DRY GRINDING OF STEEL MAKING SLAG, GROUND STEEL MAKING SLAG, AND ITS USE IN CONSTRUCTION MATERIALS

Abstract

The use of a grinding additive during the dry grinding of steel making slag, characterized in that the grinding additive is selected from the group consisting of alkanolamines, glycols, glycerol, sugars, sugar acids, carboxylic acids or their salts, superplasticizers, superabsorbent polymers, or mixtures thereof. Also, ground steelmaking slag including the additives and the use of the ground steel making slag in construction materials.

Claims

1. A method of dry grinding of steel making slag, comprising dry grinding a steel making slag together with a grinding additive selected from the group consisting of alkanolamines, glycols, glycerol, sugars, sugar acids, carboxylic acids or their salts, superplasticizers, superabsorbent polymers, and mixtures thereof.

2. The method according to claim 1, wherein the steel making slag is a basic oxygen furnace slag.

3. The method according to claim 1, wherein the steel making slag has a content of iron oxides expressed as Fe.sub.2O.sub.3 of 8-38 w %, and a content of sulfur expressed as SO.sub.3 of <1 w %, in each case relative to a total dry weight of the steel making slag.

4. The method according to claim 1, wherein the grinding additive is selected from the group consisting of triisopropanolamine (TIPA), triethanolamine (TEA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), and mixtures of at least one of TIPA, TEA, DEIPA, and EDIPA with at least one of diethylene glycol, glycerol, carboxylic acid, and sugar.

5. The method according to claim 1, wherein the grinding additive is selected from the group consisting of triisopropanolamine (TIPA), triethanolamine (TEA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), lactic acid, malonic acid, adipic acid, citric acid, galactose, glucose, lactose, maltose, sucrose, fructose, diethylene glycol, glycerol, and mixtures thereof.

6. The method according to claim 5, wherein the grinding additive is selected from the group consisting of TIPA, DEIPA, a mixture of TIPA and DEIPA, a mixture of TIPA and citric acid, a mixture of TIPA and glucose, a mixture of TIPA and fructose, a mixture of TIPA and glycerol, a mixture of TIPA and diethylene glycol, a mixture of TIPA and sugar and glycerol, a mixture of TIPA and sugar and diethylene glycol, a mixture of TIPA and carboxylic acid and glycerol, a mixture of TIPA and carboxylic acid and diethylene glycol, a mixture of DEIPA and citric acid, a mixture of DEIPA and glucose, a mixture of DEIPA and fructose, a mixture of DEIPA and glycerol, a mixture of DEIPA and diethylene glycol, a mixture of DEIPA and sugar and glycerol, a mixture of DEIPA and sugar and diethylene glycol, a mixture of DEIPA and carboxylic acid and glycerol, and a mixture of TIPA and carboxylic acid and diethylene glycol.

7. The method according to claim 1, wherein the grinding additive additionally comprises a defoamer, phosphate.

8. The method according to claim 1, wherein an amount of water present during grinding is not higher than 1 w %, relative to a total dry weight of the slag.

9. The method as claimed in claim 1, wherein the grinding additive is added to the steel making slag before and/or during grinding in a total amount of between 0.001-3 w %, relative to a total dry weight of the slag.

10. The method as claimed in claim 1, wherein the grinding is done in an attrition mill or a compressive grinder.

11. A ground steelmaking slag obtained by dry grinding a steel making slag in the presence of a grinding additive selected form the group consisting of alkanolamines, glycols, glycerol, sugars, sugar acids, carboxylic acids or their salts, superplasticizers, superabsorbent polymers, and mixtures thereof.

12. A ground steelmaking slag according to claim 11, wherein the steel making slag is a basic oxygen furnace slag and wherein the grinding additive is selected from the group consisting of triisopropanolamine (TIPA), triethanolamine (TEA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), and mixtures of at least one of TIPA, TEA, DEIPA, and EDIPA with at least one of diethylene glycol, glycerol, carboxylic acid, and sugar.

