Newer Developments in Cleaning Wet Process Phosphoric Acid

Summary:

The past decade has seen a growing demand for cleaner phosphoric acid for a variety of uses, and the firm establishment of liquid-liquid extraction in this upgrading technology. A number of novel processes have been claimed recently but on the whole there have been few striking developments since first the concept of fractionating a wet acid feed into a purer portion and a less pure portion was presented. One such novel extension of the basic fractionating approach is described in this paper; it depends on admixing an alcohol with an ether with the aim to extending the range of applicability. Basic physico-chemical properties of the modified solvent system are described for better appreciation of the essence of the modification.

A significant point in this development is that new technology is not involved, the modified solvent remaining substantially similar to the ether itself.

Another, completely different, upgrading technique discussed, relates to controlling the organics in wet phosphoric acid, and thus obviating a number of deleterious effects traceable to the organics present in colloidal solution. This upgrading technique is applied within the normal acid production facility, hence it is attractive for those who use rock of high organic content, irrespective of whether the acid is to be cleaned further or not.

Dr Ruth Blumberg, IMI – Institute for Research and Development, Haifa, Israel.

21 pages, 8 Tables, 5 Figures, 20 References.