FI60722B - FOER FARING FOER BEHANDLING AV TITANHALTIGA JAERNMALMER OCH SLIG - Google Patents

Description

• 4 & r »| [11] NOTICE OF ADVERTISEMENT

LJ UTLAGGNINGSSKRIFT Ου (£. /.

• C (45) Patents granted 10 03 1932 \ J% AdFj Patent meddelat ^ ^ (51) Kv.ik.3 / int.ci.3 C 22 B 34/12 FINLAND - FINLAND (21) P «» "« | h »| '·"' "* - p« «nt» n * öknin | 1081/71 + (22) H »k« mlspl) vt - Ansöknlnpdaf 09-0H.7h

(23) AlkupUv »—Glltlfhetidi * O9.Oli.7U

(41) Tullut lulklMktl - Bllvlt offentllj 12.10.7¼

Patent and Registration Office . .

_ ^. , (44) N »ht * v» k * lp «i * is j» moon. | Ullulsun pvm. -

Patent- och registerstyrelsen 'Anrtkin utlijd oeh utl.tkrlfun publicerad 30.11.81 (32) (33) (31) Pyydetty «tuolta» - Begird prloritct 11.0U. 7 3

Canada (CA) 168670 (71) SociSt £ Quebecoise d’Exploration Miniere, 2U06, des Quatre-Bourgeois,

Sainte Foy, Quebec, G1V 1W5 Canada (CA) (72) Joseph Palmer, Gatineau, Quebec, Guy Handfield, Loretteville, Quebec,

Canada (CA) (7¼) Berggren Oy Ab (5¼) Method for the treatment of titanium-containing iron ores and concentrates - Förfarande för behandling av titanhaltiga järnmalmer och slig

The present invention relates to a process for the treatment of titanium-containing iron ores and concentrates made from these ores. After processing, these ores can be used directly as a raw material in steelmaking. Alternatively, however, the treated ore may be pre-reduced and separated magnetically or by any other suitable method to produce a purified concentrate that can be treated to produce steel and titanium-rich slag.

It is known that certain titanium-bearing ore precipitates contain large amounts of titanium and are called ilmenites and are used to produce titanium dioxide in a state that can be used as a pigment. It is also known that other titanium-bearing ore deposits, such as titanium-containing magnetites, contain a relatively large amount of iron and should normally be considered a good source of iron for steelmaking. Such ores are commonly referred to as titanium-containing iron ores. They contain impurities such as oxides of titanium, chromium and vanadium and are therefore not normally used in the manufacture of steel 2 60722. As a result, it is desirable to provide a method by which most of the harmful impurities together with the side rock can be separated and thus make the ore suitable for the production of steel and slag rich in titanium oxide. In this context, the expression "titanium-containing iron ore" also includes ores containing small amounts of oxides, such as oxides of chromium and vanadium, with an iron content of more than 40% and a titanium content of less than 25% ·

As is known to the person skilled in the art, several methods can effectively separate titanium dioxide from ilmenite ores, but they cannot be used effectively in the case of titanium-containing iron ores. However, these ores can now be processed by the method according to the invention. In addition, this method requires only conventional simple processing equipment that is commonly marketed.

According to the present invention, this new method allows the treatment of titanium-containing iron ores, whereby iron can be separated from chromium, aluminum, vanadium and other metals, which are recovered and separated due to their high commercial value. Consequently, the process according to the invention is such that it makes it possible to prepare an iron concentrate which is suitable for use in the manufacture of iron and steel and also enables the recovery of valuable impurities.

In general, the process of the invention comprises roasting finely divided titanium-containing iron ores or concentrates in an oxidizing atmosphere and in the presence of a roasting agent prepared from a mixture of a sodium oxide-forming compound and calcium or magnesium oxides or a calcium or magnesium oxide-forming compound, valuable oxides such as chromium , are converted into soluble salts which are extracted from the ore.

The roast obtained in the roasting step is extracted with an alkaline solution in order to dissolve valuable salts, such as chromium, vanadium and aluminum salts, which can be recovered later from the alkaline solution, leaving a solid residue containing 3,60722 mainly iron oxide, calcium and magnesium aluminates, silicates and amount of calcium titanate.

The extracted residue is then reduced. The iron oxide content of the residue is converted to metal iron while the other constituents are only affected in small amounts during the reduction. After grinding the reduced mass, the ferrous metal can be separated by means of a magnetic separator or some other well-known separation device. The magnetic concentrate thus obtained is then melted, so that pure iron can be recovered and used in the production of steel, while the residual slag with a high titanium content is suitable for the production of titanium dioxide pigments.

