CN112553457B

CN112553457B - Method for preparing titanium-rich material from titanium middling

Info

Publication number: CN112553457B
Application number: CN202011186492.XA
Authority: CN
Inventors: 陈建立; 李珍珍; 陈树忠; 贺高峰; 豆君
Original assignee: Henan Billions Advanced Material Co Ltd
Current assignee: Henan Billions Advanced Material Co Ltd
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2022-08-09
Anticipated expiration: 2040-10-30
Also published as: AU2021254548B2; CN112553457A; ZA202107984B; AU2021254548A1

Abstract

The invention discloses a method for preparing a titanium-rich material from titanium middlings, wherein the titanium middlings comprise titanium minerals and weak magnetic gangue minerals, and the method comprises the following steps: s1, contacting titanium middling with a reducing agent, and deeply reducing to enable Fe in the titanium middling to be Fe ²⁺ And/or Fe ³⁺ Reduction to Fe wholly or partially ⁰ Fe in weakly magnetic gangue minerals ²⁺ And/or Fe ³⁺ Keeping the non-reduction state to obtain reduced titanium middling; s2, carrying out magnetic separation on the reduced titanium middling, and separating to obtain a reduced ferrotitanium material and tailings containing weak magnetic gangue minerals; and S3, further preparing the reduced ferrotitanium material to obtain a titanium-rich material. The invention is beneficial to magnetic separation by increasing the magnetic difference between the reduced ferrotitanium material and the weak-magnetic gangue minerals. Then the deep reduction of the titanium middling purification and the deep reduction of the ilmenite for preparing the high-purity titanium-rich material are combined, so that the process route is shortened, the production cost is reduced, and the industrial production is easy to realize.

Description

Method for preparing titanium-rich material from titanium middling

[ technical field ] A method for producing a semiconductor device

The invention belongs to the technical field of metallurgy and mineral processing, and particularly relates to a method for preparing a titanium-rich material from titanium middling.

[ background of the invention ]

Titanium dioxide is the white pigment with the best performance at present, and is widely applied to the fields of paint, rubber, plastics, papermaking, printing ink and the like. Its production mainly includes two processes, sulfuric acid process and chlorination process. The production process of titanium dioxide by a chlorination process is a new generation advanced technology which is internationally recognized to replace a sulfuric acid process due to environmental protection and high product quality in the production process. At present, the production of titanium dioxide by the sulfuric acid method in China is moving to the middle and high end, the application field of products is completely covered, the titanium dioxide by the chlorination method is broken through and deeply developed in recent years, and the production process is substantially improved.

Ilmenite is an extractThe main mineral for refining titanium and producing titanium dioxide is FeTiO ₃ But also contains other impurity minerals such as CaO, MgO and SiO ₂ 、Al ₂ O ₃ 、MnO ₂ 、V ₂ O ₅ 、Cr ₂ O ₃ And the like, and the presence of these impurity elements can affect the quality of the ilmenite product. The titanium white produced by the chlorination process has very strict requirements on raw materials, particularly has higher requirements on impurity content, such as CaO, MgO and SiO ₂ 、Al ₂ O ₃ 、MnO ₂ 、V ₂ O ₅ 、Cr ₂ O ₃ And the like. Generally speaking, if trace impurities such as iron, cobalt, chromium and copper are mixed into titanium dioxide, the whiteness of the titanium dioxide is reduced, because the existence of the impurities ions, especially metal ions, can distort the crystal structure of the titanium dioxide and lose the symmetry, and the rutile type titanium dioxide is more sensitive to the appearance of the impurities, wherein if the titanium is rich in chromium (Cr), the rutile type titanium dioxide is more sensitive to the impurities ₂ O ₃ ) The content is higher than 0.15 percent, and the method cannot be used for producing titanium white by a chlorination process.

However, as the titanium dioxide production capacity is continuously increased and ilmenite is continuously mined and used, ilmenite directly used for producing high-quality titanium-rich materials is gradually reduced. However, there are currently a number of high chromium titanium resources worldwide, such as: ilmenite with a wide alluvial product and a coastal deposit on or near the coast of the Mediterranean sea along the protruded Nile river Delta has high chromium content, and a large amount of chromium-containing titanium resources exist in Mornebick, Australia and Vietnam. The research on how to use ilmenite with high impurity content and low titanium grade to produce high-quality raw materials for the chlorination process has important significance for the development of the chlorination process.

Seashore placer is the most industrially valuable titanium sand deposit, 30% of ilmenite in the world comes from seashore placer, which mainly has coastal sedimentary placer, and has the characteristics of various mineral types, high monomer dissociation degree, uniform particles, small mud content and the like, and the main useful minerals include ilmenite, zirconite, rutile, monazite, leucolite, anatase and the like. The main impurity minerals comprise chromite, titanopentite, maghemite, iron nodule, limonite, hematite, pyrite and the like. The main gangue minerals include quartz, feldspar, tourmaline, garnet, andalusite, topaz, kyanite, apatite, kaolin, etc. (chromite, titandiopside, etc. are also gangue minerals in seashore placer). The common process flow of the concentration of the seaside placer is the traditional combined flow of gravity separation, dry magnetic separation and electric separation.

TABLE 1 physical Properties of Weak magnetic gangue minerals and ilmenite

For titanium resources containing weak magnetic gangue minerals, the physical properties (shown in table 1) of the weak magnetic gangue minerals such as chromite, titandiopside, garnet and ilmenite are very close, the separation of the minerals by using a conventional physical separation method is very difficult, and most of the weak magnetic gangue minerals are enriched along with the ilmenite, so that the impurity content in the titanium concentrate exceeds the requirement of being used as a raw material for producing titanium dioxide and is not utilized, and the waste of resources is caused.

At present, the titanium concentrate (middling) ore of the titanium resource can only be stockpiled in a tailing form because the chromium content exceeds the requirement of being used as a titanium dioxide raw material. Chromium in ilmenite (neutral) generally exists in the form of chromite and belongs to a monomer dissociation mineral. Because the physical properties of ilmenite and chromite are similar, the chromite in the ilmenite cannot be well separated by adopting the conventional modes of gravity separation, magnetic separation, electric separation or combination of the three, so that how to remove impurities in the ilmenite and obtain high-quality titanium concentrate has extremely important significance for comprehensive utilization of titanium raw materials.

At present, the titanium middling is treated mainly by oxidizing, magnetizing and modifying the titanium middling, and the separation effect is poor because the process conditions are limited and difficult to control. Austpac resources Inc. studies two ilmenite magnetizing roasting methods, called ERMS roasting method and LTR roasting method, respectively. The ERMS roasting method (US5595347 'Process for Separating Ilmenite') is to roast Ilmenite under high temperature (750-950 ℃) and controlled oxygen partial pressure for about 60min, and the roasted Ilmenite is cooled under the oxygen-deficient condition. Is calcined toThe magnetic susceptibility of ilmenite is increased, TiO in the ore ₂ The titanium concentrate is acidinsoluble and roasted ore is easy to magnetically separate gangue minerals, so that the quality of the titanium concentrate is improved. The roasted concentrate is suitable for producing artificial rutile or smelting titanium slag. The LTR roasting method is to roast ilmenite at a low temperature of less than 650 ℃ for 20-30 min, so that the magnetization rate of the ilmenite is increased and TiO in the ilmenite is reduced ₂ The roasted ore is easy to magnetically separate to remove gangue minerals and improve the quality of the titanium concentrate, and the roasted concentrate is suitable for producing titanium white by a sulfuric acid method. The ERMS roasting method is strong oxidation-weak reduction roasting, and the roasted ore is used for manufacturing artificial rutile by a hydrochloric acid leaching method.

