Occurrence State of Carbon and Electrolyte in Anode Carbon Residue From Electrolytic Aluminum

Song Mao,Qin Zhang

doi:10.3389/fmats.2021.719563

Song Mao, Qin Zhang

Open Access

https://doi.org/10.3389/fmats.2021.719563

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Abstract

Anode carbon residue is produced in the production of electrolytic aluminum. Its properties need to be studied for secondary utilization. In this paper, mineralogy of anode carbon residue from an electrolytic aluminum plant in Guizhou was studied. The anode residue chemical composition, structure, mineral composition, occurrence state of main elements, etc, was investigated. The results show that: Anode carbon residue is mainly composed of 14 minerals such as cryolite, cryolithionite, elpasolite and graphite. Among them, the opaque minerals are mainly graphite and the transparent minerals are mainly cryolite. Carbon in the form of independent mineral occurrence in graphite; fluoride in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite and fluorite; aluminum in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite, aluminium oxide and magnesium aluminate; sodium in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite. The mineralogical characteristics and occurrence state of carbon and electrolyte were studied, which provided a basis for the separation and recovery of carbon and electrolyte in anode carbon residue.

Highlights

Hall-Heroult electrolysis process is the most commonly used method for aluminum production (Grjotheim and Krohn, 2020)
Occurrence State of Potassium The potassium content in anode carbon residue is 2.77%, and it occurs in the form of independent mineral in potassium cryolite with a distribution rate of 100.00%
In the anode carbon residue, the content of carbon is 14.16%, which occurs in graphite as independent minerals

Summary

Introduction

Hall-Heroult electrolysis process is the most commonly used method for aluminum production (Grjotheim and Krohn, 2020). Anode carbon residue produced in the process of electrolytic aluminum is a kind of dangerous solid waste. It contains fluorine ions, the direct storage and landfill treatment will have a serious impact on the environment (Lifeng et al, 2019). Carbon anode is one of the key components in the production of electrolytic aluminum. It is mainly composed of calcined petroleum coke, coal tar pitch and regenerated carbon materials (Bhattacharyay et al, 2017).

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