Zircon processing in sodium carbonate melt

Abstract

Abstract The process of alkaline zircon processing with soda and a mixture of soda with intensifying additives carbon and NaOH was studied. As a result, a complete exclusion of acid-soluble sodium zirconosilicate formation was ensured. The introduction of carbon into soda melt increased the agent’s reactivity due to the formation of highly reactive Na2O. At 1100 °C, the optimal amount of introduced carbon is 4 wt.%, while the duration of the process is reduced to 10 minutes. Zircon processing in two stages – at 1150 °C and 1000 °C with the soda addition from 2.5 to 4.0 wt.% provided the production of metazirconate and sodium silicate, excluding the transition of silicon to the solid phase, providing an opening degree > 99%. The novel bakor-lined electric furnace of high operational reliability has been successfully tested. Carbonization of the sodium silicate solution in the presence of water vapor ensures complete precipitation of hydrated silicon dioxide, with a bulk density of 150 g/L. The optimal concentration of CO2 is ~ 8%, which allows using off-gases from thermal power plants for carbonization. The presence of water vapor in the gaseous phase increases the utilization of CO2 and Na2CO3 regeneration.