CARBONATED COMPOSITE

Abstract

The invention relates to a process for producing a composite comprising: a. providing a particulate material, wherein the particulate material comprises minerals having a content of at least 30% m/m of calcium, magnesium, aluminium, silicon, potassium or iron, or a combination of two or more thereof. b. providing an aggregate, c. providing a primary additive, wherein the primary additive comprises a sugar or derivative thereof, a polyol or derivative thereof, an organic acid, an organic acid salt or an inorganic acid, or any combination of two or more thereof, d. mixing the particulate material, the aggregate and the primary additive with water to form a mixture, and e. carbonating the mixture in the presence of carbon dioxide, wherein the concentration of carbon dioxide is greater than about 2 vol %.

Claims

1. A process for producing a composite comprising: a. providing a particulate material, wherein the particulate material comprises minerals having a content of at least 30% m/m of calcium, magnesium, aluminium, silicon, potassium or iron, or a combination of two or more thereof, b. providing an aggregate, c. providing a primary additive, wherein the primary additive comprises a sugar or derivative thereof, a polyol or derivative thereof, an organic acid, an organic acid salt or an inorganic acid, or any combination of two or more thereof, d. mixing the particulate material, the aggregate and the primary additive with water to form a mixture, and e. carbonating the mixture in the presence of carbon dioxide, wherein the concentration of carbon dioxide is greater than about 2 vol %.

2. (canceled)

3. A process according to claim 1, wherein the particulate material comprises blast furnace slag, meta kaolin, calcinated clay, olivine, serpentine, Portland cement, cement by-pass dust, lime kiln dust, cement kiln dust, air pollution control residue, Portland clinker, cement, limestone powder, quicklime, rock fines, concrete fines, mine tailings, fly ash, bottom ash, biomass ash, metallurgy slag, red mud, paper ash, dusts, oil shale ash, metal silicate powder, metal hydroxide powder, calcium sulphate, pozzolanic material or bleaching earth material, or any combination of two or more thereof.

4. (canceled)

5. A process according to claim 1, wherein the particulate material has an average particle size of about 1 mm to about 60 mm.

6.-7. (canceled)

8. A process according to claim 1, wherein the aggregate has an average particle size of about 0.1 mm to about 90 mm.

9. (canceled)

10. A process according to claim 1, wherein the primary additive is provided in the in the form of a solution, a colloidal suspension, or a powder.

11. A process according to claim 1, wherein the primary additive comprises a sugar or derivative thereof, a polyol or derivative thereof, an organic acid, or an organic acid salt or any combination of two or more thereof.

12.-17. (canceled)

18. A process according to claim 1, wherein the organic acid comprises a carboxylic acid.

19. A process according to claim 1, wherein the organic acid salt comprises a carboxylate salt.

20. (canceled)

21. A process according to claim 1, wherein the mixture comprises about 0.001 wt % to about 10 wt % of the primary additive as a percentage of the particulate material.

22.-23. (canceled)

24. A process according to claim 1, wherein the mixture is shaped prior to step (e).

25. A process according to claim 24, wherein the mixture is shaped using a mold or a support, wherein the mixture is separated from the mold or the support before undergoing carbonation in step (e).

26. (canceled)

27. A process according to claim 24, wherein in step (e), the mixture undergoes carbonation whilst in the mold or on the support either (i) immediately after the mixture has been shaped, or (ii) after the mixture has remained in the mold or on the support for a period of from about 1 hour to about 72 hours.

28. A process according to claim 1, wherein the process comprises removing water from the mixture.

29.-31. (canceled)

32. A process according to claim 1, wherein the carbonation is carried out for a period of from about 1 hour to about 48 hours.

33-36. (canceled)

37. A process according to claim 1, wherein the composite is a concrete composite.

38. A composite produced by the process according to claim 1.

39. A composite according to claim 38, wherein the composite is in a molded shape.

40. (canceled)

41. Use of a composite produced by the process according to claim 1, or a composite according to claim 38, as a construction/building material.

42. A process according to claim 1, wherein for the process is for producing a concrete composite comprising: a. providing a particulate material, wherein the particulate material comprises minerals having a content of at least 30% m/m of calcium, magnesium, aluminium, silicon, potassium or iron, or a combination of two or more thereof. b. providing an aggregate, c. providing a primary additive, wherein the primary additive comprises a sugar or derivative thereof, a polyol or derivative thereof, an organic acid comprising a carboxylic acid, or an organic acid salt comprising a carboxylate salt, or any combination of two or more thereof, wherein the primary additive is provided in the in the form of a solution, a colloidal suspension, or a powder, d. mixing the particulate material, the aggregate and the primary additive with water to form a mixture, and e. carbonating the mixture in the presence of carbon dioxide, wherein the concentration of carbon dioxide is greater than about 2 vol %, wherein the mixture is shaped prior to step (e).

