FIELD OF THE INVENTION

THIS INVENTION relates to fines agglomeration. More specifically the invention relates to mineral fines agglomeration, particularly by means of sintering. The invention provides a mineral fines sintering reactor vessel for mineral fines agglomeration by means of sintering. The invention extends to a mineral fines sintering reactor vessel installation comprising the mineral fines sintering reactor vessel. The invention also provides use of the mineral fines sintering reactor vessel and/or the mineral fines sintering reactor vessel installation in mineral fines agglomeration by means of sintering. The invention further provides a method of mineral fines agglomeration by means of sintering.

BACKGROUND TO THE INVENTION

DURING THE PRODUCTION OF FERRO-ALLOYS, iron, steel and other metals, raw materials are required to be of a certain, sufficiently large (“lumpy”), particle size for conversion in metallurgical furnaces as electric arc furnaces, submerged arc furnaces, blast furnaces and the like. Ore fines, typically of a particle size below 6mm, are undesirable for conversion in metallurgical furnaces.

To be rendered suitable for conversion in metallurgical furnaces, ore fines are agglomerated to form sinters, pellets or briquettes. Generally speaking, sintering involves heating a particulate solid material, without liquefaction (i.e. to a level below its melting point) such that it coalesces into an agglomerated mass. Typically this may include igniting a solid fuel in proximity to or in contact with at least part of the particulate solid material, to provide the heat necessary for sintering to take place.

Traditional sintering processes use moving grate equipment in which a sinter is produced on a traveling grille with air suction from under the sinter-mix. Ignition of a sinter mix (precursor to the sinter) is effected on the top of the sinter-mix, and the sintering reaction occurs from top to bottom.

The Applicant has found prior art sintering processes cumbersome, and believes that a need exists for an alternative, simpler technology, which the present invention seeks to provide.

SUMMARY OF THE INVENTION

IN ACCORDANCE WITH ONE ASPECT OF THE INVENTION IS PROVIDED a mineral fines sintering reactor vessel for mineral fines agglomeration by means of sintering, the reactor vessel comprising

a hollow body with an open top, the body comprising a continuous side wall and a base which define a hollow interior of the body; and

a gas inlet in and/or adjacent to the base, through which gas can be introduced into the hollow interior of the body. The mineral fines may generally speaking be any mineral fines, but it may in particular for the purpose of the invention be manganese- or chrome- or iron-based mineral fines. It may also, alternatively, be vanadium-, titanium-, cassiterite-, nickel-, silicon-, or zinc-based fines. In particular, the fines may be mined ore fines, e.g. of the abovementioned minerals.

The gas that would, in use, typically be introduced into the hollow interior of the body would typically be air, optionally being enriched with oxygen or reducing gas, and thus the gas inlet may be an air inlet.

The body may include handling formations, for displacement of the reactor vessel. Typically, the handling formations may be configured to allow displacement of the reactor vessel by way of tilting, effectively to pour contents contained in its interior in use out of its interior. For example, the handling formations may include at least one pair of oppositely located lugs located adjacent the open top of the reactor vessel. In one embodiment of the invention the body may have a circular cross section, in which case the lugs may be located diametrically opposite each other.

Inside the interior of the body, the side wall and, typically, the base, may comprise a refractory material, e.g. as a lining material.

The open top of the body may have a width dimension in a range of from about 1 2m to about 3m. In the embodiment in which the body has a circular cross section, the width dimension would be a diameter. The body may have a height dimension, typically measured from its open top to the bottom of its base outside the interior of the body, in a range of from about 1 .5m to about 3m.

The interior of the body may have a volume in a range of from about 8m ³ to about 18m ³ .

When the vessel includes a gas inlet adjacent to the base, such a gas inlet would typically be provided in the side wall, located closely to the base.

