High-chromium vanadium-titanium ore concentrate pellets and method for producing same

Abstract

The present application relates to a kind of high-chromium vanadium-titanium ore pellets and its production method, high-chromium vanadium-titanium ore pellets is by the mixed material A of inner layer and the mixed material B of outer layer after balling, roasting composite type pellet prepared;The components of mixed material A include: iron ore concentrate 75%~90%, gas mud 5%~20%, coking dust 3%~15%, bentonite 0.2%~1.5%;Mixed material B is made of high-chromium vanadium-titanium ore plus the pretreatment binder of 3.5%~4.5% of outer mass percentage.The present application realizes high-chromium vanadium-titanium ore is used in pellet production in large proportion by improving the production process of pellet, when, the index of pellet can meet the requirement of blast furnace smelting, while realizing the full use of coking dust, gas mud and other secondary resources, realizing titanium ball protecting furnace, the purpose of prolonging the service life of blast furnace.

Description

Technical Field

[0001] This invention relates to the field of pellet production technology, and in particular to a high-chromium vanadium-titanium ore pellet and its production method that can improve product quality. Background Technology

[0002] The world possesses abundant iron ore reserves, ranking fifth globally in terms of total iron content. However, my country's iron ore resources are generally characterized by a scarcity of high-grade ores, an abundance of low-grade ores, and complex ore structures. Most are difficult-to-process complex iron ores, including vanadium-titanium magnetite from the Panzhihua region, Bayan Obo complex iron ore, lichenified hematite, and high-iron bauxite from Guangxi. The average grade is only 31%, with iron ore reserves below 50% accounting for approximately 95% of the total. As the reserves of high-quality iron ore resources dwindle, developing efficient processing technologies for low-grade, difficult-to-process associated complex iron ore resources is essential.

[0003] Vanadium-titanium magnetite is a major carrier of iron, vanadium, and titanium resources. It is an important raw material for iron smelting, vanadium and chromium extraction, production of strategic metal titanium, and manufacturing of titanium dioxide, possessing high comprehensive utilization value. my country's demand for vanadium-titanium magnetite and its products is increasing. Vanadium-titanium magnetite is a typical polymetallic symbiotic (associated) complex mineral, characterized by being "poor, fine, scattered, and mixed." Based on its chromium trioxide (Cr2O3) content, it can be further divided into ordinary vanadium-titanium magnetite and high-chromium vanadium-titanium magnetite.

[0004] Chromium, as an important alloying element, is usually added to alloys in the form of metallic chromium or ferrochrome. Ferrochrome alloys, as additives in steel, are used to produce various high-strength, corrosion-resistant, wear-resistant, high-temperature-resistant, and oxidation-resistant special steels, such as stainless steel, acid-resistant steel, heat-resistant steel, ball bearing steel, spring steel, and tool steel. Metallic chromium is mainly used to smelt special alloys with elements such as cobalt, nickel, and tungsten. These special steels and alloys are indispensable materials for the production of guns, missiles, rockets, and ships in civilian aerospace, automotive, shipbuilding, and defense industries. Currently, my country's chromium resources are extremely scarce, and it is heavily reliant on imports.

[0005] High-chromium vanadium-titanium magnetite can meet the iron ore raw material requirements of blast furnace production. Furthermore, given the high chromium and high vanadium characteristics of imported high-chromium vanadium-titanium magnetite, high-value-added vanadium-chromium products can be further developed, thus cultivating new economic growth points for enterprises. Although my country has begun small-scale mining and utilization of high-chromium vanadium-titanium magnetite resources, its system integration technology has not yet been formed. When using high-chromium vanadium-titanium ore as raw material to produce pellets, the finished pellets have low compressive strength, high reduction expansion rate, and poor reduction performance. If used as furnace charge in blast furnace production, it will lead to increased dust, which will worsen the blast furnace permeability and affect the stable and smooth operation of the blast furnace. Summary of the Invention