43. A process according to claim 1, wherein in the primary additive comprises sucrose, sodium gluconate, glucose, lactic acid, calcium citrate or glycerol, or a combination of two or more thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0176] FIG. 1 shows the compressive strength of a composite with different primary additives.

[0177] FIG. 2 shows the compressive strength of a composite with different primary additives.

[0178] FIG. 3 shows the compressive strength of a composite with different compositions of particulate materials.

EXAMPLES

Example 1

[0179] A composite was formed by mixing 450 g ground steel slag (0 to 90 μm), 1350 g aggregate (sand 0 to 5 mm), 160 to 180 ml water and an optional primary additive. Table 1 shows the amounts of the primary additive used in each composite, as a percentage of the particulate content. The mixture was cast into cylindrical mold and pressure applied to form a cylindrical sample with a height of about 3.5 cm and a diameter of about 6 cm. The samples were then cured for 8 hours with 80% CO.sub.2, at 30° C., 60 to 80% relative humidity. The compressive strength of each sample was then measured with a compressive strength device machine according to EN196.1-2016. The compressive strength was measured for three cylindrical samples for each example shown below. The compressive strength is shown in Table 1. The standard deviation was +/−2-3 MPa showing a slight deviation between samples, however the values between the samples with and without additives show a clear difference in compressive strength.

[0180] As shown in the results in Table 1 and FIGS. 1 and 2, the compressive strength of the composite increased by using a primary additive. The results show a particularly high increase in compressive strength when glucose, sucrose and sodium gluconate are used as the primary additive as the compressive strength more than doubles (over 40 MPa) compared to no primary additive being used (20 MPa). Further using glycerol nearly doubles the compressive strength. Calcium citrate and lactic acid also show an increase in compressive strength, with the calcium citrate showing a larger increase than lactic acid. It is believed that the increase in compressive strength for composites of the invention increases the chemical resistance of the composite. The data shows some of the technical advantages of the invention.

TABLE-US-00001 TABLE 1 Additive Sodium Lactic Calcium wt % Sucrose gluconate Glucose acid citrate Glycerol additive Compressive Strength MPa 0 20 20 20 20 20 20 0.17 42 32 37 22 28 21 0.34 50 36 39 25 35 24 0.5 49 40 39 28 36 29 0.7 46 41 38 31 32 36 0.9 41 40 41 31 33 39

Example 2

[0181] A composite was formed as set out for Example 1, except a proportion of the ground steel slag was replaced with cement (CEM 52.5R) as shown in Table 2. In these composites, the primary additive was sodium gluconate and the amount is shown in Table 2. The standard deviation was +/−2-3 MPa showing a slight deviation between samples, however the values between the samples with and without additives show a clear difference in compressive strength.

TABLE-US-00002 TABLE 2 Amount of ground steel slag replaced Amount of Sodium Compressive with CEM 52.5R gluconate wt % Strength MPa REF (0% CEM) 0 23 5% CEM 0 23 10% CEM 0 25 20% CEM 0 30 REF (0% CEM) 0.5 42 5% CEM 0.5 52 10% CEM 0.5 58 20% CEM 0.5 59

[0182] As shown in the results in Table 2 and FIG. 3, the compressive strength of the composite still increased by using an additive when the composition of the particulate material is changed. It is believed that the increase in compressive strength for composites of the invention increases the chemical resistance of the composite. The data shows some of the technical advantages of the invention.

[0183] Within this specification, the term derivative preferably refers to a chemical compound or molecule made from a parent compound by one or more chemical reactions, and having a substantially similar chemical structure, or a salt thereof, preferably by any of carboxylation, oxidation, amination, reductive amination or chlorination. Preferably, the term derivative means (i) the product of incorporating one or more of a carboxylic acid, amine, sulfonic acid or sulfuric ester functional group into a parent compound, or a salt thereof, preferably for one or more of a carboxylic acid or amine, or a salt thereof, preferably for one or more carboxylic acid or a salt thereof, and/or (ii) the product of hydrogenation of a parent compound, or a salt thereof. Preferably the salt is a sodium salt or a calcium salt

[0184] It will be appreciated that air pollution control residue has a known meaning in the art and is a by-product of industry. Air pollution control residue is typically a mixture of ash, carbon and lime. It may comprise further components.

[0185] Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to all aspects of the invention described herein and vice versa.

[0186] Within this specification, the term “about” means plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%.

[0187] Within this specification, the term “substantially” means a deviation of plus or minus 20%, more preferably plus or minus 10%, even more preferably plus or minus 5%, most preferably plus or minus 2%.

[0188] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications are covered by the appended claims.