For example, along a height dimension of the vessel, such a gas inlet may be located in the side wall within the first 50% of that part of the height dimension above the base inside the interior of the vessel (i.e. the depth of the interior of the vessel), or within the first 45%, or within the first 40%, or within the first 35%, or within the first 30%, or within the first 25%, or within the first 20%, or within the first 15%, or within the first 10%, or within the first 5%. Thus, for example, if that part of the height dimension above the base inside the interior of the vessel is 2.5 meters, such a gas inlet may be located in the side wall within the first 1.25m, or within the first 1 125m, or within the first 1 m, or within the first 0.875m, or within the first 0.75m, or within the first 0.625m, or within the first 0.5m, or within the first 0.375m, or within the first 0.25m, or within the first 0.125m of that part of the height dimension.

Preferably, the vessel has gas inlets both in and adjacent to the base, with the gas inlet adjacent to the base, as noted above, typically being provided in the side wall, located closely to the base. The gas inlet, or gas inlets when there are inlets both in and adjacent to the base, may comprise openings in and/or adjacent to the base. The openings may be defined by suitable formations of the base and/or the side wall.

It will be appreciated that the definition of the invention provides for the gas inlet being provided in the base, or adjacent to the base, in which case it would typically be in the side wall, or for separate gas inlets to be provided both in and adjacent to the base. That the vessel may include further gas inlets is, of course, not excluded.

Thus, where the singular“gas inlet” is used in conjunction with“and/or” in referring to its possible location, the above meaning at least should be afforded to it, i.e. that there may be one or more gas inlets. IN ACCORDANCE WITH ANOTHER ASPECT OF THE INVENTION IS PROVIDED a mineral fines sintering reactor vessel installation for mineral fines agglomeration by means of sintering, the installation comprising

a mineral fines sintering reactor vessel as hereinbefore described; and a gas supply in fluid communication with the gas inlet in the side wall and/or in the base of the body of the reactor vessel.

The mineral fines may generally speaking be any mineral fines, but it may in particular for the purpose of the invention be manganese- or chrome- or iron-based mineral fines. It may also, alternatively, be vanadium-, titanium-, cassiterite-, nickel-, silicon-, or zinc-based fines. In particular, the fines may be mined ore fines, e.g. of the abovementioned minerals.

As noted above, the gas would typically be air. Thus, the gas supply would typically be an air supply.

The gas supply may include a gas supply pipe that extends between the gas inlet in and/or adjacent to the base and a gas source. The gas source may typically be a gas, e.g. air, blower or compressor, which in use delivers gas to the interior of the body of the reactor vessel through the gas inlet/s in and/or adjacent to the base thereof, through the gas supply pipe.

The installation may include a handling device for handling the reactor vessel, typically to pour its contents from it in use e.g. a hydraulic lifting device, a hydraulic or other tilting platform, a hoist, a crane, or the like.

THE INVENTION EXTENDS TO use of the mineral fines sintering reactor vessel and/or of the mineral fines sintering installation hereinbefore described in mineral fines agglomeration by means of sintering.

The mineral fines may generally speaking be any mineral fines, but it may in particular for the purpose of the invention be manganese- or chrome-based mineral fines. It may also, alternatively, vanadium-, titanium-, cassiterite-, nickel-, silicon-, or zinc-based fines. In particular, the fines may be mined ore fines, e.g. of the abovementioned minerals. The use of the mineral fines sintering reactor vessel and/or of the mineral fines sintering installation in this regard may be in accordance with the method of the invention hereinafter described.

IN ACCORDANCE WITH A FURTHER ASPECT OF THE INVENTION IS PROVIDED

a method of mineral fines agglomeration by means of sintering, the method including subjecting a body of solid particulate material comprising mineral fines and solid fuel to sintering in a mineral fines sintering reactor vessel as hereinbefore described, wherein the sintering includes feeding a gas into the interior of the reactor vessel through the gas inlet in and/or adjacent to the base of the reactor vessel.

The mineral fines may generally speaking be any mineral fines, but it may in particular for the purpose of the invention be manganese- or chrome- or iron-based fines. It may also, alternatively, vanadium-, titanium-, cassiterite-, nickel-, silicon-, or zinc-based fines. In particular, the fines may be mined ore fines, e.g. of the abovementioned minerals.

