BINDER COMPRISING CARBONATED BIOMASS ASH

Abstract

A binder including at least 1% of carbonated biomass ashes and construction material including the cementitious composition.

Claims

1. A binder comprising at least 1% of of carbonated biomass ashes.

2. The binder according to claim 1, wherein it contains at least 5% of carbonated biomass ashes.

3. The binder according to claim 2, wherein it contains at least 10% of carbonated biomass ashes.

4. The binder according to claim 1, wherein it contains up to 45% of biomass ashes.

5. The binder according to claim 1, wherein the carbonated biomass ashes contain at least 5% of inorganic carbon.

6. The binder according to claim 1, wherein it contains from 65% to 99% of hydraulic binder or alkali-activated binder.

7. The binder according to claim 1, wherein the binder is a hydraulic binder.

8. The binder according to claim 7, wherein the binder is a cement.

9. The binder according to claim 8, wherein the binder is an aluminous cement, a quick natural cement, a Portland cement, a sulfo-aluminous cement or a mixture of at least two of these cements.

10. The binder according to claim 1, wherein it contains kalcinite, carbo-hydroxyapatite and/or hydrocalumite.

11. A construction material comprising a binder as defined in claim 1.

Description

EXAMPLE 1

Carbonated Biomass Ashes

[0075] Different carbonated biomass ashes are obtained by placing a mixture of approximately 250 g of ashes obtained by combustion of different biomasses and 15% by mass of water ashes in a hermetically sealed bowl which is itself fixed on the base of a heated mixing robot.

[0076] The compositions and features of the used biomass ashes (Ashes 1 to 4) before carbonation are reported in Table 1 below, in comparison with the composition and features of fly ashes (non-carbonated) usually used in the cement industry.

TABLE-US-00001 TABLE 1 Composition and features of biomass ashes before carbonation Type C Composition Wood Wood Paper Paper coal fly (% (w/w))/ ashes ashes Ashes ashes ashes Features (Ashes 1) (Ashes 2) (Ashes 3) (Ashes 4) (Ref.) CaO 31 21 54 63 18.3 SiO.sub.2 4 2 20 10 43.5 Al.sub.2O.sub.3 1 2 9 67 20.4 Fe.sub.2O.sub.3 1 1 1 5.4 SO.sub.3 12 14 2 1 1.8 P.sub.2O.sub.5 4 3 1 Na.sub.2O 1 1 1 1 1.5 K.sub.2O 25 26 1 1 MgO 5 3 2 2 4.3 TiO.sub.2 1 Loss on 15 20 8 14 0.9 ignition CIT 3.4 3.1 1.9 3.9

[0077] The reactor is equipped with a cup containing water to regulate the relative humidity in the reactor.

[0078] The temperature of the bowl is maintained at 55 C. The bowl cover is equipped with 2 orifices which allow the injection of a gas and its evacuation.

[0079] The gas is injected for a mixing time of 1 hour and is made up of 100% CO.sub.2.

[0080] The biomass ashes thus carbonated have the following features (Table 2), in comparison with non-carbonated biomass ashes.

TABLE-US-00002 TABLE 2 Ashes/carbonate ashes CIT (%) Ashes 1 Before carbonation 3.4 Carbonated 4.8 Ashes 2 Before carbonation 3.1 Carbonated 8.6 Ashes 3 Before carbonation 1.9 Carbonated 4.8 Ashes 4 Before carbonation 3.9 Carbonated 7.8

EXAMPLE 2

Binders According to the Invention

[0081] A reference Portland cement of class CEM I 52.5 R is mixed with different amounts of non-carbonated or carbonated ashes from Example 1.

[0082] The compositions of binders 2 to 5 (binders according to the invention) and 6 to 9 (binders prepared from non-carbonated ashes) thus obtained are reported in the following Tables 3.1, 3.2 and 3.3.

