2) and MgO in inhibiting the alkaline dissolution of steel slag was investigated.The results show that the formation of free CaO and 2CaO·SiO_(2)-3CaO·P_(2)O_(5) phases in steel slag can be significantly reduced by using SiO_(2) and MgO to modify steel slag.With the increase of SiO_(2) and MgO addition,the content of Ca^(2+)in the dissolution solution is gradually reduced,and the maximum pH value is significantly reduced.When the addition amount of SiO_(2) is 30%and the addition amount of MgO is 10%,the maximum pH value of the leaching solution is reduced to 10.1,which is very close to the maximum pH value(10.03)of the CaCO_(3) leaching solution.It can be considered that the modified steel slag will not cause serious alkali dissolution problems in practical applications.