"thermodynamic analysis of ilmenite magnetizing roasting separation" ("ferrous metallurgy" vol.34, 3 rd and 6 th 2013) of Liuyunlong et al adopts oxygen or air to oxidize and roast ilmenite to generate Fe ₂ O ₃ And Fe ₂ TiO ₅ Then, CO with lower concentration can be used to reduce the Fe ₃ O ₄ Then ball milling is carried out by using a ball mill, and iron concentrate powder and titanium slag can be obtained by means of magnetic separation, so that the purpose of iron-titanium separation is achieved.

Wangming and other ' research on selection test of ilmenite abroad ' (2015 university of Kunming university of Master ' academic thesis) mixed rough concentrate of ilmenite and chromite is subjected to oxidizing roasting by adopting a rotary kiln, a fluidized bed or a fluidized bed furnace under roasting process parameters of 770 ℃ of operation temperature, 3.0Kg/h of quick feeding speed and 36 minutes of corresponding average retention time, and is naturally cooled, so that titanium can be well enriched. The minerals enriched by the oxidizing roasting are subjected to dry separation on a dry magnetic separator with a magnetic field of 0.3t, so that the titanium grade is 47.94%, the recovery rate is 78.52%, and the Cr content is obtained ₂ O ₃ It is 0.23% titanium concentrate.

Chinese patent CN103316761B discloses a separation method of ores containing ilmenite and chromite, which mainly aims at seashore heavy placer containing ilmenite and chromite, and the separation method comprises the steps of pre-selecting ores to respectively enrich ilmenite and chromite into chromium-titanium-containing middlings, oxidizing roasting to change the magnetism of ilmenite, and performing magnetic separation on chromite and ilmenite to obtain chromium concentrate and titanium concentrate.

The existing research mainly focuses on increasing the magnetism of ilmenite through a weak oxidation method, a magnetic separation and mineral separation method is adopted to remove chromite and the like to produce high-grade titanium concentrate, the technology for increasing the magnetism through the weak oxidation of the ilmenite has strict requirements on oxidation temperature, oxygen content and time, is not beneficial to large-scale industrial production, and meanwhile, the titanium concentrate purification process is not combined with the subsequent titanium concentrate deep processing process.

[ summary of the invention ]

The invention aims to provide a method for preparing a titanium-rich material from titanium middling to overcome the defects in the prior art.

The purpose of the invention is realized by the following technical scheme:

a method for preparing a titanium-rich material from titanium middlings, wherein the titanium middlings comprise titanium minerals and weakly magnetic gangue minerals, and the method comprises the following steps:

s1, contacting titanium middling with a reducing agent, and deeply reducing to enable Fe in the titanium middling to be Fe ²⁺ And/or Fe ³⁺ Reduction to Fe wholly or partially ⁰ Fe in weakly magnetic gangue minerals ²⁺ And/or Fe ³⁺ Keeping the non-reduction state to obtain reduced titanium middling;

s2, carrying out magnetic separation on the reduced titanium middling, and separating to obtain a reduced ferrotitanium material and tailings containing weak magnetic gangue minerals;

and S3, preparing the reduced ferrotitanium material to obtain a titanium-rich material.

Preferably, the titanium mineral of the titanium middling comprises one or more of ilmenite or rutile, the weak magnetic gangue mineral comprises one or more of chromite spinel, titandiopside or garnet, and the titanium middling at least comprises one titanium mineral and one weak magnetic gangue mineral.

Preferably, the titanium-rich material is artificial rutile or high-titanium slag; the artificial rutile is prepared by adopting an acid leaching or corrosion method.

Preferably, when the titanium-rich material is prepared by adopting an acid leaching method, the metallization rate of the adopted reduced ferrotitanium material is more than 85%; when the titanium-rich material is prepared by a corrosion method, the metallization rate of the adopted reduced ferrotitanium material is more than 90%.

Preferably, the conditions for preparing the titanium-rich material by the acid leaching method are as follows: and (2) reacting the reduced ferrotitanium material with leaching acid for 0.5-2 h at normal pressure, wherein the reaction temperature is 20-60 ℃, the mass-to-volume ratio of the reduced ferrotitanium material to the leaching acid is 1 (2-5), and the mass fraction concentration of the leaching acid is 13-25%.

Preferably, the conditions for preparing the titanium-rich material by the corrosion method are as follows: taking the reduced ferrotitanium material and a corrosion solution, and reacting for 2-6 h under the condition of charging air to obtain primary artificial rutile; the reaction temperature is 30-110 ℃, the mass ratio of the reduced ferrotitanium material to the corrosion liquid is 1 (2-8), the corrosion liquid is an ammonium salt aqueous solution, and the ammonium salt in the corrosion liquid is NH ₄ Cl、(NH ₄ ) ₂ SO ₄ One or two of the corrosion solutions are mixed, and the concentration of ammonium salt in the corrosion solution is 0.05-4 mol/L;

and then taking the primary artificial rutile and 15-25% of inorganic acid by mass percent, wherein the solid-to-liquid ratio is 1 (3-6), and reacting for 3-5 h at 80-100 ℃ to obtain the artificial rutile.

Preferably, the preparation conditions of the high titanium slag are as follows: and (3) taking the reduced ferrotitanium material and a reducing agent, and smelting in an electric furnace at the smelting temperature of 1600-1750 ℃.

Preferably, in the step S1, the deep reduction temperature is 800-1100 ℃, and the deep reduction time is 0.5-4 h.

Preferably, the reduced ferrotitanium material obtained after the deep reduction and magnetic separation in the step S2 is subjected to at least one deep reduction and magnetic separation.

Preferably, the temperature of the after-depth reduction is not lower than that of the before-depth reduction.

Preferably, the deep reduction times are two, the first deep reduction temperature is 800-1000 ℃, and the second deep reduction temperature is 1000-1100 ℃.

The invention is different from the prior art in that:

the ERMS roasting method (US5595347 "Process for Separating Ilmenite") is roasting at high temperature (750-950 ℃) by controlling oxygen partial pressureBurning ilmenite for about 60min, cooling the roasted ilmenite under the condition of oxygen deficiency, and increasing the susceptibility of ilmenite by roasting. The method for increasing the magnetic susceptibility of ilmenite by the technology is still oxidation, and FeO in the ilmenite is converted into magnetite (Fe) ₃ O ₄ ) This technique avoids magnetite (Fe) due to its controlled oxygen partial pressure ₃ O ₄ ) Further oxidation to nonmagnetic hematite (Fe) ₂ O ₃ ) The technique is carried out under oxidizing atmosphere conditions. In the invention, ilmenite is reduced to metallic iron under the condition of reducing atmosphere.

Wangcha et al, "a choice test research of ilmenite abroad" uses rotary kiln, fluidized bed or fluidized bed furnace to perform oxidizing roasting under the condition of roasting technological parameter 770 deg.C to attain the goal of increasing the magnetism of ilmenite. The invention reduces the ilmenite into metallic iron under the condition of reducing atmosphere so as to achieve the purpose of increasing the magnetism of the ilmenite.

"thermodynamic analysis of ilmenite magnetizing roasting separation" ("ferrous metallurgy" vol.34, 3 rd and 6 th 2013) of Liuyunlong et al adopts oxygen or air to oxidize and roast ilmenite to generate Fe ₂ O ₃ And Fe ₂ TiO ₅ Then, it can be reduced to Fe by using CO with lower concentration ₃ O ₄ Then ball milling is carried out by using a ball mill, and iron concentrate powder and titanium slag can be obtained by means of magnetic separation, so that the purpose of iron-titanium separation is achieved. Although this technique is performed in a reducing atmosphere, it is essentially different from the present invention in that iron is reduced to magnetic ferroferric oxide, not metallic iron.

