US3215520A - Method of producing lump ores - Google Patents

Description

United States Patent 3,215,520 METHOD OF PRODUCING LUMP ORES Louis George Imperato, Jr., Tenafly, N.J., assignor to Blocked Iron Corporation, a corporation of New York "ice gical function in the open hearth steel-making furnace or to be carried out through the top of the blast furnace in iron making and are not suitable in their naturally occurring condition for use in open-hearth steel-making fur- No Drawing Ffled May 27, 1964, Sen No. 370,674 5 naces or in blast furnaces. In addition, many of these ores,

9 Clainm (CL 75 are high in sulfur and similar undesirable elements. In order to take advantage of these materials, it has been the This application is a continuation-in-part of my co-pendpractice to take these finely divided materials and either ing application Serial No. 34,359, filed June 7, 1960, now sinter, pelletize or nodulize them by heating to high temabandoned, which was an improvement over the lump ores 10 peratures or by bonding them together with hydraulic and methods of producing them disclosed in copending cement. All of these practices are relatively expensive application Serial No. 749,546, filed July 18, 1958, now and in some instances are undesirable because of the in- Patent No. 2,996,372. creased amounts of impurities such as silica and alumina This invention relates to lump ores and to methods of which are introduced into the ore by the bonding practice. producing them and particularly to a lump ore and I have discovered an improved lump ore product promethod of producing such an ore from finely divided maduced from such finely divided materials and a method of terials containing metals in the metallic state, as metallic producing it. The lump ores produced according to my compounds such as oxides or mixtures thereof. The ininvention are free from the objections common to the presvention is particularly adapted to the production of lump ently used ores produced by sintering, pelletizing and iron ores from finely divided iron ores, blast furnace flue nodulizing finely divided materials. The lump ore of this dust and other sources of iron and iron compounds which invention has the desirable thermal and chemlcal characare available in a fi State f di i i teristics of natural lump ore, and has the strength and re- In the case of iron ore, for example, natural reserves of sistance or 511mg P P E of natural 111ml) Oreshigh grade lump ores are rapidly being depleted by selec- The P ore of {1115 Y? ,moreovqri free tive mining. It has been increasingly necessary to utilize lindfaslrable added. lmpunnis contams bondnig mammals the more finely divided high grade ores as well as to turn i i to i i f gi g 3 to low grade ores which must be heneficiated. In using glca P Ices 6 0mm 0 i e or i i containing materials and has a built-in sulfur elinnnatlng such ores it is not uncommon to find them in size ranges such that the ass throu h a 200 to 325 mesh In addicomponent i I .5 l h 1 Amberg Patent 2,844,457 provldes a method of forming tf),these e y dm ed natura ares t are a lump ore products from finely divided metal containing quantities of blast furnace flue dust, fine scale, and 511111131 material by bonding the material together with an alkaline other sources of non and iron compounds available in the earth carbonate d formed by mixing the finely divided finely dlvlded State for use 111 and steel'makmg P metal containing material with an oxide or hydroxide or ScS- However, these materlals, because of thelr calcium, mixed calcium and magnesium in the presence ness, tend to fuse and bridge Over or to be flushed t of moisture Within specific limits forming the lumps and with the early slag before accomplishing their metallurtreating them with carbonic acid gas. This practice pro- Table 1 Exposure to Carbon Dioxide Parts on Atmosphere Batch Materials Dry Wgt.

of Ore 30 mins. 60 mins. 120 mins.