The titanium-containing iron ores or concentrates which can be treated in accordance with the invention are those having an iron content of at least 40% and a titanium dioxide content of not more than 25%. occurring in the province of Quebec and having the following analysis:

Malmi "A" Malmi "B" Malmi 11C "

Fri total * 49.0 54.0 60.0

TiO 2 11.9 19.15 13.0 Al 2 O 3 10.0 6.55 6.2

Cr 2 O 3 1.6 0.51 0.2 V 2 O 5 0.42 0.57 1.1

SiO 2 2.2 0.63 2.3

MgO 6.02 3.17 0.9

CaO 0.18 0.27 0.4 * Iron oxides are based on the total amount of iron.

Titanium-containing iron ore is ground to a particle size of 0.42-0.13 mm in a conventional grinding machine.

The ground titanium-containing iron ore is then pretreated for the roasting step by mixing it with a roasting agent prepared from a sodium oxide-forming compound and calcium or magnesium oxide or a calcium or magnesium oxide-forming compound 4 60722 or a mixture of calcium oxide and magnesium oxide. As the sodium oxide-forming compound, there can be mentioned compounds which decompose into sodium oxide at high temperatures, such as sodium carbonate, sodium bicarbonate, sodium hydroxide or mixtures thereof. As the calcium or magnesium oxide-forming compound, there can be mentioned compounds which decompose at high temperatures into calcium or magnesium oxide, such as calcium carbonate or calcium hydroxide or mixtures thereof, or magnesium carbonate or magnesium hydroxide or mixtures thereof. As an example of the compound forming a mixture of calcium oxide and magnesium oxide, dolomites, which are mixtures of calcium and magnesium carbonates, can be mentioned.

The amount of sodium oxide or sodium oxide-forming compound used according to the invention is proportional to the initial amount of chromium oxide, vanadium oxide and alumina in the titanium-containing iron ore. It can be used in stoichiometric amounts, but an excess of 5-50% over stoichiometric amounts is most preferred. The stoichiometric amount is calculated as follows:

Na 2 O (moles) = 2 x Cr 2 O 3 (moles) + 3 x V 2 O 3 (moles) + Al 2 O 3 (moles)

The amount of calcium oxide or magnesium oxide-forming compound used in accordance with the present invention is proportional to the initial amount of silica and titanium dioxide in the titanium-containing iron ore. It is used in stoichiometric amounts, but for better results it is most preferred to use an excess of 5-30% over the stoichiometric amount. The stoichiometric amount is calculated as follows:

CaO or MgO (moles) = 2 x SiO 2 (moles) + TiO 2 (moles) - (CaO - MgO) (moles present in the ore).

In order to treat the ground titanium-containing iron ore for the roasting step, it is preferable to mix the ground titanium-containing ore with a moist roasting agent which acts as a binder for the purpose of forming spheres, briquettes or flakes. The spheres or briquettes are formed in a suitable spheron forming or brike actuator to produce spheres or briquettes having a volume of approximately 1 cm 2.

5,60722

The spheres, briquettes, or flakes are then passed into an open vessel where air circulation is promoted to provide an oxidizing atmosphere. If desired, oxygen can be used to enhance the oxidation cycle. Roasting of balls, briquettes or flakes is carried out at a temperature of 800-1300 ° C for 1 / 2-3 hours.

The resulting calcine is a porous mass whose porosity increases as the amount of calcium or magnesium oxide used increases. The roast is ground before extraction.

The ground calcine is then extracted with an aqueous solution of sodium carbonate containing a small amount of sodium hydroxide. The composition of the solution depends on the amounts of the three calcium aluminates 12CaO., 3CaO.Al20-j, 4CaO.Al20-j.Pe20 ^, calcium chromate CaCrO ^ and calcium vanadate Ca ^ IVO ^ ^ formed during roasting. It is known that the higher the roasting temperature, the more likely the above compounds are to be formed.

An extraction solution containing 5-75 g / l Na 2 CO 2 and 2-10 g / l NaOH has been found to be satisfactory for extracting a roast containing 2-12% alumina roasted at a temperature of 900-1200 ° C. The amount of extraction solution added to the calcine is such that the liquid to solid ratio is approximately 3: 1.

