TABLE OF CONTENTS Many mineral and metallurgical processes generate secondary products, which are not usually sought after. Until recently, they were either stock piled or disposed off as wastes . Interestingly, many of these secondary or waste products contain valuable material, which can be recovered through new technologies (discussed in Chapter 8) or they can be directly used for specific industrial, construction or agricultural purposes, sometimes after appropriate treatment. Conversion of such materials to valuable, marketable products could lead to development of secondary or spin off industries and they can be useful by-products of the original process. Some examples of such by-product processing and utilization of those products will be discussed in the present Chapter.
Slag is the molten byproduct or coproduct of many metallurgical and special (coal fired thermal plants for instance) operations, that is subsequently cooled (air, pelletized, foamed or granulated) for use, or, unfortunately in too many cases, disposal. Ferrous (iron and steel) and nonferrous (copper and nickel for instance) metals are the most commonly used, world-wide, structural and functional materials. The resulting large quantities of slags produced and their potential impact on the environment have prompted material scientists and civil engineers to explore the technically-sound, cost-effective and environmentally-acceptable use of a wide range of slags in construction. There is a full range of proven construction uses - from aggregate to cementitious materials - for copper, nickel and phosphorus nonferrous slag.
The use of iron blast furnace slag as a...
