【作者】 郭军；

【导师】 黄戊生；

【作者基本信息】 东北大学 ， 环境工程， 2008， 硕士

【摘要】 铬渣因产量大、毒性强,日益被关注。采用常规的方法处理,铬渣固化体的六价铬浸出浓度常常超标。本文先用水合肼做还原剂,还原六价铬,使六价铬还原成三价格,降低了铬渣中的六价铬的含量；然后用水泥固化解毒后的铬渣。实验过程用蒸馏水做浸出剂。铬渣还原解毒阶段,考察了铬渣含水量、温度、反应时间、铬渣粒径、药剂用量对还原效果的影响；浸泡时间对铬渣返黄效果的影响。结果表明,铬渣粒径在0.220-0.150mm时,加水量控制在8%左右,反应温度60°C、反应时间为l0min时,还原效果最好。同时,铬渣粒径越大,裸露的六价铬越多,要使铬渣的水浸不超标,需要更多的还原剂。由于铬渣的强碱性,解毒后的铬渣,若不进一步处理,铬渣会慢慢返黄。水合肼还原铬渣的机理分析当中,通过能斯特方程以及电极电位之间的相互关系,分析研究了水合肼、氧气、二氧化碳的电极电势随pH的变化曲线。结合六价铬和三价格之间的相互关系,可以判断水合肼还原铬渣,不受pH的限制。铬渣的固化阶段,考察了铬渣掺量、粉煤灰掺量、养护时间对铬渣固化效果的影响；盐浓度、浸泡时间对铬渣水浸效果的影响。结果表明,当养护时间为3d、粉煤灰加入量为2%时,铬渣掺量不超过40%时,固化体水浸六价铬不会超标；添加2.5%的粉煤灰能够显著增强固化效果；养护12d,固化体基本稳定；盐浓度对固化体有破坏作用,较高的浓度会引起六价铬和三价格从固化体中解离下来；浸泡时间对固化体的影响较小。更多还原

【Abstract】 The chromium slag has been greatly concerned as the chromium slag’s large quantity of producing and its high toxicity. The use of conventional curing treatment,. hexavalent chromium often exceed national standard. This paper first use hydrazine hydrate for reducing agent, to reduce hexavalent chromium, to became trivalent chromium and reduce the hexavalent chromium of chromium slag content;then use cement solidifying the chromium slag of having been reduced. Distilled water is leaching agent in experiment.The phase of reducing chromium slag, study the chromium slag moisture^ temperature、reaction time、chromium residue particle size、the amount of reducing gent that affect reducing; the soaking time on returning the previous state. The results show when the chromium slag scale is 0.220-0.150mm; the water is controlled about 8 percent; temperature is controlled 60℃; the reaction time is controlled 10min; the result is best. At the same time, the greater size chromium slag particle is, the more hexavalent chrome will be exposured, if the hexavalent chromium does not exceed the national standard, the reaction need more reducing agent. Because of the strong alkaline chromium slag, after the detoxification of chromium slag, if not further treatment, chromium slag will gradually back to yellow.The phase of hydrazine hydrate reduction of the mechanism of chromium residue, through the mutual relations between Nernst equation and the electrode potential, study the hydrazine hydrate, oxygen, carbon dioxide’electrode potential of the curve with pH. According to the interrelationship between hexavalent chromium and trivalent chromium, it can be judged that hydrazine hydrate reduction chromium slag will be not controlled by pH.The phase of the chromium slag, study the effect of the amount of chromium slag and fly ash、the time of conservation on solidifying;the effect of the rate of salt and soaking on leaching. The results showed when the conservation time for 3 d, the amount of fly ash about 2 percent, chromium slag under 40 percent, the solidifying slag will not exceeded the national standard; adding 2.5 percent of fly ash can be significantly enhanced solidifying effect; the solidifying slag will be stabilization by conservation 12days; salt has damaging effects to the slag, the higher concentration of salt has leaching hexavalent chromium and trivalent chromium from the slag; the soaking time has less effect on leaching.更多还原