阅读说明：本技术 一种攀西钛精矿制备富钛料的方法 (Method for preparing titanium-rich material from Panxi titanium concentrate ) 是由 和奔流 陈建立 彭忠辉 贺高峰 陈树忠 龚俊举 肖莎莎 张坤 王冬花 闫广英 于 2020-05-11 设计创作，主要内容包括：本发明公开了一种攀西钛精矿制备富钛料的方法,本方法主要包括钛精矿选矿、冶炼、筛分、氧化焙烧、还原焙烧、碱浸、加压酸浸、煅烧等步骤。本发明公开了制备合格沸腾氯化原料低硅钙钛精矿中的CaO和SiO<Sub>2</Sub>最高含量,为选矿工序提供了生产目标,确保钛的综合利用；在氧化－还原工序之后加了碱浸除硅,得到的产品中的CaO和SiO<Sub>2</Sub>含量更低,更利于大型沸腾氯化进行；本发明将钛铁矿中的铁元素制成生铁,价值较高并且减少其二次污染；冶炼破碎产生的小颗粒酸渣可直接作为产品销售或用做硫酸法钛白原料,减少再回炉的能耗,合理地利用了钛资源；本发明酸浸过程中酸的浓度和液固比都较低,浸后母液可完全实现循环利用,减少废液处理。(The invention discloses a method for preparing a titanium-rich material from Panxi titanium concentrate, which mainly comprises the steps of titanium concentrate ore dressing, smelting, screening, oxidizing roasting, reducing roasting, alkaline leaching, pressure acid leaching, calcining and the like. The invention discloses CaO and SiO in low-silicon calcium titanium concentrate for preparing qualified boiling chlorination raw materials 2 The highest content provides a production target for the ore dressing process and ensures the comprehensive utilization of titanium; adding alkali to remove silicon after the oxidation-reduction process to obtain CaO and SiO in the product 2 The content is lower, and the large-scale boiling chlorination is more favorably carried out; the invention prepares the iron element in the ilmenitePig iron, which has higher value and reduces the secondary pollution; the acid sludge in small particles generated by smelting and crushing can be directly sold as a product or used as a titanium dioxide raw material by a sulfuric acid process, so that the energy consumption of re-melting is reduced, and the titanium resource is reasonably utilized; the concentration of acid and the liquid-solid ratio in the acid leaching process are low, the mother liquor after leaching can be completely recycled, and the waste liquid treatment is reduced.)

1. A method for preparing a titanium-rich material from Panxi titanium concentrate is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

step 1, further sorting conventional Panxi titanium concentrate to remove calcium and silicon minerals, and obtaining low-calcium silicon titanium concentrate;

step 2, placing the low-calcium silicon titanium concentrate and a reducing agent into a titanium slag furnace for smelting to obtain titanium slag and pig iron; crushing and screening the titanium slag, and screening the titanium slag with the granularity meeting the boiling chlorination requirement;

step 3, placing the titanium slag which meets the boiling chlorination requirement and is obtained in the step 2 in an oxidizing atmosphere for oxidizing roasting treatment to obtain titanium oxide slag;

step 4, placing the titanium oxide slag in a reducing atmosphere for reducing roasting treatment to obtain reduced titanium slag;

step 5, placing the reduced titanium slag in an alkali solution for alkali leaching, and then filtering and washing to obtain desiliconized titanium slag;

step 6, placing the desiliconized titanium slag in a reaction kettle, and performing pressurized acid leaching treatment by using a hydrochloric acid leaching solution;

and 7, carrying out pressure filtration, washing, drying and calcining on the slurry obtained after the pressure acid leaching to obtain a titanium-rich material product.

2. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: in the step 1, the separation mode of the Panxi titanium concentrate is flotation or electric separation; the low-calcium silicon titanium concentrate obtained after separation comprises the following components: TiO 2₂≥49.0％，SiO₂≤2.5％，CaO≤0.45％。

3. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: the titanium slag furnace in the step 2 is an electric furnace; the reducing agent is one or more of anthracite, metallurgical coke and petroleum coke; when smelting is carried out by using a titanium slag furnace, the mass ratio of the low-calcium silicon titanium concentrate to the reducing agent is 1: 0.05-0.4, and the smelting temperature is 1450-1700 ℃; TiO in titanium slag obtained after smelting₂The grade is 65-85%; the granularity of the titanium slag which meets the requirement of boiling chlorination is 8-200 meshes.

4. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 3, wherein the method comprises the following steps: TiO in titanium slag obtained after smelting₂The grade is 74-79%; the granularity of the titanium slag which meets the requirement of boiling chlorination is 10-160 meshes.

5. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: in the oxidizing roasting process in the step 3, the oxidizing roasting temperature is 950-1100 ℃, and the oxidizing roasting time is 0.5-3 hours; oxidizing the roasting tail gas with O₂The oxygen content is more than or equal to 5 vol%.

6. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: in the reducing roasting process in the step 4, the used reducing atmosphere is one or more of electric furnace gas, coal, natural gas, hydrogen and CO; the reduction temperature is 750-950 ℃, and the reduction time is 1.0-5.0 h.

7. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: in the alkaline leaching process in the step 5, the mass liquid-solid ratio of the alkaline solution to the reduced titanium slag is 2.0-10.0: 1, the alkaline leaching temperature is 30-90 ℃, and the alkaline leaching time is 2-4 h; the alkali in the alkali solution is NaOH, KOH, LiOH and Na₂CO₃、K₂CO₃、Li₂CO₃One or more of; the mass fraction of alkali in the alkali solution is 5-25%.

8. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: in the pressurized acid leaching process in the step 6, the liquid-solid mass ratio of the hydrochloric acid leaching solution to the desiliconized titanium slag is 1.0-3.0: 1, leaching at 130-160 ℃, for 1.0-6.0 h, and under 0.3-0.6 MPa; the hydrochloric acid concentration in the hydrochloric acid leaching solution is 180-250 g/L, and metal ions M in the hydrochloric acid leaching solution^2+/3+The concentration is 20-80 g/L; the metal ion M^2+/3+Is Fe²⁺、Fe^{3 +}、Ca²⁺、Mg²⁺、Al³⁺、Mn²⁺One or more of (a).

9. The method for preparing titanium-rich material from Panxi titanium concentrate according to claim 8, wherein: the metal ion M in the hydrochloric acid leaching solution^2+/3+Metal ion M^2+/3+Is added to the hydrochloric acid leaching solution in the form of metal chloride salt.

10. The method for preparing the titanium-rich material from the Panxi titanium concentrate according to claim 1, wherein the method comprises the following steps: in the calcining process in the step 7, the calcining temperature is 500-950 ℃, and the calcining time is 20-180 min.

Technical Field

The invention relates to the technical field of metallurgy and chemical industry, in particular to a method for preparing a titanium-rich material from Panxi titanium concentrate.

Background

Titanium chloride white is a project which is preferentially encouraged by the nation due to the unique product performance advantage and environmental friendliness. But it has very strict requirements for raw materials except for TiO with high requirements₂In addition to the content, low impurity contents, in particular calcium and magnesium contents, are also required. The two elements react with chlorine in a chlorination furnace to produce chloride with low melting point and high boiling point, which can seriously deteriorate the fluidity of a fluidized bed furnace, and generally requires that CaO + MgO is less than or equal to 1.5 percent and CaO is less than or equal to 0.15 percent. At present, domestic titanium white chloride raw materials or titanium concentrates needed by upgrading the titanium white chloride raw materials are seriously depended on import, and are very unfavorable for the development of the titanium industry in China.

The titanium resource reserves in China are rich, more than 90 percent of the titanium ore resources in China are concentrated in the Panzhihua in SichuanAnd (4) regions. However, because the ilmenite structure in the Panzhihua region is compact, the titanium concentrate has high content of impurities such as calcium, magnesium, silicon and the like, fine granularity and good acid solubility, most of the ilmenite is directly used for sulfuric acid process titanium white, and a small amount of ilmenite is used for upgrading acid-soluble titanium slag. Most of the iron in the titanium concentrate is converted into FeSO which has low value and is very easy to cause secondary pollution₄And titanium is converted into a low-quality sulfuric acid process titanium dioxide product, and the utilization value of the whole titanium concentrate is low.

On one hand, Chinese titanium has abundant resources, but the titanium can only be used for producing low-value products and has larger pollution due to poor quality, and on the other hand, a large amount of titanium raw materials are imported from abroad. How to improve the utilization value of Chinese titanium resources and process the titanium resources into high-quality titanium chloride white or titanium sponge raw materials is the key for improving the competitiveness of the Chinese titanium industry.

A great deal of research is carried out at home and abroad around the upgrade of high-quality titanium-rich materials of Panxi ilmenite. Chinese patent CN109499744A discloses a method for preparing a chlorinated titanium-rich material by using high-calcium magnesium silicon titanium concentrate, which comprises the steps of firstly carrying out ball milling on titanium concentrate, then obtaining low-silicon titanium concentrate through flotation, mixing the low-silicon titanium concentrate with hydrochloric acid, carrying out acid leaching, filtering, washing and drying to obtain a fine-grained titanium-rich material; and heating, melting, cooling and crushing the fine material-grade titanium-rich material to obtain a finished product titanium-rich chloride material. The patent fully utilizes the advantages of various disciplines, integrates mineral separation, chemical engineering and metallurgy into a whole, obtains a titanium-rich material with CaO + MgO less than or equal to 1.5 percent and the granularity meeting the requirement of titanium white chloride, and solves the problem that the granularity of the artificial rutile prepared by the Panxi mineral hydrochloric acid method can not meet the requirement of boiling chlorination. However, the patent also has certain defects that iron in the ilmenite is converted into ferrous chloride which has low value and is easy to cause secondary pollution in the acid leaching process, and the iron utilization value is low. In addition, this patent melts the leached slag and then breaks the slag after melting. Due to leaching slag (TiO)₂) The melting point of the alloy is high, the fluidity of the alloy is poor, which brings troubles to smelting production, even no high-temperature electric furnace which can meet the technological conditions of the patent is available, and the industrialization has great challenges. Meanwhile, the crushing can not avoid producing a part of fine materials, although the part of fine materials can be returned to be beneficial to smelting, the defect of high energy consumption still exists, and because a large amount of fine materials are contained,the materials are difficult to enter the furnace in the melting process, and the production difficulty is increased.

