US-20260125551-A1 - BINDING COMPOSITION FOR ORE AGGLOMERATES

Abstract

The present invention relates to a binding composition, for the manufacture of ore agglomerates, comprising at least the following two distinct organic binding agents CP 1 and P 2: a polymeric composition CP 1 comprising a non-ionic or anionic water-soluble synthetic polymer P 1 with a weight average molecular weight of between 500,000 and 3 million Daltons, a non-ionic or anionic water-soluble synthetic polymer P 2 with a weight average molecular weight greater than 2 million Daltons, wherein the polymeric composition CP 1 and the polymer P 2 are both present in the form of solid particles, wherein P 1 is obtained by a gel polymerization process of at least one non-ionic or anionic monomer in the presence of: at least 1% by weight of a polymer P 3 , said polymer P 3 contains at least one hydrophobic monomer, or at least one hydrophobic monomer, the polymeric composition CP 1 comprising from 0.1% to 20% by weight of the at least one hydrophobic monomer, said hydrophobic monomer being polymerized. The invention also relates to an ore agglomerate containing between 2,000 and 50,000 ppm of this binding composition.

Inventors

• Cédrick Favero
• Gilles Zakosek
• Aurélien BONNEAU
• Aurélien DUCHADEAU

Assignees

• SNF GROUP

Dates

Publication Date

20260507

Application Date

20231025

Priority Date

20221104

Claims (20)

1. 1 . A binding composition, for the manufacture of ore agglomerates, comprising at least the following two distinct organic binding agents CP 1 and P 2 : a polymeric composition CP 1 comprising a non-ionic or anionic water-soluble synthetic polymer P 1 with a weight average molecular weight of between 500,000 and 3 million Daltons, a non-ionic or anionic water-soluble synthetic polymer P 2 with a weight average molecular weight greater than 2 million Daltons, wherein the polymeric composition CP 1 and the polymer P 2 are both present in the form of solid particles, wherein P 1 is obtained by a gel polymerization process of at least one non-ionic or anionic monomer in the presence of: at least 1% by weight of a polymer P 3 , said polymer P 3 contains at least one hydrophobic monomer, or at least one hydrophobic monomer, the polymeric composition CP 1 comprising from 0.1% to 20% by weight of the at least one hydrophobic monomer, said hydrophobic monomer being polymerized.
2. 2 . The binding composition according to claim 1 , wherein said binding composition contains at least 50% by weight of polymeric composition CP 1 .
3. 3 . The binding composition according to claim 1 , wherein the polymer P 1 contains at least 50 mol % of at least one non-ionic monomer.
4. 4 . The binding composition according to claim 1 , wherein the polymer P 1 is non-ionic.
5. 5 . The binding composition according to claim 3 , wherein the non-ionic monomer(s) of P 1 are chosen from the group consisting of acrylamide, methacrylamide, N-vinylformamide (NVF), N-vinyl acetamide, N-vinylpyridine, N-vinylpyrrolidone (NVP), N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, hydroxyalkyl (meth)acrylates, aminoalkyl (meth)acrylates, aminoalkyl (meth)acrylamido, thioalkyl (meth)acrylates and mixtures thereof.
6. 6 . The binding composition according to claim 3 , wherein at least one non-ionic monomer of the polymer P 1 is acrylamide.
7. 7 . The binding composition according to claim 1 , wherein the polymer P 1 is a copolymer of acrylamide and sodium acrylate.
8. 8 . The binding composition according to claim 1 , characterized in that wherein the polymer P 1 comprises at least one hydrophobic monomer chosen from haloalkyl derivatives of methacrylamidodimethyl aminopropyl comprising a C 8 -C 16 alkyl chain, ethoxylated behenyl methacrylate, diethylacrylamide, n-tert-butylacrylamide, and mixtures thereof.
9. 9 . The binding composition according to claim 1 , that wherein the polymer P 3 contains between 10 and 90% by weight of at least one hydrophobic monomer.
10. 10 . The binding composition according to claim 1 , characterized in that wherein the polymer P 3 is a terpolymer of diethylacrylamide, n-tert-butylacrylamide and sodium 2-acrylamido-2-methylpropanesulfonate.
11. 11 . The binding composition according to claim 1 , wherein the polymer P 3 is functionalized at the end of the polymer chain by at least one group chosen from: hydroxyl, cyano, amine, phosphate, phosphonate, sulphate, sulphonate, xanthate, trithiocarbonate, dithiocarbamate, and dithioester.
12. 12 . The binding composition according to claim 1 , wherein the polymer P 3 is free of carbon-carbon double bonds.
13. 13 . The binding composition according to claim 1 , wherein the polymer P 2 is a copolymer containing between 5 and 100 mol % of sodium acrylate.
14. 14 . The binding composition according to claim 1 , wherein the polymer P 2 has a weight average molecular weight greater than the weight average molecular weight of the polymer P 1 .
15. 15 . Ore agglomerate containing between 2,000 and 50,000 ppm of the binding composition according to claim 1 , relative to the weight of the ore agglomerate.
16. 16 . The binding composition according to claim 2 , wherein the polymer P 1 contains at least 50 mol % of at least one non-ionic monomer.
17. 17 . The binding composition according to claim 16 , wherein the polymer P 1 is non-ionic.
18. 18 . The binding composition according to claim 17 , wherein the non-ionic monomer(s) of P 1 are chosen from the group consisting of acrylamide, methacrylamide, N-vinylformamide (NVF), N-vinyl acetamide, N-vinylpyridine, N-vinylpyrrolidone (NVP), N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), acryloyl chloride, glycidyl methacrylate, glyceryl methacrylate, diacetone acrylamide, hydroxyalkyl (meth)acrylates, aminoalkyl (meth)acrylates, aminoalkyl (meth)acrylamido, thioalkyl (meth)acrylates and mixtures thereof.
19. 19 . The binding composition according to claim 18 , wherein at least one non-ionic monomer of the polymer P 1 is acrylamide.
20. 20 . The binding composition according to claim 19 , wherein: the polymer P 1 is a copolymer of acrylamide and sodium acrylate; or the polymer P 1 comprises at least one hydrophobic monomer chosen from haloalkyl derivatives of methacrylamidodimethyl aminopropyl comprising a C 8 -C 16 alkyl chain, ethoxylated behenyl methacrylate, diethylacrylamide, n-tert-butylacrylamide, and mixtures thereof.