I Liberian Ore/Cone. (50%/50%) 100. 00

Hydrated Lime. 4. 00 32% 89% 91% Calcium Chlorid 0. 20 Molasses 0. 40 Sodium Hydroxide. 0. 27 (Retained on 0.371 mesh sieve after Wat 0. 00 rev. on A.S.T.M. tumbler) II Liberian Ore/Cone. (50%/50%) 100. 00

Hydrated Lime 3. 3 83% 83% 0127 (Retained on 0.371 mesh sieve after 6. 50 50 rev. on A.S.T.M. tumbler) III Liberian Ore/0on0. (50%/50%) 100. 00

Hydrated Limo 4.00 61% 69% 71% Calcium Oh1oride 0. 20 Molasses" 0. 40 (Retained on 0.371 mesh sieve after Water 6. 50 50 rev. on A.S.T.M. tumbler) IV L'b o o s0 50 100. 00 38 42 ityiitid iilneififni ffn'ii 4.00 46% Calcium Chloride v 0. 20 (Retained on 0.371 mesh sieve after Water 7. 00 50 rev. o n A.S.T.M. t umbler) V Liberian Ore/Cone. (50%/50%) 100.00 29% I 30% 34% Hydrated Lune 4. 00 (Retained on 0.371 mesh sieve after Water 7. 25 50 rev. on A.S.'I.M. tumbler) VI L'b o 0 50 50 100.00 29 29 2 sits. a i... 6% Sodium HYdI'OXI 0. 27 (Retained on 0.371 mesh sieve after Water 7. 00 50 rev. on A.S.T.M. tumbler) VII Liberian Ore/Cone. (50%/50%) 100. 00

Hydrated Lime 4. 00 20% 15% 22% Calcium Chloride.-- 0.20 Sodium Hydroxide..- 0.27 (Retained on 0371 mesh sieve after Water 7. 00 50 rev. olu A.S.T.M. tlumbler) 3 duces a lump ore product having highly desirable characteristics and being superior to anything previously available. I have found, however, that the product of the Amberg patent can be significantly improved particularly when the following examples which show the significance of the practice according to my invention:

EXAMPLE I A Liberian ore concentrate was divided into seven parts finely divided high calcium Oxides hydroxides are used 5 and formed into various admixtures. These mixtures in the mixhll'e, and When the Ore contains Significant were exposed to carbon dioxide for varying times and the amounts of sulfur. I have discovered that the addition block strength determined as percent remamlng on .371 of sugars, such as maltose, sucrose, dextrose and glucose, mesh sieve after 50 revolutions 1n an A.S.T.M. tumbler. and sugar containing materials, such as molasses, syrups The results appear in Table I above. and carbohydratesand other materials such as starch and EXAMPLE II the sodium salt of ethylene-diamene tetraacetic acid as dis- Venezuelan Ore fi e were di id d i t ti Closed Patent 2,996,372 which are capable of These portions were mixed and formed as indicated in solubilizing alkaline. earth metals to the mixture, together T bl 11 b l Th i t r briquetted and with certain basic compounds of the alkali metals prior to 15 treated with carbon dioxide for 2 /2 hours. After carcarbonation will significantly improve the resistance of bonation, the briquettes were tumbled as in Example I. thelump ores to crushing and disintegration under impact, The results are shown in Table II.

Table II Exposure to Carbon Dioxide Parts on Atmosphere (in minutes) Batch Materials Dry Wgt of Ore mlns. 60mins. 180 mins.

I Venezuelan Ore Fines 100. 00 91% 92% Hydrated Lime 5. 00 Calcium Chloride 0.20 (Retained on 0.371 mesh sieve alter Molasses 0.50 50 rev. on A.S.T.M. tumbler) Sodium Hydroxide. 0.27 Water 12.00

II Venezuelan Ore Fines- 100.00 08% 66% 82% Hydrated Lime 5. 00 Calcium Chloride 0.20 (Retained on 0.371 mesh sieve alter Molasses 0.50 50 rev. on A.S.T.M. tumbler) Water 12.00

as well as providing the power to eliminate sulfur from the EXAMPLE III bath. I have found that the addition of small amounts of sugars and certain solubilizing agents for calcium and magnesium oxides and hydroxides, particularly in the range .025 to 1% by weight together with such basic alkali metal compounds will more than double the resistance of the lump..ores tophysical shock. By alkali metals I mean sbdium, potassium, lithium, and ammonium (including the Table 111 Parts on Ex osure Percent of Sod'um H dr lde Ad Batch Materials Dry Wgt. to al-hon 1 y 0x dad of Ore Dioxide,