Chinese patent CN201811404803.8 discloses a method for preparing a titanium-rich chloride material by using high-silicon-calcium-magnesium titanium concentrate, which comprises the following steps: (a) silicon removal, (b) electric furnace smelting, (c) oxidation modification, (d) reduction modification, (e) acid leaching, and (f) filtering and calcining. The method starts from the source, integrates mineral separation, smelting and acid leaching methods, and removes SiO from the high-silicon calcium magnesium titanium concentrate through flotation₂And then smelting the low-silicon titanium concentrate into low-silicon slag, crushing the low-silicon slag to obtain qualified granularity, performing oxidation-reduction modification, and then performing pressure acid leaching to successfully prepare the chlorinated titanium-rich material with qualified granularity and grade. This patent first obtains SiO2 by flotation<1.5% low silicon titanium concentrate, in order to sort the purer low silicon titanium concentrate from the high silicon calcium magnesium titanium concentrate, it is necessary to either (1) concentrate (low silicon titanium concentrate) yield is low but SiO is the case₂The grade of the titanium concentrate tailings can meet the requirement of titanium dioxide used by sulfuric acid method; (2) the yield of the concentrate (low-silicon titanium concentrate) is high, but the titanium concentrate tailings contain SiO₂The grade is too high to meet the requirement of producing the titanium dioxide by the sulfuric acid method. So the patent is due to the SiO in the low-silicon titanium concentrate₂The content is determined to be less than 1.5% to limit its economical efficiency and practicality.

Chinese patent CN109399706A discloses a method for upgrading UGS slag by using high-calcium magnesium titanium slag, which takes the high-calcium magnesium titanium slag produced in Panxi area as a raw material, and finally obtains the UGS slag with CaO + MgO less than or equal to 1.5 percent through alkali leaching, oxidizing roasting, reducing sodium salt roasting, pressure acid leaching and roasting. The titanium slag is mainly composed of titanium black M₃O₅Solid solution of type, silicate glass phase and a small amount of metallic iron. Wherein the black titanium stone phase is mainly composed of Ti₃O₅、MgTi₂O₅And FeTi₂O₅And the like, and the silicate glass phase mainly comprises impurities of Ca, Al, Si and the like. The patent firstly aims to destroy a silicate structure in titanium slag through alkaline leaching, and then destroys a black titanium stone structure of the titanium slag through oxidation-sodium reduction roasting treatment, so that the black titanium stone structure forms a loose pore structure, the contact area of impurity elements and acid in the subsequent acid leaching process is increased, and most importantly, the contact area of the impurity elements and the acid is increasedFinally removing impurities and enriching TiO₂The purpose of (1). The titanium slag obtained by high-temperature smelting has a compact structure, wherein the titanium black and the silicate are dispersed and distributed, and the normal-pressure alkaline leaching can only destroy the silicate phase on the surface of the titanium slag and can not effectively destroy the silicate phase in the titanium slag, so that the product finally obtained in the patent can also obtain a certificate. SiO in UGS slag of final product₂High content up to 6% SiO₂High content, large influence on boiling chlorination, SiO₂Can be enriched in a bed layer, greatly shortens the operation time of the chlorination furnace and influences the production efficiency. In addition, the patent adds more Na in the reduction process₂CO₃And NaOH. Because the sodium salt is a low-melting-point substance, the introduction of the sodium salt is easy to cause material hardening, and the subsequent steps are also greatly influenced. In the acid leaching stage, the solid-to-solid ratio of the hydrochloric acid to the titanium slag liquid is large, the solution after leaching is difficult to recycle, the treatment difficulty is large, and the cost is high.

