Selective bromide recycle from waste streams by solvent extraction

eyal barnea, ICL central R&D institute, quiryat ata, israel
sarit yadid-sarmili, inorganic, ICL central R&D institute, quiryat ata, israel
david fuks, ICL central R&D institute, quiryat ata, israel
gideon friedman, ICL central R&D institute, quiryat ata, israel
moti cohen, DSBG, be'er sheva, israel
mira freiberg, DSBG, be'er sheva, israel
ronit shafrir, DSBG, be'er sheva, israel

Bromine or bromine based chemicals (organic or inorganic) have many uses in the chemical, electrical and drilling industries. In some cases the bromides find their way into the waste streams or process effluents. The aim of the work we will present was to selectively recover these bromides from waste streams (usually containing also chlorides, sulphates), and convert them to a reusable salt form. The two optional salt products of the process – NaBr and CaBr₂ are the most common inorganic bromine compounds used by industry today.

The talk will start with a short introduction of ICL's central R&D institute (TAMI-IMI) and the concept of selective anionic solvent extraction. We will then focus in more detail on the whole path of process development according to the following methodology:

Screening for suitable and approved solvent systems and extractant. Feasibility tests of limiting conditions in the lab. Determination of critical parameters for the different solvent extraction stages (extraction, purification and washing). Finally the results of the last development stage - optimization of the process on a mini-pilot scale continuous extraction system will be presented. The results of the process development confirmed that recycling of bromides from effluents can be achieved by solvent extraction, with high efficiency and very good selectivity.