The invention deeply reduces the titanium mineral in the titanium middling ore into the reduced ferrotitanium material containing metallic iron, so that the weakly magnetic gangue mineral such as chromite still keeps the unreduced state and the original crystal form, thereby reducing and increasing the magnetic difference between the reduced ferrotitanium material and the weakly magnetic gangue mineral and being beneficial to magnetic separation. Then the deep reduction of the titanium middling purification and the deep reduction of the ilmenite for preparing the high-purity titanium-rich material are combined, so that the process route is shortened, the production cost is reduced, and the industrial production is easy to realize.

[ description of the drawings ]

FIG. 1 is an X-ray diffraction (XRD) of a high chromium titanium middlite;

FIG. 2 is an X-ray diffraction (XRD) of reduced high chromium titanium middlings;

FIG. 3 is an X-ray diffraction (XRD) of a reduced titaniferous material;

FIG. 4 is an X-ray diffraction (XRD) of chromium concentrate;

FIG. 5 is a first stage deep reduction/magnetic separation scheme;

FIG. 6 is a two-stage deep reduction/magnetic separation scheme.

[ detailed description ] embodiments

The titanium middling containing the weak-magnetic gangue mineral cannot meet the requirements for producing titanium dioxide by a sulfuric acid method or producing raw materials by a chlorination method due to high impurity content, and the impurities mainly comprise CaO, MgO and SiO ₂ 、Cr ₂ O ₃ And the impurities mainly come from weakly magnetic gangue minerals such as chromite, titanophyte, garnet and the like.

The invention discloses a method for preparing a titanium-rich material from titanium middlings, wherein the titanium middlings comprise titanium minerals and weak magnetic gangue minerals, and the method comprises the following steps:

s1, contacting titanium middling with a reducing agent for deep reduction to enable Fe in the titanium minerals ²⁺ And/or Fe ³⁺ Reduction to Fe wholly or partially ⁰ Fe in weakly magnetic gangue minerals ²⁺ And/or Fe ³⁺ Keeping the non-reduction state to obtain reduced titanium middling; the reducing agent can be coal, petroleum coke, CO or H ₂ One or more combinations of (a).

and S3, further preparing the reduced ferrotitanium material to obtain a titanium-rich material.

Iron in naturally oxidized minerals is generally FeO or Fe ₃ O ₄ Or Fe ₂ O ₃ Exists in the form of magnetite Fe only ₃ O ₄ (FeO·Fe ₂ O ₃ ) Has strong magnetism, and the rest of ferrous oxide (FeO) and hematite (Fe) ₂ O ₃ ) Is weakly magnetic mineral. Therefore, the difference of iron reducibility in each mineral can be utilized to selectively reduce iron in a given mineral into Fe ₃ O ₄ Or elemental iron to increase the magnetic properties of the mineral. Due to magnetite (Fe) ₃ O ₄ ) The invention adopts deep reduction mode to reduce partial or all iron in titanium ore into simple substance iron to increase the magnetism of ilmenite, while weak magnetic gangue ore such as Fe of chromite ²⁺ And/or Fe ³⁺ Keeping the unreduced state, and separating the unreduced state and the unreduced state better through magnetic separation to finally obtain a magnetic reduced ferrotitanium material and tailings of non/weak magnetic gangue minerals; and the reduced ferrotitanium material is combined with the deep reduction of titanium minerals for preparing high-purity titanium-rich materials to obtain the high-purity titanium-rich materials, so that the process route is shortened, the production cost is reduced, and the industrial production is easy to realize. The method for preparing the titanium-rich material can adopt the conventional acid leaching, corrosion or electric furnace melting method and the like.

As can be understood by those skilled in the art, the ilmenite is a magnetic separation concentrate obtained by performing conventional mineral separation methods such as gravity separation and magnetic separation on an ilmenite placer titanium resource, and generally mainly contains titanium minerals (ilmenite, weathered ilmenite, rutile and the like), iron minerals (titanomagnetite, pseudohematite, hematite and the like), weak-magnetic gangue minerals (chromite, hercynite, titanpside, garnet and the like), and in addition, generally contains a small amount of gangue minerals common to sand ilmenite such as zircon, quartz, plagioclase, kaolinite, chlorite and the like.

After deep reduction, ilmenite, weathered ilmenite, iron oxide minerals, rutile and the like enter into the reduced ilmenite material; fe in iron minerals ²⁺ And/or Fe ³⁺ Also reduced wholly or partially to Fe ⁰ When the reduced titanium middlings are magnetically separated in step S2, the reduced titanium middlings are separated from weakly magnetic gangue minerals such as chromite and the like along with ilmenite, rutile is generally symbiotic with the ilmenite and enters the reduced titaniferous material along with the ilmenite. The weak magnetic gangue minerals in the titanium middling generally contain chromite, and generally contain one or more of hercynite, spodumene or garnet in addition to the chromite, and the weak magnetic gangue minerals enter tailings together through magnetic separation. The zircon minerals such as zircon, quartz, plagioclase feldspar, kaolinite or chlorite and the like are magnetically separated from the reduced titanium middling in the step S2 and are mixed with the weakly magnetic gangue minerals such as chromite and the likeAnd is separated from ilmenite to enter tailings.

Therefore, the tailings after magnetic separation generally contain chromite, ferrochrome spinel, coal ash, coal (when coal, petroleum coke and the like are used for reduction, coal ash and residual coal and petroleum coke are generated), and a small amount of reduced ferrotitanium materials, zircon minerals common to sand ilmenite such as zircon, quartz, plagioclase, kaolinite, chlorite and the like.

The simple substance iron greatly improves the magnetism of the ferrotitanium material and increases the magnetism difference with the weak-magnetism gangue minerals. The higher the metallization rate of the reduced ferrotitanium material is, the stronger the magnetism of the ferrotitanium material is, and the larger the difference between the magnetism of the ferrotitanium material and the gangue minerals is, the more beneficial to magnetic separation. However, when reducing the metallization ratio (percentage of metallic iron to total iron, Fe) of a titaniferous material ⁰ and/TFe multiplied by 100 percent), when the concentration is too high, the phenomena of magnetic chain, magnetic agglomeration and the like are easily generated in the reduction of the ferrotitanium material under the action of a magnetic field, and the inclusion of the magnetic chain and the magnetic agglomeration can reduce the magnetic separation effect. Therefore, the metallization rate of the reduced ferrotitanium material is preferably 5-95%.

Step S1 deep reduction to make Fe in ilmenite ²⁺ And/or Fe ³⁺ Reduction to Fe wholly or partially ⁰ While the weakly magnetic gangue minerals such as Fe in chromite ²⁺ And/or Fe ³⁺ Keeping the non-reduction state, selecting proper deep reduction conditions, preferably selecting the deep reduction temperature of 800-1100 ℃ and the deep reduction time of 0.5-4 h. When the reducing agent is a solid reducing agent such as coal, petroleum coke and the like, the addition amount is preferably 10-30% (mass ratio) of the titanium middling, and when the reducing agent is CO or H ₂ When the gas reducing agent is used, the content of CO and H in the tail gas is controlled to be more than or equal to 3 percent.