TABLE-US-00003 TABLE 3.1 Binders 1 to 9 Binder (% w/w) 1 (Ref.) 2 3 4 5 6 7 8 9 CEM I 52.5 100 75 75 75 75 75 75 75 75 Carbonated 0 25 0 0 0 0 0 0 0 ashes 1 Carbonated 0 0 25 0 0 0 0 0 0 ashes 2 Carbonated 0 0 0 25 0 0 0 0 0 ashes 3 Carbonated 0 0 0 0 25 0 0 0 0 ashes 4 Non-carbonated 0 0 0 0 0 25 0 0 0 ashes 1 Non-carbonated 0 0 0 0 0 0 25 0 0 ashes 2 Non-carbonated 0 0 0 0 0 0 0 25 0 ashes 3 Non-carbonated 0 0 0 0 0 0 0 0 25 ashes 4

TABLE-US-00004 TABLE 3.2 Binders 1 to 9 (phasic composition) Binder (% w/w) 1 2 3 4 5 6 7 8 9 C.sub.3S 61.2 48.6 47.3 46.5 46.8 48.6 48.1 46.7 46.8 C.sub.2S AlphaH 2.8 2.8 2.3 5.3 2.8 2.6 2.2 6.3 5.9 C.sub.2S beta 7.0 7 6.2 7.8 7.5 6.4 6.9 8.5 7.6 C.sub.3A 3.3 3.3 3.1 2.9 2.9 3.1 2.5 2.9 2.9 C.sub.4AF 12.2 9 8.3 9.3 9 9.2 9.8 9.1 9 C.sub.12A.sub.7 0.5 0.5 0.5 0.7 0.6 1.1 0.8 0.7 1.6 Calcite 5.2 6.1 12.5 19.6 2.6 4.9 3.9 8.5 Kalicinite 3.3 0 Sylvite 0.5 Lime 0.1 0.1 0.2 0.7 0.3 0.9 5.6 6.5 Periclase 0.9 0.5 1.4 0.6 0.4 1.4 0.6 0.8 0.5 Hydroxyapatite 2.1 1.7 Carbo- 2 2.7 0.2 hydroxyapatite Hydrocalumite 0.7 0.5 Quartz 0.6 0.2 0.1 1.6 0.4 0.3 0.3 1.7 0.9 Anhydrite 0.9 1 1.1 1.3 1 1.2 1.1 1.4 1.1 Bassanite 1.8 1.6 1.3 1.5 1.5 1.8 2 1.5 1.5 Gypsum 2.3 2 1.9 1.2 1.2 2.2 1.9 1.2 1.2 Syngenite 1.7 1.3 1.5 1.5 1.4 Aphtithalitis 1.2 0.3 0.3 0.2 0.2 0.5 0.4 0.2 0.2 Arcanite 1.0 8.9 10.8 0.3 0.3 6.9 8.9 0.3 0.3 Ca-Langbeinite 0.3 0.1 0.2 0.3 Portlandite 0.2 2.1 1.8 1.9 1.6 5 4.6 1.8 1.6 Amorphous 7 6.7 5.7 5.3 6.5 6.3 5.1 3.6

TABLE-US-00005 TABLE 3.3 Binders 1 to 9 (elemental analysis) Binder (% p/p) 1 2 3 4 5 6 7 8 9 SiO.sub.2 20.3 15.9 15.6 19.8 17.6 16.1 15.8 20.1 17.8 Al.sub.2O.sub.3 4.6 3.7 3.9 5.5 4.9 3.8 4 5.8 5.3 Fe.sub.2O.sub.3 3.3 2.5 2.7 2.7 2.6 2.6 2.7 2.7 2.6 CaO 61.6 52.4 51 57.3 57.8 53.1 51.3 59.8 61.9 MgO 1.9 2.4 2.2 1.9 1.7 2.6 2.2 1.9 1.8 SO.sub.3 3.6 5.2 6.4 3.2 3 5.4 6.5 3.3 3 K.sub.2O 1.0 7 7.7 0.9 1 7.1 8.1 0.9 0.8 Na.sub.2O 0.2 0.4 0.5 0.3 0.4 0.4 0.5 0.3 0.4 SrO 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 TiO.sub.2 0.3 0.2 0.2 0.4 0.3 0.2 0.2 0.5 0.3 P.sub.2O.sub.5 0.2 0.9 1 0.4 0.2 1 1 0.4 0.1 MnO 0.07 0.3 0.4 0.1 0.1 0.3 0.43 0.1 0.1 Na2O eq. 5 5.5 0.9 1 5.5 5.8 0.9 1 Loss on ignition 1.86 8.6 7.6 5.3 8.4 6.1 6.7 1.9 3.6 (950 C.)