Description

FIELD OF THE INVENTION The invention belongs to the technical field of ore agglomerates. The invention relates to a binding composition improving, in particular, the agglomeration step for obtaining ore low-temperature agglomerates. Said binding composition comprises a mixture of at least two organic polymeric binding agents. The invention also relates, as a product, to an ore agglomerate containing said binding composition. PRIOR ART Most metals are obtained from ores found in their natural state in the ground or in mines. During the first stage of the recovery process for said metals, the element of interest, i.e., the metal (for example iron to make steel), is recovered from the melted ore in a blast furnace. In order to be introduced directly into this blast furnace, the ore of the element of interest must be in a standard form of significant size. If this is not the case, it is necessary to convert the ore particles into agglomerates larger than the particle size. Agglomeration is a process based on the adhesion of ore particles to each other. Five agglomeration technologies exist in metallurgy: briquetting, nodulization, extrusion, pelletization and sintering. These techniques are known and described in numerous documents such as the work “Agglomeration in Industry” by Wolfgang Pietsch or, in particular, in patent EP 0097486. Nowadays, the increasing use of lower quality ores forces manufacturers to grind the ore finer, which makes the agglomeration step essential. During this agglomeration step, the use of a bonding agent or a binding composition is necessary to ensure good physical properties such as the mechanical strength of the agglomerates. A “binding agent” or a “binding composition” makes it possible to optimize the adhesion of the ore particles between them in order to form an agglomerate having sufficient mechanical properties allowing it to resist the vibrations and movements to which it is subjected during its various handling operations. Among the binding agents traditionally used, mention will be made of cement (Portland), clays and more particularly bentonites, starch, cellulose, molasses, optionally by combining them with lime, etc. The use of these binding agents poses problems given the high presence of impurities which are harmful to the industrial process (such as the sulfur impurity for the steel industry) and/or leads to agglomerates having unsatisfactory physical properties. In recent years, new binding compositions have been developed by manufacturers to counter these undesirable effects. Documents U.S. Pat. No. 5,002,607 and EP 2,548,978 describe processes for which agglomerates are produced using a binding composition comprising at least one synthetic polymer of organic nature and at least one inorganic binding agent. U.S. Pat. No. 5,833,937 relates to a method comprising a binding step involving the sequential addition to mineral fines of a solution of anionic polymers and a solution of cationic polymers. Generally, agglomerates such as iron ore pellets are formed by adding a binding agent to crushed ores and agitating it in the presence of a small amount of water to form a wet mixture, then shoveling the mixture to form (wet) green pellets. These green pellets are then fired in an oven from an entry temperature of 200-400° C. to a final temperature of almost 1400° C. Such a process for forming iron ore pellets is disclosed in document EP 0 225 171, for example. For the final agglomerate to have good physical properties, the baking step is essential. However, this step is very energy-intensive in terms of fossil matter. This has a considerable impact on agglomerate plants, both ecologically and economically. In view of the current energy situation, it is more than necessary to find sustainable and effective solutions that make it possible to obtain quality agglomerates, i.e., respecting the physical properties expected from the technique, while combining productivity and energy savings. One of the solutions found by manufacturers to limit the impact of manufacturing these agglomerates was to agglomerate the ore at low temperature, i.e., at a firing temperature not exceeding 250° C. Unfortunately, this type of process does not make it possible to obtain the expected physical properties of the agglomerates, on the basis of the binding compositions mentioned above. The agglomerates crack before they even reach production equipment such as blast furnaces. Their handling becomes arduous and their storage is difficult. The present invention overcomes the drawbacks of the prior art by disclosing a binding composition improving the agglomeration step in order to allow manufacturing ore agglomerates at low temperature with satisfactory physical properties. DISCLOSURE OF THE INVENTION The invention relates to a binding composition for the manufacture of ore agglomerates generally at low temperature, comprising at least the following two distinct organic binding agents (a polymeric com