湿法解毒铁铬渣作混凝土掺合料的性能研究

铁铬渣是以铬铁矿为原料生产金属铬和铬盐后产生的工业废渣。经硫酸亚铁湿法解毒的铁铬渣仍然具有一定的火山灰活性,可作混凝土矿物掺合料使用。然而由于湿法解毒铁铬渣含有水溶性铬（Ⅵ）,影响了其建材化资源利用。研究了湿法解毒铁铬渣的粒径分布、火山灰活性;以湿法解毒铁铬渣作为矿物掺合料代替粉煤灰用于C30混凝土,考察了混凝土的工作性能、力学性能和水溶性铬（Ⅵ）的浸出量。结果表明：湿法解毒铁铬渣的粒径主要分布在1~20 μm,28 d活性指数达到68%;当湿法解毒铁铬渣取代20%（以质量分数计）粉煤灰时,混凝土坍落度增加了38.2%,7 d和28 d强度分别增加了7%和6%;混凝土浸出液中水溶性铬（Ⅵ）的浓度,根据标准的不同其要求也不同。湿法解毒铁铬渣有作为矿物掺合料的可能性,但是需要考虑其水溶性铬（Ⅵ）的浸出量,以确保混凝土的安全使用。

Study on properties of wet detoxification Fe-Cr slag as concrete admixture

Fe-Cr slag is an industrial waste produced after using chromite as raw material to produce metal chromium and chromium salts.After wet detoxification by FeSO4,the Fe-Cr slag still has certain volcanic ash activity,which can be used as concrete mineral admixture.However,the water-soluble Cr (Ⅵ ) in wet detoxification of Fe-Cr slag affects the utilization of building materials resources.The particle size distribution and volcanic ash activity of the wet detoxification Fe-Cr slag were studied.The wet detoxification Fe-Cr slag was used as mineral admixture instead of fly ash in C30 concrete.The working properties,mechanical properties and leaching amount of water-soluble Cr(Ⅵ) of concrete were investigated.The results showed that the particle size of the wet detoxification Fe-Cr slag was mainly distributed in the range of 1~20 μm,and the activity index of 28 d reached 68%.When the fly ash was replaced by 20% by the wet detoxification Fe-Cr slag,the slump of concrete increased by 38.2%,and the strength of concrete at 7 d and 28 d increased by 7% and 6%,respectively.The amount of water soluble Cr(Ⅵ) was different according to the different standard.Wet detoxification Fe-Cr slag may be used as mineral admixture,but the leaching of water-soluble Cr(Ⅵ) should be considered to ensure the safe use of concrete.