Competitive adsorption on wollastonite: an atomistic simulation approach.

Area of Science:

• Mineral processing and surface chemistry
• Computational materials science

Background:

• Wollastonite is a scarcely floatable mineral, posing challenges in mineral processing.
• Understanding surface interactions is crucial for optimizing flotation efficiency.

Purpose of the Study:

• To investigate the surface structure and adsorption behavior of wollastonite using atomistic simulations.
• To evaluate the impact of water, methanoic acid, and methylamine on wollastonite surface energy and adsorption.
• To determine the effectiveness of carboxylic acid and amine collector head-groups for wollastonite flotation.

Main Methods:

• Atomistic simulation techniques, including static energy minimization using the METADISE code.
• Simulation of surface energy and adsorption energy in the presence of molecular and dissociated water, methanoic acid, and methylamine.
• Surface hydroxylation and charge neutralization modeling.

Main Results:

• All additives (water, methanoic acid, methylamine) stabilize wollastonite surfaces, with methylamine showing the greatest stabilization.
• Specific crystal faces ({100}, {102}, {001}) exhibit preferential adsorption of dissociated water or methylamine based on highly negative adsorption energies.
• The adsorption preference sequence for molecular adsorption is methylamine > methanoic acid > water.

Conclusions:

• Both carboxylic acid and amine head-group molecules exhibit preferable adsorption on wollastonite surfaces.
• Simulation results validate the use of carboxylic acid head-groups as effective collectors for wollastonite flotation.
• Amine head-group collectors are predicted as potential modifiers, aligning with experimental findings.