Chinese patent CN104045111A discloses a method for preparing artificial rutile, which comprises subjecting titanium-containing materials (titanium concentrate or titanium slag) to high-temperature oxidation treatment at 850-1200 ℃, then subjecting the oxidized titanium-containing materials to reduction modification treatment at 650-900 ℃ in a reducing atmosphere, leaching the redox-modified titanium-containing materials with heated acid in a fluidized manner, filtering the slurry obtained after leaching, and washing and calcining the solid phase to obtain the artificial rutile. The patent carries out redox roasting on the titanium-containing material, mainly aims to destroy the structure of the titanium-containing material, form holes and enlarge the contact area of the subsequent acid leaching impurity elements and acid, thereby removing the impurity elements and enriching TiO₂The purpose of (1). The method is effective for upgrading titanium concentrate, and for titanium slag, the structure is compact, and the acid sludge impurity content in Panxi area is high, especially CaO, MgO and SiO₂The content of the titanium-rich material required by large-scale boiling chlorination is difficult to obtain by atmospheric pressure leaching only through oxidation-reduction roasting. In particular, in this patent, only acid leaching is used, and the removal rate of Si element is limited.

Chinese patent CN201810036072.X 'a method for selectively leaching and upgrading high-titanium slag' discloses that oxygen-adding, heating, pressurizing and alkaline leaching is carried out on titanium smelting slag to remove aluminum and silicon, and then heating, pressurizing and acid leaching is carried out to remove elements such as iron, magnesium, calcium and the like. The patent does not oxidize/reduce the smelting slag, so that titanium dioxide is not red, and only by introducing oxygen to oxidize trivalent titanium in the titanium smelting slag during alkaline leaching, which is an incomplete oxidation process, the trivalent titanium can be subjected to acid hydrolysis in acid leaching to form metatitanic acid, so that the leaching slag is difficult to filter and the recovery rate of titanium is lost.

At present, although many researches are conducted around the processing technology of the Panxi mine for upgrading raw materials required for meeting large-scale boiling chlorination, no industrialized technology exists yet.

Disclosure of Invention

The invention aims to overcome the defects and provide a method for preparing a titanium-rich material from Panxi titanium concentrate, wherein the Panxi titanium concentrate is used for preparing the titanium-rich material required by boiling chlorination so as to meet the requirement of large boiling chlorination.

In order to achieve the purpose, the invention is implemented according to the following technical scheme:

a method for preparing titanium-rich material from Panxi titanium concentrate comprises the following steps,

step 1, further sorting conventional Panxi titanium concentrate to remove calcium and silicon minerals, and obtaining low-calcium silicon titanium concentrate;

step 2, placing the low-calcium silicon titanium concentrate and a reducing agent into a titanium slag furnace for smelting to obtain titanium slag and pig iron; crushing and screening the titanium slag, and screening the titanium slag with the granularity meeting the boiling chlorination requirement;

step 3, placing the titanium slag which meets the boiling chlorination requirement and is obtained in the step 2 in an oxidizing atmosphere for oxidizing roasting treatment to obtain titanium oxide slag;

step 4, placing the titanium oxide slag in a reducing atmosphere for reducing roasting treatment to obtain reduced titanium slag;

step 5, placing the reduced titanium slag in an alkali solution for alkali leaching, and then filtering and washing to obtain desiliconized titanium slag;

step 6, placing the desiliconized titanium slag in a reaction kettle, and performing pressurized acid leaching treatment by using a hydrochloric acid leaching solution;

and 7, carrying out pressure filtration, washing, drying and calcining on the slurry obtained after the pressure acid leaching to obtain a titanium-rich material product.

Preferably, in the step 1, the separation mode of the Panxi titanium concentrate is flotation or electric separation; the low-calcium silicon titanium concentrate obtained after separation comprises the following components: TiO 2₂≥49.0％，SiO₂≤2.5％，CaO≤0.45％。

The purpose of further sorting the conventional titanium concentrate is to reduce both silicon and calcium in the titanium concentrate. At present, Panzhihua titanium concentrate generally contains TiO₂47.0％、CaO 1.09％、MgO 3.99％、SiO₂3.17 percent, because the contents of calcium, magnesium and silicon are too high, the method is not suitable for producing high-quality boiling chlorination high-titanium slag, and the contents of silicon and calcium in the titanium concentrate must be further reduced. However, the lower the silicon and calcium content of the titanium concentrate, the lower the yield of low calcium silicon titanium concentrate, i.e. the poorer its economics. In order to produce high-quality high-titanium slag, comprehensively balance economy, titanium liquid filterability in low-grade titanium concentrate production and the like, SiO in low-calcium silicon ilmenite must be subjected to₂CaO content is controlled below 2.5 percent and 0.45 percent respectively, and TiO₂≥49.0％。

Preferably, the titanium slag furnace in the step 2 is an electric furnace; the reducing agent is one or more of anthracite, metallurgical coke and petroleum coke; when smelting is carried out by using a titanium slag furnace, the mass ratio of the low-calcium silicon titanium concentrate to the reducing agent is 1: 0.05-0.4, and the smelting temperature is 1450-1700 ℃; TiO in titanium slag obtained after smelting₂The grade is 65-85%; the granularity of the titanium slag which meets the requirement of boiling chlorination is 8-200 meshes.

Preferably, TiO in the titanium slag obtained after smelting₂The grade is 74-79%; the granularity of the titanium slag which meets the requirement of boiling chlorination is 10-160 meshes.