13. Construction material comprising a ground steelmaking slag as claimed in claim 11.

14. A construction material as claimed in claim 13 comprising a) 5-95 w % of a ground steel making slag; b) 5-95 w % of at least one mineral binder; c) optionally 15-85 w % of aggregates; d) optionally 0.1-10 w % of further additives; and e) optionally water in an amount to realize a mass ratio of water:mineral binder between 0.1-0.8.

15. A method to increase the efficiency of the dry grinding of steel making slag, wherein the steel making slag is dry ground together with an additive selected from the group consisting of triisopropanolamine (TIPA), triethanolamine (TEA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), and mixtures of at least one of TIPA, TEA, DEIPA, and EDIPA with at least one of diethylene glycol, glycerol, carboxylic acid, and sugar, and wherein the additive is added to the slag prior and/or during grinding.

16. A method to increase the early strength of a cementitious material comprising a ground steel making slag, wherein an additive is added to the slag prior and/or during the grinding of the slag and wherein the additive is selected from from the group consisting of triisopropanolamine (TIPA), triethanolamine (TEA), diethanolisopropanolamine (DEIPA), ethanoldiisopropanolamine (EDIPA), and mixtures of at least one of TIPA, TEA, DEIPA, and EDIPA with at least one of diethylene glycol, glycerol, carboxylic acid, and sugar.

Description

EXAMPLES

[0145] The following table 1 shoes an overview of the raw materials used.

TABLE-US-00001 TABLE 1 raw materials BOF slag Basic oxygen furnace slag with an initial Blaine surface of 1410 g/cm.sup.2 56% retained on 45 ?m sieve; 68% retained on 32 ?m sieve TIPA Triisopropanolamine (1,1,1-nitrilotris(propan- 2-ol)), Sigma-Aldrich, 95% purity TEA Triethanolamine, Sigma-Aldrich, >99% purity DEIPA Diethanolisopropanolamine, Sigma-Aldrich, 94% purity EDIPA Ethanoldiisopropanolamine, 95% purity Polyaspartic acid Baypure Lactic acid Sigma-Aldrich, >98% purity Malonic acid Sigma-Aldrich, 99% purity Adipic acid Sigma-Aldrich, 99% purity Citric acid Sigma-Aldrich, 99% purity Calcium lactate As pentahydrate, Sigma-Aldrich Fructose D-(?)-Fructose, Sigma-Aldrich, >99% purity Glucose D-(+)-Glucose, Sigma-Aldrich, >99.5% purity GLY Glycerol, Sigma-Aldrich, >99.0% purity DEG Diethylenglycol, Sigma-Aldrich, >99.0% purity TiBp Triisobutyl phosphate, Sigma-Aldrich, >99.0% purity

[0146] Measurement of Elaine surface was done according to standard NF EN 196-6.

[0147] Sieve analysis was done according to standard ASTM C136/C136M.

[0148] Determination of amount of material sticking to balls and vessel was determined by weighing.

[0149] Compressive strength was measured according to EN 12190 on 4?4?16 cm prisms after 7 d curing at 23? C./50% r.h. of a mixture consisting of 90 w % BOF slag milled as per the respective example, 10 w % of hydrated air lime and mixed with water in a weight ratio of water:powder of 0.36.

Example 1

[0150] 90 g of BOF slag was heated to 100? C. and was then charged into a ball mill. 260 g of steel balls were then added (vessel and balls were pre-heated to 100? C.). Then the respective grinding additives as shown in the following table 2 were added in an amount of 0.015 w % relative to the weight of the BOF slag. All grinding additives were diluted with water prior to addition in an amount to introduce 0.06 w % of water relative to the BOF slag. In case where a mixture of two grinding additives was used, each of the grinding additives was introduced in an amount of 0.015 w % relative to the weight of the BOF slag and the mixture was diluted in water prior to addition in an amount to introduce 0.06 w % of water relative to the BOF slag.

[0151] Milling was then effected for 5 minutes. After this time, a sample was taken for the analysis of Blaine surface and milling was continued for another 5 minutes. After the total milling time of 10 minutes, the Blaine surface of the resulting slag was measured, and the amount of material sticking to the balls and vessel was determined.

