METHOD FOR TREATMENT OF SLAG

Abstract

The invention relates to a process for the wet milling of slag, wherein more than 100 kWh of milling energy are introduced per metric ton of slag and the weight ratio of slag to water is 0.05-4:1 and from 0.005 to 2% by weight, based on the slag, of a milling auxiliary which comprises at least one compound selected from the group consisting of polycarboxylate ether, phosphated polycondensation product, lignosulfonate, melamine-formaldehyde sulfonate, naphthalene-formaldehyde sulfonate, monoglycols, diglycols, triglycols and polyglycols, polyalcohols, alkanolamine, amino acids, sugar, molasses and curing accelerators based on calcium silicate hydrate is added to the material being milled before or during the milling.

Claims

1. A process for the wet milling of slag, wherein more than 100 kWh of milling energy are introduced per metric ton of slag, and the weight ratio of slag to water is 0.05-4:1; and wherein from 0.005 to 2% by weight, based on the slag, of a milling auxiliary which comprises at least one compound selected from the group consisting of polycarboxylate ether, phosphated polycondensation product, lignosulfonate, melamine-formaldehyde sulfonate, naphthalene-formaldehyde sulfonate, monoglycols, diglycols, triglycols, polyglycols, polyalcohols, alkanolamine, amino acids, sugar, molasses, and curing accelerators based on calcium silicate hydrate, is added to the material being milled before or during the wet milling.

2. The process according to claim 1, wherein the slag is blast furnace slag.

3. The process according to claim 1, wherein milling media are used in the wet milling, with the weight ratio of slag to milling media being 1-15:1.

4. The process according to claim 1, wherein the slag has the following composition: from 20 to 50% by weight of SiO.sub.2 from 5 to 40% by weight of Al.sub.2O.sub.3 from 0 to 3% by weight of Fe.sub.2O.sub.3 from 20 to 50% by weight of CaO from 0 to 20% by weight of MgO from 0 to 5% by weight of MnO from 0 to 2% by weight of SO.sub.3; and >80% by weight of glass content.

5. The process according to claim 1, wherein the milling auxiliary is at least one polymer comprising acid groups selected from the group consisting of polycarboxylate ether and phosphated polycondensation product, wherein the milling auxiliary comprises a structural unit (I),
*—U—(C(O).sub.k—X-(AlkO).sub.n—W   (I) where * indicates the point of bonding to the polymer comprising acid groups, U is a chemical bond or an alkylene group having from 1 to 8 carbon atoms, X is oxygen, sulfur or an NR.sup.1 group, k is 0 or 1, n is an integer having an average in the range from 1 to 300, Alk is C.sub.2-C.sub.4-alkylene, where Alk can be identical or different within the group (Alk-O).sub.n, W is a hydrogen radical, a C.sub.1-C.sub.6-alkyl radical or an aryl radical or the group Y—F, where Y is a linear or branched alkylene group which has from 2 to 8 carbon atoms and may optionally bear a phenyl ring, F is a 5- to 10-membered nitrogen heterocycle which is bound via nitrogen and may optionally have, apart from the nitrogen atom and apart from carbon atoms, 1, 2 or 3 additional heteroatoms selected from oxygen, nitrogen and sulfur as ring members, where the nitrogen ring members may optionally bear an R.sup.2 group and 1 or 2 carbon ring members may optionally be present as carbonyl group, R.sup.1 is hydrogen, C.sub.1-C.sub.4-alkyl or benzyl and R.sup.2 is hydrogen, C.sub.1-C.sub.4-alkyl or benzyl.

6. The process according to claim 5, wherein the phosphated polycondensation product comprises (II) at least one structural unit having an aromatic or heteroaromatic group and a structural unit (I) and (III) at least one phosphated structural unit having an aromatic or heteroaromatic group.

7. The process according to claim 6, wherein the structural units (II) and (III) are represented by the following general formulae
A-U—(C(O)).sub.k—X-(AlkO).sub.n—W   (II) where the radicals A are identical or different and are represented by a substituted or unsubstituted aromatic or heteroaromatic compound having from 5 to 10 carbon atoms in the aromatic system, where the further radicals have the meanings indicated for structural unit (I);
A-U—(C(O)).sub.k—X-(AlkO).sub.n—P(O)(OM.sub.a).sub.2   (III) where the radicals A are identical or different and are represented by a substituted or unsubstituted aromatic or heteroaromatic compound having from 5 to 10 carbon atoms in the aromatic system, where the further radicals have the meanings indicated for structural unit (I) and M is hydrogen, a monovalent, divalent or trivalent metal cation, an ammonium ion or an organic amine radical a is ⅓, ½ or 1.

