RU2448042C1 - Method of silicone desorption from anionites - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: anionites are treated with solutions of hydrofluoric acid or its salts, which contain 2.5 mol/l of fluorine-ion, 10% of sulphuric acid and ions of ferric iron at Fe³⁺/F molar ratio equal to 1:2.

EFFECT: excluding corrosion of the used equipment at maintaining technical silicone desorption parameters.

1 tbl, 2 ex

Description

The invention relates to hydrometallurgy, in particular to ensuring the corrosion resistance of equipment used for sorption processing of solutions of acid leaching of rare metal ores.

A known method of restoring the physico-chemical properties of anion exchangers by treating the latter with a solution of 5 M HF for 3 hours (USSR AS No. 339501, IPC C01B 33/00, 1976). However, this method requires special expensive means of protecting equipment from ordinary stainless steel from the corrosive effect of fluorine ions and is characterized by increased destruction of the sorbent in the sorption-desorption cycles.

A known method of desorption of silicon from anion exchangers (AS USSR No. 1334613 from 05/27/1980, publ. 08/27/1999). In this method, the treatment is initially carried out with an acidic solution containing 2.5-3 g-eq / l of fluorine ion and 10-15% nitric or sulfuric acid, and desorption is carried out with a solution of hydrofluoric acid or its salts in the presence of nitric or sulfuric acid for 2-3 hours.

The disadvantage of this method is the low chemical resistance of the equipment used in the stripping solution, which leads to the necessity of either using measures to protect the installed equipment from the influence of fluoride ion, or replacing it with containers made of materials resistant to these conditions.

The objective of the invention is the creation of a desorption solution that would eliminate corrosion of the applied equipment from ordinary stainless steel (type X18H9T), without compromising the technical performance of silicon desorption.

The method of desorption of silicon from anion exchangers is carried out by treating them with solutions of hydrofluoric acid or its salts, containing 2.5 mol / l of fluorine ion and 10% sulfuric acid. Ferric ions are additionally introduced into the stripping solution at a molar ratio of Fe ³⁺ / F as 1: 2.

Example 1. A portion of VP-1Ap anion exchange resin containing 37% by mass SiO ₂ was treated with a mixture of 2.5 M HF and 10% H ₂ SO ₄ in two stages with an anion exchange rate / solution of 1: 3–5). At the same time, corrosion tests are carried out on the resistance of samples of equipment material (X18H9T steel) in a stripping solution for the presence or absence of corrosion.

Example 2. A portion of the same anion exchange resin is treated with a solution of 2.5 M HF, 10% H ₂ SO ₄ and 1.25 M Fe ³⁺ with a volume ratio of anion exchange resin 1: (3 ÷ 5) and corrosion tests are also carried out in a stripping solution for the presence or absence of corrosion.

The table shows the compositions of the stripping solution, the residual SiO ₂ content after desiliconization, the total exchange capacity for Cl-ion (POE) and corrosion resistance on a 5-point scale: H - unstable, B - very stable.

Way The composition of the stripping solution SiO ₂ ,% wt. residual Mechanical strength,% rel. POE by Cl ^- -ion Corrosion resistance: on a 5-point scale / mm per year (according to GOST) Source Ultimate Source After desilicon-
vania Prototype 2.5 M HF + 10% H ₂ SO ₄ eleven 85 82 4.20 4.12 N / a> 3 Proposed 2.5 M HF + 1.25 M Fe ³⁺ + 10% H ₂ SO ₄ 10 85 88 4.20 4.15 B / <0.1

Claims (1)

The method of desorption of silicon from anion exchangers by treating them with solutions of hydrofluoric acid or its salts containing 2.5 mol / l of fluorine ion and 10% sulfuric acid, characterized in that ferric ions are additionally introduced into the stripping solution at a molar ratio of Fe ³⁺ / F equal to 1: 2.