Abstract
The desilication of sodium aluminate solutions prior to precipitation of aluminum tri-hydroxides is an essential step in the production of high purity alumina for aluminum production. This study evaluates the desilication of sodium aluminate solutions derived from the leaching of calcium-aluminate slags with sodium carbonate, using CaO, Ca(OH)2, and MgO fine particles. The influence of the amount of CaO used, temperature, and comparisons with Ca(OH)2 and MgO were explored. Laboratory scale test work showed that the optimal conditions for this process were using 6 g/L of CaO at 90 °C for 90 min. This resulted in 92% of the Si being removed with as little as 7% co-precipitation of Al. The other desilicating agents, namely Ca(OH)2 and MgO, also proved effective in removing Si but at slower rates and higher amounts of Al co-precipitated. The characteristics of solid residue obtained after the process indicated that the desilication is via the formation of hydrogarnet, Grossular, and hydrotalcite dominant phases for CaO, Ca(OH)2 and MgO agents, respectively.
Funder
European Union’s Horizon 2020
Subject
Process Chemistry and Technology,Chemical Engineering (miscellaneous),Bioengineering
Reference13 articles.
1. Dessilication of Bayer Process Solution;George;U.S. Patent,1992
2. Production of alumina;Metson,2011
3. Application of Hydrometallurgy in Alumina Production: The Bayer Process;Balomenos,2021
4. Investigating Aluminum Tri-Hydroxide Production from Sodium Aluminate Solutions in the Pedersen Process
5. Adaptation of the Pedersen Process to the Ferruginous Bauxites of the Pacific Northwest,1966
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