Preparation method of magnesium vanadium titanium base alkali extraction pellet

Abstract

The application discloses a preparation method of magnesium vanadium-titanium base-extracting pellets, which comprises roller grinding, mixing, pelletizing and roasting. The specific method is that the concentrate is sent to a roller grinder to increase the specific surface area, and then bentonite, lightly calcined dolomite and slaked lime are added and mixed sufficiently; the mixed material is pelletized on a disc pelletizer to obtain green pellets, and the green pellets are sent to a belt roaster to obtain target magnesium vanadium-titanium base-extracting pellets; wherein the proportion of vanadium-titanium concentrate, other concentrate, bentonite, lightly calcined dolomite and slaked lime is 5-10%, 81-92%, 1-3%, 1-3% and 1-3% respectively. The application combines the production practice, reduces the content of dolomite in the sinter by adding lightly calcined dolomite in the pellets, improves the quality of the sinter, improves the pellet basicity by adding slaked lime, increases the amount of the pellets, increases the effect of the vanadium-titanium concentrate on protecting the furnace, and meets the production requirements through the production practice.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of sintered pellets, and particularly relates to a preparation method of magnesium vanadium titanium alkali extraction pellets. BACKGROUND

[0002] Theoretical research and production practice prove that increasing the MgO content in acid pellets can significantly reduce the reduction expansion rate of the pellets, improve the high-temperature metallurgical properties thereof, realize the transfer of magnesium oxide from high-alkalinity sintered ore to acid pellets, achieve the win-win of the quality of the pellets and the sintered ore, increase the proportion of the pellets into the furnace, and realize the optimization of the blast furnace burden structure. The burden structure of the low-MgO sintered ore with the MgO-containing pellets can meet the demand of the MgO content of the blast furnace slag and improve the metallurgical properties of the comprehensive burden, and has important reference value for producing the blast furnace burden with excellent performance, improving the permeability of the material column, and optimizing the metallurgical properties of the blast furnace slag.

[0003] For a long time, the blast furnace adopts the composite burden structure of high-alkalinity sintered ore plus acid pellets or natural lump ore. In a certain factory in the inland area, the high-grade lump ore is not easy to transport to the inland area, and the price is high, which is poor in economy. Compared with the sintered ore, the pellets have the characteristics of good metallurgical properties and low cost, and the sintered ore has high alkalinity. In order to ensure the alkalinity of the blast furnace slag, it is difficult to increase the proportion of the pellets.

[0004] The application aims to provide a magnesium vanadium titanium alkali extraction pellet with low cost and furnace protection effect. SUMMARY

[0005] The application aims to provide a magnesium vanadium titanium alkali extraction pellet with low cost and furnace protection effect.

[0006] The application is achieved by providing a preparation method of a magnesium vanadium titanium alkali extraction pellet, which comprises roller grinding, mixing, pelletizing, and roasting. The specific method is that the concentrate is ground by a roller grinder to increase the specific surface area, and then bentonite, light-burned dolomite, and slaked lime are added and mixed uniformly; the mixed material is pelletized into green balls by adding water on a disc pelletizer, and the green balls are roasted by a belt roaster to obtain the target magnesium vanadium titanium alkali extraction pellet; wherein the concentrate comprises vanadium-titanium concentrate and other concentrates, and the proportion of the vanadium-titanium concentrate, the other concentrate, the bentonite, the light-burned dolomite, and the slaked lime is 5-10%, 81-92%, 1-3%, 1-3%, and 1-3%.

[0007] In the pellet production process, light-burned dolomite is added to increase the content of magnesium oxide in the pellet, which can reduce the reduction expansion rate of the pellet, improve its high-temperature metallurgical properties, and strengthen the blast furnace smelting. The magnesium oxide added to the blast furnace is also beneficial to reducing the impact of magnesium oxide on sintering. Adding a certain proportion of vanadium-titanium concentrate to the pellet can play a role in protecting the blast furnace. The added slaked lime can improve the binary basicity of the pellet, create conditions for increasing the proportion of pellet in the blast furnace, achieve the effect of energy saving and consumption reduction, improve the economic and technical indicators of the blast furnace, and strengthen the blast furnace smelting.

[0008] The beneficial effects of the present application are: the present application combines the actual production, by adding light-burned dolomite, slaked lime and vanadium-titanium concentrate, to improve the basicity of the pellet, create conditions for increasing the proportion of pellet in the blast furnace, improve the quality of the pellet, and reduce the impact of magnesium oxide on the quality of the sinter. In addition, the added vanadium-titanium concentrate can also play a role in protecting the furnace, ensuring the stable operation of the blast furnace, and meeting the production requirements. DETAILED DESCRIPTION

[0009] The present application will be further described below in conjunction with examples, but in no way limits the present application, any transformation or replacement based on the teaching of the present application belongs to the protection scope of the present application.

[0010] The present application is a kind of magnesium vanadium-titanium base pellet preparation method, including roll grinding, mixing, pelletizing and roasting. The specific method is that concentrate is passed through a roll grinder to increase the specific surface area, then bentonite, light-burned dolomite and slaked lime are added and fully mixed;The mixed material is atomized and watered on the disc pelletizer to obtain green balls, and the final moisture content of the green balls is controlled at 8-9.5%, and the target magnesium vanadium-titanium base pellet is obtained after the green balls are passed through a belt roaster;

[0011] Among them, the concentrate includes vanadium-titanium concentrate and other concentrates, and the proportion of vanadium-titanium concentrate, other concentrate, bentonite, light-burned dolomite and slaked lime is 5-10%, 81-92%, 1-3%, 1-3%, 1-3%.

