GB2082884A - Apparatus for dispersing pulverulent material - Google Patents

Abstract

Apparatus (10) for dispersing pulverulent material comprises a rotatable drum (23) having a plurality of blades (24) extending radially outwardly thereof, a chute (19) located in spaced relation to the drum (23) so that on rotation of the drum (23), material delivered into the curved space between the drum (23) and the chute (19) is propelled by the blades (24) outwardly of the space to disperse the material. Material is delivered to the chute from a hopper (11) by a belt (14). <IMAGE>

Description

SPECIFICATION Apparatus for dispersing pulverulent material This invention relates to apparatus for dispersing pulverulent material.

In modern integrated iron and steel works, steel making slags are transported in liquid form in slag ladles to specially constructed pits outside the steel plant where they are tipped and cooled by water sprays. After solidification, the slags are excavated and passed through a slag handling plant. As processed steel slags, after the removal of the metallic materials, are still high in iron, lime and manganese (Fe 21% CaO 45% MnO 7%), it is desirable to recycle slags of 0--8 mm grain size through a blast furnace and sinterplant and thereby partially replace the more expensive fluxes.

It is also desirable to remove fine dust particles from waste gases of blast furnaces and steel plant in order that the gases can be utilised without damage to plant to which the gases are supplied.

This is achieved by means of water sprays which separate the dust particles from the gases. The dust particles are collected in the form of a sludge which is pumped to settling ponds.

The sludge is useful for recycling because it is rich in iron. However, before it can be recycled it must first be treated in a drying and roasting plant wherein carbon is introduced in order to drive off undesirable alkali and zinc components present in the sludge. Such plants require high capital investment and consume a considerable amount of energy.

As an alternative to using drying plants, the sludge may be pumped on to slag in slag pits. The latent heat of the liquid slag drives off water in the sludge. Coke may additionally be poured into the slag pits so that the carbon in the coke will effect a roasting operation. In this manner, the sludge is utilised without expensive treatment and the siag is enriched with the iron from the sludge.

However there are problems connected with pouring sludge onto slag. Unless the sludge is introduced as a fine spray, there is risk of explosion and yet, when the sludge is sprayed onto the slag, there is a tendency for the sludge to form a crust on the surface of the slag. When an additional layer of slag is added followed by further layers of sludge and coke, the layers of sludge tend to form insulating layers between the slag layers with a result that the slag is not cooled sufficiently for excavation purposes and crumbling of the slag is not sufficiently extensive to reduce the cost of crushing the slag.

According to the present invention, there is provided apparatus for dispersing pulverulent material comprising: a rotor having a plurality of blades extending therefrom, a guide located in spaced relation to the rotor so that when the rotor rotates the blades sweep out a curved space between the rotor and the guide, and means for rotating the rotor so that on rotation of the rotor, material delivered into said space is propelled by the blades outwardly of the space to disperse the material.

The guide may extend in the curved path such that the material on leaving said space is propelled in an upward trajectory.

The rotor may be located below a hopper for dispensing material to said space.

The hopper may be provided with an aperture for dispensing material therethrough to said space.

The hopper may be provided with means for varying flow of material through the aperture.

The hopper may be provided with means for conveying material to the aperture.

The conveying means may comprise an endless conveyor.

The conveyor may be provided with selectively variable drive means.

The means for rotating the rotor may be provided with control means for selectively varying speed of operation of the rotor.

Following is a description, by way of example only and with reference to the accompanying drawing which is a diagrammatic representation, of one method of carrying the invention into effect.

Referring now to the drawing, there is shown apparatus 10 for dispersing pulverulent materials, the apparatus comprising a rectangular hopper 11 having end walls 12, 1 3. Located below the hopper ills an endless belt 14 extending around two sets of pulleys 1 5, 16, the pulley 16 being driven. The belt 14 is arranged such that an upper run thereof extends below the hopper 11 for a distance in excess of the distance between the end walls 12, 13. A lower portion of the end wall 12 is located in spaced relation above the upper run of the belt 14 to provide an outlet 17 of the hopper 11. The end wall 12 is provided with a shutter 1 8 adapted to close the outlet 1 9.