Ilmenite (FeTiO) ₃ ) By thermal reduction with a reducing agent (e.g. coal) to produce a reduced ferrotitanium material (FeTiO) ₃ ·TiO ₂ ·Fe、FeTiO ₃ ·Ti ₂ O ₃ ·2Fe、FeTiO ₃ ·Ti ₂ O ₃ 2Fe, etc.), reducing a titaniferous material mainly from FeTiO ₃ 、Fe、TiO ₂ 、Ti ₂ O ₃ Etc., and the content of each component mainly depends on the reduction conditions (temperature and time). Reduction temperatureHigher and longer Fe, TiO ₂ Higher content and FeTiO ₃ The lower the content. The reduction equipment is usually a rotary kiln, and other reduction equipment such as a boiling bed and the like can also be adopted. The reducing agent, such as coal, serves primarily to provide the CO required for the reaction, on the one hand, and the heat required for the reaction, on the other hand. In the rotary kiln, ilmenite reacts with reducing agent coal mainly as follows:

FeTiO ₃ +C＝TiO ₂ ·Fe+CO

FeTiO ₃ +CO＝TiO ₂ ·Fe+CO ₂

3FeTiO ₃ +4C＝Ti ₃ O ₅ ·3Fe+4CO

3FeTiO ₃ +4CO＝Ti ₃ O ₅ ·3Fe+4CO ₂

2FeTiO ₃ +3C＝Ti ₂ O ₃ ·2Fe+3CO

2FeTiO ₃ +3CO＝Ti ₂ O ₃ ·2Fe+3CO ₂

2FeTiO ₃ +C＝FeTi ₂ O ₅ ·Fe+CO

2FeTiO ₃ +CO＝FeTi ₂ O ₅ ·Fe+CO ₂

Fe ₂ O ₃ +3C＝2Fe+3CO

CO ₂ +C＝2CO

C+O ₂ ＝2CO

at the temperature of 800-1100 ℃, more or less metallic iron can be separated out from ilmenite, ilmenite particles are kept in the original state and are symbiotic with the metallic iron, so that the magnetism of the ilmenite is increased geometrically, and weak-magnetic gangue minerals such as chromite can be further grown into simple substance iron only at the temperature of 1100-1500 ℃, and the related reaction formula is as follows:

FeCr ₂ O ₄ +C＝Fe·Cr ₂ O ₃ +CO

3FeCr ₂ O ₄ +4C＝3Fe·2Cr ₃ O ₄ +4CO

thus, since the reduction activity of ilmenite is higher than that of chromite, when both ilmenite and chromite are present, ilmenite reduces prior to chromite under the conditions of the present invention. Under the conditions of 800-1100 ℃ and reduction for not more than 4h, the chromite keeps the original crystal lattice as weak magnetic mineral, and is easily separated from the reduced ferrotitanium material by magnetic separation.

S1 oxidizing roasting can be carried out before reducing the titanium middlings to improve the reduction activity of the ilmenite in the titanium middlings, wherein the oxidizing roasting of the titanium middlings is to oxidize iron in the ilmenite to produce TiO ₂ And Fe ₂ O ₃ ，Fe ₂ O ₃ Has reduction activity higher than that of FeTiO ₃ Reduction Activity of (ilmenite), Fe ₂ O ₃ The reduction is more controllable. The oxidizing condition is preferably 600-1000 ℃ and the roasting time is 0.5-2 h. When the titanium middling activity is low, a method of oxidizing firstly can be preferentially used, and deep reduction is carried out after the activity is improved. And after the oxidation activity is improved, the subsequent deep reduction can adopt lower reduction temperature and/or shorter reduction time.

Deep reduction of titanium middlings is the selective reduction of ilmenite to an iron-containing titaniferous material, while weakly magnetic gangue minerals such as chromite retain their original crystal lattice (weak magnetic properties). The deep reduction of the titanium middling increases the magnetic difference between the ferrotitanium material and the chromite, and is beneficial to the magnetic separation effect. Of course, the metallic iron in the ferrotitanium material is a ferromagnetic substance, and the phenomena of magnetic linkage and magnetic agglomeration are easy to occur in a magnetic field, so that the effect of magnetic separation of chromite is also influenced. Therefore, the multi-stage reduction-magnetic separation is beneficial to the magnetic separation effect, the flow of the multi-stage reduction-magnetic separation (figure 6) is an extension of the flow of the first-stage reduction-magnetic separation (figure 5), and the reduced ferrotitanium material obtained after deep reduction and magnetic separation is subjected to at least one deep reduction and magnetic separation to obtain the multi-stage reduced ferrotitanium material. The latter deep reduction temperature is preferably not lower than the former deep reduction temperature. For example, the first-stage reduction adopts low-temperature reduction (such as 800-1000 ℃), the second-stage reduction adopts higher-temperature reduction (such as 1000-1100 ℃), the low-temperature reduction aims at reducing the metallization rate and magnetism of the ferrotitanium material and is beneficial to the separation effect of the ferrotitanium material and chromite, and the high-temperature reduction aims at improving the metallization rate of the ferrotitanium material and is beneficial to preparing a titanium-rich material. Of course, the magnetic separation process is not limited to the reduction-magnetic separation process shown in fig. 5 and fig. 6, and scavenging can be added in the magnetic separation process so as to increase the recovery rate of titanium and the grade of chromium concentrate, or concentration so as to increase the grade of titanium in the reduced ferrotitanium material.

In the step S2, the magnetic field is preferably selected to be magnetic separation with medium and low field intensity, and the intensity is preferably 800-4000 GS. The magnetic separation equipment can adopt dry magnetic separation or wet magnetic separation. The wet magnetic separation is favorable for breaking magnetic chains and magnetic agglomeration, so that the wet magnetic separation effect is better than the dry magnetic separation effect. And the flow of dry magnetic separation is simpler than that of wet magnetic separation and the cost is lower.

The titanium-rich material is TiO ₂ Synthetic rutile or high titanium slag with content more than 75%. The artificial rutile can be produced by acid leaching or a corrosion method, and the high-titanium slag can be used for melting and producing reduced titanium iron materials in an electric furnace, so that the deep reduction process of magnetic separation of titanium middlings and the reduced titanium iron ore process for producing the titanium-rich materials are organically combined, and the process of producing the titanium-rich materials by the titanium middlings is simplified. However, different titanium-rich material production processes have different requirements on the degree of ilmenite reduction, which is determined by the metallization rate (Fe) of the reduced ilmenite material ⁰ /TFe). The metallization rate of the reduced ferrotitanium material is controlled to be between 85 and 90 percent when the acid leaching method is adopted to produce the artificial rutile. The metallization rate of the reduced ferrotitanium material is controlled to be between 90 and 95 percent when the artificial rutile is produced by the corrosion method. The high-titanium slag produced by melting in the electric furnace has no strict requirement on the metallization rate of the reduced ferrotitanium material, but the metallization rate of the reduced ferrotitanium material is between 65 and 85 percent, and the production cost of the titanium-rich material is the lowest in balance from the perspective of cost. Specifically, the method comprises the following steps:

the acid leaching method for producing the artificial rutile comprises the following steps:

and (2) taking the reduced ferrotitanium material and leaching acid, reacting for 0.5-2 h at normal pressure, wherein the reaction temperature is 20-60 ℃, the mass-to-volume ratio of the reduced ferrotitanium material to the leaching acid is 1 (2-5), and the mass fraction concentration of the leaching acid is 13-25%. The leaching reaction of the reduced ferrotitanium material and leaching acid (taking sulfuric acid as an example) mainly comprises the following reactions:

FeO+H ₂ SO ₄ ＝FeSO ₄ +H ₂ O

Fe+H ₂ SO ₄ ＝FeSO4+H ₂ ↑

CaO+H ₂ SO ₄ ＝CaSO ₄ +H ₂ O

MgO+H ₂ SO ₄ ＝MgSO ₄ +H ₂ O

MnO+H ₂ SO ₄ ＝MnSO ₄ +H ₂ O

Al ₂ O ₃ +3H ₂ SO ₄ ＝Al ₂ (SO ₄ ) ₃ +3H ₂ O

leaching to remove Fe mainly in reduced ferrotitanium material ⁰ 、FeO、MgO、Al ₂ O ₃ MnO, etc. and produces sulfate impurity which can be dissolved in water, the main impurity iron is converted into ferrous sulfate, and the reaction produced gas is hydrogen gas. To reduce TiO in the titaniferous material ₂ The titanium dioxide is not reacted with sulfuric acid, the titanium dioxide is remained in the solid phase of the synthetic rutile, and the synthetic rutile is obtained after solid-liquid separation and calcination.

