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1. (WO2018195624) MANUFACTURING PROCESS OF POZZOLAN WITH COLOR CHANGE AND POZZOLAN THUS OBTAINED
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Claims

1. Manufacturing process of pozzolan with color change, characterized for comprising the following steps:

- Heating (1): consists of heating the raw material blend to a temperature between 100-350 °C until the material is dried to a range of moisture between 0-5% (wet basis).

- Mixture (2): consists of mixing the dry raw materials that came from the heating step, with 1-5% of fuel mass fraction according to the hematite concentration of the raw material.

- Calcining (3): consists of heating the blend of fuel with dry raw materials to a temperature between 700-900 °C, with oxygen concentration between 1-5%.

- Cooling (4): consists of an initial step with fast decrease in temperature until 600 °C and a final step with pozzolan temperature decrease until 120 °C.

2. A process, according to claim 1, characterized by a mixture step (1) preceding the heating step (2), this last one consisting of heating a blend of raw materials and solid fuel to a temperature between 100- 350 °C until drying of the blend to a moisture mass fraction of 0-5% (wet basis).

3. A process, according to claim 1 or 2, characterized by the fact that the fuel is a solid one and shall be selected among the following: mineral coal, charcoal, petroleum coke, pulverized coal, biomass or other carbon rich wastes.

4. A process, according to claim 1 or 2 or 3, characterized by the fact that during the mixture step (1) the amount of solid fuel added is around 0% for a hematite concentration below 3% in the raw material composition; around 1.5% for a hematite concentration between 3-5% in the raw material composition; around 3% for a hematite concentration between 5-8% in the raw material

composition; and around 5% for a hematite concentration between 8-12% in the raw material composition.

5. A process, according to claim 1 or 2, characterized by the fact that the calcining step (3) can make use of low oxygen recirculated gases from exhaustion.

6. A process, according to claim 1 or 2, characterized by the fact that during the calcining step (3) the combustion of solid, liquid or gaseous fuel takes place inside a compact combustion pre-chamber, according to BR PI 1000417-3.

7. A process, according to claim 1 or 2, characterized by the fact that the calcining equipment is selected among: rotating kiln or fluidized bed or flash calciner.

8. A process, according to claim 1 or 2, characterized by the fact that the cooling step (4) takes place in a cooler that shall be selected among: rotary cooler or fluidized bed or flash cooler.

9. A process, according to claim 8, characterized by the fact that the first step of cooling process consists of keeping the external side of the drum wet, in case of a rotary or flash cooler, or by the use of a water serpentine, in case of a fluidized bed.

10. A process, according to claim 1, 2 or 8, characterized by the fact that the second step of cooling process (4) is selected according to the concentration of hematite in the raw material.

11. A process, according to claim 10, characterized by the fact that the second step of cooling process comprises:

- Direct use of ambient air, for a concentration of hematite below 3%;

- Direct use of recirculated gases, for a concentration of hematite between 3-6%;

- Direct use of ambient air combined with indirect use of water, for a concentration of hematite between 6-10%;

- Direct use of recirculated gases combined with indirect use of water, for a concentration of hematite above 10%.

12. Pozzolan, characterized for being manufactured according to the process of claim 1.

13. Pozzolan, characterized for being manufactured according to the process of claim 2.

14. Pozzolan, characterized for being manufactured according to the process of any claim amongst 3 to 11.