油页岩废渣提取Al(Ⅲ)处理水中硫酸盐的研究

Study on Al(Ⅲ)Extraction from Oil Shale Waste Residue to Treat Sulfate in Aqueous

本研究通过对油页岩废渣进行加热、浸提处理得到Al(Ⅲ)浸提液,并采用钙铝复盐(Ca^(2+),Al^(3+))工艺对废水中SO_(4)^(2-)的去除进行了研究,Ca^(2+)、Al^(3+)通过化学沉淀反应和SO_(4)^(2-)生成硫酸铝钙复合物或钙矾石,进而达到去除SO_(4)^(2-)的目的。研究了pH、铝盐投加量,反应时间、振荡速度和初始硫酸盐含量对SO_(4)^(2-)去除率的影响。结果表明,反应体系在c(SO_(4)^(2-))=1.0g/L,n(Al^(3+)):n(SO_(4)^(2-))=1.4,CaO调节pH至12,200rmin的条件下反应25min,SO_(4)^(2-)的去除率为97%。SEM-EDS和XRD测试结果表明反应生成的白色沉淀为针状钙矾石结晶,具有膨胀性和稳定性的特点,可用于建筑领域。本研究为油页岩废渣的综合利用及硫酸根废水的处理提供参考。

In this study,the Al(Ⅲ)extract was obtained by heating and leaching the oil shale waste residue,and the removal of SO_(4)^(2-)in the wastewater was studied using the calcium-aluminum double salt(Ca^(2+),Al^(3+))process.The precipitation reaction of Ca^(2+),Al^(3+)and SO_(4)^(2-)produces cal-cium aluminum sulfate complex or ettringite,thereby achieving the purpose of removing SO_(4)^(2-).The effects of pH,aluminum salt dosage,reaction time,rotation speed and initial sulfate content on the removal rate of SO_(4)^(2-)were studied.The results showed that the removal rate of SO_(4)^(2-)was 97%under the conditions of C(SO_(4)^(2-))=1.0 g/L,n(Al^(3+)):n(SO_(4)^(2-))=1.4,CaO adjusted pH to 12,200 r/min and reaction for 25 min.The results of SEM-EDS and XRD showed that the white precipitate was acicular ettringite crystallization,which was characterized by expansibility and stability,and was of-ten used in the field of construction.This study provides reference for comprehensive utilization of oil shale waste residue and treatment of sulfate con-taining wastewater.