mins. 0.00 0.14 0.27 0.41 0.54 0.78

I through IV Venezuelan Ore Fines 100. 00

1\E/EyIdrated Lime 5.00

o asses 0.50 667 767 927 85 85 85 Calcium Chloride 0. 20 (R tained on 0.3 71 me h siev e aiter Water 12. 00 50 rev. on A.S.T.M. tumbler) amines). These alkali metal oxides and hydroxides are EXAMPLE IV added in an amount equalto at least 0.1% by weight and preferably between about 0.15 to 0.35% by Weight. The

The identical process of Example III was carried out substituting varied percentages of potassium hydroxide invention can perhaps-best be explained by reference to 75 for the varied percentages of sodium hydroxide of Ex ample III. The pieces were tested with the following re- The industry accepted standard is to drops to sults. failure. 1

Table IV Exposure Percent of Potassium Parts on to Carbon Hydroxide Added Batch Materials Wgt. of Dioxide,

Dry Ore mins.

I through IV Venezuelan Ore Fines 100. 00 90 Hydrated Lime 5.00 66% 85% 91% Molasses 0. 50 Calcium Chloride- 0.20 (Retained on 0.371 mesh sieve after ater 12. 00 50 rev. on A.S.T.M. tumbler) EXAMPLE VII EXAM PLE V A specular hematite ore was admixed in the propor- In order to compare the efiiciency of other basic comtions shown in Table V. The mixture was briquetted and pounds of alkali metals and ammonium, magnetite contreated with carbon dioxide for 2 hrs. The resulting centrates were admixed in the proportions shown in Table blocks were tested by tumbling as described in Example VII. These mixtures were briquetted and subjected to I with the following results.

Table V Parts on Strength Index Percent Batch Materials Dry Wgt. Retained on a 0.371 Mesh of Ore Sieve after Revolutions in an A.S.T.M. Tumbler I through VI Lac Jeannine Concentrates--. 100. 00 82 Hydrated Lime 5.00 Calcium Chloride. 0.20 Molasses 0.50 4. 82

VII through IX--- 100. 00 22 X through XV 11-. Lac Jeannine Concentrates 100. 00 90 Hydrated Lime 5.00 Calcium Chloride- 0. 20 Molasses 0.50 Sodium Hydro 0. 27 Water 3.95

EXAMPLE VI In order to determine the efifect of various additives 50 on green strength Venezuelan ore fines were admixed in the proportions shown in Table VI below. These mixtures were formed into inch pellets and dropped from a height of 12" to a steel plate and the number of drops a treatment with carbon-dioxide for 2 hours. The resulting briquettes were tested in the manner outlined in Example I with the following results. In the table Mea is monoethanol amine and the semicolons separating the percentages indicate percentages obtained on separate determinations.

to fracture recorded as a 20 ball average.

Table VI Parts on Percent of Strength Batch Materials Dry Wgt. Moisture of Index Averof Ore Formed Pelage Drops let to Failure Venezuelan Ore Fines 100. 00

II+III Venezuelan Ore Fines 100.00 10.8 35. 34

Hydrated Lime 5.00 0. 20 0. 50 11. 00

IV+V Venezuelan Ore Fines 100. 00 10. 5 37. 32

Hydrated Lime 5.00 Calcium Chloride 0. 20 Molasses 0. 50 Sodium Hydroxide- 0. 27 10. 00

Table V11 Tumbler Test: Percent Parts on Dry Wgt. Retained on a 0.371 Mesh Batch Materials of Ore Sieve After 200 Revolutions in an A.S.T.M. Tumbler I Magnetite Concentratcs 100.00

Hydrated Lime 5.00 59; 56% CaCl 0.20 Control Hi 5.93

II Magnetite Concentrates..." 100. 00 Hydrated Lime 5.00 05.0 O. "Control 68; 65% Molasses 0. 50 E 0 5.49