The apparatus 10 further comprises a chute 1 9 an upper portion of which is disposed below the set of pulleys 1 6. The chute extends downwardly and has a lower curved portion 20 defining an inner convex surface 21 contiguous with an inclined outer portion 22.

Located adjacent the curved portion 20 of the chute 19 is a drum 23 having a plurality of blades 24 extending radially outwardly thereof each blade being spaced equi-distant from an adjacent blade in a circumferential direction of the drum 23. The drum 23 is rotatably mounted on a central longitudinal axis such that, on rotation, the blades 24 sequentially sweep out a space between the inner convex surface 21 of the curved portion 20 of the chute 1 9 and an adjacent circumferential surface of the drum 23.

In operation, the hopper 11 receives a sludge of pulverulent material. The sludge, when contained in the hopper 11, is supported on an upper run of the belt 14. When the belt 14 and the drum 23 are driven and the shutter 1 8 is supported in a raised position, the material contained in the hopper 11 is fed by the belt 14 through the outlet 17. As the belt 14 passes around the set of pulley wheels 16, the material falls from the belt 14 and slides downwardly of the chute 19. As the material passes along the curved portion 20 of the chute 19, it is swept by the blades 24 longitudinally of the curved portion 20 and upwardly along the inciined portion 22 of the chute 19 and is impelled outwardly therefrom in an upward trajectory.

The apparatus 10 preferably is mounted on a mobile unit, such as a truck. The unit is then transported to a slag pit in which slag has previously been poured. The sludge contained in the hopper 11 then is dispersed from the apparatus 10 so as to form a layer on the slag in the slag pit.

It will be appreciated that the material dispersed from the apparatus 10 forms pellets which collect on the surface of the slag in the pit.

In consequence, the material does not form a crust on the slag.

It will also be appreciated that the speed of the belt 14 can be adjusted in order to regulate the flow of material fed from the hopper 11. Further adjustment may be achieved by raising or lowering the shutter 1 8 reiative to the outlet 1 7.

The size of particles of material dispersed from the apparatus 10 may be varied by varying the speed of rotation of the drum 23.

It will also be appreciated that the apparatus 10 is suitable for dispensing materials other than sludge containing iron ores, such other materials including, for example, lime, limestone and dolomitic material.

An embodiment of apparatus 10 may comprise a hopper 11 having a 3 m3 capacity capable of receiving 5-6 tons of material. Assuming that a typical slag pit contains 30 tons of slag, the contents of the hopper would add 20% of material to the slag. Operation of the apparatus 10 is such that 60 tons of material per hour would be dispersed.

Claims (9)

1. Apparatus for dispersing pulverulent material comprising: a rotor having a plurality of blades extending therefrom, a guide located in spaced relation to the rotor so that when the rotor rotates the blades sweep out a curved space between the rotor and the guide, and means for rotating the rotor so that on rotation of the rotor, material delivered into said space is propelled by the blades outwardly of the space to disperse the material.

2. Apparatus as claimed in claim 1 wherein the guide extends in the curved path such that the material on leaving said space is propelled in an upward trajectory.

3. Apparatus as claimed in claim 2 wherein the rotor is located below a hopper for dispensing material to said space.

4. Apparatus as claimed in claim 3 wherein the hopper is provided with an aperture for dispensing material therethrough to said space.

5. Apparatus as claimed in claim 4 wherein the hopper is provided with means for varying flow of material through the aperture.

6. Apparatus as claimed in any one of claims 3 to 5 wherein the hopper is provided with means for conveying material to the aperture.

7. Apparatus as claimed in claim 6 wherein the conveying means comprises an endless conveyor.

8. Apparatus as claimed in claim 7 wherein the conveyor is provided with selectively variable drive means.

9. Apparatus as claimed in any one of the preceding claims wherein the means for rotating the rotor is provided with control means for selectively varying speed of operation of the rotor.

1 0. Apparatus for dispersing pulverulent material substantially as hereinbefore described and as illustrated in the accompanying drawing.