Metallic Ore Pellets

Patent metadata

Field	Value
Publication number	US-2020190623-A1
Application number	US-201716464511-A
Country	US
Kind code	A1
Filing date	Nov 30, 2017
Priority date	Nov 30, 2016
Publication date	Jun 18, 2020
Grant date	—

Abstract

The present invention concerns the use of a magnesium-including compound as binder for producing metallic ore fluxed pellets, in particular iron ore fluxed pellets, said magnesium-including compound comprising semi-hydrated dolime fitting the general formula aCa(OH) 2 ·bMg(OH) 2 ·cMgO, a, b, and c being weight fractions wherein the weight fraction b of Mg(OH) 2 is between 0.5 and 19.5 % by weight with respect to the total weight of said semi-hydrated dolime.

First claim

1 - 18 . (canceled)

19 . A process for manufacturing metallic ore fluxed pellets, comprising the steps of:
feeding a fine metallic ore concentrate into a container, wherein said fine metallic ore concentrate presents a Blaine fineness comprised between 1500 cm 2 /g and 2500 cm/g; feeding a binder in said container; adjusting moisture in said container to form a wet mixture; balling and sieving said wet mixture into crude metallic ore fluxed pellets;
wherein said binder is a compound which includes magnesium, the compound comprising a semi-hydrated dolime fitting the general formula aCa(OH) 2 ·bMg(OH) 2 ·cMgO, a, b and c being weight fractions wherein the weight fraction b of Mg(OH) 2 is between 0.5 and 19.5% by weight with respect to the total weight of said semi-hydrated dolime.

20 . The process of claim 19 , further comprising a firing step for hardening the crude metallic ore fluxed pellets in an induration furnace.

21 . the process of claim 20 , wherein said firing step comprises the steps of:
drying the crude metallic ore fluxed pellets at about 300° C. during a predetermined period of time comprised between 5 min and 15 min for forming dried crude pellets; pre-heating the dried crude metallic ore fluxed pellets at a temperature equal to or higher than 800° C. during a predetermined period of time comprised between 5 min and 20 min for forming pre-heated crude pellets; firing the pre-heated crude metallic ore fluxed pellets at a temperature equal to or higher than 1200° C. during a predetermined duration comprised between 5 min and 20 min to form fired metallic ore fluxed pellets.

22 . The process of claim 19 , wherein the step of adjusting moisture is a step of adding an aqueous phase to form said mixture.

23 The process of claim 19 , wherein the step of adjusting moisture is performed until said mixture presents a moisture content comprised between 5% et 15% by weight with respect to the total weight of said mixture.

24 . (canceled)

25 . The method of claim 19 , further comprising a step of feeding a flux before the step of adjusting moisture, the flux being preferably selected from the group consisting of calcium carbonate, olivine, pyroxenite, other magnesium silicates and mixture thereof.

26 . The process of claim 19 , wherein the weight fraction c of MgO is greater than or equal to 5%, by weight of MgO with respect to the total weight of said semi-hydrated dolime and is less than or equal to 41% by weight of MgO with respect to the total weight of said semi-hydrated dolime, and wherein the weight fraction a of Ca(OH) 2 is greater than or equal to 15% by weight of Ca(OH) 2 with respect to the total weight of said semi-hydrated dolime and is less than or equal to 85% by weight of Ca(OH) 2 with respect to the total weight of said semi-hydrated dolime.

27 . The process of claim 19 , wherein the weight fraction of said binder is between 0.5% and 5% by weight with respect to the total weight of the pellets.

28 . (canceled)

29 . A metallic ore fluxed pellets composition, the composition comprising:
a metallic ore concentrate present in a quantity comprised between 80 weight % and 99 weight % with respect to the total weight of the metallic ore fluxed pellets composition; a magnesium-including compound present as binder in a quantity comprised between 0.1 weight % and 5 weight % with respect to the total weight of the metallic ore fluxed pellets composition; a moisture content comprised between 5 weight % and 15 weight % with respect to the total weight of the metallic ore fluxed pellets composition;
wherein the magnesium-including compound comprises a semi-hydrated dolime fitting the general formula aCa(OH) 2 ·bMg(OH) 2 ·cMgO, a, b and c being weight fractions wherein the weight fraction b of Mg(OH) 2 is between 0.5 and 19.5% by weight with respect to tire total weight of said semi-hydrated dolime.