Feeding the gas into the interior of the vessel may be effected such that gas rises through the body of solid particulate material.

As hereinbefore described, the gas would typically be air.

The reactor vessel would preferably form part of a mineral fines sintering reactor vessel installation as hereinbefore described. In such a case, the gas would be supplied to the gas inlet in and/or adjacent to the base along the gas supply pipe and would be generated by one or more gas sources, e.g. blowers or compressors that form part of the installation.

The method may include a prior step of constituting the body of solid particulate material.

Constituting the body of solid particulate material may include mixing, with the mineral fines as a major component of the body of solid particulate material, and one or more of reductants, the solid fuel, by-products of industrial operations, and chemicals.

Reductants, and the solid fuel, may include carbon bearing materials such as coke, coal, charcoal, anthracite, and the like.

By-products of industrial operations may include dust, and sludge from de-dusting operations.

Chemicals may include water, and binders such as bentonite and cement.

The method may include another prior step of charging the interior of the reactor vessel with the body of solid particulate material.

The method may include a further prior step of igniting the solid fuel. The solid fuel that is ignited may be solid fuel comprise in the body of solid particulate material inside the interior of the reactor vessel, and/or it may be solid fuel that is charged into the interior of the reactor vessel before charging the reactor vessel with the body of solid particulate material e.g. by igniting the fuel and then charging it into the interior of the reactor vessel or charging the fuel into the reactor vessel and then igniting it, and thereafter charging the reactor vessel with the body of solid particulate material.

BRIEF DESCRIPTION OF THE DRAWINGS

IN THE ACCOMPANYING DRAWINGS:

FIGURE 1 shows diagrammatically, in top view, a mineral fines sintering reactor vessel in accordance with the invention;

FIGURE 2 shows diagrammatically, in sectional side view, the mineral fines sintering reactor vessel of Figure 1 , along A-A’; and

FIGURE 3 shows diagrammatically a mineral fines sintering reactor vessel installation according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

THE INVENTION WILL NOW BE DESCRIBED IN MORE DETAIL with reference to the drawings.

Referring to Figures 1 and 2, reference numeral 10 generally indicates an exemplary embodiment of a mineral fines sintering reactor vessel in accordance with the invention. The vessel 10 may be a vessel generally known in the art of the invention as a“ladle”, which is generally an embodiment that the invention as hereinbefore described includes in respect of the vessel of the invention, the ladle being adapted at least in respect of the gas inlet/s as described, and in respect of its usefulness in the application as described. The reactor vessel 10 comprises a body 11 of circular cross section.

The body 11 comprises, more specifically, a continuous side wall 12 and a base 14, thus defining a hollow interior 16. A top 18 of the reactor vessel 10 is open.

The body 11 has a diameter in a range of from about 2m to about 3m.

The body 11 has a height dimension, typically measured from its open top 18 to the bottom of its base 14 outside the interior 16, in a range of from about 1.5m to about 3m.

The interior 16 of the body 11 has a volume in a range of from about 8m ³ to about 18m ³ .

Interiors 12A, 14A of the side wall 12 and the base 14 comprise a refractory lining. Other than the refractory lining, the side wall 12 and the base 14 are each either of steel plates or of cast iron.

The body 11 also includes displacement formations in the form of two diametrically oppositely located lugs 20.

Respective gas inlets 22A, 22B are defined respectively in the side wall 12, adjacent to the base 14, and in the base 14. The inlets 22A, 22B are in the form of through apertures that allow for gas to be fed into the interior 16 of the reactor vessel 10. The inlet 22A may be located in the side wall 12 within the first 50% of that part of the height dimension above the base inside the interior of the vessel (i.e. the depth of the interior of the vessel), or within the first 45%, or within the first 40%, or within the first 35%, or within the first 30%, or within the first 25%, or within the first 20%, or within the first 15%, or within the first 10%, or within the first 5%. Thus, for example, if that part of the height dimension above the base inside the interior of the vessel is 2.5 meters, such a gas inlet may be located in the side wall within the first 1 25m, or within the first 1 .125m, or within the first 1 m, or within the first 0.875m, or within the first 0.75m, or within the first 0.625m, or within the first 0.5m, or within the first 0.375m, or within the first 0.25m, or within the first 0.125m of that part of the height dimension.