Filtration is carried out using suitable equipment, such as a conventional vacuum filter. In order to recover more soluble salts, the filter cake is washed with hot water (40-70 ° C) and the filtrates are combined.

The combined filtrates containing a mixture of soluble sodium chromate, aluminate and vanadate are set aside for further processing to recover chromium, aluminum and vanadium in the form of sodium salts and oxides using methods well known in the art.

After drying, the solid residue is then heated under reducing conditions to reduce the iron oxide to a lower oxidation state, allowing recovery of the ferrous metal and a few oxides formed by magnetic separation. This reduction is carried out in the presence of a reducing agent such as hydrogen, carbon monoxide or a mixture thereof, or in the presence of a carbonaceous compound which is a suitable reducing agent such as coal, coke or oil. The amount of reducing agent is preferably greater than the stoichiometric amount required to convert the iron oxides to ferrous metal. Depending on the reducing agent used, the temperature varies between 700-1300 ° C. For example, when using hydrogen, the temperature is above 700 ° C, when using carbon monoxide, the temperature is above 900 ° C, and when using coal or coke, the temperature is above 1000 ° C. The reduction is carried out between 30 minutes and 4 hours.

The reduced material thus obtained is then ground to a particle size of about 325 (mesh) and then passed through a magnetic separator to recover the ferrous metal magnetic concentrate, and non-magnetic wastes containing mainly calcium and magnesium aluminates and silicates and also a small amount of calcium titanate are removed. the magnetic fraction from the other side, which is obtained after the melt-formed titania and PROGRAM OF separation, is suitable for use in the manufacture of steel, whereas titanium dioxide slag can be used in the manufacture of titanium dioxide pigment.

The method according to the invention can be better understood from the following examples thereof, which are presented only to illustrate the invention but not to limit it.

Example I

The titanium-bearing ore used as the starting material is called "ore A" and was obtained from the Canadian province of Quebec and was analyzed as follows:

Elements Weight% Gram mole / 100 g

Fri 49.0 0.878 in total

TiO2 11.9 0.1487 ai2o3 10.0 0.098

Cr203 1.60 0.0105 V205 0.42 0.00231

SiO 2 2.2 0.0366

MgO 6.02 0.1494

CaO 0.18 0.00321 7 60722 1. Preparation of the initial charge

The ore (100 g) was ground to 100% fineness below 0.13 mm in a conventional grinder. Any technical grade of sodium carbonate and calcium carbonate is suitable for roasting, but reagent grade was used in this experiment and no grinding was required. Any conventional crushing or grinding equipment can be used on a factory scale. This material was then mixed with the required amount of reagents, i. Na2 and CaO-forming materials. The required amounts of reagents were determined as follows.

The ore was ground in a conventional grinder until 100% passed through a 0.13 mm sieve. In order to obtain the best possible contact between water-soluble Na 2 O 2 and ore, the following mixing procedure was used. 15> 0 g of Na 2 CO 3 and 7.7 g of CaCO 3 were mixed together in a separate vessel, after which the dry mixture was passed into a shallow pan containing 30 ml of water and 100 g of ground ore and the ingredients were mixed together until a slurry was obtained. The vessel containing the slurry was placed in an oven which was heated to 125 ° C for 6 hours, and when all the water had evaporated, a hard, solid mixture of ore and roasting agent was obtained. This solid mass was removed and crushed into small particles with a volume of about 1 cm 2.

The amounts of frying agents were calculated as follows:

Na 2 O (moles) = 2 x Cr 2 O 2 (moles) + 3 x V 2 O 3 (moles) + Al 2 O 2 (moles) = 2 x 0.011 + 3 x 0.00231 + 0.098 = 0.128 g-moles Using a 10% excess of 0.128 x 1.1 = 0.14 g-moles = 0.141 x 106 (Na 2 CO 3) = 15 g Na 2 CO 5 CaO (moles) = 2 x SiO 2 (moles) + TiO 2 (moles) - (MgO + CaO) moles = 2 x 0, 0366 + 0.1487 - (0.1494 + 0.00321) = 0.0693 g-moles 8 60722 Using a 10% excess of 0.0693 x 1.1 = 0.0714 g-moles = 0.0714 x 100 , 1 (CaCO 3) = 7.63 g CaCO 2 2. Batch roasting a) Apparatus

The roasting pan was formed from a vessel made of iron tube with a diameter of 15 cm, in the middle of which a perforated plate with a diameter of 15 cm was fitted. A 12.7 mm tube was fitted through the center of the perforated plate and screwed to the bottom of the tube section. Between the perforated plate and the bottom of the 12.7 mm pipe, four 6.3 mm holes were drilled in the perimeter of the pipe for the introduction of air.

