Introduction
At IPRI.Tech AG, the International Plasma Research Institute, we are pioneering a transformative approach in mineral processing through our proprietary Ultra High Temperature Pyrometallurgical™ (UHTP™) technologies. Our flagship processes, Plasma Assisted Digestion™ (PAD™) and Plasma Accelerated Oxidation™ (PAO™), leverage ultra-high temperatures to enable chemical-free, green, and efficient recovery of valuable metals from complex and refractory ores. A foundational aspect of this technology is the significant mass reduction that occurs in the sample during plasma processing, driven by the volatilisation of specific mineral components.
Mechanism of Mass Reduction in Plasma Processing
During IPRI.Tech’s plasma treatment, minerals are subjected to extremely high temperatures. These temperatures are sufficiently high to cause thermal dissociation and decomposition of volatile mineral phases present in the ore or concentrate. The key volatile mineral categories that contribute to mass loss include:
- Sulfur-bearing minerals: Pyrite (FeS2), chalcopyrite (CuFeS2), arsenopyrite (FeAsS)
- Carbonates: Calcite (CaCO3), dolomite (CaMg(CO3)2)
- Sulfates: Gypsum (CaSO4·2H2O)
- Hydrated minerals and clays: Minerals containing structural water or hydroxyl groups
- Halides: Halite (NaCl)
- Organic matter: Carbonaceous material and other volatiles
These volatile minerals undergo thermal decomposition, releasing gases such as sulfur dioxide (SO2), carbon dioxide (CO2), water vapor (H2O), and other volatile compounds.
Chemical and Physical Processes
The high temperature environment promotes several concurrent effects:
- Thermal decomposition and volatilization:
The ultra-high temperature environment (often exceeding several thousand degrees Celsius) decomposes minerals that contain volatile elements or compounds. For example, pyrite decomposes to release sulfur gases, while carbonates release CO2. - Gas-phase removal:
The volatile compounds generated are vaporised and pass through the reactor system as gases. This continuous off-gassing results in a measurable decrease in the solid sample’s mass. - Mineral dissociation and liberation:
The removal of volatiles facilitates the breakdown of refractory mineral matrices, thereby releasing encapsulated nanometals such as nanogold™ and other nanometal™, which are typically inaccessible to conventional processing. - Spheroidization and nanoparticle formation:
High reactor energy can cause fragmentation and spheroidisation of particles, often creating metallic nanoparticles that are amenable to subsequent extraction.
Quantitative Aspects of Mass Reduction
The degree of mass loss depends on the mineralogical composition of the sample. Samples rich in sulphide minerals or carbonates experience significant mass reductions, sometimes up to 20-30% or more by weight, consistent with the extent of volatile mineral decomposition. For example:
- Sulfur content volatilization is a major contributor to mass loss as sulfur gases like SO2 escape.
- Carbonate decomposition contributes CO2 loss.
- Moisture and humidity from hydrated minerals are vaporized as H2O.
The residue left behind is a denser, metal-enriched material, significantly reduced in mass yet higher in value concentration, improving subsequent recovery efficiency.
Environmental and Operational Benefits
IPRI.Tech’s proprietary process is chemical-free and environmentally friendly, avoiding hazardous reagents commonly used in conventional hydrometallurgical routes. The selective volatilisation of impurities and volatiles reduces not only mass but also potential environmental impact from waste streams. The gaseous byproducts like SO2 is captured and treated further to minimise emissions.
Summing Up
Mass reduction during UHTP™ processing at IPRI.Tech is fundamentally a function of thermal dissociation and volatilisation of minerals containing sulphur, carbonates, sulphates, hydrated compounds, halides, and organic matter. The high-temperature plasma environment efficiently vaporises these volatile phases, allowing them to escape as gases, which leads to the solid material becoming mass-reduced yet enriched in critical and precious metals. This mechanism is central to unlocking the full potential of ores that are refractory or otherwise difficult to process, positioning IPRI.Tech’s UHTP™ technology as a game-changer in sustainable mineral processing.
This detailed understanding of mass reduction via volatilisation and gas-phase removal emphasises the technological advance IPRI.Tech provides in transforming ore treatment and resource recovery, offering a potent solution to industry challenges in value extraction and environmental stewardship.ipri+3
This report is tailored for technical audiences with interests in mineral processing, pyrometallurgy, and plasma technologies.
References
- https://ipri.tech
- https://pure.tue.nl/ws/files/3534817/Metis255463.pdf
- https://pubmed.ncbi.nlm.nih.gov/32129239/
- https://ch.linkedin.com/company/ipri-tech
- https://ipri.tech/services/
- http://www.plasmaindia.com/News%20letter/Issue_92_Nov_2022.pdf
- https://www.setcor.org/conferences/plasma-tech-2024
- https://en.wikipedia.org/wiki/Institute_for_Plasma_Research
- https://patents.google.com/patent/US7229485B2/en