The present invention relates to the process of producing artificial aggregate from tailings from ore dams. The iron ore sandy tailings are mixed with a binder and, through the mixing and pelletizing process, form the artificial aggregate. The artificial aggregate produced has a spheroidal shape, a large size, a rough surface and a color that ranges between pink and dark red. This artificial aggregate is able to replace the natural aggregate, and can be used in the manufacture of a more resistant concrete, for the base and sub-base of roads, as a decorative element for gardens and beds, in addition to being a form of storage of ore dam tailings in the form of pellets, adding value to these tailings and reducing the environmental mining impacts.

The use of a clay including: less than 25% of kaolinite; and at least 20% of muscovite and/or illite; the muscovite and/or illite/kaolinite weight ratio being greater than 1, for the preparation of a pozzolanic material.

The present invention refers to a manufacturing process of artificial pozzolan which has the final color gray. In order to perform the processes in the desired way, the kiln atmosphere shall contain low oxygen concentration and the presence of reducing agents. However the presence of carbon monoxide at the kiln outlet is not desirable, due to environmental impacts and the increase in specific heat consumption of the kiln. So the process described in this invention comprises the following steps: heating (1), which consists of heating the raw materials to a temperature between 100-350° C. until drying of the material to a moisture mass fraction of 0-5% (wet basis); mixing (2), which consists of mixing the dry raw materials from the heating process with the right proportion of fuel, in from 1% to 5% in mass fraction, according to the concentration of hematite present in the raw material; calcining (3), which consists of heating the fuel and raw materials blend to a temperature between 700-900° C., with oxygen concentration between 1-5% and, finally, cooling (4), which consists of an initial step of rapid decrease in pozzolan temperature until 600° C. and a final step of slow decrease in pozzolan temperature until 120° C.

An apparatus for thermal treatment of mineral materials may include a first combustion chamber, a second combustion chamber, and a reactor for the thermal treatment of mineral materials. The first combustion chamber is configured for burning a first fuel fed by a first fuel feed device, and the first combustion chamber and the second combustion chamber are connected via a first conduit for transferring hot gases from the first combustion chamber into the second combustion chamber. The second combustion chamber is configured for burning a second fuel that is different than the first fuel and is fed by a second fuel feed device. The second combustion chamber and the reactor are connected via a second conduit for transferring hot gases from the second combustion chamber into the reactor. The reactor has a third feed conduit for introducing a third fuel.

The invention relates to a method for producing a supplementary cementitious material for use in a cement product or concrete, the method comprising the steps of activating clay to the supplementary cementitious material at between 600 to 1000 degree Celsius; treating the activated supplementary cementitious material under reduced conditions to form a reduced product and cooling the reduced product to 300-400 degrees Celsius by a quenching process under oxidizing conditions.

The invention relates to a method for producing a supplementary cementitious material for use in a cement product or concrete, the method comprising the steps of activating clay to the supplementary cementitious material at between 600 to 1000 degree Celsius; treating the activated supplementary cementitious material under reduced conditions to form a reduced product and cooling the reduced product to 300-400 degrees Celsius by a quenching process under oxidizing conditions.

The present invention relates to a device for heat-treating solid material, in particular in granular form, wherein the device comprises a kiln and an external heat generator, wherein said kiln comprises at least one sloped sliding surface on which a bed of said solid material slides down within said kiln due to gravity while a hot gas generated by the external heat generator is led through said solid material to heat said solid material to a desired temperature in order to change the substance properties of said solid material. According to the invention, said external heat generator for generating said hot gas is external to said kiln, wherein said kiln further comprises at least one kiln gas inlet through which said hot gas enters said kiln, such that the necessary temperature of said hot gas can be controlled precisely in that said hot gas is generated in said external heat generator, ensuring that the solid material does not experience temperatures above an allowed maximum temperature, and further such that the solid material is not exposed to radiation from a burner.

The invention comprises a composition comprising hyaloclastite having a volume-based mean particle size of less than or equal to 40 μm. The invention also comprises a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm. The invention further comprises a cementitious-based material comprising aggregate, a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm and water sufficient to hydrate the cementitious material. A method of using the composition of the present invention is also disclosed.

The invention comprises a composition comprising hyaloclastite having a volume-based mean particle size of less than or equal to 40 μm. The invention also comprises a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm. The invention further comprises a cementitious-based material comprising aggregate, a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm and water sufficient to hydrate the cementitious material. A method of using the composition of the present invention is also disclosed.

The invention comprises a composition comprising hyaloclastite having a volume-based mean particle size of less than or equal to 40 μm. The invention also comprises a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm. The invention further comprises a cementitious-based material comprising aggregate, a cementitious material comprising a hydraulic cement and hyaloclastite, wherein the hyaloclastite has a volume-based mean particle size of less than or equal to approximately 40 μm and water sufficient to hydrate the cementitious material. A method of using the composition of the present invention is also disclosed.