[0006] This invention provides a high-chromium vanadium-titanium ore pellet and its production method, solving the problems of poor compressive strength, low reducibility, high reduction expansion rate, and poor softening and dripping performance of pellets when using high-chromium vanadium-titanium ore to produce pellets in the prior art. Through the improvement of the pellet production process, when a large proportion of high-chromium vanadium-titanium ore is used in pellet production, all the indicators of the pellets can meet the requirements of blast furnace smelting. At the same time, it realizes the full utilization of secondary resources such as coking dust and gas sludge, and achieves the purpose of titanium ball furnace protection and extending the blast furnace life.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A high-chromium vanadium-titanium ore pellet is a composite pellet obtained by pelletizing and roasting an inner layer of mixture A and an outer layer of mixture B; the mass percentage of mixture B in the composite pellet is 50%–90%, and the remainder is mixture A; wherein:

[0009] The components of mixture A, by mass percentage, include: 75%–90% iron concentrate, 5%–20% gas mud, 3%–15% coking dust, and 0.2%–1.5% bentonite;

[0010] Mixture B consists of high-chromium vanadium-titanium ore and a pre-treated binder with a mass percentage of 3.5% to 4.5%. The pre-treated binder is made by fine grinding of the binder. The binder includes, by mass percentage: sodium carboxymethyl cellulose 0.5% to 6%, bentonite 0.5% to 2%, and magnesite powder 95% to 98%. An additional 7.0% to 8.5% water is added to mixture B.

[0011] Furthermore, the moisture content of the mixture A is 6.5% to 8.0%, and the alkalinity value is 0.8 to 1.8.

[0012] Furthermore, in the adhesive and the pretreated adhesive, the mass percentage content of magnesium oxide is 38% to 52%; the particle size composition of the pretreated adhesive, by mass percentage, is: the proportion of particles smaller than 0.074 mm is greater than 90%.

[0013] Furthermore, the chemical composition of the high-chromium vanadium-titanium ore, by mass percentage, is as follows: 55%–65% iron, 1.0%–4.5% silicon dioxide, 0.1%–1.5% magnesium oxide, 2.5%–7.0% titanium dioxide, 0.5%–3.0% vanadium pentoxide, 0.5%–3.5% chromium trioxide, with the balance being impurity elements.

[0014] Furthermore, in the particle size composition of the high-chromium vanadium-titanium ore, the proportion of particles smaller than 0.074 mm by mass percentage is 20% to 40%, and the proportion of particles smaller than 0.045 mm is 10% to 20%.

[0015] Furthermore, in the binder and pretreated binder, the chemical composition of the magnesite powder, by mass percentage, is: silicon dioxide 5.0%–8.5%, calcium oxide 0.8%–2.5%, magnesium oxide 40%–47%, aluminum oxide 1.0%–2.5%, with the remainder being impurity elements.

[0016] Furthermore, in the binder, the proportion of magnesite powder with a particle size distribution of less than 0.074 mm by mass percentage is greater than 80%.

[0017] Furthermore, in the pretreated binder, the proportion of magnesite powder with a particle size distribution of less than 0.074 mm by mass percentage is 85% to 95%.

[0018] Furthermore, the mass percentage content of magnesium oxide in the mixture B is 1.4% to 2.2%.

[0019] The method for producing high-chromium vanadium-titanium ore pellets includes the following steps:

[0020] (1) Mix iron concentrate, bentonite, gas mud and coking dust to obtain mixture A; spray a mist of slaked lime water solution to wet the mixture during the mixing process;

[0021] (2) Sodium carboxymethyl cellulose, bentonite, and magnesite powder are mixed to obtain a binder; the binder is then finely ground to obtain a pretreated binder.

[0022] (3) Spray high-chromium vanadium-titanium ore and pretreated binder with water mist to mix and wet them to obtain mixture B;

[0023] (4) Pelletize the mixture A. During pelletizing, spray mist water to promote the growth of green pellets. Stop spraying mist water when the pellet core size range is 2-5 mm. After the pellet core is rolled and compacted for 1-2 minutes, start adding mixture B and spray mist calcium permanganate solution. Stop spraying mist calcium permanganate solution when the green pellets grow to 4-8 mm, and switch to spraying mist water. Continue adding mixture B until the green pellet size range is 10-20 mm.

[0024] (5) After drying, preheating and roasting, the green pellets are used to obtain high-chromium vanadium-titanium ore pellets. The drying and preheating temperature is 400-900℃, the drying and preheating time is 8-15 minutes, the roasting temperature is 1100-1350℃, and the roasting time is 20-35 minutes.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] (1) This invention overcomes the problem of poor quality of pellets when high-chromium vanadium-titanium ore is used in pellet production. By different mineral distributions in the inner and outer layers of the pellets, it achieves the purpose of improving the compressive strength of the finished pellets, increasing the reducibility of the pellets, reducing the reduction expansion rate of the finished pellets, and improving the soft melting and dripping performance of the finished pellets.