[0152] The following table 2 gives an overview of the results. Example 1 is a comparative example not according to the invention. Examples 2-13 are according to the present invention.

TABLE-US-00002 TABLE 2 Results 1 2 3 4 5 6 7 8 Grinding none TIPA TEA DEIPA EDIPA Polyaspartic Lactic Adipic additive type acid acid acid Blaine @ 5 min 2050 2250 2340 2900 2250 2220 2320 2160 [g/cm.sup.2] Blaine @ 10 min 2470 2630 2630 3220 2640 2630 2770 2700 [g/cm.sup.2] Residue on 22 21 15 13 13 14 16 22 45 ?m sieve [%] Residue on 48 42 37 29 40 32 37 37 32 ?m sieve [%] Material 14 11 10 4 10 8 5 5 sticking*.sup.1 [%] Compressive 0.7 9.7 n.m. 7.6 n.m. n.m. n.m. n.m. strength [MPa] 9 10 11 12 13 Grinding Malonic Calcium TIPA & TIPA & TIPA & additive type acid lactate Glucose Fructose citric acid Blaine @ 5 min 2390 2480 2630 2520 2520 [g/cm.sup.2] Blaine @ 10 min 2710 2670 2850 2950 3170 [g/cm.sup.2] Residue on 19 16 22 18 18 45 ?m sieve [%] Residue on 40 41 38 35 38 32 ?m sieve [%] Material 7 4 8 5 4 sticking*.sup.1 [%] *.sup.1sum of material sticking to balls and vessel relative to the total BOF slag introduced n.m.: not measured

[0153] As can be seen from the above results, the addition of an additive during dry grinding of basic oxygen slag leads to a higher Blaine surface obtainable after 5 min or after 10 min of grinding. This means that the grinding efficiency is higher with the respective grinding additive added. A higher Blaine surface can be obtained within the same grinding time or less time is needed to grind the BOF slag to a desired Blaine surface.

[0154] It can also be seen from the above results, that the inventive use of grinding additives during grinding leads to a ground BOF slag comprising more fine particles. Meaning that the overall particle size is reduced. This is obvious from a lower amount of particles being retained on a 45 ?m or 32 ?m sieve in case where grinding was done with the additive as compared to where no additive was added.

[0155] Finally, it can be seen from the above results, that the inventive use of grinding additives leads to a lower amount of ground material sticking to the balls and vessel of the ball mill. This is also an indication of increased grinding efficiency.

Example 2

[0156] Example 2 was conducted in the same way as example 1. Except that the type of grinding additives and amounts thereof were used as indicated in below table 3. Examples 14-42 are according to the present invention.

