US 5,676,916 AGranted

Process for extracting the boron content in the brine of natural or industrial salt mines

AssigneeSociedad Minera Salar de Atacama S.A.

InventorIgor Wilkomirsky

Life of this patent

Estimating the term…

Loading patent…

Abstract

A process for extracting boron from brines of natural or industrial salt mines which includes the steps of reacting borates contained in the brine with a solution of hydrochloric acid and forming boric acid, cooling the brine containing boric acid, separating the boric acid from the remainder of the brine to obtain impure boric acid and brine having a low boron content, washing the impure boric acid with distilled or demineralized water to obtain purified boric acid, and drying the purified boric acid. Boric acid crystals thus obtained are washed and recrystallized. The remaining boron in the low boron content brine can be removed by extraction in a paraffin solvent. The boron can then be re-extracted from the solvent and converted to boric acid for isolation and purification as above.

Claims15

Dependent claims

A process for recovering boron from brine, which comprises:

(a) reacting a borate-containing brine with a sufficient amount of hydrochloric acid to maintain a pH of from 0 to 4, measured for a dilution of water/brine of 10/1, in order to form boric acid-containing brine;
(b) cooling said boric acid-containing brine to a temperature of from -10.degree. C. to 10.degree. C. to precipitate said boric acid;
(c) separating said boric acid precipitate from said brine to obtain impure boric acid crystals and boron depleted brine;
(d) washing said impure boric acid crystals with distilled or demineralized water to obtain purified boric acid;
(e) contacting, in one or more stages, said boron depleted brine with an organic medium comprising a paraffin solvent having dissolved therein one or more extractants selected from the group consisting of aliphatic alcohols having at least 5 carbon atoms, diols and mixtures thereof, to extract additional borate from said boron depleted brine and form a borate-loaded organic medium;
(f) contacting, in one or more stages, said borate-loaded organic medium with an aqueous alkaline solution to re-extract said borate from said borate-loaded organic medium to regenerate said organic medium and form a borate-containing aqueous solution;
and
(g) evaporating said borate-containing aqueous solution to form a borate precipitate.

5 more elements

Dependencies are inferred from the claim text.