[0027] (2) This invention broadens the raw materials for pellet production, enabling the use of inexpensive high-chromium vanadium-titanium ore in a large proportion of pellet production, thereby reducing the production cost of pellets.

[0028] (3) This invention makes full use of coking dust and gas sludge, realizing the effective utilization of secondary resources and reducing the pollution caused by industrial waste dumping to the environment.

[0029] (4) The pellets produced by this invention have the advantages of high alkalinity and high magnesium oxide content, which can replace part of the sintered ore in blast furnace ironmaking, increase the proportion of feed into the furnace, and at the same time have the function of protecting the furnace with titanium balls, thus extending the service life of the blast furnace body. Detailed Implementation

[0030] The high-chromium vanadium-titanium ore pellets of this invention are composite pellets obtained by pelletizing and roasting an inner layer of mixture A and an outer layer of mixture B; the mass percentage of mixture B in the composite pellets is 50% to 90%, and the remainder is mixture A; wherein:

[0031] The components of mixture A, by mass percentage, include: 75%–90% iron concentrate, 5%–20% gas mud, 3%–15% coking dust, and 0.2%–1.5% bentonite;

[0032] Mixture B consists of high-chromium vanadium-titanium ore and a pre-treated binder with a mass percentage of 3.5% to 4.5%. The pre-treated binder is made by fine grinding of the binder. The binder includes, by mass percentage: sodium carboxymethyl cellulose 0.5% to 6%, bentonite 0.5% to 2%, and magnesite powder 95% to 98%. An additional 7.0% to 8.5% water is added to mixture B.

[0033] Furthermore, the moisture content of the mixture A is 6.5% to 8.0%, and the alkalinity value is 0.8 to 1.8.

[0034] Furthermore, in the adhesive and the pretreated adhesive, the mass percentage content of magnesium oxide is 38% to 52%; the particle size composition of the pretreated adhesive, by mass percentage, is: the proportion of particles smaller than 0.074 mm is greater than 90%.

[0035] Furthermore, the chemical composition of the high-chromium vanadium-titanium ore, by mass percentage, is as follows: 55%–65% iron, 1.0%–4.5% silicon dioxide, 0.1%–1.5% magnesium oxide, 2.5%–7.0% titanium dioxide, 0.5%–3.0% vanadium pentoxide, 0.5%–3.5% chromium trioxide, with the balance being impurity elements.

[0036] Furthermore, in the particle size composition of the high-chromium vanadium-titanium ore, the proportion of particles smaller than 0.074 mm by mass percentage is 20% to 40%, and the proportion of particles smaller than 0.045 mm is 10% to 20%.

[0037] Furthermore, in the binder and pretreated binder, the chemical composition of the magnesite powder, by mass percentage, is: silicon dioxide 5.0%–8.5%, calcium oxide 0.8%–2.5%, magnesium oxide 40%–47%, aluminum oxide 1.0%–2.5%, with the remainder being impurity elements.

[0038] Furthermore, in the binder, the proportion of magnesite powder with a particle size distribution of less than 0.074 mm by mass percentage is greater than 80%.

[0039] Furthermore, in the pretreated binder, the proportion of magnesite powder with a particle size distribution of less than 0.074 mm by mass percentage is 85% to 95%.

[0040] Furthermore, the mass percentage content of magnesium oxide in the mixture B is 1.4% to 2.2%.

[0041] The present invention discloses a method for producing high-chromium vanadium-titanium ore pellets, comprising the following steps:

[0042] (1) Mix iron concentrate, bentonite, gas mud and coking dust to obtain mixture A; spray a mist of slaked lime water solution to wet the mixture during the mixing process;

[0043] (2) Sodium carboxymethyl cellulose, bentonite, and magnesite powder are mixed to obtain a binder; the binder is then finely ground to obtain a pretreated binder.