The roasting vessel was fitted in a muffle furnace and the crucible was connected to a cylinder containing compressed air via a 2.5 cm outlet of the furnace. Rotary ovens, shaft ovens and stove ovens can be used for roasting.

(b) Roasting method

A roasting vessel containing ore and roasting agent was placed in a cold oven. The electric power was then turned on and the oven was allowed to reach a temperature of 800 ° C in about an hour. At this temperature, 50 ml of air per minute was continuously passed under the perforated plate and through the roasting vessel. When the desired temperature (1150 ° C) was reached, the oven temperature was kept constant for 2 hours. The supply of air and electricity was then stopped and the roasting vessel was allowed to cool in an oven to give 110 g of a porous dark brown mass, which was then ground in a conventional grinder to a size of 0.25 mm.

3 · Extraction of roasted material To 110 g of ground roasted material was added 300 ml of an extraction solution prepared from 40 g of Na 2 CO 3 and 10 g of NaOH dissolved in 1 liter of water. This mixture was stirred continuously and maintained at 70-80 ° C for 4 hours.

Filtration was performed using conventional vacuum filtration and the filter cake was washed several times with hot water (40-70 ° C) to achieve optimum recovery of soluble salts from the ore.

9 60722

The filtrate containing a mixture of sodium chromate, aluminate and vanadate was recovered for further processing to recover chromium, aluminum and vanadium in the form of sodium salts and oxides according to methods known in the art.

The products obtained from the extraction step of the roasted material are a metal-containing solution and a solid residue which can be further processed.

4. Treatment of the metallic solution

The metal-containing solution contains most of the valuable chromium, vanadium and aluminum salts, as well as the sodium salts. These valuable salts can be recovered from solution using conventional techniques well known in the art. Similarly, sodium salts can be recovered from solution and recycled in the process of the invention.

5 · Solid residue treatment

The solid residue is heated under reducing conditions to reduce the iron oxide to a lower oxidation step, allowing the ferrous metal and a few oxides formed to separate from the non-magnetic side rock material. The reduction is performed in the presence of carbonaceous material.

A horizontal tube furnace was used for the reduction. 50 g of material was mixed with 12.5 g of graphite powder and placed in an alumina crucible. The oven was gradually heated to 1200 ° C and maintained at this temperature for 2 hours. The power was then turned off and the oven was allowed to cool. When the oven temperature reached 150 ° C, the alumina crucible and the reduced material therein were removed from the oven. Rotary kilns, shaft kilns and fluidized bed furnaces are a few of the embodiments that can be used in this reduction.

The reduced material was then ground to a particle size of 0.078 mm in a conventional grinder and separated magnetically (Davis tube). Any separation device based on magnetic separation, difference in specific gravity, wetting properties, etc. can be used in this separation.

10 60722

Analysis of reduced ore concentrate% Fe (metal) 7 * 1% Fe total 75% SiO 2 0.96% TiO 2 12.0% Al 2 O 3 3.31% Cr 2 O 3 0.89% V 2 O 5 nd *% MgO 4.2% CaO 2.29% Na 2 O, 18 98.83 xn.d .: could not be determined.

Example 2 The starting titanium-bearing ore, designated "ore B", was obtained from the Canadian province of Quebec and was analyzed as follows:

Elements Weight% Grams per mole / 100 g

Fe total 54.0 0.968

TiO 2 19.15 0.240 Al 2 O 5 6.55 0.0642

Cr203 0.51 0.00336 V205 0.57 0.00313

SiO 2 0.63 0.0105

MgO 3.17 0.0787

CaO 0.27 0.00481

The reagents and grinding technique used were similar to Example 1. The amounts of reagents used to prepare the roaster were calculated as follows:

Na 2 O (moles) = 2 x Cr 2 O 3 (moles) + 3 x V 2 O 3 (moles) + N 2 O 2 moles) = 2 x 0.00336 + 3 x 0.00313 + 0.0642 = 0.0803 g moles Using 10% excess 0.0803 X 1.1 = 0.0883 g-moles 0.0883 x 106 = 9.36 g Na 2 CO 3 60722