30 . The metallic ore fluxed pellets composition of claim 29 further comprising from 0.5 weight % to 15 weight % of additives as fluxes with respect to the total weight of the metallic ore fluxed pellets composition.

31 . The metallic ore fluxed pellets composition of claim 29 , wherein the weight fraction c of MgO is greater than or equal to 5% by weight of MgO with respect to the total weight of said semi-hydrated dolime and is less than or equal to 41% by weight of MgO with respect to the total weight of said semi-hydrated dolime, and wherein the weight fraction a of Ca(OH) 2 is greater than or equal to 15% by weight of Ca(OH) 2 with respect to the total weight of said semi-hydrated dolime and is less than or equal to 85% by weight of Ca(OH) 2 with respect to the total weight of said semi-hydrated dolime.

32 . The metallic ore fluxed pellets composition of claim 29 , wherein the semi-hydrated dolime comprises particles presenting BET specific surface area obtained from nitrogen adsorption comprised between 5 and 25 m 2 /g.

33 . The metallic ore fluxed pellets composition of claim 29 , wherein the semi-hydrated dolime comprises particles presenting a total BJH pore volume consisting of pores with a diameter lower than 1000 Å, obtained from nitrogen desorption comprised between 0.05 and 0.15 cm 3 /g.

34 - 35 . (canceled)

36 . The metallic ore fluxed pellets composition of claim 29 , wherein the fine iron ore concentrate is selected from the group consisting of magnetite, hematite and mixture thereof.

37 . The metallic ore fluxed pellets composition of claim 29 , further comprising a flux selected from the group consisting of calcium carbonate, dolomite, olivine, pyroxenite, other magnesium silicates and mixture thereof.

38 . Crude metallic ore fluxed pellets, comprising
a fine metallic ore concentrate in a quantity comprised between 80 weight % and 99 weight % with respect to the total weight of the crude metallic ore fluxed pellets; a magnesium-including compound present as binder in a quantity comprised between 0.1 weight % and 5 weight % with respect to the total weight of the crude metallic ore fluxed pellets; a moisture comprised between 5 weight % and 15 weight % with respect to the total weight of the crude metallic ore fluxed pellets;
wherein the magnesium-including compound comprises a semi-hydrated dolime fitting the general formula aCa(OH) 2 ·bMg(OH) 2 ·cMgO, a, b and c being weight fractions wherein the weight fraction b of Mg(OH) 2 is between 0.5 and 19.5% by weight with respect to the total weight of said semi-hydrated dolime, wherein said crude metallic ore fluxed pellets further present a shock temperature equal to or higher than 250° C.

39 . The crude metallic ore fluxed pellets of claim 38 , further comprising from 0.5 weight % to 15 weight % of additives as fluxes with respect to the total weight of the crude metallic ore fluxed pellets.

40 . (canceled)

41 . The crude metallic ore fluxed pellets of claim 38 , wherein said crude metallic ore fluxed pellets present a size distribution wherein 90% to 98% of the pellets presents a diameter comprised between 8 to 16 mm.

42 - 43 . (canceled)

44 . Fired metallic ore fluxed pellets, comprising:
a metal content equal to or higher than 55%, by weight with respect to the total weight of the pellets;
wherein the pellets present a Ca/Mg ratio between 0.8 and 2 and present a crushing strength measured according to standard ISO 4700 comprised between 2000 and 5000 N/pellet.

Assignees

• Lhoist Rech Et Developpement Sa

Inventors

• Da Costa Eduardo
• Pelletier Marc

Classifications

• C22B1/2413

  enduration of pellets · CPC title

• C22B1/2406 Primary

  pelletizing · CPC title

• C22B1/243 Primary

  inorganic · CPC title