- Jordan Dick
Energy Requirements for Comminution
Comminution is the process of reducing the size of ore particles to liberate the minerals in preparation for extraction in downstream processes. It is a critical piece of almost all mineral processing circuits. Traditional comminution techniques such as SAG mill, ball mills, and rod mills break the ore by applying impact, compression, and shear forces using steel balls, rods, or other grinding media. These processes have very high energy consumption with very low efficiency. As a whole, comminution in the mining industry consumes up to 4% of all global electricity and size reduction alone can account for up to 50% of an individual mine site’s energy consumption. Comminution energy and the resulting CO2 emissions have been high on the list of problems for the mining industry to address for many years.
Disa Technologies’ patented High Pressure Slurry Ablation (HPSA) Technology does just that. The HPSA technology utilizes high-pressure slurry pumps to process solid feed material, in slurry form by pumping that slurry through a set of impinging nozzles, creating a high-energy, particle-to-particle collision zone contained in a collision housing. By utilizing this high energy collision region, HPSA has circumvented the requirement of grinding media such as pebbles, balls, or rods used in traditional grinding circuits. HPSA can reduce the overall processing energy consumption by up to 40% over traditional grinding circuits.
Figure 1: HPSA Batch Unit (Left) and CFD Image of Collision Region (right)
The greatest liberation and recoveries with traditional grinding unit operations are observed for particles ground to less than 30 microns. As such, the mining industry is currently geared toward reducing the particle size as much as possible to separate the valuable minerals from their impurities. However, as particle size decreases, energy consumption to reduce the particle size even further increases exponentially. As a result, HPSA has the potential to drastically reduce the energy consumption and by extension GHG emissions of the minerals processing sector and the world. Due to HPSA’s unique ability to liberate composite material into its discrete subfractions along intergranular boundary lines, HPSA makes it easier to separate waste earlier in the processing sequence which reduces environmental risks and long-term liabilities.
Figure 2: Particle Size Vs. Energy Consumption Curve