Environmentally friendly flotation methods increase mineral yield

Buoyancy is one of the most important processes for separating minerals in the raw materials industry. The appropriate selection and dosage of reagents is required to achieve the highest possible mineral concentration. This is a complex, time-consuming, cost-intensive procedure.

Researchers at the Helmholtz Institute Freiberg for Resource Technology (HIF), part of the Helmholtz-Zentrum Dresden-Rossendorf, have developed a workflow for economic and ecological optimization and rise of ascending reagents. Initial testing on an industrial scale showed a significant increase in the concentration of valuable minerals, confirming the effectiveness of the developed approach.

This paper is published in Journal Colloids and Surface A: Physicochemical and Engineering Aspects.

Within the flotation process, the gas bubble is added to a liquid with finely ground particles, and the bubbles adhere to particles with water-repeated surfaces. These rise to the top with attached air bubbles, forming a layer of bubbles that can be skimmed. Mineral particles have different surface properties, but it is the selective adsorbing reagent that determines which particles gas bubbles can adhere to.

Various reagents (which trigger reactions when contacted with certain other substances) are used to increase the efficiency of particle separation. However, quantifying the potential of new reagents in industrial flotation processes is extremely expensive and time-consuming.

“Flotation reagents are important for concentration efficiency. Our knowledge of their effects is often based on laboratory-scale experiments. Reagent selection and administration were often informal, subjective and empirical based on empirical use. However, reagent systems consist of several components that have complex interactions.

“Therefore, simply replacing the reagents rarely leads to the desired success. Instead, factors such as dosage, application methods, and interactions with other reagents and minerals should be taken into consideration.”

The new workflow was successfully tested on an industrial scale – spinoffs in preparation

In the Cosilflot project, Ben said he used colloidal silica as a reagent to investigate the selective separation of celite and calcite. The experiments were statistically designed, numerically optimized and digitally processed, allowing numerous flotation trials to be excluded early stages, and the optimal administration range for single reagents on an industrial scale was quickly determined.

This methodology was successfully tested in industrial buoyancy plants in Europe, achieving an increase in valuable mineral content of up to 16%. “This highlights the huge potential of the workflow.

“We are currently working on various case studies from our follow-up project Cosilflot+, which includes replacing highly toxic fluoride acids with sodium fluoride and sodium fluoride in feldspar flotation and implementing biopolymers for the separation of chalcopylite and molybdenite,” explains the next step.

This result provides appropriate use opportunities for mining companies and flotation reagent manufacturers, as it is better able to accommodate changes in complex mineral composition cases. The mining industry relies on future ecologically compatible reagents, which also offers flexibility in the implementation of environmentally friendly flotation reagents. Additionally, this workflow offers a good prospect of being spin-off as a company.

“After successful verification, we plan to establish a spinoff that will provide Cosilflot+ workflow as an engineering service for mining companies and chemical manufacturers. The aim is to bring both players together to develop efficient and environmentally friendly solutions and further optimize the process results.

“At the same time, flotation reagent manufacturers can open new applications for their products and improve market opportunities,” Ben said.