[0044] (3) Spray high-chromium vanadium-titanium ore and pretreated binder with water mist to mix and wet them to obtain mixture B;

[0045] (4) Pelletize the mixture A. During pelletizing, spray mist water to promote the growth of green pellets. Stop spraying mist water when the pellet core size range is 2-5 mm. After the pellet core is rolled and compacted for 1-2 minutes, start adding mixture B and spray mist calcium permanganate solution. Stop spraying mist calcium permanganate solution when the green pellets grow to 4-8 mm, and switch to spraying mist water. Continue adding mixture B until the green pellet size range is 10-20 mm.

[0046] (5) After drying, preheating and roasting, the green pellets are used to obtain high-chromium vanadium-titanium ore pellets. The drying and preheating temperature is 400-900℃, the drying and preheating time is 8-15 minutes, the roasting temperature is 1100-1350℃, and the roasting time is 20-35 minutes.

[0047] The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0048]

Example 1

[0049] In this embodiment, the mass percentage of mixture B in the high-chromium vanadium-titanium ore pellets is 70%, and the mass percentage of mixture A is 30%. The production process is as follows:

[0050] (1) Iron concentrate, bentonite, gas mud, and coking dust are mixed in a high-power mixer to obtain mixture A. During the mixing process, a mist of slaked lime water is sprayed to wet the mixture. The mass percentage of iron concentrate in mixture A is 80%, the mass percentage of gas mud is 9.5%, the mass percentage of coking dust is 9.5%, and the mass percentage of bentonite is 1%. The amount of slaked lime water added meets the following requirements: the moisture content of mixture A is controlled at 7.2%, and the alkalinity value is 1.2.

[0051] (2) Sodium carboxymethyl cellulose, bentonite and magnesite powder are mixed in a high-power mixer to obtain a binder. The binder is then finely ground to obtain a pretreated binder. The pretreated binder has a particle size composition of 90% of particles smaller than 0.074 mm by mass percentage.

[0052] The binder contains 3.5% sodium carboxymethyl cellulose by mass, 1.5% bentonite by mass, and 95% magnesite powder by mass. The binder and pretreated binder contain 41% magnesium oxide by mass.

[0053] The particle size distribution of the magnesite powder in the binder is 85% by mass percentage of particles smaller than 0.074 mm; the chemical composition of the magnesite powder by mass percentage is: silicon dioxide 5.5%, calcium oxide 1.5%, magnesium oxide 42.5%, aluminum oxide 1.5%, with the balance being impurity elements.

[0054] (3) Add 4.1% by mass of pretreatment binder to high-chromium vanadium-titanium ore, spray water mist in a high-power mixer to mix and wet it, and obtain mixture B. The amount of water added is 7.5% by mass of mixture B. The mass percentage of magnesium oxide in mixture B is 1.8%.

[0055] The particle size distribution of high-chromium vanadium-titanium ore, by mass percentage, is as follows: 25% of particles smaller than 0.074 mm and 15% smaller than 0.045 mm. The chemical composition of high-chromium vanadium-titanium ore, by mass percentage, is: 58.5% iron, 2.5% silicon dioxide, 0.5% magnesium oxide, 3.2% titanium dioxide, 0.6% vanadium pentoxide, 1.2% chromium trioxide, with the balance being impurities.

[0056] (4) The mixture A is transported to the disc pelletizer for pelletizing. During pelletizing, mist water is sprayed to promote the growth of green pellets. When the particle size distribution of the pellet core is 5 mm, the mist water spraying is stopped. After the pellet core is rolled and compacted in the disc pelletizer for 1 minute, the mixture B is added and mist calcium permanganate aqueous solution is sprayed. When the green pellets grow to 8 mm, the mist calcium permanganate aqueous solution is stopped and mist water is sprayed instead. The mixture B is added until the particle size distribution of the green pellets is 10-20 mm.

[0057] (5) After drying, preheating and roasting, the green pellets are used to obtain high-chromium vanadium-titanium ore pellets. The drying and preheating temperature is 500℃ and the drying and preheating time is 10 minutes. The roasting temperature is 1200℃ and the roasting time is 25 minutes. The oxygen decomposed by calcium permanganate during the high-temperature roasting process forms an oxygen supply layer, which enables the high-chromium vanadium-titanium ore to be fully oxidized and solidified during the roasting process. Another decomposition product, calcium oxide, can indirectly increase the basicity value of the pellets.