III Magnetite C0ucentrates. 100.00 Hydrated Lime 5.00 C8012 0.20 Molasses 0.50 79; 77%

ea 0. E10 5. 38

IV Magnetite Concentrates 100.00 Hydrated Lime 5.00 09.012 0.20 Molasses 0. 75% Ammonium Hydroxide 0. 25 E10 5. 16

V Magnetite Concentrates 100. 00 Hydrated Lime 5.00 03012 0. 20 73% Molass 0. 50 Sodium Hydroxide" 0. 20 2O a 4. 93

VI Magnetite Concenrrates 100. 00 Hydrated Lime. 5. 00 09.01 0.20 Molasses 0. 50 71% Potassium Sulfa 0.75 H20 5. 16

The combination of an alkaline earth solubilizing agent such as molasses with a basic compound of an alkali metal or ammonium, a hydroxide of calcium or magnesium and an ore appears to have a profound synergistic eflect in producing high green strength and high cured strength. Both of these properties are of great impor-- tance in the industry. Moreover, a lesser amount of water in the forming process is needed and, therefore, less drying prior to carbonation. In addition, the alkali metal compounds appear to have some favorable desulfurizing action since they are fixed in the mixture adjacent to the ore and are immediately available to react as the-sore is melted.

In the foregoing specification, I have set out certain preferred practices and embodiments of my invention, however, it will be understood that the invention may be otherwise practiced within the scope of the following claims:

I claim:

1. The method of producing lump ore from finely divided iron containing materials, comprising the steps of admixing the finely divided material with at least one of the group consisting of the oxides and hydroxides of alkaline earth metals and with a material capableof' solubilizing alkaline earth metals selected from the group consisting of water soluble carbohydrates and the sodium salt of ethylene-diamene tetraacetic acid, and at least 0.1% of an alkaline compound selected from the group consisting of alkali metal oxides and hydroxides, ammonium compounds and amines, forming the mixture into lumps and reacting the resulting lumps with carbon dioxide in the presence of moisture to form alkaline earth carbonates prior to charging in a metallurgical furnace.

2. The method of producing lump ore from finely divided iron-containing materials, comprising the steps of admixing the finely divided material with at least one of the group consisting of the oxides and hydroxides of alkaline earth metals and mixtures thereof, with a sugar containing material, and at least 0.1% of an alkaline compound selected from the group consisting of alkali metal oxides and hydroxides, ammonium compounds and amines, forming the'mixture into lumps, and reacting the resulting lumps with carbon dioxide in'the presence of moisture to form alkaline earth carbonates prior to charging in a metallurgical furnace;

3. Themethod of producing lump ore fromfinelv divided iron-containingmaterials, comprising the steps of admixing the finely divided-material with at least one of the group consistingof theoxidesand hydroxides of alkaline earth metals and a material capable of solubilizing alkaline earth metals selected from the group consisting of water soluble carbohydrates and the sodium salt of ethylene-diamene tetraacetic' acid, and at least 0.1% of an alkaline compound selected from the group consisting of alkali metal oxides and hydroxides; ammonium compounds and amines, formingthe mixture 'into' lumps" and reacting the resultingmixture with carbonic acidgas in the presence of up to about 10% moisture and at least one soluble salt from the group coiisi'stingof the chlorides; sulfates and carbonatesof alkali" metals,--alkaline' earth metals and iron to form alkaline earth carbonates prior to charging in a metallurgical furnace.

4. The method- 0f producing lump iron ore from finely divided iron-containing materials; comprisingthe steps of admixing the finely divided material with at least one of the oxides and hydroxides of calcium together with at least one starch containing material, and at least 0.1% of an'alkali metal hydroxide 'and'reacting the'resulting mixture with carbon dioxide in the presence of'up to about 10% moisture prior to charging .in-a metallurgical furnace whereby to form calcium carbonatein the formed lumps.

