Purification and Preparation of Graphene-like Nanoplates from Natural Graphite of Canindé, CE, Northeast-Brazil

TL;DR

This study explores methods to purify and prepare graphene-like nanoplates from natural graphite in Brazil for use in advanced technologies.

Contribution

A novel process combining flotation, hydrothermal purification, and acid leaching to produce graphene-like nanoplates from natural graphite.

Findings

Flotation produced a graphite concentrate with 76.6% graphite carbon content.

Acid leaching destabilized graphite layers, forming graphene-like nanoplates including monolayer graphene.

The process shows potential for applications in lithium-ion batteries and electric vehicles.

Abstract

In this study, flotation tests were conducted on a laboratory scale using a sample of microcrystalline graphite ore from the Canindé region, Ceará, Brazil. The objective was to investigate the grinding time, reagent dosage, and purification process for obtaining graphene-based nanomaterials. Natural graphite has a stacked planar structure and exhibits polymorphism with rhombohedral, hexagonal, and turbostratic geometries, characteristics that directly influence its properties and technological applications. The results demonstrated that it was possible to obtain rougher concentrate with a graphite carbon content of 23.4% and a recovery of 86.4%, using a grinding time of 7.5 min and reagent dosages of 150 g/t of kerosene and 100 g/t of Flotanol D-25. This flotation process resulted in a graphite concentrate with 76.6% graphite carbon content. To increase the purity of the concentrate and expand its industrial applications, the graphite was purified in an alkaline autoclave using the hydrothermal method. In the next stage, acid leaching was performed, and this chemical treatment destabilized the regular stacking of the graphite layers, promoting the formation of graphene-like nanoplates, including monolayer graphene. Thus, the nanomaterials obtained through the process developed in this study have potential for various innovative applications, such as lithium-ion batteries, electric vehicles, and two-dimensional graphene-based materials.

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