Institute of Minerals and Materials Technology, Council of Scientific & Industrial Research, Bhubaneswar 751 013, India.
J Hazard Mater. 2012 Aug 30;229-230:390-7. doi: 10.1016/j.jhazmat.2012.06.022. Epub 2012 Jun 19.
The generation and disposal level of thermal power plant ash in India is a challenging task. The conventional mode of dilute phase ash slurry (10-20% solids by weight) transport through pipelines being practiced in majority of these plants not only consumes huge amount of precious water and pumping energy but also causes serious environmental problem at the disposal site. The present study investigates the rheological and leaching characteristics of an Indian ash samples at high solids concentrations (>50% by weight) using sodium silicate as an additive. The flow behaviour of ash slurry in the concentration range of 50-60% by weight is described by a Bingham-plastic model. It was indicated that the addition of sodium silicate (0.2-0.6% of the total solids) could able to reduce both the slurry viscosity and the yield stress. The analysis of the ash samples for the presence of heavy metals such as Fe, Cd, Ni, Pb, Zn, Cu, Co, As and Hg were carried out following Hansen and Fisher procedure. The addition of sodium silicate affected the leaching characteristics of the ash samples over a period of 300 days resulting in the reduction of leaching of heavy metals.
印度火电厂灰分的产生和处置水平是一项具有挑战性的任务。大多数这类工厂采用的传统稀相灰浆（重量比 10-20%的固体）输送管道模式不仅消耗大量宝贵的水和泵送能源，而且在处置场还会造成严重的环境问题。本研究使用硅酸钠作为添加剂，研究了一种印度灰分样品在高固体浓度（>50%重量）下的流变学和浸出特性。灰浆在 50-60%重量浓度范围内的流动行为用宾汉塑性模型描述。结果表明，添加硅酸钠（占总固体的 0.2-0.6%）可以降低浆料的粘度和屈服应力。按照汉森和费舍尔的程序，对灰分样品中存在的重金属如铁、镉、镍、铅、锌、铜、钴、砷和汞进行了分析。硅酸钠的添加在 300 天的时间内影响了灰分样品的浸出特性，导致重金属浸出减少。
