IL31271A - Method of separating particulate or granular materials - Google Patents

Description

A method of separating particulate or granular materials LESLIE CHARLES RICHARD HENRY MOZLET and WHITEHEAD This invention relates to the separation of particulate or granular materials of different densities or for the separation of crushed ore into its constituent Mineral ration by gravity methods is already known and two examples are represented by the pinched sluice and the Reichert In each of the material to be separated travels down a slope during which stratification occurs and as a result the different density components are projected different distances off the end of the slope and can be separated into different The efficiency of separation of these materials improved by making the slope of porous material and introducing fluid beneath the materials to be A further improvement is obtained if the flow of the fluid is certain mixtures of materials cannot be separated because they cannot be fluidized and will flow down the According to this invention there is provided a method of dry separating particulate and or granular materials of different densities from a the method comprising the steps of passing the mixture down a pinched sluice having a porous floor downwardly inclined at an angle of at least ten degrees and through which air or gas is characterized in that a fine particulate material is added so as to pass with the feed material down the the quantity of additive material and the angle of the sluice being such that the additive material does not form a fluidized bed aids or enables the flow of the contact with the floor of incline to behave like a fluid particularly where the the mixture are such that open passages form through which the air or gas would tend to pass without affecting the mixturet the ials of the mixture separating into layers under gravitational forces for division at the bottom of the inoline and subsequent removal of the additive material which is preferably recycled to the input of the Materials suitable for this medium are for metal such as copper or or heavy minerals such as magnetite or The choice of the medium and of its size range depends upon the nature of separation to be carried The medium may be removed from the separated materials by screen if the medium is magnetic by magnetic The method of operation employing the separate medium may be used in a pinched sluice separator or a Reichart British patent specification discloses apparatus for separating particulate material in a gas fluidized bed of dense medium into two or more fractions ing different the apparatus comprising a trough or the the base of which is porous so that gas can be passed therethrough under The trough is inclined downwardly at a small angle to the horizontal so that as the fluidized bed is formed from the dense mediuii by the flow of gas through the the bed passes along the In that separator the separation of the particulate materiel is caused by choosing the apparent density of the expanded medium to be between the densities of the two fractions of partioulate the bed travels along the while the lighter i fraction floats to the top of the The angle of the trough is chosen to be not more than about to the otherwise the fluidised bed move too rapidly down the trough since the bed behaves almost exactly like a there is no mention or hint of the nor for obvious reasons is it desirable that the trough should be so The invention will be more readil understood from the following description taken in conjunction with the ing drawings in 1 is a diagrammatic view of a pneumatic pinched sluice suitable for use with the method of the 2 is view of two pinched sluices for carrying out a two stage separation By way of an the process will be described for separation of chopped copper wire its associated but released plastic and rubber A suitable medium is magnetite having a size range of 200 BS mesh in a weight ratio which is dependent on the flow ietics of the material to be A typical ratio is one part by weight wire and insulation to two parts b weight of though ratios of one to one or as high as one to four are A suitable sluice 1 for this purpose is shown in This particular sluice is 30 long and tapers from wide at the feed end to at the The sluice is inclined at to the horizontal and is supplied with air at 2000 hour per of porous deck via the air box The porous deck 2 is a preferably plastic though ceramic or metal may be having a resistance to air flow of the order of 6 in at a flow rate of 1500 per hour per Low pressure air is supplied to the air box la which the lower part of the layer the first sluice but this is unnecessary the separation of wire In most cases it will be found desirable to the medium by the entrained fine mesh A small of the medium may be treated on magnetic separator or air The cleaned is returned the circuit and adventitious materials With feed containing very coarse or very heavy particles for example it be found advantageous to apply vibration to the sluice to assist in transporting the material in contact with heavier and lighter layers leaving the sluice are separated by a of medium in contrast to a more continuous gradation of the obtained when operating without the The 7 b located further from the end of the sluice than when ao medium is With such as fine it is advantageous to vibrate the splitter to prevent a build up of wire on its It is considered tha the perforins several Firstly it enables a difficult feed to be fluidised by filling up gaps between the feed he medium also provides buoyancy to the heavier thus reducin the drag of porous surface and enabling the heavier material to be more readily discharg momentum of the medium helps to impel the heavier material along the sluice and finally the helps to keep such as from becoming Other difficult mixtures separable by the addition insufficientOCRQuality

Claims (2)

1. CLAIMS A method of dry separating particulate granular materials of different densities from a the method c ing the mixture down a pinched sluice having a porous floor downwardly inclined at an angle of at least ten degrees and through which air or gas is characterised in that a fine particulate material is added so as to pass with the feed material down the the quantity of additive material and the angle of the sluice being such the additive material does not form a bed aids or enables the flow of the mixture down the incline by of the incline to behave like a fluid the materials of the mixture separating into layers under gravitational forces for divisio at the bottom of the incline and subsequent removal of the A method as claimed in Claim in which the removed additive material is recycled to the top of the A method as claimed in Claim 1 or Claim which the additive material is mixed with mixture to be separated before delivery to the top of the A as
2. Claim 2 whoroin incline used to a width at bot A method as claimed in any one of Claims 1 to 4 which at least one of the separated materials together with additive operating such as set out in Claim A method separating particulate granular materials as hereinbefore described with reference to the accompanying For the Applicants AND PARTNERS insufficientOCRQuality