[0058] The high-chromium vanadium-titanium ore pellets prepared in this embodiment have a uniform internal and external structure, without delamination, overmelting, or adhesion. The finished pellets have excellent metallurgical properties, with a compressive strength of 3368 N / pellet, a drum strength of 98.5%, a reduceability of 93.6%, a reduction expansion rate of 5.8%, and a softening range of 72°C.

[0059]

Example 2

[0060] In this embodiment, the mass percentage of mixture B in the high-chromium vanadium-titanium ore pellets is 85%, and the mass percentage of mixture A is 15%. The production process is as follows:

[0061] (1) Iron concentrate, bentonite, gas mud, and coking dust are mixed in a high-power mixer to obtain mixture A. During the mixing process, a mist of slaked lime water is sprayed to wet the mixture. The mass percentage of iron concentrate in mixture A is 85%, the mass percentage of gas mud is 7.5%, the mass percentage of coking dust is 7%, and the mass percentage of bentonite is 0.5%. The amount of slaked lime water added meets the following requirements: the moisture content of mixture A is controlled at 7.8%, and the alkalinity value is 2.0.

[0062] (2) Sodium carboxymethyl cellulose, bentonite, and magnesite powder are mixed in a high-performance mixer to obtain a binder. The binder is then finely ground to obtain a pretreated binder. The pretreated binder has a particle size distribution of 95% by mass percentage of particles smaller than 0.074 mm.

[0063] The binder contains 2.2% sodium carboxymethyl cellulose by mass, 0.8% bentonite by mass, and 97% magnesite powder by mass. The binder and pretreated binder contain 50% magnesium oxide by mass.

[0064] The particle size distribution of the magnesite powder in the binder is 90% by mass percentage of particles smaller than 0.074 mm. The chemical composition of the magnesite powder by mass percentage is: silicon dioxide 6.2%, calcium oxide 2.2%, magnesium oxide 46.5%, aluminum oxide 2.1%, with the balance being impurity elements.

[0065] (4) The high-chromium vanadium-titanium ore and the pretreated binder are mixed and moistened by spraying water mist in a high-power mixer to obtain mixture B. The amount of water added is 8.0% of the mass of mixture B, and the mass percentage of magnesium oxide in mixture B is 2.0%.

[0066] The particle size distribution of high-chromium vanadium-titanium ore, by mass percentage, is as follows: 22% of particles smaller than 0.074 mm and 12% of particles smaller than 0.045 mm. The chemical composition of high-chromium vanadium-titanium ore, by mass percentage, is: 61.5% iron, 2.8% silicon dioxide, 1.1% magnesium oxide, 5.9% titanium dioxide, 2.8% vanadium pentoxide, 3.2% chromium trioxide, with the balance being impurities.

[0067] (4) The mixture A is transported to the disc pelletizer for pelletizing. During pelletizing, mist water is sprayed to promote the growth of green pellets. When the particle size distribution of the pellet core is 3 mm, the mist water spraying is stopped. After the pellet core is rolled and compacted in the disc pelletizer for 1.5 minutes, the mixture B is added and mist calcium permanganate aqueous solution is sprayed. When the green pellets grow to 5 mm, the mist calcium permanganate aqueous solution is stopped and mist water is sprayed instead. The mixture B is added until the particle size distribution of the green pellets is 10-20 mm.

[0068] (5) After drying, preheating and roasting, the green pellets are used to obtain high-chromium vanadium-titanium ore pellets. The drying and preheating temperature is 700℃ and the drying and preheating time is 12 minutes. The roasting temperature is 1250℃ and the roasting time is 30 minutes. The oxygen decomposed by calcium permanganate during the high-temperature roasting process forms an oxygen supply layer, which enables the high-chromium vanadium-titanium ore to be fully oxidized and solidified during the roasting process. Another decomposition product, calcium oxide, can indirectly increase the basicity value of the pellets.

[0069] The high-chromium vanadium-titanium ore pellets prepared in this embodiment have a uniform internal and external structure, without delamination, overmelting, or adhesion. The finished pellets have excellent metallurgical properties, with a compressive strength of 3512 N / pellet, a drum strength of 98.8%, a reduceability of 94.5%, a reduction expansion rate of 5.2%, and a softening range of 68°C.