The hydrogen generated by the leaching reaction of the titaniferous iron material can be used as a reducing agent of the titanium middling ore or a fuel for oxidizing the titanium middling ore after the hydrogen is recovered. The leaching reaction kettle can be an acid-resistant reaction kettle which is normal pressure, closed and provided with a stirrer.

The leaching acid is preferably sulfuric acid process titanium dioxide waste acid, and any one or any mixture of other inorganic acids, such as industrial hydrochloric acid, sulfuric acid, nitric acid, titanium chloride waste acid or other industrial waste acid, in any proportion. Hydrochloric acid and titanium chloride waste acid are less recommended to be used, because the synthetic rutile prepared by adopting hydrochloric acid is easy to pulverize, and the use is influenced.

The reduced ferrotitanium material obtained by deep reduction contains elementary substance iron, and the activity of the elementary substance iron is higher than that of Fe ²⁺ 、Fe ³⁺ Preferably, the reaction temperature is lower than that of the prior art (generally about 100 ℃ or higher than 100 ℃ in the prior art), and the reduced ferrotitanium material can be completely leached at 20-60 ℃, so that the reduced ferrotitanium material with low metallization rate can cause Fe at low reaction temperature ²⁺ 、Fe ³⁺ Leaching is incomplete, so the metallization rate of the reduced ferrotitanium material is required to be at least 85%, and the metallization rate is preferably 85-90% for cost consideration.

The steps for producing the artificial rutile by the corrosion method are as follows:

taking a reduced ferrotitanium material and a corrosion solution, reacting for 2-6 h under the condition of charging air, carrying out cyclone separation on a product to obtain primary artificial rutile and hydrated ferric oxide, and drying the hydrated ferric oxide to finally obtain iron oxide red; wherein the reaction temperature is 30-110 ℃, the mass ratio of the reduced ferrotitanium material to the corrosion liquid is 1 (2-8), the corrosion liquid is an ammonium salt aqueous solution, and the ammonium salt in the corrosion liquid is NH ₄ Cl、(NH4) ₂ SO ₄ One or two of the components are mixed, and the concentration of ammonium salt in the corrosion liquid is 0.05-4 mol/L.

And then adding the primary artificial rutile and inorganic acid (hydrochloric acid, sulfuric acid and the like) with the mass fraction of 15-25% into a reaction kettle, wherein the solid-liquid ratio is 1 (3-6), reacting for 3-5 hours at 80-100 ℃, and performing solid-liquid separation, washing and drying on the solid matters to obtain an artificial rutile product.

The corrosion process is an electrochemical corrosion process, and is carried out in an electrolyte solution. The metallic iron crystallites in the reduced ferrotitanium material particles correspond to the anode of the galvanic cell and the outer surface of the particles correspond to the cathode. At the anode, Fe loses electrons to Fe ²⁺ Ion entering solution:

Fe→Fe ²⁺ +2e ^-

in the cathode region, oxygen in the solution accepts electrons to form OH ^- Ion:

O ₂ +2H ₂ O+4e ^- →4OH ^-

fe dissolved in the particles ²⁺ The ions diffuse along the micropores into the electrolyte solution at the outer surface of the particles, and if the solution contains oxygen, it is further oxidized to form iron oxide fine particle precipitates:

the produced hydrated iron oxide particles are particularly fine, and can be separated from the parent body of the reduced ferrotitanium material according to the difference of the physical properties (granularity and specific gravity) of the hydrated iron oxide particles and the reduced ferrotitanium material, and the synthetic rutile can be obtained after solid-liquid separation and calcination.

The metallic iron microcrystal in the reduced ilmenite particles by the corrosion method is equivalent to the anode of a primary battery to participate in the reaction, so that the metallization rate of the reduced ilmenite material is required to be higher and at least more than 90%, and in order to take the cost into consideration, the metallization rate is preferably 90-95%, and the progress of the corrosion reaction is not facilitated when the metallization rate is lower than the range.

The specific steps of the electric furnace melting method for producing the high titanium slag are as follows:

the principle of smelting high-titanium slag by an electric furnace method is that a reduced ferrotitanium material and a solid reducing agent (anthracite, petroleum coke or coke and the like) are mixed according to a certain proportion (2-5%) and added into an electric furnace for reduction smelting, high-temperature electric arc is generated between an electrode and a furnace charge to form a molten pool (the temperature is about 1600-1750 ℃), the furnace charge is heated and melted, and a reduction reaction occurs, titanium dioxide is reduced into low-valent titanium (Ti, Ti and the like) in the process ₃ O ₅ 、Ti ₂ O ₃ ) The smelting process is that under the condition of not supplying enough carbon, the reduced ferrotitanium material is smelted at high temperature in an electric furnace, so that iron oxide in the reduced ferrotitanium material is reduced into metallic iron which is deposited on the bottom of the furnace, and titanium dioxide, calcium oxide, magnesium oxide, aluminum oxide, silicon dioxide, most of manganese oxide and the like enter a slag phase together, and are finally separated from iron, and the titanium dioxide is enriched in slag to prepare the high-titanium slag. Titanium, calcium, magnesium, aluminum, silicon and manganese in the reduced ferrotitanium material exist in the form of associated elements, calcium oxide, magnesium oxide and aluminum oxide do not generate chemical reaction in the production process, part of titanium dioxide is converted into low-valence titanium, and trace silicon dioxide and a small part of manganese oxide are reduced into simple substances to enter molten iron. Reducing iron oxide in the reduced ferrotitanium material into metallic iron, enriching titanium oxide into slag, and separating slag from iron to obtain high-titanium slag and by-product metallic iron.

The invention will be further illustrated below by taking Mosangbice titanium ore as an example.

Mosangbike certain titanium ore, which is a typical seashore placer, has thicker ore disseminated granularity, complex ore property and special gangue composition, and belongs to the difficult-to-select seashore placer. The raw material used in the invention is high-chromium titanium middling with high chromium content, and is concentrate after conventional gravity separation and magnetic separation, and the chemical composition of the concentrate is shown in table 2.

TABLE 2 Mosangbice certain high chromium titanium middlings chemical composition (%)

Composition (I)	TiO ₂	TFe	Fe ₂ O ₃	CaO	Cr ₂ O ₃	MgO	SiO ₂	Al ₂ O ₃	MnO	V ₂ O ₅
											Sample No. 1	38.88	35.01	50.01	0.03	5.42	0.91	1.65	1.77	0.98	0.08
Sample No. 2#	37.321	35.95	51.358	0.025	5.634	0.78	1.87	1.79	0.95	0.09
											Sample No. 3	37.692	35.41	50.586	0.024	4.321	0.84	1.41	1.768	0.963	0.08
Sample No. 4#	38.145	36.39	51.987	0.035	2.145	0.78	1.59	1.746	0.98	0.07
											Sample No. 5#	39.79	37.34	51.51	0.04	4.43	0.94	1.47	1.76	1.02	0.09

TABLE 2X-ray diffraction (XRD) of Mosangbicg certain high chromium titanium middlings as shown in FIG. 1, containing mainly ilmenite (FeTiO) ₃ ) Hematite (Fe) ₂ O ₃ ) Chromite ((Mg, Fe) (Cr, Al) of weak magnetic gangue mineral ₂ O ₄ ，MgCr ₂ O ₄ ) And gangue mineral quartz (SiO) ₂ ) And the like.

The main minerals of the high-chromium titanium middling are basically consistent with the chemical components of the ilmenite, part of grains contain higher MgO and MnO in the form of similar images, and the average content of TiO ₂ The combined sample is 51.31%. The particle size is generally varied from 0.04 to 0.25 mm.