TiO in titanium slag₂The lower the grade, the higher the capacity of the electric furnace, but the lower the recovery of iron. The titanium slag is crushed by adopting conventional crushing equipment and screening equipment, wherein the crushing equipment comprises a pair-rod crusher, a hammer crusher, a jaw crusher and the like.

Preferably, the oxidation of step 3In the roasting process, the oxidizing roasting temperature is 950-1100 ℃, and the oxidizing roasting time is 0.5-3 h; oxidizing the roasting tail gas with O₂The oxygen content is more than or equal to 5 vol%.

Oxidizing and roasting: changing iron in the titanium slag into ferric iron; breaking the crystal lattice of the calcium-silicon glass phase mineral in the titanium slag, and facilitating the hydrochloric acid leaching of calcium; the trivalent titanium in the titanium slag is oxidized and the titanium dioxide is rutile-phase, thereby preventing the chemical refinement in the hydrochloric acid leaching process and improving the recovery rate of the titanium.

Preferably, in the reducing roasting process in the step 4, the reducing atmosphere used is one or more of electric furnace gas, coal, natural gas, hydrogen and CO; the reduction temperature is 750-950 ℃, and the reduction time is 1.0-5.0 h. The reduction is to reduce ferric iron in the titanium oxide slag into ferrous iron, and the ferrous iron is not only leached quickly, but also has low acid consumption.

Preferably, in the alkaline leaching process in the step 5, the mass liquid-solid ratio of the alkali solution to the reduced titanium slag is 2.0-10.0: 1, the alkaline leaching temperature is 30-90 ℃, and the alkaline leaching time is 2-4 hours; the alkali in the alkali solution is NaOH, KOH, LiOH and Na₂CO₃、K₂CO₃、Li₂CO₃One or more of; the mass fraction of alkali in the alkali solution is 5-25%.

The alkaline leaching serves two purposes: firstly, silicon is an impurity of boiling chlorination, the removal of silicon in titanium slag is beneficial to improving the quality of a titanium-rich material, and the silicon and alkali (NaOH) can react to generate water-soluble Na₂SiO₄(ii) a And secondly, the calcium-silicon-glass phase minerals in the titanium slag are further destroyed, so that the next acid leaching process is facilitated to remove CaO in the calcium-silicon-glass phase, and the content of CaO in the titanium-rich material is reduced.

Preferably, in the pressure acid leaching process in the step 6, the liquid-solid mass ratio of the hydrochloric acid leaching solution to the desiliconized titanium slag is 1.0-3.0: 1, leaching at 130-160 ℃, for 1.0-6.0 h, and under 0.3-0.6 MPa; the hydrochloric acid concentration in the hydrochloric acid leaching solution is 180-250 g/L, and metal ions M in the hydrochloric acid leaching solution^2+/3+The concentration is 20-80 g/L; the metal ion M^2+/3+Is Fe²⁺、Fe³⁺、Ca²⁺、Mg²⁺、Al³⁺、Mn²⁺One or more of (a).

Preferably, the metal ion M in the hydrochloric acid leaching solution^2+/3+Metal ion M^2+/3+Is added to the hydrochloric acid leaching solution in the form of metal chloride salt.

Preferably, in the calcining process in the step 7, the calcining temperature is 500-950 ℃, and the calcining time is 20-180 min. The filtration can be carried out by conventional filtration methods, such as pressure filtration, vacuum filtration or centrifugal filtration, and the washing is carried out with a HCl solution having a pH of < 2.

The invention has the following function principle:

at present, the main problems of producing the titanium-rich material by using the Panxi titanium concentrate are CaO and SiO in the titanium-rich material₂Too high to meet the requirements of large boiling chlorination. In order to meet the long-term smooth operation of large-scale boiling chlorination production, except the granularity of the titanium-rich material, CaO, MgO + CaO and SiO in the titanium-rich material₂Should be less than 0.15%, 1.5% and 1.5%, respectively.

