Industrially Useful Properties of South American Puna Borates

FLORES, H. R.; MATTENELLA, L. E; KWOK, L. H.; VALDÉZ, S. K.

Handbook on Borates: Chemistry, Production and Applications

Nova Science Publishing Inc.

Lugar: New York; Año: 2009;

Since most of the borates produced in Argentina (concentrates and processed products) are exported and the technical marketing regulations have become stricter, producers have to improve competitiveness through technology, including some concentration and/or purification stage in the mill circuit. The objective of the separation is to obtain a B2O3 upgraded product and also with lowered undesirable impurities (mainly iron, arsenic, chlorides and sulphates). Concentration steps usually involved in the borate processing are gravity separation, froth flotation, magnetic separation and size classification, based on the differences of specific weight, superficial energy, magnetic susceptibility and hardness, respectively between borates and gangue. Another easy grading method is calcination; that is, the conversion to a less hydrated crystalline form. Unfortunately, impurities are also graded, thus the raw material fed  to the calcination step must be previously concentrated. This paper reports the results obtained from measurements of the above mentioned properties for the South American borates of industrial interest (colemanite, hydroboracite, ulexite and tyncal), and it also reports the techniques employed to collect pure samples.