Luciana Andrea Castillo

Integrated Process for Purification of Low Grade Talc Ores

This study examines the development of an integrated process for separation and purification of low grade talc ores. This procedure involves leaching with HCl to dissolve gangue minerals and to purify a low purity talc ore containing up to 40% gangue minerals. Also, all cations from gangue minerals are recovered as hydroxides via selective precipitation. The effects of acid concentration, talc/acid solution ratio, time, and reaction temperature on talc purification were studied and the optimal conditions were determined. Laboratory-scale tests revealed that the resulting talc is free of gangue minerals, consisting of small particles with nanometric thicknesses. Reactants are fully consumed during dissolution and byproducts like ammonium chloride could be recirculated and reused. Resulting hydroxides can be used as a coagulation aid for water treatment.

Modified Starches Used as Additives in Enhanced Oil Recovery (EOR)

Enhanced oil recovery (EOR) implementation arises as a supplementary technology to conventional ones, optimizing the not-easily recoverable oil phase. Estimation of oil remnant in reservoirs approaches to seven billion of barrels, after primary and secondary recoveries. One of the EOR strategies implies the use of displacing fluids, such as water-soluble polymers, which are pumped into the reservoir forcing the oil to flow toward the production wells. Thus, the state of the art related to the use of different starch derivatives in EOR is included in this chapter. Besides, diverse synthesis methodologies of the modified starches are presented, analyzing the optimal conditions of each reaction. Particularly, the synthesis of cationic starches is reported since they are the most used in EOR. Modification degree and physicochemical properties of the derivatives are included. Rheological and flow properties of displacing fluids are also discussed as a function of starch concentration.

Composites and Nanocomposites Based on Starches. Effect of Mineral and Organic Fillers on Processing, Structure, and Final Properties of Starch

Composites development, by incorporating organic or mineral fillers to starch matrices, can be used to improve their final properties. Accordingly, composites of different starch matrices reinforced with organic fillers, as well as, with mineral particles are described in this chapter. In this sense, it was reported, among others, the use of cellulose fibers from different botanical origins and clays particles. Nowadays, both academic and industrial interest in nanoscale fillers is growing since a nanostructured composite could be developed from a polymeric matrix and layered mineral particles. Thus, in this chapter is also included the development of nanocomposites based on thermoplastic starch and talc nanoparticles from different geological origins and morphologies. Processing methods and structural and final properties of composites are described.