TABLE-US-00003 TABLE 3 Results 14 15 16 17 Grinding TIPA & DEIPA TIPA & DEIPA TIPA & DEIPA TIPA & DEIPA additive type (25:75 w %) (50:50 w %) (75:25 w %) (75:25 w %) Total amount of 0.015 0.015 0.015 0.075 grinding additive added*.sup.1 Blaine @ 5 min 2260 2310 2520 3170 [g/cm.sup.2] Blaine @ 10 min 2920 2830 3030 3400 [g/cm.sup.2] Residue on 14 5 6 8 45 ?m sieve [%] Residue on 34 39 33 24 32 ?m sieve [%] Material 2.5 1.9 2 0.9 sticking*.sup.2 [%] Compressive 6.5 6.1 6.5 8.9 strength [MPa] 18 19 20 21 Grinding TIPA & GLY DEIPA & GLY TIPA & DEG DEIPA & DEG additive type (50:50 w %) (50:50 w %) (50:50 w %) (50:50 w %) Total amount of 0.015 0.015 0.015 0.015 grinding additive added*.sup.1 Blaine @ 5 min 2320 2470 2370 2390 [g/cm.sup.2] Blaine @ 10 min 3020 2470 2370 2390 [g/cm.sup.2] Residue on 12 14 13 4 45 ?m sieve [%] Residue on 39 30 32 30 32 ?m sieve [%] Material 1.6 1.6 1.9 1.8 sticking*.sup.2 [%] Compressive 6.8 7.1 6.6 6.5 strength [MPa] 22 23 24 25 Grinding TIPA & DEG TIPA & DEG DEIPA & DEG DEIPA & DEG additive type (80:20 w %) (30:70 w %) (60:40 w %) (33:66 w %) Total amount of 0.075 0.075 0.1 0.1 grinding additive added*.sup.1 Blaine @ 5 min 2970 2750 3420 2860 [g/cm.sup.2] Blaine @ 10 min 3250 3250 3540 3390 [g/cm.sup.2] Residue on 6 10 4 15 45 ?m sieve [%] Residue on 22 25 22 20 32 ?m sieve [%] Material 0.9 1.3 0.7 0.8 sticking*.sup.2 [%] Compressive 10 6.9 10.6 10.5 strength [MPa] 26 27 28 29 Grinding TIPA & GLY TIPA & GLY DEIPA & GLY DEIPA & GLY additive type (60:40 w %) (14:86 w %) (60:40 w %) (33:66 w %) Total amount of 0.1 0.1 0.1 0.1 grinding additive added*.sup.1 Blaine @ 5 min 3090 2760 3170 2930 [g/cm.sup.2] Blaine @ 10 min 3380 3250 3390 3410 [g/cm.sup.2] Residue on 6 10 6 15 45 ?m sieve [%] Residue on 20 28 20 24 32 ?m sieve [%] Material 0.8 1.3 1.0 1.5 sticking*.sup.2 [%] Compressive 10.0 10.1 11.4 10.2 strength [MPa] 30 31 32 33 34 Grinding TIPA TIPA DEIPA DEIPA TEA additive type Total amount of 0.1 0.15 0.1 0.15 0.06 grinding additive added*.sup.1 Blaine @ 5 min 3390 3310 3540 3580 n.m. [g/cm.sup.2] Blaine @ 10 min 3600 3900 3370 3910 2720 [g/cm.sup.2] Residue on 7 5 6 11 25 45 ?m sieve [%] Residue on 24 21 25 22 36 32 ?m sieve [%] Material 0.7 0.6 0.9 0.7 2.1 sticking*.sup.2 [%] Compressive 9.9 15.9 10.6 12.3 4 strength [MPa] 35 36 37 39 Grinding DEIPA + glucose DEIPA + citric TIPA + Glucose + TIPA + citric acid + additive type (50:50 w %) acid (50:50 w %) DEG (13:13:74 w %) DEG (13:13:74 w %) Total amount of 0.06 0.06 0.12 0.12 grinding additive added*.sup.1 Blaine @ 5 min 2520 2330 2860 2790 [g/cm.sup.2] Blaine @ 10 min 3010 3080 3300 3300 [g/cm.sup.2] Residue on 17 19 18 17 45 ?m sieve [%] Residue on 32 31 29 26 32 ?m sieve [%] Material 1.7 1.3 0.9 1.0 sticking*.sup.2 [%] Compressive 8.6 8.6 n.m. n.m. strength [MPa] 40 41 42 Grinding DEIPA + fructose + TIPA + DEG + TiBp DEIPA + DEG + TiBp additive type GLY (30:30:40 w %) (49.8:49.8:0.4 w %) (24.9:74.7:0.4 w %) Total amount of 0.1 0.12 0.12 grinding additive added*.sup.1 Blaine @ 5 min 2780 3330 2950 [g/cm.sup.2] Blaine @ 10 min 3310 3620 3500 [g/cm.sup.2] Residue on 20 15 15 45 ?m sieve [%] Residue on 26 24 24 32 ?m sieve [%] Material 1.5 0.6 1.0 sticking*.sup.2 [%] Compressive n.m. 8.2 8.9 strength [MPa] *.sup.1in w % relative to the weight of the BOF slag *.sup.2sum of material sticking to balls and vessel relative to the total BOF slag introduced n.m.: not measured