8. The process according to claim 6, wherein the polycondensation product comprises a further structural unit (IV) which is represented by the following formula ##STR00005## where the radicals Y are, independently of one another, identical or different and are represented by (II), (III) or further constituents of the polycondensation product.

9. The process according to claim 5, wherein the polycarboxylate ether is at least one copolymer obtained by polymerization of a mixture of monomers comprising (V) at least one ethylenically unsaturated monomer which comprises at least one radical selected from the group consisting of carboxylic acid, carboxylic acid salt, carboxylic ester, carboxamide, carboxylic anhydride and carboximide; and (VI) at least one ethylenically unsaturated monomer having a structural unit (I).

10. The process according to claim 9, wherein the ethylenically unsaturated monomer (V) is represented by at least one of the following general formulae from the group (Va), (Vb) and (Vc) ##STR00006## where R.sup.7 and R.sup.8 are each, independently of one another, hydrogen or an aliphatic hydrocarbon radical having from 1 to 20 carbon atoms B is H, —COOM.sub.a, —CO—O(C.sub.qH.sub.2qO).sub.r—R.sup.9, or —CO—NH—(C.sub.qH.sub.2qO).sub.r—R.sup.9 M is hydrogen, a monovalent, divalent or trivalent metal cation, ammonium ion or an organic amine radical a is ⅓, ½ or 1 R.sup.9 is hydrogen, an aliphatic hydrocarbon radical having from 1 to 20 carbon atoms, a cycloaliphatic hydrocarbon radical having from 5 to 8 carbon atoms, or an optionally substituted aryl radical having from 6 to 14 carbon atoms the indices q are, independently of one another, identical or different for each (C.sub.qH.sub.2qO)— unit and are in each case 2, 3 or 4 and r is from 0 to 200 Z is O, NR.sup.16 the radicals R.sup.16 are, independently of one another, identical or different and are each represented by a branched or unbranched C.sub.1-C.sub.10-alkyl radical, C.sub.5-C.sub.8-cycloalkyl radical, aryl radical, heteroaryl radical or H, ##STR00007## where R.sup.10 and R.sup.11 are each, independently of one another, hydrogen or an aliphatic hydrocarbon radical having from 1 to 20 carbon atoms, a cycloaliphatic hydrocarbon radical having from 5 to 8 carbon atoms, or an optionally substituted aryl radical having from 6 to 14 carbon atoms the radicals R.sup.12 are identical or different and are represented by (C.sub.nH.sub.2n)—SO.sub.3M.sub.a where n=0, 1, 2, 3 or 4, (C.sub.nH.sub.2n)—OH where n=0, 1, 2, 3 or 4; (C.sub.nH.sub.2n)—PO.sub.3(M.sub.a).sub.2 where n=0, 1, 2, 3 or 4, (C.sub.nH.sub.2n)—PO.sub.3(M.sub.a).sub.2 where n=0, 1, 2, 3 or 4, (C.sub.6H.sub.4)—SO.sub.3M.sub.a, (C.sub.6H.sub.4)—PO.sub.3(M.sub.a).sub.2, (C.sub.6H.sub.4)—PO.sub.3(M.sub.a).sub.2 or (C.sub.nH.sub.2n)—NR.sup.14.sub.b where n=0, 1, 2, 3 or 4 and b=2 or 3 and M is hydrogen, a monovalent, divalent or trivalent metal cation, ammonium ion or an organic amine radical and a is ⅓, ½ or 1 R.sup.13 is H, —COOM.sub.a, —CO—O(C.sub.qH.sub.2qO).sub.r—R.sup.9, or —CO—NH—(C.sub.qH.sub.2qO).sub.r—R.sup.9, where M.sub.a, R.sup.9, q and r are as defined above R.sup.14 is hydrogen, an aliphatic hydrocarbon radical having from 1 to 10 carbon atoms, a cycloaliphatic hydrocarbon radical having from 5 to 8 carbon atoms, or an optionally substituted aryl radical having from 6 to 14 carbon atoms, the radicals Q are identical or different and are represented by NH, NR.sup.15 or O; where R.sup.15 is an aliphatic hydrocarbon radical having from 1 to 10 carbon atoms, a cycloaliphatic hydrocarbon radical having from 5 to 8 carbon atoms or an optionally substituted aryl radical having from 6 to 14 carbon atoms.

11. The process according to claim 1, wherein the particle size d.sub.50 of the curing accelerator based on calcium silicate hydrate is less than 5 μm.

12. The process according to claim 1, wherein the wet milling is carried out in a stirred ball mill.

13. A milled slag produced according to claim 1, wherein the milled slag comprises the milling auxiliary.

14. A binder or a binder composition, having a binder component which comprises from 5 to 99% by weight of the milled slag according to claim 13 and from 1 to 95% by weight of cement.

