Journal Published Online: 14 May 2021
Volume 10, Issue 1

Amelioration of Bauxite Residues by Sequential Slurry Carbonation

CODEN: MPCACD

Abstract

The safe handling, storage, disposal, and use of the bauxite residues (BRs) has become a bug bear to alumina refineries not only because of the enormous quantity that gets generated but also because of its characteristics, namely, extremely high alkalinity and sodicity. One of the ways to negotiate with this situation would be to “neutralize the BRs,” a hypothesis that would transform them into a nonhazardous (chemically less or partially inert) material that could be used as a man-made resource for its bulk utilization in various infrastructure development and agronomical projects. In order to demonstrate the feasibility of this hypothesis, BRs from an alumina refinery of India were collected in their slurry form and neutralized by resorting to sequential slurry carbonation (SSC) technique. The SSC was achieved by employing (1) gaseous phase carbon dioxide, CO2, and (2) synthetic flue gas, which has a composition like that of stack gases produced from the industries. The study observed a sharp decline in pH of the BRs slurry in the initial phase of treatment, which lasted for 120 min, and the formation of neutralized BRs, designated as NBRs. The exposure, when continued beyond 120 min to 1,440 min, yielded NBRs that exhibit almost constant pH. The exposure of NBRs to the atmosphere resulted in a pH rebound with time.

Author Information

Kuntikana, Ganaraj
Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, India
Syed, Sayeeda
Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, India
Singh, Devendra Narain
Department of Civil Engineering, Indian Institute of Technology Bombay, Mumbai, India
Pandit, Sagar S.
Bayer Process Development and Engineering, Hindalco Innovation Center-Alumina, Belgavi, Karnataka, India
Kapuri, Nageswar
Hindalco Innovation Centre-Alumina, Belgavi, Karnataka, India
Pages: 18
Price: $25.00
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Stock #: MPC20190240
ISSN: 2379-1365
DOI: 10.1520/MPC20190240