[0070] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-chromium vanadium-titanium ore pellet, characterized in that, It is a composite pellet obtained by pelletizing and calcining an inner layer of mixture A and an outer layer of mixture B; the mass percentage of mixture B in the composite pellet is 50% to 90%, and the remainder is mixture A; wherein: The components of mixture A, by mass percentage, include: 75%–85% iron concentrate, 5%–9.5% gas sludge, 3%–9.5% coking dust, and 0.2%–1.5% bentonite; the moisture content of mixture A is 6.5%–8.0%. Mixture B consists of high-chromium vanadium-titanium ore plus a pre-treatment binder at a mass percentage of 3.5%–4.5%. The chemical composition of the high-chromium vanadium-titanium ore, by mass percentage, is: 55%–65% total iron, 1.0%–4.5% silicon dioxide, 0.1%–1.5% magnesium oxide, 2.5%–7.0% titanium dioxide, 0.5%–3.0% vanadium pentoxide, 0.5%–3.5% chromium trioxide, with the balance being impurity elements. The pre-treatment binder is prepared by fine grinding of binder. The binder, by mass percentage, includes: 0.5%–3.5% sodium carboxymethyl cellulose, 0.5%–2% bentonite, and 95%–98% magnesite powder. An additional 7.0%–8.5% water is added to mixture B.

2. The high-chromium vanadium-titanium ore pellet according to claim 1, characterized in that, The alkalinity of the mixture A is 0.8 to 1.

8.

3. The high-chromium vanadium-titanium ore pellet according to claim 1, characterized in that, The adhesive and pretreated adhesive contain 38% to 52% magnesium oxide by mass; the pretreated adhesive has a particle size distribution of more than 90% by mass, with particles smaller than 0.074 mm.

4. The high-chromium vanadium-titanium ore pellet according to claim 1, characterized in that, The high-chromium vanadium-titanium ore has a particle size distribution of 20% to 40% by mass percentage of particles smaller than 0.074 mm and 10% to 20% by mass percentage of particles smaller than 0.045 mm.

5. The high-chromium vanadium-titanium ore pellet according to claim 1, characterized in that, The chemical composition of the magnesite powder in the binder and pretreated binder, by mass percentage, is: silicon dioxide 5.0%–8.5%, calcium oxide 0.8%–2.5%, magnesium oxide 40%–47%, aluminum oxide 1.0%–2.5%, with the remainder being impurity elements.

6. A high-chromium vanadium-titanium ore pellet according to claim 1 or 5, characterized in that, In the binder, the proportion of magnesite powder with a particle size distribution of less than 0.074 mm by mass percentage is greater than 80%.

7. A high-chromium vanadium-titanium ore pellet according to claim 1 or 5, characterized in that, In the pretreated binder, the proportion of magnesite powder with a particle size distribution of less than 0.074 mm by mass percentage is 85% to 95%.

8. The high-chromium vanadium-titanium ore pellet according to claim 1, characterized in that, The mass percentage content of magnesium oxide in the mixture B is 1.4% to 2.2%.

9. The method for producing high-chromium vanadium-titanium ore pellets as described in claim 1, characterized in that, Includes the following steps: (1) Mix iron concentrate, bentonite, gas mud and coking dust to obtain mixture A; spray a mist of slaked lime water solution to wet the mixture during the mixing process; (2) Sodium carboxymethyl cellulose, bentonite, and magnesite powder are mixed to obtain a binder; the binder is then finely ground to obtain a pretreated binder. (3) Spray high-chromium vanadium-titanium ore and pretreated binder with water mist to mix and wet them to obtain mixture B; (4) Pelletize the mixture A. During pelletizing, spray mist water to promote the growth of green pellets. Stop spraying mist water when the pellet core size range is 2-5 mm. After the pellet core is rolled and compacted for 1-2 minutes, start adding mixture B and spray mist calcium permanganate solution. Stop spraying mist calcium permanganate solution when the green pellets grow to 4-8 mm, and switch to spraying mist water. Continue adding mixture B until the green pellet size range is 10-20 mm. (5) After drying, preheating and roasting, the green pellets are used to obtain high-chromium vanadium-titanium ore pellets. The drying and preheating temperature is 400-900℃, the drying and preheating time is 8-15 minutes, the roasting temperature is 1100-1350℃, and the roasting time is 20-35 minutes.