**Abstract**

Mineral engineering is an interdisciplinary branch which includes many branches like physics, chemistry, math and sub branches like instrumentation, chemical engineering, mechanical engineering, geology etc. Amongst the various separation/beneficiation techniques of mineral processing, froth flotation is one of the most important fines beneficiation technique, which depends upon the surface and colloid chemical phenomena as the basis of selectivity. The method of separation relies on the surface state and colloidal chemistry of the ore particles and chemical reagents. Adsorption at the mineral solution interface is of major importance for the behaviour of mineral particles in the solution and for successful flotation performance. Adsorption of simple ions determine the change of the particle surface and electrochemical properties of the pulp/slurry phase and therefore affect the colloidal stability and the adsorption behaviour of reagent on the mineral surface. This chapter describes in detail about the role, importance and application of colloidal chemistry in mineral processing especially froth flotation. Froth flotation will remain a key unit operation for the treatment of low-grade ore fines for the decades to come with the overarching challenge as the need of the hour is to modify and improve existing process conditions so as to maintain an acceptable grade and recovery response for the feed whose liberation is more finer, more complex association of minerals and of lower grade.

**Keywords:** mineral processing, iron minerals, colloids chemistry, surface chemistry, adsorption, zeta potential, interfacial chemistry

### **1. Introduction**

Mineral Engineering is a multidisciplinary and inter disciplinary branch, which includes many other branches and sub branches. Due to depletion of high-grade ores and liberation size being finer, particles are approaching colloidal size range, mineral processing is becoming more and more applied colloid chemistry. Colloid chemistry is inevitably involved in all aspects of mineral processing, ranging from rheological phenomena in grinding, in froth flotation in which selective adsorption of various chemical additives (flotation collectors, flocculants, dispersants, depressants etc.) onto mineral surfaces, dewatering, tailings management and analysing the forces which control the stability of dispersion as well as the wettability of mineral surfaces. Surface phenomena control both the dewatering of "fines" and area involved in dust suppression. So, to understand the colloidal science and colloidal chemistry in mineral engineering, a basic knowledge on surface science (surface physics, surface chemistry, surface mineralogy etc.) should be there. Colloidal solution is formed by dispersing one phase into another and the phase change can be easily described in terms of attractive and repulsive

interactions in the dispersed phase. Different mineral beneficiation processes along with the application of colloid chemistry are depicted in **Figure 1.**

Along with the application in Mineral industry, colloidal chemistry has the application in non-mineral industry also in deinking, waste water treatment etc. We can't just use the word colloid science, in this modern era, interdisciplinary is more accurate word for Mineral Engineers as it has been justified. Fine mineral particles (colloidal particles), when present in slurry exert an affect on the ionic environment surrounding the particle. To understand or to get an extensive knowledge about colloidal systems in mineral processing, a knowledge on basic surface science is required.

So, as flotation, flocculation are (physico-chemical surface based separation processes), involves the application of certain surfactants in the slurry phase, hence valuable understanding of intermolecular forces at the interfaces in mandated.