The reactor vessel 10 further includes a grid 25 (not shown in Figure 1 ) that is spaced from the interior 14A of the base 14. In use, the grid supports material that would be sintered and spaces it from some or all solid fuel that is used to ignite the material.

Referring now to Figure 3, reference numeral 100 generally indicates an exemplary embodiment of a mineral fines sintering reactor vessel installation in accordance with the invention.

The installation 100 includes the reactor vessel 10 of Figures 1 and 2.

Gas, and specifically air in the illustrated embodiment, supply pipes 102 lead to the gas inlets 22A, 22B of the reactor vessel 10. A first pipe section 102A is a main air supply pipe, and a second pipe section 102B is an alternative air supply pipe.

A third pipe section 102C connects the first and second pipe sections 102A, 102B to an air blower 104, which supplies air to the supply pipes 102 in use, and therefore also to the interior of the reactor vessel 10 through the gas inlets 22A, 22B.

In use the reactor vessel 10 is used to subject a body of particulate solid material, comprising at least a major proportion of solid mineral fines, to sintering. The fines may typically have a particle size of less than 10mm. The body of particulate solid material may include solid fuel, and other additives in accordance with the invention.

In accordance with one exemplary embodiment of the method of the invention, solid fuel is ignited and is then charged into the interior 16 of the reactor vessel 10, separately of the body of particulate solid material.

At this time air is already being introduced into the interior 16 of the reactor vessel 10 through the inlets 22A, 22B (either through one or through both), supplied by the blower 104 along the supply pipes 102.

Subsequently, the body of particulate solid material, including additional solid fuel comprised therein, is charged into the interior 16 of the reactor vessel 10. The introduction of air into the interior 16 of the reactor vessel 10 is maintained throughout, and after the body of particulate solid material has been charged into the reactor vessel

10. Charging of the interior 16 of the reactor vessel 10 with the solid fuel and with the body of solid particulate material and constitution of the body of solid particulate material may be effected through conventional techniques/equipment such as mixers, homogenizers, pelletizing, discs, re-rolling drums, scales, conveyors, silos, feeders, and the like.

The continued air flow sustains burn of the solid fuel that is comprised in the body of particulate solid material. Thus, sintering of the fines in the body of particulate solid material occurs in a direction from the base 14 of the reactor vessel 10 to its top 18.

The rate of air flow and the amount of fuel initially introduced into the interior 16 of the reactor vessel 10 and comprised by the body of solid particulate material are selected so that sintering is achieved, i.e. agglomeration through heating, without liquefaction.

When the body of solid particulate material has been sintered, which would typically take about 30 to 90 minutes, the air flow is ceased and the contents of the reactor vessel 10, which have now been converted to a sinter product, are discharged, e.g. onto a truck or a metallic container. Such discharge may e.g. be achieved by tilting the reactor vessel 10, e.g. by way of a gear motor, hoisting, hydraulic lifting, or the like.

When compared with traditional sintering processes, this invention provides:

Lower capital and operating costs;

Higher degree of flexibility in the use of low cost reductants and low-grade ores with good productivity; - Inexpensive increase of plant capacity by adding reactor vessels to an existing production line;

- Reducing production level is done by simply operating the numbers of reactor vessels necessary for a particular campaign;

- Minimum quantity of movable parts drastically reduces maintenance cost;

- Except for the grid which is easily replaceable at neglectable cost, there is no other metallic part exposed to high temperature during sintering;

- Maintenance is provided in each reactor vessel without discontinuing the production.