Abstract
This work evaluates the characteristics of calcium aluminate slag and pig iron samples obtained from the smelting of calcined and reduced diasporic bauxite ore. The study is conducted in the Pedersen process framework, which is a method to produce alumina from low-grade resources. Parameters such as the effect of crucible type, lime addition, and atmospheric conditions are studied considering the characteristics of the product pig irons and calcium aluminate slags for further uses. The behavior of the bauxite and distribution of the species between slag and metal was assessed based on the applied analytical techniques and thermodynamic calculations. Iron was reduced and separated from the slags in the presence of carbon (graphite crucible) for both the reduced and calcined bauxite. Si and Ti were mainly concentrated in the slags. Iron was separated from the slag in the absence of carbon (alumina crucible) for the H2-reduced bauxite. The results show that slags with increased lime additions are composed mainly of 5CaO.Al2O3 and CaO.Al2O3, that are considered highly leachable compounds. An optimum CaO/Al2O3 mass ratio of 1.12 was suggested. The presence of O2 and/or OH- in the furnace atmosphere will result in the formation of 12CaO.7Al2O3.
Highlights
Considering the depleting tendency of the high-grade ore deposits, alternative processes are necessary to be developed and utilize the available resources efficiently and holistically
Iron was separated in the form of pig iron that was found to contain low level of impurities such as Si, S, and Ti, and :
Si and Ti were mainly distributed in the slag; In the absence of carbon, iron was separated from the slag for the reduced bauxite, and this offers promising perspective for a process with reduced
Summary
Considering the depleting tendency of the high-grade ore deposits, alternative processes are necessary to be developed and utilize the available resources efficiently and holistically. Even though the Bayer process has been adapted for years, it has environmental challenges—the main being the formation of the Bauxite Residue (BR) [1,2,3]. Another limitation relates with the characteristics of the utilized ore since they will affect the overall process [4]. Low Al2 O3 /Fe2 O3 ratio in the bauxite ore is prohibited in the Bayer process since higher amount of the generated BR will be produced [5]. The development of processes that can utilize lower grade alumina-containing sources is essential
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