Chromium mineral ((Mg, Fe) Cr) in high-chromium titanium middling ₂ O ₄ ～(Mg,Fe)(Cr,Al) ₂ O ₄ ) Basically all are monomer particles, are rarely continuous with other minerals, have weak secondary change, have slightly smaller particle size than ilmenite, generally change between 0.04 and 0.2mm, and are mainly expressed in Cr ₂ O ₃ 、FeO、Al ₂ O ₃ The content of main components such as MgO is greatly changed and a certain amount of V is generally contained ₂ O ₅ Average content of Cr ₂ O ₃ 47.25％、FeO 28.28％、Al ₂ O ₃ 14.91％、V ₂ O ₅ 0.48％。

Deeply reducing to obtain iron (Fe) in titanium mineral and iron mineral in high-chromium titanium middling ²⁺ 、Fe ³⁺ ) Reducing part or all of the iron into metallic iron (Fe) by using a reducing agent ⁰ ) Reduction of metallic iron (Fe) of high chromium titanium middlings ⁰ ) Fe from titanium and iron minerals ³ ⁺ And Fe ²⁺ The metallic iron increases the magnetic properties of titanium minerals and iron minerals. However, the iron in the weakly magnetic gangue minerals chromite and garnet (iron-containing silicate minerals) is not reduced to metallic iron (Fe) ⁰ ) The crystal lattices of other non-ferrous gangue minerals (quartz, feldspar, tourmaline, andalusite and the like) are not changed in the reduction process, the simple substance metal iron greatly improves the magnetism of the ferrotitanium material and increases the magnetic difference with the weak-magnetic gangue minerals, the higher the metallization rate of the reduced ferrotitanium material is, the stronger the magnetism of the ferrotitanium material is, and the larger the magnetic difference between the ferrotitanium material and the gangue minerals is, the more beneficial to magnetic separation. Through magnetic separation, reduced ferrotitanium materials and tailings containing iron-chromite are obtained, and the tailings can be further processed to obtain chromium concentrate.

FIG. 2 is an X-ray diffraction (XRD) of reduced high chromium titanium middlings after deep reduction, the reduced high chromium titanium middlings containing mainly ilmenite (FeTiO) ₃ ) Rutile (TiO) ₂ ) Metallic iron (Fe), chromite ((Mg, Fe) (Cr, Al) ₂ O ₄ ,MgCr ₂ O ₄ ) Quartz (SiO) ₂ ) And the like. FIG. 3 is an X-ray diffraction (XRD) of a reduced titaniferous material, and as can be seen from FIGS. 2 and 3, has characteristic peaks of X-ray diffraction of metallic iron at 44.77 ℃ and 65.17 ℃. Fig. 4 is an X-ray diffraction (XRD) pattern of the chromium concentrate, and it can be seen from fig. 4 that no elemental iron is generated in the chromium concentrate.

The following examples take the high chromium titanium middlings of table 2 as examples and further illustrate the invention with reference to specific examples.

Example 1

2.0Kg of sample No. 1 high chromium titanium middling in Table 2 and 0.35Kg of reducing agent coal are placed in a rotary kiln, reduced for 3 hours at 1050 ℃, and rapidly cooled to obtain the reduced high chromium titanium middling with the metallization rate of 90.46 percent and the reduced high chromium titanium middlingThe X-ray diffraction (XRD) of the chromium titanium middlings is shown in FIG. 2. Carrying out dry magnetic separation on the reduced high-chromium titanium middling at the strength of 3000GS to obtain a reduced ferrotitanium material containing metallic iron and magnetic separation tailings; and washing, sorting and removing impurities from the magnetic separation tailings, and drying to obtain chromium concentrate. X-ray diffraction (XRD) of reduced titaniferous material containing metallic iron containing Cr ₂ O ₃ 0.098% and a titanium recovery of 99.18% (titanium recovery-reduction of TiO in the titaniferous material) ₂ Mass/(reduction of TiO in ferrotitanium Material) ₂ Mass + TiO in chromite ₂ Quality), the recovery rate of chromium in chromite can reach 97.92%.

Example 2

2.0Kg of the high chromium titanium middlings of sample No. 1 in Table 2 was first placed in a rotary kiln and oxidized at 750 ℃ for 1 hour under an air atmosphere. After cooling, 0.35Kg of reducing agent coal is added, and reduction is carried out for 0.5h at 1000 ℃, and the reduced high chromium titanium middling is obtained after rapid cooling. Carrying out dry magnetic separation on the reduced high-chromium titanium middling under the strength of 2000GS to obtain a titanium material containing metallic iron and magnetic separation tailings; and washing, sorting and removing impurities from the magnetic separation tailings, and drying to obtain chromium concentrate. Reduced titaniferous materials containing metallic iron containing Cr ₂ O ₃ 0.052 percent, the recovery rate of titanium is 99.25 percent, and the recovery rate of chromium in chromite can reach 98.93 percent.

The oxidation can oxidize iron in ilmenite to TiO ₂ And Fe ₂ O ₃ ，Fe ₂ O ₃ Has reduction activity higher than that of FeTiO ₃ Reduction Activity of (ilmenite), Fe ₂ O ₃ The reduction is more controllable. When the activity of the chromium-titanium-containing middling is low, a method of firstly oxidizing can be preferentially used, and then deep reduction is carried out after the activity is improved. And the subsequent reduction after oxidation can adopt lower reduction temperature or/and shorter reduction time.

Example 3

1.0Kg of the high chromium titanium middlings of sample No. 1 in Table 2 was loaded in a fluidized bed containing 3.5% H in the exhaust gas of the fluidized bed using hydrogen as a reducing agent ₂ Reducing for 4h at 950 ℃, and rapidly cooling to obtain the reduced high-chromium titanium middling. Carrying out dry magnetic separation on the reduced high-chromium titanium middling under the intensity of 2500GS to obtain ferrotitanium material containing metallic iron and magnetismSelecting tailings; and washing, sorting and removing impurities from the magnetic separation tailings, and drying to obtain chromium concentrate. Reduced titaniferous materials containing metallic iron containing Cr ₂ O ₃ 0.07 percent, the recovery rate of titanium is 99.14 percent, and the recovery rate of chromium in chromite can reach 98.99 percent.

From the above examples, it can be known that by using the method of the present invention, the content of chromium in the reduced ilmenite material can be reduced to below 0.1%, the removal rate of chromium can reach about 99%, and the impurity element chromium in the ilmenite can be recovered to obtain chromium concentrate (chromite), so that the quality of the ilmenite itself can be improved, and the value of the impurity element can be improved. The method has the advantages of simple process, short flow, low cost and easy industrial production.

Example 4

Sample No. 2 titanium middling (Cr) in Table 2 ₂ O ₃ 5.634%) in a rotary kiln, reducing for 4h at 800 deg.C with petroleum coke as reducing agent and the addition amount of 30% of ore amount, rapidly cooling, reducing chromium-titanium-containing middlings, performing dry magnetic separation for 2 times at 2500GS intensity to obtain reduced ferrotitanium material (titanium concentrate (Cr) containing iron ₂ O ₃ 0.062%) and magnetic separation tailings; washing, sorting and removing impurities from the magnetic separation tailings, and drying to obtain chromium concentrate (Cr) ₂ O ₃ 53.64%), wherein the recovery of chromium in the chromium concentrate is 98.97%, and the recovery of titanium in the reduced titaniferous material, i.e. the titanium concentrate, is 98.35%.