5. The method of producing lump iron ore from finely divided iron-containing materials, comprising the steps of admixing the finely divided material with at least one of the oxides and hydroxides of calcium, glucose, and with at least 0.1% of an alkali metal hydroxide in the presence of moisture, forming the resulting mixture into lumps and reacting the formed lumps prior to charging in a metallurgical furnace with carbonic acid gas in the presence of up to about 10% moisture to cause crystallization of calcium carbonate in the interstices of the formed lumps.

6. The method of producing lump iron ore from finely divided iron-containing materials, comprising the steps of admixing the finely divided material with at least one of the oxides and hydroxides of calcium, maltose, and with at least 0.1% of an alkali metal hydroxide in the presence of moisture, forming the resulting mixture into lumps and reacting the formed lumps prior to charging in a metallurgical furnace with carbonic acid gas in the presence of up to about 10% moisture to cause crystallization of calcium carbonate in the interstices of the formed lumps.

7. The method of producing lump iron ore from finely divided iron-containing materials, comprising the steps of admixing the finely divided material with at least one of the oxides and hydroxides of calcium, dextrose, and with at least 0.1% of an alkali metal hydroxide in the presence of moisture, forming the resulting mixture into lumps and reacting the formed lumps prior to charging in a metallurgical furnace with carbonic acid gas in the presence of up to about 10% moisture to cause crystallization of calcium carbonate in the interstices of the formed lumps.

8. The method of producing lump iron ore from finely divided iron-containing materials, comprising the steps of admixing the finely divided material with at least one of the oxides and hydroxides of calcium, fructose, and with at least 0.1% of an alkali metal hydroxide in the presence of moisture, forming the resulting mixture into lumps and reacting the formed lumps prior to charging in a metallurgical furnace with carbonic acid gas in the presence of up to about 10% moisture to cause crystallization of calcium carbonate in the interstices of the formed lumps.

9. The method of producing lump iron ore from finely divided iron-containing materials, comprising the steps of admixing the finely ground material with at least one of the group consisting of the alkaline earth metal oxides and hyrdoxides in an amount equivalent to about 2% to 8% of oxide based on the dry weight of the 'ore, from about 0.025% to 2% by Weight of a solubilizing agent for alkaline earth metals selected from the group consisting of water soluble carbohydrates and the sodium salt of ethylene-diamene tetraacetic acid, and about 0.1 to 0.5% of a material selected from the group consisting of alkali metal oxides and hydroxides, amines and ammonium hydroxide, forming the resulting mixture into lumps in the presence of up to about 10% moisture, and reacting the formed lumps with carbon dioxide to convert at least a part of the admixed member of the group oxide and hydroxide to carbonate, prior to charging in a metallurgical furnace.

References Cited by the Examiner UNITED STATES PATENTS 2,914,394 11/59 Dohmen --3 2,931,717 4/60 Lee 753 2,996,372 8/61 Imperato 75-3 BENJAMIN HENKIN, Primary Examiner.

Claims (1)

1. THE METHOD OF PRODUCING LUMP ORE FROM FINELY DIVIDED IRON CONTAINING MATERIALS, COMPRISING THE STEPS OF ADMIXING THE FINELY DIVIDED MATERIAL WITH AT LEAST ONE OF THE GROUP CONSISTING OF THE OXIDES AND HYDROXIDES OF ALKALINE EARTH METALS AND WITH A MATERIAL CAPABLE OF SOLUBILIZING ALKALINE EARTH METALS SELECTED FROM THE GROUP CONSISTING OF WATER SOLUBLE CARBOHYDRATES AND THE SODIUM SALT OF ETHYLENE-DIAMENE TETRAACETIC ACID, AND AT LEAST 0.1% OF AN ALKALINE COMPOUND SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL OXIDES AND HYDROXIDES, AMMONIUM COMPOUNDS AND AMINES, FORMING THE MIXTURE INTO LUMPS AND REACTING THE RESULTING LUMPS WITH CARBON DIOXIDE IN THE PRESENMCE OF MOISTURE TO FORM ALKALINE EARTH CARRBONATES PRIOR TO CHARGING IN A METALLURGICAL FURNACE.