Fly ash is a by-product generated from combustion of coal in thermal power plant. Disposal of fly ash is a major environmental concern for the power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, substantial quantity remains unutilized. Silica and alumina are the major constituents in fly ash along with lime. Alumino-silicates and unhydrated lime present in fly ash, in presence of water, undergo a pozzolanic reaction and form cementitious bond which holds the particles together. Bentonite is commonly used as binder in micropelletization of process waste to attain the mechanical strength required for handling and transportation. The bonding of particles by bentonite is a physical mechanism, while fly ash bonding is a chemical mechanism. The present paper deals with the partial replacement of bentonite with fly ash in micropelletization without affecting the quality of micropellets.

粉煤灰是火力发电厂燃烧煤产生的副产品。粉煤灰的处理是发电厂的主要环境问题。尽管相当一部分粉煤灰用于水泥制造和制砖，但仍有大量未使用。二氧化硅和氧化铝与石灰一起是飞灰中的主要成分。飞灰中存在的铝硅酸盐和未水合石灰，在有水的情况下，会发生火山灰反应并形成将颗粒粘合在一起的胶结键。膨润土通常用作工艺废物微丸化过程中的粘合剂，以获得处理和运输所需的机械强度。膨润土对颗粒的结合是一种物理机制，而粉煤灰结合是一种化学机制。