One-part alkali-activated slag binder for cemented fine tailings backfill: proportion optimization and properties evaluation

In this study, a one-part alkali-activated slag (AAS) composed of ground-granulated blast furnace slag, desulfurized gypsum, and hydrated lime is proposed as alternative to cement for the production of cemented fine tailings backfill (CFTB), which is an environmentally friendly binder consisting of 93.72 wt.% industrial solid waste. Results show that AAS with 67.83 wt.% slag, 25.92 wt.% desulfurized gypsum, and 6.25 wt.% hydrated lime yields the highest strength, which is 1.7–3.2 times that of ordinary Portland cement (OPC). Aside from calcium silicate hydrate gel, appreciable quantity of ettringite characterized by interlocking needles structure and high bound water is also produced during the AAS hydration process. In addition, the hydration heat of the AAS binder is 48% less than that of OPC. Moreover, CFTB made of AAS provides better workability than that of CFTB with OPC up to 20 h. The findings of this study will contribute to the production of more cost-effective, durable, and environmental-friendly cemented fine tailings backfill.

     

孔隙含水介质的Pb分配系数

Pb分配系数是描述Pb在地下水中迁移性质的重要参数。研究对象和目的不同 ,计算Pb分配系数的方法也不同。静态吸附平衡实验方法简便易行 ,适用于计算不同岩性的Pb分配系数 ;动态土柱实验方法难度较大 ,主要用于建立Pb迁移方程 ;阳离子交换系数方法计算过程复杂 ,适用于解决野外实际问题。     

包气带中造纸废水COD天然生物降解作用

通过野外试验和土柱实验,研究了造纸废水渠底部包气带中,天然形成的生化层分布特征及其对ＣＯＤ降解能力和机制．结果表明,包气带中生化层由生物氧化带和生物还原带组成,生化层的发育厚度受包气带厚度控制,当包气带厚度大于１０ｍ 时,生化层发育良好,对ＣＯＤ的降解率达到９７％ 以上．     

二甲基苯蒽和苯并(a)芘对小鼠肝脏金属硫蛋白及氧化损伤的诱导作用

观察两种致癌性多环芳烃化合物二甲基苯蒽（DMBA）和苯并（a)芘（BaP）对小鼠肝脏脂质过氧化产物和金属硫蛋白含量的影响。选用雄性C57BL／OLA129小鼠，观察DMBA和BaP各50mg/kg一次腹腔注射染毒后24、48、72和144h后的动物肝脏重量、金属硫蛋白（MT）含量和脂质过氧化程度的变化。MT测定采用镉－血红蛋白亲和分析法；脂质过氧化指标为硫代巴比妥酸测定丙二醛法。结果表明，DMBA和BaP均能引起小鼠肝脏重量增加、MT含量增加和MDA含量增加。随着DMBA和BaP染毒后的时间延长小鼠肝脏的重量不断增加，呈现时间效应关系。小鼠肝脏MT的含量在染毒后24和48h后明显增加1倍。肝脏MDA的含量增加在染毒后24h后达到高峰。本研究观察到DMBA和Bap可以MT增加。MT的增加与MDA的增加呈现一定平行的关。提示MT诱导可能与多环芳烃化合物所致的氧化损伤有关。