The Utilization of CO2, Alkaline Solid Waste, and Desalination Reject Brine in Soda Ash Production

Abstract

Conventional Solvay process, which utilizes CO2 to synthesize sodium carbonate, has been well-known for more than a century, but the only purpose of this process is to produce soda ash. Annually, significant amounts of CO2 are converted into soda ash using Solvay process; however, this conventional process does not sustain CO2 and waste cycle. Increasing the awareness of global warming and climate change linking to CO2 emission has pressured this industry to move for a more eco-friendly process that should exploit its potential for CO2 utilization and sequestration and thus contribute to both CO2 emission and waste management. In conventional Solvay process, to produce one mole of Na2CO3, at least one mole of CO2 might be emitted to atmosphere due to the use of CaO. Therefore, a number of studies have been done to explore novel processes or to modify the Solvay process in order for it to engage more in CO2 mitigation. This chapter introduces the most up-to-date modified Solvay process and novel pathways to produce soda ash and baking soda in the consideration of waste and CO2 utilization. Simultaneous waste and CO2 utilization offers a great opportunity for shifting to a green production, not only soda ash industry but others where their exhausted CO2, alkaline solid wastes, or reject brine can be utilized. However, there are challenges which require further research and technological development initiatives for the idea to be industrially implemented.