The main reason why the Panxi titanium concentrate can not produce the boiling chlorination raw material is that the Panxi titanium concentrate contains high contents of Ca, Mg and Si. From the mineralogical analysis, about 70 percent of CaO and 80 percent of SiO are found in the Panxi titanium concentrate₂From the mineral spodumene, the remaining 30% CaO from ilmenite and other minerals, the calcium in ilmenite being present in the crystal lattice of ilmenite in a homogeneous manner, about 20% SiO₂From other minerals such as quartz and silicon-aluminium compounds. More than about 90% of the MgO originates from ilmenite and is present in the crystal lattice of ilmenite in a homogeneous manner. Therefore, the main impurity mineral in the Panxi titanium concentrate is the titanium pyroxene. Conventional flotation separation is currently difficult due to the fact that the magnetic properties and floatability of titanopentite are relatively close to those of ilmenite. The low-silicon-calcium-titanium concentrate can be obtained by adopting selective inhibition flotation and electric separation and other separation technologies. When the high-grade low-silicon-calcium titanium concentrate is obtained, the low-grade titanium concentrate containing high silicon and calcium is also generated. In order to fully utilize resources, the low-grade titanium concentrate can be used as a raw material of titanium dioxide in a sulfuric acid process, but the overhigh silicon can cause difficult filtration of titanium liquid and influence the application of the titanium liquid. Therefore, CaO and SiO of the high-grade low-silicon-calcium titanium concentrate₂The determination of grade should be balanced: (1) the contents of calcium oxide and silicon oxide in the low silicon-calcium titanium concentrate and CaO and SiO in the titanium-rich material₂The relationship of (1): the lower the contents of calcium oxide and silicon oxide in the low-silicon-calcium titanium concentrate are, the better the quality of the produced titanium-rich material is, and the easier the production process of the titanium-rich material is; (2) the content of calcium oxide and silicon oxide in the low silicon calcium titanium concentrate is related to the yield of the low silicon calcium titanium concentrate: the higher the content of calcium oxide and silicon oxide in the low-silicon-calcium-titanium concentrate is, the higher the yield of the low-silicon-calcium-titanium concentrate is, and the lower the cost of the low-silicon-calcium-titanium concentrate is; (3) the relationship between the content of silicon oxide in low-grade titanium concentrate (separation tailings) and the filtering performance of titanium liquid is as follows: the higher the content of silica in the low-grade titanium concentrate is, the poorer the filtering performance of the titanium liquid is. So that CaO and SiO of the high-grade low-silicon-calcium titanium concentrate are determined reasonably₂The grade of titanium can be optimized, the economic cost of the production can be optimized, and the comprehensive utilization of titanium can be improved.

The principle of titanium slag production by a titanium concentrate electric furnace smelting method is that ilmenite and reducing agent anthracite or petroleum coke are mixed in an electric furnace, and iron oxide in the ilmenite is reduced to metallic iron at 1650-1750 ℃ to remove iron selectively, so that titanium is enriched. Thereby obtaining a TiO-containing₂The pyrometallurgical process of 65-85% titanium slag.

The main reaction formula is as follows:

FeTiO₃+C→Fe+TiO₂+CO；

2FeTiO₃+3C→2Fe+Ti₂O₃+3CO；

FeTiO₃+2C→Fe+TiO+2CO；

Fe₂O₃+3C→2Fe+3CO。

the electric furnace smelting process of the titanium concentrate mainly removes iron in the titanium concentrate, elements such as silicon, aluminum, magnesium, calcium and the like in the titanium concentrate are enriched, and the silicon and the calcium form CaTiSiO₅Of a glass phase mineral, CaTiSiO₅Is proportional to the content of silicon and calcium in the titanium concentrate, which is not acid-decomposed by hydrochloric acid. Magnesium can be homomorphic with iron to produce (Mg, Fe) Ti₂O₅。

Selecting proper granularity after crushingOxidizing and roasting the titanium slag to oxidize all the low valence titanium into tetravalent titanium to form rutile TiO₂Preventing subsequent acid leaching of TiO₂The dissolution of (3); while oxidizing other suboxides, such as FeO, to Fe₂O₃And Ca²⁺、Mg²⁺、Al³⁺、Si⁴⁺Remain unchanged. Due to the transformation of the valence state of the compound, the compact structure of the titanium slag is destroyed by oxidizing roasting to form holes, and the chemical reaction generated in the oxidation process is as follows:

(FeTi₂O₅)_0.32(MgTi₂O₅)_0.33(Ti₃O₅)_0.35+0.255O₂→(Fe₂TiO₅)_0.16(MgTi₂O₅)_0.33+1.53TiO₂；

and then reducing the titanium oxide slag at the reduction temperature of 750-950 ℃, wherein only the reduction of iron oxide occurs, and the reduction of titanium oxide does not occur. The obtained heat treatment slag mainly consists of rutile (Ti)_0.993Fe_0.001V_0.005Al_0.001Cr_0.001)O₂And ferromanganese (Fe)_0.178Mg_0.266Mn_0.006)(Ti_1.100Al_0.040V_0.0075Cr_0.0025)₂O₅And (4) forming. The oxidation-reduction roasting treatment can greatly increase the contact area of titanium slag and liquid, enhance the leaching rate of the contained impurities, has the lowest hydrochloric acid consumption and the least titanium dioxide dissolution, and can keep the original-grade granularity.