Example 5

Sample No. 3 titanium middling (Cr) in Table 2 ₂ O ₃ 4.32%) in a fluidized bed, oxidizing at 730 deg.C for 1H in air atmosphere, reducing at 950 deg.C with hydrogen as reducing agent, and discharging gas containing 3.5% H in the fluidized bed ₂ Reducing for 2h under the condition, rapidly cooling, performing primary and secondary dry magnetic separation at 3000GS intensity to obtain reduced ferrotitanium material (titanium concentrate (Cr) ₂ O ₃ 0.07%) and tailings. Washing, sorting and removing impurities from the tailings to obtain chromium concentrate (Cr) ₂ O ₃ 48.89%), wherein the recovery of chromium in the chromium concentrate is 99.17%, and the recovery of titanium in the reduced titaniferous material, i.e. the titanium concentrate, is 98.96%.

Example 6

The sample No. 4 titanium middling in Table 2(Cr ₂ O ₃ 2.14%) in a rotary kiln, reducing for 0.5h at 1100 deg.C with coal as reducing agent and 30% of ore amount, rapidly cooling, and performing primary-coarse-secondary-fine dry magnetic separation for 3 times at 2500GS intensity to obtain reduced ferrotitanium material (titanium concentrate (Cr) with high purity ₂ O ₃ 0.057%) and tailings, wet magnetic separation is carried out on the tailings under the strength of 4500GS, and the tailings are dried to obtain chromium concentrate (Cr) ₂ O ₃ 42.85%), wherein the recovery rate of chromium in the chromium concentrate is 98.11%, and the recovery rate of titanium in the reduced titanium iron material, i.e. the titanium concentrate, is 99.05%.

The indexes of the chromium-titanium-containing middling, the magnetically separated chromium concentrate and the reduced ferrotitanium material, namely the grade of the titanium concentrate and the recovery rate of titanium and chromium, are shown in table 3:

TABLE 3

Example 7

1kg of sample No. 5 high-chromium titanium middling in the table 2 and 300g of petroleum coke are placed in a rotary kiln, heat preservation is carried out for 1h at 950 ℃, then the mixture is rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 3000GS, reduced ferrotitanium materials and magnetic separation tailings are obtained, the magnetic separation tailings are washed, sorted and purified, and then dried to obtain chromium concentrate, wherein the flow is shown in figure 5. The results are shown in Table 4. The recovery rate of titanium is 99.31%, and the recovery rate of titanium is that TiO in the reduced ferrotitanium material ₂ Mass/(reduction of TiO in ferrotitanium Material) ₂ Quality + TiO in chromium concentrate ₂ Mass), the chromium recovery was 98.3%.

TABLE 4 chemical analysis of the composition of the product of example 7 (reduced titaniferous material) and of the chromium concentrate

Example 8

1kg of sample No. 5 high-chromium titanium middling in the table 2 and 300g of petroleum coke are placed in a rotary kiln, heat preservation is carried out for 1h at 1100 ℃, then the materials are rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 3000GS, reduced ferrotitanium materials and magnetic separation tailings are obtained, the magnetic separation tailings are washed, sorted and dried to obtain chromium concentrate, and the flow is shown in figure 5. The results are shown in Table 5. The recovery rate of titanium was 99.31% and the recovery rate of chromium was 98.31%.

TABLE 5 chemical analysis of the composition of the product of example 8 (reduced titaniferous material) and of the chromium concentrate

Example 9

1kg of sample No. 5 high-chromium titanium middling in Table 2 and 300g of petroleum coke are placed in a rotary kiln, heat preservation is carried out for 1h at 950 ℃, then the mixture is rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 3000GS to obtain magnetic separation concentrate, then the magnetic separation concentrate and 300g of petroleum coke are placed in the rotary kiln, heat preservation is carried out for 2h at 1100 ℃, then the mixture is rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 2000GS to obtain reduced ferrotitanium material, magnetic separation tailings I and magnetic separation tailings II, the magnetic separation tailings I and the magnetic separation tailings II are respectively washed with water to remove impurities, and dried to obtain chromium concentrate I and chromium concentrate II, the flow is shown in figure 6, and the results are shown in Table 6. The titanium recovery was 99.29% and the chromium recovery was 99.94%.

TABLE 6 chemical analysis results of the compositions of the product of example 9 (reduced titanium iron material) and chromium concentrate

Example 10

1kg of sample No. 5 high-chromium titanium middling in the table 2 and 300g of petroleum coke are placed in a rotary kiln, heat preservation is carried out for 1h at 1000 ℃, then the mixture is rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 3000GS to obtain magnetic separation concentrate, then the magnetic separation concentrate and 300g of petroleum coke are placed in the rotary kiln, heat preservation is carried out for 3h at 1000 ℃, then the mixture is rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 2000GS to obtain reduced ferrotitanium material, magnetic separation tailings I and magnetic separation tailings II, the magnetic separation tailings I and the magnetic separation tailings II are respectively washed with water to remove impurities, and dried to obtain chromium concentrate I and chromium concentrate II, wherein the flow is shown in figure 6. The results are shown in Table 7. The recovery rate of titanium is 99.14 percent, and the recovery rate of chromium is 98.88 percent.

TABLE 7 chemical analysis of the composition of the product of example 10 (reduced titaniferous material) and of the chromium concentrate

Example 11

1kg of sample No. 5 high-chromium titanium middling in the table 2 is placed in a rotary kiln, air is introduced to oxidize for 1h at 950 ℃, then nitrogen is introduced for 5 min, the temperature is increased to 1100 ℃ and CO is introduced, 3.5% of CO is contained in pumping gas of a fluidized bed, heat preservation is carried out for 3h, then the mixture is rapidly cooled to room temperature under the condition of air isolation, secondary dry magnetic separation of primary coarse and primary fine is carried out under the strength of 3000GS, reduced ferrotitanium materials and magnetic separation tailings are obtained, the magnetic separation tailings are washed with water and separated, and chromium concentrate is obtained after drying, wherein the flow is shown in figure 5. The results are shown in Table 8. The recovery rate of titanium is 99.52 percent and the recovery rate of chromium is 98.58 percent.

TABLE 8 chemical analysis of the composition of the product of example 11 (reduced titaniferous material) and of the chromium concentrate

Example 12

The feedstock of this example was a reduced titanium iron material prepared using the conditions of example 10, and the results of the compositional chemical analysis are shown in table 9, with a metallization rate of 90%.

TABLE 9 chemical analysis results of raw material composition of example 12

Composition (I)	TiO ₂	TFe	Fe ⁰	FeO	Cr ₂ O ₃
						Content%	45.38	33.62	30.26	5.19	0.07
Composition (I)	CaO	MgO	SiO ₂	Al ₂ O ₃	MnO
						Content%	0.13	0.62	1.06	0.75	1.07

60g of reduced ferrotitanium material is put into a 1000mL beaker with stirring, 500mL of sulfuric acid process titanium white waste acid with the mass fraction of 15 percent is added, in order to prevent over-rapid reaction and hydrogen escape, the reduced ferrotitanium material is slowly added into the beaker with stirring for three times, the temperature is controlled to be about 50 ℃, the whole reaction time is 2 hours, after the reaction is finished, solid-liquid separation is carried out, the liquid is ferrous sulfate solution, the solid is washed and dried to obtain the artificial rutile product, and the chemical component analysis of the artificial rutile product is shown in Table 10.

TABLE 10 chemical composition analysis results of example 12 synthetic rutile

Example 13

60g of reduced ferrotitanium material is put into a 1000mL beaker with stirring, 500mL of sulfuric acid process titanium white waste acid with the mass fraction of 20 percent is added, in order to prevent over-rapid reaction and hydrogen escape, the reduced ferrotitanium material is slowly added into the beaker with stirring for three times, the temperature is controlled to be about 50 ℃, the whole reaction time is 1h, after the reaction is finished, solid-liquid separation is carried out, the liquid is ferrous sulfate solution, the solid is washed and dried to obtain the artificial rutile product, and the chemical component analysis of the artificial rutile product is shown in Table 11.

