Around the world, billions of tonnes of coal refuse lay abandoned in coal mines, according to US company W.S. Tyler. This coal is often heavily contaminated with clay and soil, which greatly reduces the coal’s BTU value and can make it impossible to sell the product. While the coal refuse can sometimes be sold at a reduced price, it often stays in old coal mines, thus leaving the land unusable until the coal can be removed at an economical rate.
Washing the coal can solve the problem, with companies often using log washers and washing drums. However, W.S. Tyler says that these machines have several downfalls that deter mining firms from investing in them. For example, W.S. Tyler claims thee machines have high purchase prices and are costly to operate, while they often lack enough force and friction to effectively remove thick and sticky material, such as clay.
New washing systems
To counter this problem, W.S. Tyler has developed the Hydro-CleanTM, as a means of washing and raising the value of what would otherwise be considered waste coal.
Following recent trials, the Hydro-Clean can be used to remove contaminants from coal refuse and increase its BTU value, making the coal product acceptable for sale. W.S. Tyler also said that Hyrdo-Cleans are also available to mining companies at an economical rate.
The Hydro-Clean washing systems were originally developed for cleaning aggregates, minerals and metals. The three available models can process 18 – 360 tph and can handle coal up to 6 in. in dia. They can also be combined with a portable chassis for fast and easy movement from jobsite to jobsite.
The washing systems are self-contained and take up minimal space. The mid-size model, the HC 1000, weight around 8 t, with the lighter weight resulting in lower operating and structural costs.
Depending on the model, the HC units use between 27 – 211 gal/min, roughly 75% less than traditional washing systems, W.S. Tyler claims. The machines use the water to do most of the work, thus requiring 300 hp. to operate.
How it works
During the cleaning process, the conveyor belt feeds material into the hopper. As the material moves around the chamber in a vortex, high-pressure water nozzles rotate at 100 rpm to remove tough, sticky deposits. Jets are used to clean deep into crevices. The coal exits the drum and travels down the discharge conveyor and through the standard rinse screen, which removes any remaining dirt or clay. The dirty water is collected and directed to the unit’s water treatment system for recycling.
Adapted from press release by Sam Dodson
Read the article online at: https://www.worldcoal.com/handling/15112013/new_technology_for_washing_coal_263/