BACKGROUND TO THE INVENTION Particulate material and particularly particulate material emanating from industrial processes often have commercial value. Thus, for example, dust or fines generated in mineral beneficiation plants by abrasion as ore is transported contains traces of minerals. This dust cannot be introduced into furnaces because updrafts within the furnaces channel the dust into the chimney and into the atmosphere. Likewise, dust produced in the mining, transporting and working of coal, coke and other solid combustible fuels is also lost.

In addition, it is also often desirable to utilise waste particulate material to produce bricks and building blocks thereby conserving natural resources conventionally used to produce such items. In certain other instances it is desirable to agglomerate solid, particulate, hazardous waste material to facilitate storage and handling.

One method of agglomerating particulate waste material is to embed the material in cement, usually portland cement. This does tend to be expensive however and the expense can often negate the beneficial aspects of agglomeration. In addition, when solid, particulate, hazardous waste is embedded in cement it can leach out of the agglomeration which, to a large extent, also negates the process.

OBJECT OF THE INVENTION It is an object of this invention to provide a process for agglomerating particulate material and to provide articles produced by the agglomeration of particulate material.

SUMMARY OF THE INVENTION In accordance with this invention there is provided a process for the agglomeration of particulate material comprising the steps of: a) collecting particulate material; b) mixing said particulate material with sodium silicate, metal oxides an accelerating agent or a decelerating agent as desired, and water, if necessary, to form a slurry; c) forming the siurry into a desired shape; and, d) allowing the desired shape to cure.

There is also provided for the particulate material to be metallurgical fines, particularly chromium metal oxide fines, alternatively platinum tailing oxide fines, further alternatively gold tailing fines, and for the desired shape into which the slurry is formed to be a block which is suitable for introduction into an ore beneficiation process.

Alternatively there is provided for the particulate material to be combustible fuel dust, particularly coke dust, alternatively coal dust, further alternatively charcoal dust, and for the desired shape into which the slurry is formed to be a block, alternatively a brick, further alternatively a briquette, all of which are suitable for introduction into a furnace or a domestic fire.

Further alternatively there is provided for the particulate material to be sand, material from mine dumps or the like and for the desired shape into which the slurry is formed to be a building brick, alternatively a building block.

Still further alternatively there is provided for the particulate material to contain matter which is classifie as hazardous to human or animal health and for the desired shape into which the slurry is formed to be any shape suitable to facilitate storage of said particulate material.

There is further provided for the mixture to contain an accelerator in the form of an alkali, preferably an hydroxide, further preferably a metal hydroxide.

There is also provided for the mixture to contain, if required, a decelerator in the form of a carbon compound and preferably an organic carbon compound.

There is also provided for the slurry, when shaped, to be cured at a temperature in excess of 25 degrees centigrade, and preferably at a temperature of between 40 degrees centigrade and 50 degrees centigrade.

There is further provided for the slurry to incorporate, in the shaping stage, reinforcing and other elements which are embedded in the cured agglomerate.

The invention also extends to a shaped article produced in accordance with the above described method.

BRIEF DESCRIPTION OF THE EXAMPLES Embodiments of the invention will be described below with reference to the accompanying non-limiting examples in which:

Example 1 is an embodiment in which titanium dust is agglomerated for beneficiation; Example 2 is an embodiment in which solid, combustible fuel dust is agglomerated for use as a fuel; and, Example 3 is an embodiment in which metallurgical slags are agglomerated for use in the building industry.

DETAILED DESCRIPTION WITH REFERENCE TO THE EXAMPLES Referring to Example 1, a process for the agglomeration of particulate material, in this example, titanium dust or slag obtained from a titanium extraction plant, comprises the steps of mixing collecte titanium particulate material with sodium silicate and an accelerating agent in the form of sodium hydroxide. In this embodiment the titanium is in the form of a slag so water need not be added to form a slurry.

The slurry obtained as described above is then formed into bricks which are substantially the same size and shape as bricks used for building and the bricks are left to cure for 8 hours at 40 degrees centigrade. Once cured the bricks can be stockpiled before being channelled through a titanium extraction plant.

While the above example deals with the extraction of titanium it is envisaged that the same process can be used to recover a variety of minerals from mineral dust or slag. Examples of such minerals would include chromium, platinum, iron, aluminium and gold to mention but a few.

Referring to Example 2, a process for agglomerating a solid, combustible fuel dust, in this example, Duff coal, comprises the steps of mixing the coal with water, sodium silicate, sodium hydroxide, electric arc furnace dust, chromite ore, fly ash and granulated blast furnace slag powder to form a slurry which is formed into bricks and cured at 50 degrees centigrade for 8

hours. The bricks so formed can also be stockpiled and used in a furnace thus making the coal available for use.

In addition, it is envisaged that charcoal fines can be used instead of the Duff coal and that briquettes for use in the domestic environment for heating or cooking as opposed to industrial furnaces can be formed.

Referring to Example 3, a process for agglomerating a metallurgical slag in particulate form to form blocks for use in the building industry is described. In this embodiment the slag, which contains heavy metal oxides, is mixed with sodium silicate and sodium hydroxide. As in the previous example.

The resulting slurry is moulded to form bricks or hollow building blocks and cured at 40 degrees centigrade for 8 hours before being suitable for use.

The above embodiments illustrate three ways in which particulate material can be agglomerated but it is envisaged that the invention has a wider applicability than the above. It is envisaged that this attribute will enable the process of the invention to be utilise to encapsulate potentially hazardous and hazardous wastes rendering them suitable for storage in a non-hazardous form.

Furthermore the chemical reactions occurring in the slurry during curing are exothermic in nature thus less energy is required during the curing process at elevated temperatures.