In addition, most Si elements are removed while the glass phase mineral structure in the titanium slag is damaged through alkaline leaching, and the rest acid-soluble impurities are leached out through pressurization, so that the quality of the titanium-rich material is improved. The metal chloride is added in the acid leaching process, so that the activity of hydrochloric acid can be enhanced, the leaching rate of each impurity element is improved, the leaching concentration of the hydrochloric acid is reduced, and finally the titanium-rich material meeting the requirement of large boiling chlorination is obtained. The chemical reactions that will occur during acid leaching are as follows:

Fe₂O₃·3TiO₂+6HCl→2FeCl₃+3H₂O+3TiO₂；

FeO·2TiO₂+2HCl→FeCl₂+H₂O+2TiO₂；

CaO·2TiO₂+2HCl→CaCl₂+H₂O+2TiO₂；

CaO+2HCl→CaCl₂+H₂O。

compared with the prior art, this patent difference:

compared with the patent CN109499744A method for preparing titanium-rich chloride material by using high-calcium magnesium silicon titanium concentrate, the invention uses the mineral processing technology to process SiO in the titanium concentrate₂And the CaO content is controlled below 2.5 percent and 0.45 percent respectively to ensure higher titanium yield, and the tailings (low-grade titanium concentrate) after the separation can be used as raw materials of titanium white by a sulfuric acid process. In the patent, SiO in the titanium concentrate after concentration₂Only about 0.7 percent, a large amount of silicon enters the tailings after the selection, and the part of the tailings (low-grade titanium concentrate) has high silicon-calcium content, so that the titanium liquid is easy to settle when the tailings are directly used for the titanium white by the sulfuric acid process, and the influence on the production of the titanium white by the sulfuric acid process is large, so that the part of the tailings cannot be effectively utilized. The invention obtains the pig iron with higher value by smelting the iron in the titanium concentrate, and the patent converts the iron into FeCl which has low value and is easy to cause secondary pollution₂(ii) a The invention directly selects acid sludge with proper granularity to prepare the titanium-rich material, effectively ensures the qualified rate of product granularity, and acid sludge with smaller granularity can be directly sold as a product or used as a titanium dioxide raw material for a sulfuric acid process.

Compared with the patent CN201811404803.8 method for preparing titanium-rich chloride material by using high-silicon-calcium-magnesium titanium concentrate, the invention adopts a two-stage silicon removal process to remove part of silicon in the ore dressing stage and keep a certain high silicon content in tailings in order to improve the comprehensive utilization rate of ilmenite, namely, the invention not only can improve the comprehensive utilization rate of ilmeniteThe yield of the selected titanium concentrate is improved, the difficulty of using the tailings for sulfuric acid process titanium dioxide is reduced, the two-stage silicon removal process is placed after acid sludge oxidation reduction roasting, the silicate structure is further destroyed through a mild alkaline leaching process, and SiO is reduced₂The content of the CaO exposes more CaO, which is very beneficial to the subsequent acid leaching to remove calcium. In the oxidizing roasting stage of the patent, only the influence of temperature is considered, but the influence of oxygen concentration in the oxidizing process on the subsequent acid leaching effect is ignored, the temperature and the oxygen concentration are key factors influencing the migration of elements such as Fe, O and the like in the roasting process, the temperature is proper, and O is₂Qualified titanium-rich materials are still difficult to obtain due to improper concentration. The invention finds a key process influencing the subsequent acid leaching effect by oxidizing roasting, the roasting temperature range is narrow, the temperature is low, the migration degree of elements such as Fe, O and the like is not enough, the content structure of particles is still compact, the temperature is too high, most Fe elements migrate to the surface of the particles, and the subsequent impurity removal is not facilitated. The oxygen concentration in the oxidizing roasting process has an important influence on the phase composition and microstructure evolution behavior of titanium slag particles, and further influences the acid solubility of the titanium slag. At low oxygen concentration, Ti³⁺、Fe²⁺The outward migration degree of ions is low, so that the titanium slag structure is compact, and the hydrochloric acid internal diffusion becomes a limiting step for impurity removal of the titanium slag in the subsequent leaching process. Increasing oxygen concentration promotes Ti³⁺、Fe²⁺The ions migrate outwards, on one hand, the ions promote the titanium slag particles to form a porous structure inside, and on the other hand, the ions reduce the particle center M₃O₅The Fe/Mg ratio of the phases, at higher oxygen concentrations, the porous structure formed by the particles ensures sufficiently rapid internal diffusion of hydrochloric acid, and in addition, M of the hardly soluble acid in the particles₃O₅The phase has a high enough Fe/Mg ratio, and is reduced into M which is easy to dissolve in acid in the subsequent reduction stage₂O₃And impurity elements in titanium slag particles can be leached in a large amount. And M at the center of titanium slag particles under high oxygen concentration₃O₅The phases have a low Fe/Mg ratio and cannot be reduced to M₂O₃Therefore, although the titanium slag is loose and porous, the impurity elements in the titanium slag are difficult to leach out. The invention finds the root cause of success of upgrading the titanium-rich material in Panxi mine by controlling the oxidation temperature and the concentration.