15. A cement-based composition comprising the milled slag according to claim 13 in an amount of from 0.1 to 99% by weight based on the dry mass of the composition.

16. The process according to claim 7, wherein the polycondensation product comprises a further structural unit (IV) which is represented by the following formula ##STR00008## where the radicals Y are, independently of one another, identical or different and are represented by (II), (III) or further constituents of the polycondensation product.

Description

EXAMPLES

[0096] General Experimental Method

[0097] 12 kg of a granulated slag sand (Hüttensand Salzgitter GmbH & Co. KG) are milled in a drum ball mill for 110 minutes to a specific surface area of 3500 cm.sup.2/g (Blaine method). A suspension is produced from 700 g of the milled slag sand having a specific surface area of 3500 cm.sup.2/g and 1421 g of deionized water to which 0.1% by weight of a milling auxiliary according to the invention, based on the milled slag sand, are optionally added. This suspension is transferred into a stirring vessel of a stirred ball mill having perforated plates (Drais Pearl Mill) and the mill is operated at 2580 rpm with circulation. The volume of the milling chamber is 0.94 liters. Balls made of zirconium oxide and having a diameter of 0.8 mm are used as milling media. The degree of fill of the milling chamber with the milling media is 75%, with the weight ratio of slag to milling media being 0.066:1 and the milling time being about 2 hours. A calculated 750 kWh of milling energy are introduced per metric ton of slag by the wet milling.

[0098] The milling media are subsequently separated from the suspension by sieving. To separate off the slag sand from the suspension, the suspension is filtered through a glass fiber filter (Whatman glass fiber filter GF/F) by means of a suction bottle and the filter cake is covered with isopropanol.

[0099] The material is subsequently dried in a stream of nitrogen at 40° C.

[0100] The dry product obtained is brushed through a 250 μm sieve and mixed in a weight ratio of 50:50 with a commercially available CEM I 42.5N (Schwenk Zement KG, Mergelstetten works).

Use Example

[0101] The production of the mortar for the strength testing is carried out in accordance with EN196-1 with additional introduction of a plasticizer in order to attain a slump flow of the mortar of about 20 cm. 225 g of water are mixed with 450 g of the binder consisting of pure CEM I 42.5 R (Schwenk Zement KG, Mergelstetten works) or of a mixture of this cement with slag sand in a mixer in accordance with EN 196-1 (w/c=0.5) and, after the time indicated in EN 196-1, 1350 g of CEN standard sand, EN 196-1, are added (c/s=0.33) and mixed according to the mixing regime specified in EN196-1.

[0102] The slump flow in accordance with EN 196-1 is subsequently set to about 20 cm by addition of a polycarboxylate ether plasticizer (Master ACE 430, trade name of BASF Construction Solutions GmbH).

[0103] Compressive strength testing was carried out in accordance with EN 196-1.

TABLE-US-00001 TABLE 1 Testing of the compressive strength Compressive strength [MPa] Experiment d.sub.50 [μm] 1 day 2 days 28 days E1 — 10.7 19.2 63.6 E2 17.5 2.9 6.7 50.5 E3 8.3* 10.1 25.8 65.2 E4 6.3* 18.5 42.3 69.9 E5 1.7* 20.6 44.6 68.8 E6 1.9* 1.1 3.2 10.7 E7 2.5* 1.2 3.3 10.1 The determination of the d.sub.50 of the slag sand is carried out by means of laser light scattering (Malvern Mastersizer 2000). *in aqueous suspension E1 (comparison): Exclusively CEM I 42.5N (Schwenk Zement KG, Mergelstetten works) is used as binder. E2 (comparison): Slag sand (Hüttensand Salzgitter GmbH & Co. KG) having a specific surface area of 3500 cm.sup.2/g is used as binder. E3 (comparison): A binder produced according to the general experimental method is used, with no milling auxiliary being employed. E4 (according to the invention): A binder produced according to the general experimental method is used, with 0.1% by weight, based on the milled slag sand, of a curing accelerator based on calcium silicate hydrate (Master XSEED100, trade name of BASF Construction Solutions GmbH) being used as milling auxiliary. E5 (according to the invention): A binder produced according to the general experimental method is used, with 0.1% by weight, based on the milled slag sand, of a phosphated polycondensation product (MasterEase 3000, trade name of BASF Construction Solutions GmbH) being used as milling auxiliary. E6 (comparison): A binder produced according to the general experimental method is used, with 1421 g of isopropanol being used as solvent instead of the deionized water and no milling auxiliary being employed. E7 (comparison): A binder produced according to the general experimental method is used, with 1421 g of hexanol being used as solvent instead of the deionized water and no milling auxiliary being employed.