Completed and Ongoing Research Projects (After Joining VT)


Funding Agencies

Rare Earth and Other Critical Elements Recovery & Purification

Summary:

We are conducting applied research to recover and purify rare earth and other critical elements (Li, Co, Mn, etc.) from various resources, including but not limited to coal refuse, coal combustion ash, acid mine drainage, and municipal solid waste incineration ash. The investigated recovery approaches include size, density, magnetic, electrostatic, and flotation separations as well as leaching and roasting. After critical metals being recovered, we employ advanced purification methods, such as selective precipitation, solvent extraction, selective adsorption, and membrane separation, to obtain high-grade products. 

Disciplinary:

Mineral Processing, Hydrometallurgy, Pyrometallurgy

Selected Publications: 

1. Zhang W., Noble A., Yang X., Honaker R., 2020. Lithium leaching recovery and mechanisms from density fractions of an Illinois Basin bituminous coal. Fuel, 268, 117319. 

2. Zhang W., *Honaker R.Q., 2019. Calcination pretreatment effects on acid leaching characteristics of rare earth elements from a bituminous source coal. Fuel, 249, 130-145. 

3. Zhang W., Honaker R.Q., 2018. Rare earth recovery using staged precipitation from a leachate generated from coarse coal refuse. International Journal of Coal Geology, 195, 189-199. 

Flotation Chemistry of Rare Earth, Carbonate, Sulfide, Silicate Minerals, Etc. 

Summary:

We are studying the flotation chemistry of a wide array of minerals, including but not limited to coal, monazite, bastnaesite, chalcopyrite, pyrite, scheelite, and magnetite. Concentrate grade and valuable mineral recovery are improved by the fundamental study of collector adsorption, regulator adsorption, solution chemistry, particle-particle interaction, and particle-bubble interaction as well as the development of novel flotation reagents.

Disciplinary:

Mineral Processing, Surface Chemistry, Solution Chemistry

Selected Publications: 

1. Zhang W., Liu C., 2019. The effect of diesel emulsification using sodium petroleum sulfonate on carbon flotation from fly ash. Waste Management, 98, 144-150. 

2. Zhang W., Honaker R.Q., Groppo J., 2018. Flotation of monazite in the presence of calcite part II: Enhanced separation performance using sodium silicate and EDTA. Minerals Engineering, 127, 318-328. 

3. Zhang W., Honaker R.Q., Groppo J., 2017. Flotation of monazite in the presence of calcite part I: Calcium ion effects on the adsorption of hydroxamic acid. Minerals Engineering, 100, 40-48. 

Industrial and Urban Wastes Recycling & Re-utilization

Summary:

We are providing solutions for the recycling and re-utilization of various urban and industrial wastes, including but not limited to electronic waste, smelting waste, and red mud. Interdisciplinary skill-sets in mineral processing, hydrometallurgy, pyrometallurgy, and biology are integrated, aiming to find sustainable and economic-viable approaches for the comprehensive utilization of those secondary resources while eliminating their environmental hazards. In collaboration with other researchers, we are also providing innovative strategies for simultaneous valorization of multiple waste streams.   

Disciplinary:

Mineral Processing, Hydrometallurgy, Pyrometallurgy, Biology

Selected Publications: 









Electronic Waste

 Bauxite Residue (Red Mud)

Municipal Solid Waste Incineration Ash