超高石灰铝法去除工业废水中高浓度硫酸根离子

Removing Highly Concentrated Sulfate from Industry Wastewater with Ultra-High Lime and Aluminum Method

向模拟废水中加入脱除剂氢氧化钙和偏铝酸钠,对工业废水中高浓度硫酸根离子的去除进行研究。脱除剂使钙离子、铝离子与硫酸根离子形成不溶性沉淀钙矾石(Ca6Al2(SO4)3(OH)12·26H2O),以达到去除硫酸根离子的目的。考察反应时间、反应温度、氢氧化钙添加量、偏铝酸钠添加量对溶液中硫酸根离子去除的影响。结果表明:超高石灰铝法可以有效去除硫酸根离子,当反应时间在15 min、反应温度为25?C时,以n(Ca2+):n(Al3+):n(SO2-4)为3:1:1的比例加入氢氧化钙和偏铝酸钠,硫酸根初始浓度为19.5 g/L的废水去除率可达到90%,大大降低了高浓度硫酸根离子对人体和环境的危害。

Removal of sulfate from industry wastewater containing highly concentrated sulfate was studied by using calcium hydroxideand sodium metaaluminate as remover in simulated wastewater. Sulfate was removed by forming the complex mineral ettringite(Ca6Al2(SO4)3(OH)12￠26H2O) under the occurrence of calcium ions, aluminum ions and sulfate. The effects of reaction time andtemperature, calcium hydroxide dosage, sodium metaaluminate dosage on the removal of sulfate were also investigated. The resultsindicated that ultra-high lime and aluminum method is effective in removing sulfate. When the reaction time is 15 min, reaction temperatureis 25 ±C and ratio dosage of calcium hydroxide and sodium aluminum is n(Ca2+):n(Al3+):n(SO2?4 ) 3:1:1, the removal efficiencyof sulfate that initial concentration is 19.5 g/L in wastewater can reach 95%. The harm of highly concentrated sulfate to human andenvironment could be reduced significantly in this condition.