Water-leaching of Reaction Product of Chromite with Molten Sodium Salts

Abstract

Alumina component was insolubilized and removed selectively from the water-leached solution of reaction product of chromite with molten sodium salts by the addition of silica-containing materials to the leached solution.
Optimum conditions to insolubilize alumina component in the leached solution was proposed after experimental results as follows;
I. Added material: silicic acids ( amorphous form), amount added: molar ratio (SiO₂/Al₂O₃)= 2, reaction temperature: 100°C, reaction time: 1-2 hrs.
II. Added material: calcium silicate (amorphous mo nocalcium silicate), amonut added: molar ratio (SiO₂/Al₂O₃) ≥ 1.3, reaction temperature: 120°C, reaction time: ca.2 hrs.
Under these conditions, silica-containing materials were reacted with m ost of the alumina component in the leached solution to form zeolites.
On the basis of experimental results, a process for the production of sodium chromate from chromite was proposed.