热水解处理制革污泥过程中总Cr的转移与稳定性研究

采用热水解法研究了不同热水解温度和酸性条件下,制革污泥中重金属总铬的转移特性及浸出毒性变化.结果表明：pH对制革污泥中Cr的溶出起主要作用,H2SO4调节pH为2.5和1.5时,常温水解预处理对污泥中Cr的转移率分别达到了56%和91%.热水解温度的提高不利于Cr向液相转移,当pH=2.5时,180 ℃热水解后的水解液中Cr的质量分数比常温条件下降低了70%以上.热水解处理促进污泥中Cr的稳定,且随着热水解温度的升高,Cr的浸出毒性显著降低, 180 ℃热水解Cr的稳定化率达93.2%,而常温下只有50.8%，因此,可采用常温H2SO4浸取+热水解联合处理的方法，实验结果表明：Cr的转移和稳定化效果均较好,污泥中Cr向液相的转移率高于90%,固相中Cr的浸出毒性显著降低,稳定化率超过95%.

Study on migration and stability of total Cr in tannery sludge by thermal hydrolysis treatment

The migration characteristics and leaching toxicity of total Cr in tannery sludge were studied at different thermal hydrolysis temperatures and acid conditions. The results show that pH plays a leading role in migration of Cr from solid phase to liquid phase. At pH=2.5 and 1.5 adjusted by H2SO4, the migration rate of Cr can reach 56% and 91% at room temperature. The rise of thermal hydrolysis temperature will worsen the migration of Cr to hydrolysate. At pH of 2.5, the concentration of Cr in hydrolysate is reduced over 70% at 180 °C compared to room temperature. Thermal hydrolysis promotes the stability of Cr, and the leaching toxicity of Cr is significantly reduced as temperature rises. At 180 °C, the stabilization rate of Cr increases to 93.2%, while at room temperature it is only 50.8%. By H2SO4 extraction at room temperature and subsequently thermal hydrolysis, this combined method obtains good results of the migration and stability of Cr: more than 90% of Cr is dissolved into liquid phase, the leaching toxicity of Cr is lowered evidently and the stabilization rate is more than 95%.