CaO (moles) = 2 x SiO 2 (moles) + TiO 2 (moles) - (MgO + CaO) moles = 2 x 0.0105 + 0.240 - (0.0787 + 0.00481) = 0.1775 g-moles Using a 10% excess of 0.1775 x 1.1 = 0.1552 g-mole = 0.1952 g-mcclia x 100 (CaCO 7) = 19.5 g CaCO 3 To 100 g of ore was added 9.36 g Na 2 CO 3 and 19.5 g CaCO 2. The mixing, roasting, extraction, reduction and magnetic separation steps were performed in the same manner as in Example 1 to obtain an iron ore concentrate having the following analysis:

Analysis of reduced ore concentrate% Fe (metal) 74% Fe total 76% SiO 2 0.66% TiO 2 17.3% Al 2 O 3 1.51% Cr 2 O 3 0.47% V 2 O 5 ND *% MgO 2.29% CaO 2.00% Na 2 O 0 , 05 100.28 xn.d .: not detectable.

Example 3 The starting material, designated "ore C", was obtained from the province of Quebec *. The analysis of this ore was as follows:

Elements Weight -% _ Grams per mole / 100 g

Fe 60 1.0743

TiO 2 13.0 0.1627 Al 2 O 3 6.2 0.0608

Cr 2 O 3 0.2 0.0013 v2o5 1.1 0.0060

SiO 2 2.3 0.0383

MgO 0.9 0.0223

CeO 0.4 0.0071 1S 60722 The roasting step and grinding technique used were the same as in Example 1 except that a mixture of sodium carbonate and magnesium carbonate was used as the roasting agent. The amounts of reagents in which the roasting agent was formed were calculated as follows:

Na 2 O (moles) = 2 x Cr 2 O 3 (moles) + 3 x V 2 O 2 (moles) + Al 2 O 3 (moles) = 2 x 0.0013 + 3 x 0.0060 + 0.0608 AlgOj = 0.08l4 moles Using 10% excess 0.08l4 x 1.1 = 0.0895 0.0895 x 106 = 9.49 g Na 2 CO 5 MgO (moles) = 2 x SiO 2 (moles) + TiO 2 (moles) - (MgO + CaO) moles = 2 x 0.0383 + 0.1627 - (0.0223 + 0.0071) = 0.2099 g-moles Using a 10% excess of 0.2099 x 1.1 = 0.2309 moles 0.2309 g-moles x 84.32 (MgCO 3) = 19.46 g MgCO 3 To 100 g of ore were added 949 g Na 2 CO 3 and 19.46 g MgCO 3. The mixing, roasting, extraction, reduction and magnetic separation steps were performed in the same manner as in Example 1 to obtain a reduced iron ore concentrate having a higher ferrous metal content than that shown in Example 2.

Claims (4)

13 6072? A process for the treatment of titanium-containing iron ore, in particular magnetite or concentrate, with a total flux content of at least 40% and a titanium dioxide content of less than 25%, containing oxides of chromium, vanadium, aluminum, silicon, titanium, calcium and magnesium, by roasting this ore or concentrate in an oxidizing atmosphere, by extracting the roast, reducing the solid residue obtained during the extraction and recovering the ferrous metal concentrate, characterized in that the roasting step of finely divided titanium-containing iron ore is carried out in the presence of a roasting agent prepared from (1) sodium oxide and is selected from the group consisting of calcium oxide, magnesium oxide, a calcium oxide-forming compound, a magnesium oxide-forming compound, and mixtures thereof, wherein the sodium oxide-forming compound corresponds to at least a stoichiometric amount calculated as sodium oxide according to the following formula Na 2 O (moles) = 2 x CrnO, (moles) + 3 x Vo calculated as magnesium oxide according to the following formula: CaO or MgO (moles) = 2 x SiO 2 (moles) + TiCl 2 (moles) - (CaO + MgO) (moles in ore or concentrate). Process according to Claim 1, characterized in that the roasting is carried out in the presence of a mixture of sodium oxide and calcium oxide. 1. A method for the treatment of titanium dioxide, a special magnet or a concentrate, a total of 40% and 25% of titanium dioxide, respectively, of 25% or more of oxide from chromium, vanadium, aluminum, kisel, titanium, calcium and magnesium, genome the ore or concentrate in an oxidized atmosphere, with the addition of the iron ore or concentrate, with the reduction of the paste remaining in the extraction and with the refining of the ferrous metal concentrate,