粉煤灰复合氧化钙去除铬渣渗滤液中的总铬

粉煤灰虽然具有较大的比表面积,但单独做为处理剂处理含铬废水,效果并不理想,具有吸附容量小、溶解损失大、且有毒性浸出等特点.为了解决粉煤灰以上缺陷,提出氧化钙复合粉煤灰去除铬渣渗滤液中总铬的技术,研究表明,在室温25℃条件下,总铬初始浓度在0.30~80.00 mg/L范围内,选择粉煤灰与CaO配比为1:1时,以150 r/min转速充分振荡24 h,总铬去除率均能达到90%以上.通过空白对照实验研究表明,粉煤灰复合CaO使用,对总铬的去除远优于单独使用粉煤灰或CaO做为吸附剂的处理效果.利用SEM,XRD,红外光谱分析3种材料表征方法,对粉煤灰原料、CaO-粉煤灰处理后残渣等进行分析,结果表明,在水介质条件下,粉煤灰与CaO能生成晶体矿物.当溶液中有铬存在时,晶体矿物在形成的过程中能将铬裹入其结构中.通过浸出实验表明,此晶体矿物对铬具有很好的固定作用.

Removal of total chromium from chromium slag leachate by fly ash combined with calcium oxide

Fly ash has a large specific surface area, but as a treatment agent used alone in chromium containing wastewater was not efficient for its low adsorption capacity, high dissolution loss and leaching toxicity. In order to solve the above defects, the technology of fly ash combined with calcium oxide was used to remove the total chromium from chromium slag leachate. It could be concluded that when temperature was 25℃, the weight ratio of fly ash to calcium was 1:1, the initial concentration of total chromium was in the range of 0.30—80.00 mg/L, the rotation speed was 150 r/min, the total chromium removal rate could reach more than 90%. The control sample research showed that using fly ash combined with calcium oxide was better than the using fly ash or calcium oxide alone as adsorbent for the total chromium treatment. Using SEM, XRD and Infrared spectrum to characterize the raw material of fly ash, the treated chromium residue and so on, the results showed that the reaction with fly ash and calcium oxide could generate crystal mineral in the medium of water, in which process chromium could be included in the crystal mineral. The leaching test of residue showed that the chromium was fixed very well in crystal mineral.