含铬特殊钢渣中总铬及六价铬浸出特性及影响

Leaching characteristics and affecting factors of total chromium and chromium Ⅵ in chromium-containing special steel slag

含铬特殊钢渣中六价铬具有强氧化性和高毒性,研究不同条件下渣中总铬及六价铬的浸出行为及特征并进行环境风险评估,对后续无害化及资源化利用具有重要的意义。浸出试验结果表明,渣中总铬和六价铬的浸出量随粒度和浸出时间增加而提高,随液固比(即浸提剂溶液体积与待测固体试样质量的比值)增加而降低;六价铬浸出量随体系pH值升高而增加,当pH=11时六价铬浸出量达到最高值2.92mg/L;总铬浸出量随pH值升高呈现先降低后增加的趋势,当pH=7时,总铬达到最小浸出量2.49mg/L。经标准浸出程序测定,钢渣中铬及六价铬浸出量分别为4.71和3.36mg/L,符合固废堆存限值(GB 5085.3-2007),堆存风险较小,但高于行业利用限值(HJ/T 301-2007),需对其进行无害化处理后再进行后续资源化利用。

Chromium Ⅵ in chromium-containing special steel slag has powerful oxidization and highly poisonous.Study on leaching behavioral characteristics and assessing environmental risks is of great significance to subsequent harmless treatment and resource utilization.Results of the leaching tests on shows that the leaching value of total chromium and chromium Ⅵ in slags increases with rise of granularity of slag and leaching time,decreases with rise of solution-solid ration.The leaching value of chromium Ⅵ increases with rise of pH and reaches the highest content2.92 mg/L when pH is 11.The leaching value of total chromium decreases and then increases with the increase of pH and reaches the lowest value when pH is 7.The results shows that the leaching contents of total Cr and chromium Ⅵ is 4.71 and 3.36 mg/L in standard leaching prosess are in line with the national standard fuel GB 5085.3-2007 standards with low risk of stacking,whereas are not conforming to the industrial standard HJ/T 301-2007.Therefore it is imperative to carry on the harmless treatment ahead of recycling of the slag.