Coal washing plant employing a feed equalizer and a critically dimensioned deflector surface in the inlet pipes of a plurality of cyclones

Claim 1

A continuously operating centrifugal separating cyclone coal washing plant for raw crushed coal having a make up water reservoir, a crushed coal supply, a slurry tank for mixing raw crushed coal from said supply and water in a water line from said reservoir and a pump for pumping water in said water line from said reservoir into said slurry tank and into an inlet pipe of circular cross section at the top of the cyclone, the cyclone having a clean coal outlet at the top and a refuse outlet at the bottom, that improvement comprising: a plurality of centrifugal separating cyclones fed by a pump delivering slurry of high solids content at fixed pressure and a bowl velocity of about 8 to 28 linear feet per second, each of the cyclones operating at a pressure difference between the inlet and outlet due to said pumping velocity under deflected streamlined flow conditions from said slurry tank by means of a flat generally bodied deflector having a truncated spherical triangle cap portion to separate the coal into a clean coal fraction at the top of each cyclone and refuse which is withdrawn at the bottom of each cyclone; said flat deflector having a center angle of 114° to 148°, deflector angle of 8° to 12° and an included angle of 120° to 170°; a dewatering screen to separate clean coal particles from water; a centrifugal dryer for said clean coal particles; a silt pond which receives the water separated from the refuse; the supernatant liquid from said silt pond feeding water into said make up reservoir; and a caustic soda tank to dose aqueous sodium hydroxide into the water line between the pump and the make up water reservoir to adjust the pH to about 6-7 and compensate for acidity developed during continuous operation.