Table 11 chemical composition analysis results of example 13 synthetic rutile

Example 14

Adding a reduced ferrotitanium material into a corrosion tank, wherein the corrosion liquid is a mixed solution of 2mol/L ammonium chloride solution and 2mol/L ammonium sulfate, the solid-to-liquid ratio of the solution is controlled to be 1:4, introducing air, reacting for 2 hours at 80 ℃, obtaining primary artificial rutile and hydrated ferric oxide by rotary separation of a product, and drying the hydrated ferric oxide to finally obtain iron oxide red;

then adding the primary synthetic rutile and sulfuric acid with the mass fraction of 20% into a reaction kettle, wherein the liquid-solid ratio is 1:4, reacting for 4 hours at the temperature of 80 ℃, and carrying out solid-liquid separation, washing and drying on the solid matters to obtain the synthetic rutile product, wherein the chemical component analysis of the synthetic rutile product is shown in the table 12.

Table 12 chemical composition analysis results of example 14 synthetic rutile

Example 15

The feedstock of this example was a reduced titanium iron material prepared using the conditions of example 7 and the compositional analysis results are shown in table 13 for a reduced titanium iron material having a metallisation of 40.13%.

TABLE 13 chemical analysis results of raw material composition of example 15

Composition (I)	TiO ₂	TFe	Fe ⁰	FeO	Cr ₂ O ₃
						Content%	42.99	35.06	14.07	32.31	0.09
Composition (I)	CaO	MgO	SiO ₂	Al ₂ O ₃	MnO
						Content%	0.04	0.64	1.01	0.70	1.11

The reduced ferrotitanium material of 6kg and petroleum coke of 250 g were mixed and added into an electric furnace, and smelted at 1650 ℃, the slag/iron melt was poured into a furnace basin, and slag/iron separation was performed after cooling, and the chemical component analysis of the titanium slag (titanium-rich material) product is shown in table 14.

TABLE 14 chemical composition analysis results of example 15 titanium slag (titanium-rich material)

From the above cases, it can be seen that the recovery rate of chromium can reach about 98% basically by using the method of the present invention, and at the same time, titanium can be reducedChromium (Cr) in titanium concentrate of iron material ₂ O ₃ ) The content is reduced to be below 0.1 percent, and the quality of the titanium concentrate is improved while the chromite is recovered. Meanwhile, the method combines the deep reduction of the titanium middling purification with the deep reduction of the ilmenite for preparing the high-purity titanium-rich material, shortens the process route, reduces the production cost and is easy for industrial production.

Comparative example 1

2.0Kg of sample No. 1 high chromium titanium middling in Table 2 is oxidized for 1 hour at 750 ℃ in a rotary kiln, and the high chromium titanium middling is subjected to dry magnetic separation at 6000GS strength to obtain a titanium oxide iron material and tailings, wherein the titanium oxide iron material contains Cr ₂ O ₃ 0.24% and the titanium recovery was 78.53%.

Comparative example 2

2.0Kg of sample No. 1 high chromium titanium middling in Table 2 is oxidized for 1 hour in a rotary kiln at 650 ℃, and the high chromium titanium middling is subjected to dry magnetic separation under the intensity of 6000GS to obtain a titanium oxide iron material and tailings, wherein the titanium oxide iron material contains Cr ₂ O ₃ 0.35% and the titanium recovery was 79.96%.

The indexes of the chrome-titanium-containing middling and the chrome concentrate/tailings after magnetic separation (the chrome content is more than 30 percent and is chrome concentrate, less than 30 percent is called tailings), the reduced/oxidized titanium-iron material, namely the titanium concentrate grade and the titanium and chrome recovery rate are shown in table 15:

TABLE 15 results of chemical analysis of comparative example products (reduced titaniferous material) and chromite composition

From the above comparative example, it can be seen that the chromium content in the titanium concentrate is difficult to be reduced to below 0.15%, the chromium content in the titanium concentrate is not satisfactory, and the chromium content in the tailings is low by using the oxidation method for chromium removal.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A method for preparing a titanium-rich material from titanium middlings, wherein the titanium middlings comprise titanium minerals and weakly magnetic gangue minerals, and is characterized by comprising the following steps:

s1, contacting titanium middling with a reducing agent to carry out deep reduction, wherein the deep reduction temperature is 800-1100 ℃, and the deep reduction time is 0.5-4 h, so that Fe in the titanium minerals is obtained ²⁺ And/or Fe ³⁺ Reduction to Fe wholly or partially ⁰ Fe in weakly magnetic gangue minerals ²⁺ And/or Fe ³⁺ Keeping the non-reduction state to obtain reduced titanium middling; the titanium mineral comprises ilmenite, and the weakly magnetic gangue mineral comprises chromite; the titanium middling also comprises iron minerals, and after deep reduction, Fe in the iron minerals ²⁺ And/or Fe ³⁺ Also reduced wholly or partially to Fe ⁰ ；

2. The method for preparing the titanium-rich material from the titanium middling according to claim 1,

the titanium mineral of the titanium middling also comprises rutile, the weak magnetic gangue mineral also comprises one or more of ferrochrome, spodumene or garnet, and the titanium middling at least comprises one titanium mineral and one weak magnetic gangue mineral.

3. The method for preparing titanium-rich material from titanium middling according to claim 1,

the titanium-rich material is artificial rutile or high titanium slag; the artificial rutile is prepared by adopting an acid leaching or corrosion method.

4. The method for preparing titanium-rich material from titanium middling according to claim 3,

when the titanium-rich material is prepared by adopting an acid leaching method, the metallization rate of the adopted reduced ferrotitanium material is more than 85%, and when the titanium-rich material is prepared by adopting a corrosion method, the metallization rate of the adopted reduced ferrotitanium material is more than 90%; the metallization rate is the percentage of metallic iron to total iron in the reduced ferrotitanium material, Fe ⁰ /TFe×100％。

5. The method for preparing titanium-rich material from titanium middling according to claim 4,

the acid leaching method for preparing the titanium-rich material comprises the following conditions: and (2) reacting the reduced ferrotitanium material with leaching acid for 0.5-2 h at normal pressure, wherein the reaction temperature is 20-60 ℃, the mass-to-volume ratio of the reduced ferrotitanium material to the leaching acid is 1 (2-5), and the mass fraction concentration of the leaching acid is 13-25%.

6. The method for preparing titanium-rich material from titanium middling according to claim 4,

the conditions for preparing the titanium-rich material by the corrosion method are as follows: taking the reduced ferrotitanium material and a corrosion solution, and reacting for 2-6 h under the condition of charging air to obtain primary artificial rutile; the reaction temperature is 30-110 ℃, the mass ratio of the reduced ferrotitanium material to the corrosion liquid is 1 (2-8), the corrosion liquid is an ammonium salt aqueous solution, and the ammonium salt in the corrosion liquid is NH ₄ Cl、(NH ₄ ) ₂ SO ₄ One or two of the corrosion solutions are mixed, and the concentration of ammonium salt in the corrosion solution is 0.05-4 mol/L;

7. The method for preparing titanium-rich material from titanium middling according to claim 3,

the preparation conditions of the high titanium slag are as follows: and smelting the reduced ferrotitanium material and a reducing agent at 1600-1750 ℃.

8. The method for preparing titanium-rich material from titanium middling according to claim 1,

and (4) carrying out at least one deep reduction and magnetic separation on the reduced ferrotitanium material obtained after the deep reduction and magnetic separation in the step S2.

9. The method for preparing titanium-rich material from titanium middling according to claim 8,

the temperature of the reduction at the back depth is not lower than that at the front depth.

10. The method for preparing titanium-rich material from titanium middling according to claim 9,

the deep reduction times are two, the first deep reduction temperature is 800-1000 ℃, and the second deep reduction temperature is 1000-1100 ℃.