Compared with CN109399706A method for upgrading UGS slag by high calcium magnesium titanium slag, the invention removes more SiO in the mineral processing stage₂And CaO, obtaining acid-soluble titanium slag with relatively low content of calcium-silicon glass phase minerals by smelting, forming a pore structure by oxidation/reduction roasting, increasing the contact area of silicate glass phase and sodium hydroxide in the titanium slag by subsequent alkali leaching to achieve the purpose of destroying the silicate glass phase, and finally removing impurities by acid leaching to obtain the titanium-rich material meeting the requirement of large-scale boiling. In the patent, high-calcium magnesium titanium Slag is subjected to alkaline leaching treatment, and due to the compactness of the titanium Slag structure, the glass phase structure in the Slag is difficult to destroy only by normal-pressure alkaline leaching, so that the CaO + MgO content of the finally obtained UGS (Up-grade Slag) Slag is lower than 1.5%, but the SiO & lt + & gt content of the Slag is lower than 1.5%₂The content is as high as more than 6 percent, the influence on boiling chlorination is large, the liquid-solid ratio of hydrochloric acid to titanium concentrate in the acid leaching process is high, more waste liquid is generated, and the treatment cost is high. The liquid-solid ratio in the acid leaching process is low, and the mother liquor after leaching can be completely recycled.

Compared with CN104045111A A method for preparing artificial rutile, the method comprises the steps of carrying out high-temperature oxidation treatment on a titanium-containing material (titanium concentrate or titanium slag) at 850-1200 ℃, then carrying out reduction modification treatment on the oxidized titanium-containing material at 650-900 ℃ in a reducing atmosphere, leaching the redox-modified titanium-containing material in a fluidized manner by using heated acid, filtering the obtained slurry after leaching, and washing and calcining the solid phase to obtain the artificial rutile. The patent carries out redox roasting on the titanium-containing material, mainly aims to destroy the structure of the titanium-containing material, form holes and enlarge the contact area of the subsequent acid leaching impurity elements and acid, thereby removing the impurity elements and enriching TiO₂The purpose of (1). The method is effective for upgrading ilmenite, and for titanium slag, the structure is compact, and the acid slag impurity content in Panxi area is high, especially CaO, MgO and SiO₂The content is that the titanium-rich material required by large-scale boiling chlorination is difficult to obtain by normal pressure acid leaching only through oxidation reduction roasting. The invention mainly develops around the upgrading of high-quality titanium-rich material of acid sludge by oxidationReducing and roasting to destroy the structure of the titanium black in the titanium slag, then destroying the glass phase structure in the titanium slag through alkaline leaching while removing part of Si elements, and increasing the leaching rate of each impurity element through pressure leaching to finally obtain the titanium-rich material meeting the requirement of large-scale boiling chlorination.

Compared with patent CN 108300874A, a method for selectively leaching and upgrading high titanium slag, the patent crushes the high titanium slag to be less than 0.074mm, then heats and pressurizes alkaline leaching by introducing oxygen and concentrated alkali, and mixes the solid after alkaline leaching and hydrochloric acid and pressurizes and leaches to finally obtain upgraded titanium slag. The modified titanium slag is subjected to alkaline leaching, the alkaline leaching is only normal pressure leaching, the temperature is not more than 90 ℃, the alkaline leaching temperature of the patent is as high as more than 180 ℃, the titanium-rich material with qualified granularity can be directly obtained, and the patent can only obtain a fine material-grade titanium-rich material and cannot be directly used for large-scale boiling chlorination. In addition, the patent only adopts an alkaline leaching and acid leaching working section, and has higher requirement on the raw material of the titanium slag.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention discloses CaO and SiO in low-silicon calcium titanium concentrate for preparing qualified boiling chlorination raw materials₂The highest content provides a production target for the dressing process, increases the yield of the low-silicon calcium titanium concentrate, and reduces SiO in the dressing tailings₂The content of the titanium is reduced, so that the tailings (high-silicon calcium titanium concentrate) can be directly used for a sulfuric acid method to ensure the comprehensive utilization of titanium;

2. according to the invention, alkaline leaching is added after the oxidation-reduction process to remove silicon, so that the characteristic of large pores of titanium slag after oxidation-reduction modification is fully utilized, the leaching rate of silicon is increased, and the alkali consumption is reduced; alkaline leaching not only removes impurity SiO₂And the silicate glass phase is destroyed, so that the acid leaching rate of calcium can be improved, and CaO and SiO in the obtained product₂The content is lower, and the large-scale boiling chlorination is more favorably carried out;

3. the invention prepares the iron element in the ilmenite into pig iron, has higher value and reduces the secondary pollution; the acid sludge in small particles produced by smelting and crushing can be directly sold as a product or used as a titanium dioxide raw material by a sulfuric acid process, so that the energy consumption of re-melting is reduced, and the titanium resource is reasonably utilized; the concentration of acid and the liquid-solid ratio in the acid leaching process are low, the mother liquor after leaching can be completely recycled, and the waste liquid treatment is reduced.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The present invention will be further described with reference to specific examples, which are illustrative of the invention and are not to be construed as limiting the invention.