Boron Industry, Sources, and Evaporitic Andean Deposits: Geochemical Characteristics and Evolution Paths of the Superficial Brines

Abstract

This study accounts for boron deposits in Chile. In addition, a vision is given of the geochemical evolution of its waters that depend largely on the evaporation of water and various factors among which are the geomorphology, climate, and volcanic activity that favor the conditions for the deposition of various salts between that accentuate lithium, potassium, and boron. Borates are found in lenticular stratified bodies, known as "bars," interspersed in detrital-saline sequences and always in the first meters of the saline surface part or as high-grade nodules (up to 30% B 2 O 3) that can reach tens of centimeters. In the first part, a description is made of the saline deposits to coming of the salars of South America, because it is the most important reserves of boron-rich minerals known in this continent are directly related to this type of deposits. Subsequently, the deposits in Chile and their characteristics are described. The only mineral of economic recovery known in Chile is ulexite. The second part refers to the Pitzer ion interaction model that is applied to predict the precipitation of salts in multicomponent aqueous systems with high ionic strength in a temperature range of 0-60°C, using the three natural brines of Andean borates.