Implementation of Mathematical Equation for Calculating Alumina Extraction from Bauxite Tailing Digestion

DOI

10.2991/amsm-16.2016.16How to use a DOI?

Keywords

bauxite tailing; digesting; percent yield; alumina extraction; mathematical model; Bayer process

Abstract

Research on bauxite digesting using pressurized reactor at a capacity of 86,66 kg of feed/batch had been conducted. Bauxite with -150 mesh of particle size is reacted with 42,15 kg of caustic soda with concentration of 433,49 g/l at the temperature of 140oC for 1.0 to 2.5 hours using steam as heating media. Lime added are varied from 3 to 9 kg. After processing for a certain period of time, slurry product is transferred into a Mixer. To evaluate percent yield of Al2O3 extraction from this process, measuring the height of slurry level in the Mixer, densities of the slurry, filtrate, and solid residue are conducted. Head sample of bauxite, filtrate and residue are analysed by using wet method to get Al2O3 content of each sample taken from the Mixer. There are four equations that are used for obtaining percent yield of Al2O3 extraction, namely:1)Vsl=4.176x+15.83; 2)Wsl=(4.176x+15.83)*" "s; 3)S=(" "sl-" "l)/(" "s-" "l)(" "s/" "sl)*100% and 4) E=[10 (4.176x+15.83) [1- (" "sl - " "l) / (" "s - " "l)]*[cl / FxF]%. Where: Vsl is volume of slurry in the Mixer (litre); x is height of slurry level in the Mixer (cm); Wsl is weight of slurry in the Mixer (kg); S is solid percentage of slurry (%); " "sl is density of slurry (kg/l); " "s is density of residue (kg/l); " "l is density of filtrate (kg/l); Cl is concentration of Al2O3 in filtrate (g/l); E is percent yield of Al2O3 extraction (%). By using those four equations, it can be obtained the results of the research as follows: by the increase of lime added into slurry, percent yield of Al2O3 extraction tend to decrease from 46.63% for 3 kg of lime to 15,84% by using 9 kg of lime. Whereas by varying reaction time between 1.0-2.5 hours, percent yield of Al2O3 extraction are fluctuation in the range of 42,07-60,54% with 1.5 hours of reaction time is the highest result. By implementing those four equations above for evaluating the data, we do not need to weigh the slurry in the Mixer.

Copyright

© 2016, the Authors. Published by Atlantis Press.

Open Access

This is an open access article distributed under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

Download article (PDF)

TY  - CONF
AU  - Saini Hu
PY  - 2016/05
DA  - 2016/05
TI  - Implementation of Mathematical Equation for Calculating Alumina Extraction from Bauxite Tailing Digestion
BT  - Proceedings of the 2016 International Conference on Applied Mathematics, Simulation and Modelling
PB  - Atlantis Press
SP  - 66
EP  - 71
SN  - 2352-538X
UR  - https://doi.org/10.2991/amsm-16.2016.16
DO  - 10.2991/amsm-16.2016.16
ID  - Hu2016/05
ER  -