A Knelson concentrator is a centrifuge device used primarily in gold mining. The device is a gravity concentration apparatus, which retrieves pieces of fine gold from ore without having to use gold cyanidation, an expensive process that uses chemicals to extract gold from ore. By bypassing this process, Knelson concentrators have become a major type of mining equipment utilized by some of the largest gold mines in the world.
In 1978, Byron Knelson developed the first piece of Knelson concentrator equipment. The success of the machine led to the rapid growth of the company, which has offices in Africa, Asia, Australia, North America, Russia, and South America. The Knelson company has five sectors to help customers more effectively meet their mining and milling needs; these divisions include Knelson Gravity Solutions, Knelson Milling Solutions, and Knelson Engineering and Manufacturing. The company is based in Langley, British Columbia, Canada.
The standard Knelson concentrator utilizes gravitational force in conjunction with a process of liquefaction. The force of gravity separates particles based on their density. This causes pieces of fine gold to break apart from the lower grade ore to which they are attached.
The main components of the Knelson concentrator are a cone-shaped basin, an electric motor, and a pressurized water covering that envelops the basin. From a high vantage point, substances that have been transformed into slurry are poured into the central basin. When the slurry hits the base plate of the bowl, the electric motor induces a gravitational force, and the slurry begins a process of rotation. During rotation, the slurry is naturally spread in a variety of directions around the inside of the basin, which is covered in grooves that catch the heavier particles without retaining the lighter substances. This results in the fine gold extracted from the slurry resting in the grooves of the sides of the basin.
As the process continues, pressurized water is introduced into the bowl. Strategically placed holes in the grooves let the water in, permitting the heavier particles that have been caught to become concentrated. The entire process is typically conducted with large amounts of slurry, and the machine is sporadically cleaned out with water while the lighter particles leave the basin via overflow.
Since their inception in 1978, Knelson concentrators have grown to include many different makes and models, though all follow this same central idea. Batch concentrators allow miners to separate massive amounts of fine gold in little time. Continuous variable-discharge concentrators were designed to take on issues surrounding minerals that could not be separated utilizing the traditional batch process.