[0083] The gain in CO.sub.2 emissions for the binders 2 to 5 compared to the reference binder 1 is reported in the following Table 4.

TABLE-US-00006 TABLE 4 CO.sub.2 gain for the binders 2 to 5 Binder 2 3 4 5 CO.sub.2 gain compared to the 213 201 219 226 reference (KgCO.sub.2eq/t)

EXAMPLE 3

Workability (Spreading)

[0084] A spreading measurement was carried out in accordance with standard EN 1015-3 on 3 mortars manufactured according to standard 196-1 by mixing 450 g of binder 1, 4 or 8, 1350 g of sand and 225 g of water.

[0085] The results are reported in the following Table 5.

TABLE-US-00007 TABLE 5 Spreading measurement for the binders 1, 3 and 8 Mortar prepared Mortar prepared Mortar prepared from binder 1 from binder 3 from binder 8 Spread (in mm) 185 142 133

[0086] As these results show, the use of a mixture of cement and non-carbonated ashes leads to a loss of almost 30% in workability. Carbonating the ashes before mixing with the cement makes it possible to limit the loss of rheology and maintain it at an acceptable level for a good implementation.

EXAMPLE 4

Mechanical Performances

[0087] The compressive strength of the binders obtained in Example 2 was measured on prismatic specimens of standardized mortar (4416 cm3), at different time periods (1, 2, 7 and 28 days) according to standard EN 196-1.

[0088] The obtained results are reported in the following Table 6.

TABLE-US-00008 TABLE 6 Compressive strength of binders 1 and 4 to 9 Binder 1 4 5 6 7 8 9 R.sub.c (in MPa) 29.3 17.4 18.8 3 at 1 day R.sub.c (in MPa) 41.7 30.7 35.1 26.1 7 at 2 days R.sub.c (in MPa) 52.9 43.7 48.1 3.2 17.8 41.4 15 at 7 days R.sub.c (in MPa) 62 52.5 51 3.5 25.5 43.4 21 at 28 days

[0089] The binders according to the invention (i.e. binders 4 and 5) present acceptable performances with regard to those observed for the reference CEM I at all deadlines. It is thus noted that mechanical performance is maintained in the short, medium and long term at an acceptable level.

[0090] On the other hand, there is a sharp reduction in the mechanical performance of binders containing non-carbonated biomass ashes.

EXAMPLE 5

Comparative Examples

5.1-Coal-Type Fly Ashes-Based Binder

[0091] The coal-type fly ashes whose composition is reported in Table 1 are carbonated according to the protocol of Example 1.

[0092] The binder 10 is obtained by mixing a reference Portland cement of class CEM I 52.5 R with the carbonated ashes thus obtained in a proportion (% w/w) 75/25.

5.2Carbonated Binder after Addition of Non-Carbonated Ashes

[0093] The binder 11 is obtained by carbonation according to the protocol of Example 1 of a 75/25 mixture (% w/w) of a reference Portland cement of class CEM I 52.5 R with paper ashes no 4 of example 1 (non-carbonated ashes).

5.3Comparative Results

5.3.1Workability (Spreading)

[0094] The workability of the binder 11 is evaluated according to the protocol of Example 3.

[0095] The mortar prepared from the binder 11 is too dry and therefore does not spread, making its implementation impossible.

5.3.2Compressive Strength

[0096] The compressive strength of binders 10 and 11 is evaluated according to the protocol of Example 4.

[0097] The obtained results are reported in the following Table 7.

TABLE-US-00009 TABLE 7 Compressive strength of binders 10 and 11 Binder 10 11 R.sub.c (in MPa) at 2 days 29.5 14 R.sub.c (in MPa) at 7 days 40.6 28.8 R.sub.c (in MPa) at 28 days 48.5 30.8

[0098] The compressive strengths of binders prepared from fly ashes from coal combustion are significantly lower than the compressive strengths of binders prepared from carbonated biomass ashes at 2, 7 and 28 days. The obtained results for binder 11 are extremely low (loss of more than 50% of performance compared to the 100% Portland reference) and render this binder unusable.