1983 Volume 69 Issue 8 Pages 929-936
Chemical reactions for the recovery of Na2CO3 from the slag obtained in the refining of hot metal with Na2CO3 were studied. The process for the Na2CO3 recovery consisted of three main unit operations.
1) Dissolving of the slag in the circulating aqueous solution.
2) Removal of residue and impurities (Si, P) from the solution.
3) Recovery of Na2CO3 from the solution.
More than 90% of Na, P, V and 40 to 50% of S, Si contained in the slag dissolved in the solution and main ion species in the solution were proved as Na+, V5+, OH-, CO2-3, SiO2-3, PO3-4, S2-, S2O2-3and SO2-4. With the addition of CO2, OH-/CO2-3 ratio in the solution turned to nil and Si concentration in the solution reduced to 2g/l because of hydrolysis of SiO2-3 ion. Addition of Ca(OH)2 in the solution caused reduction of P concentration to less than 3g/l, due to the formation of Ca3(PO4)2·Removal of V and S ion were also studied. From these experiments, a process-flow for the Na2CO3 recovery from the slag was proposed.