[0012] The light-burned dolomite composition is: MgO≥27.00%, SiO2≤3.5%;Particle size is (-200 mesh)≥85.00%.

[0013] The slaked lime (CaO+MgO) is ≥65%, the free water is 0%, and the particle size is (-150 mesh)≥85.00%.

[0014] Vanadium-titanium concentrate TiO2≤12%, V2O5≥5%, balling index K≥0.35.

[0015] During the drying, preheating, roasting and cooling processes, the layer thickness is 380-430 mm, the speed of the belt machine is 1.9-2.4 m / s, the temperature of the blast drying section is controlled at 150-280℃, the temperature of the exhaust drying section is controlled at 480-580℃, the preheating temperature is controlled at 600-850℃, the roasting temperature is controlled at 1180-1230℃, the temperature of the soaking section is controlled at 750-1100℃, and the temperature of the cooling section is 200-850℃.

[0016] Example 1

[0017] The raw materials are mixed according to the proportions (see Table 1). The concentrate is first roller-milled, and the pre-processed concentrate, bentonite, lightly calcined dolomite and slaked lime are mixed and then fed into a disc balling machine. Water is added by atomization, and the moisture content of the green balls is controlled at 8.5%. The finished balls are sieved, and the 8-18 size fraction is fed into a belt roaster to obtain finished magnesium-based vanadium-titanium alkali extraction pellets. During the preheating, roasting and cooling processes, the layer thickness is 390 mm, the speed of the belt machine is 2.3 m / min, the temperature of the blast drying section is 200℃, the drying time is 3.91 min, the temperature of the exhaust drying section is 550℃, the drying time is 5.22 min, the preheating temperature is 660℃, the preheating time is 5.21 min, the roasting temperature is 1230℃, the roasting time is 9.13 min, the temperature of the soaking section is 1000℃, the soaking time is 3.91 min, the temperature of the pre-cooling section is 840℃, the cooling time is 9.13 min, the temperature of the post-cooling section is 380℃, and the cooling time is 5.22 min.

[0018] Table 1 Raw material proportions for magnesium-based pellets in Example 1

[0019]

[0020] Example 2

[0021] The raw materials are mixed according to the proportions (see Table 2). The concentrate is first roller-milled, and the pre-processed concentrate, bentonite, lightly calcined dolomite and slaked lime are mixed and then fed into a disc balling machine. Water is added by atomization, and the moisture content of the green balls is controlled at 8%. The finished balls are sieved, and the 8-18 size fraction is fed into a belt roaster to obtain finished pellets. During the preheating, roasting and cooling processes, the layer thickness is 400 mm, the speed of the belt machine is 2.2 m / min, the temperature of the blast drying section is 180℃, the blast drying time is 4.09 min, the temperature of the exhaust drying section is 510℃, the exhaust drying time is 5.45 min, the preheating temperature is 620℃, the preheating time is 5.45 min, the roasting temperature is 1180℃, the roasting time is 9.54 min, the temperature of the soaking section is 960℃, the soaking time is 4.09 min, the temperature of the pre-cooling section is 820℃, the cooling time is 9.54 min, the temperature of the post-cooling section is 300℃, and the cooling time is 5.45 min.

[0022] Table 2 Raw material ratio of magnesium ore pellet in Example 2

[0023]

[0024] Example 3

[0025] According to the ratio (see Table 3), the concentrate was first roller milled, and the roller-milled concentrate, bentonite, light-burned dolomite and slaked lime were mixed and then entered the disc balling machine. The water was added by atomization to control the moisture content. The green ball moisture content was controlled at 9.5%. The finished ball was sieved, and the 8-18 size fraction entered the belt roaster for roasting to obtain the finished pellet. In the preheating, roasting and cooling process, the layer thickness was 420 mm, the belt speed was 2.0 m / min, the blast drying section temperature was controlled at 200℃, the blast drying section time was 4.5 min; the exhaust drying section temperature was controlled at 540℃, the exhaust drying section time was 6 min; the preheating temperature was 640℃, the preheating section time was 6 min; the roasting temperature was controlled at 1210℃, the roasting section time was 10.5 min; the soaking section temperature was controlled at 990℃, the soaking section time was 4.5 min; the pre-cooling section temperature was 860℃, the pre-cooling section time was 10.5 min, the post-cooling section temperature was 300℃, and the post-cooling section time was 6 min.

[0026] Table 3 Raw material ratio of magnesium ore pellet in Example 3

[0027]

[0028] Example 4

[0029] According to the ratio (see Table 4), the concentrate was first roller milled, and the roller-milled concentrate and bentonite, light-burned dolomite and slaked lime were mixed and then entered the disc balling machine. The water was added by atomization to control the moisture content. The green ball moisture content was controlled at 9.5%. The finished ball was sieved, and the 8-18 size fraction entered the belt roaster for roasting to obtain the finished pellet. In the preheating, roasting and cooling process, the layer thickness was 420 mm, the belt speed was 2.0 m / min, the blast drying section temperature was controlled at 200℃, the blast drying section time was 4.5 min; the exhaust drying section temperature was controlled at 540℃, the exhaust drying section time was 6 min; the preheating temperature was 640℃, the preheating section time was 6 min; the roasting temperature was controlled at 1210℃, the roasting section time was 10.5 min; the soaking section temperature was controlled at 990℃, the soaking section time was 4.5 min; the pre-cooling section temperature was 860℃, the pre-cooling section time was 10.5 min, the post-cooling section temperature was 300℃, and the post-cooling section time was 6 min.

[0030] Table 4 Raw material ratio of magnesium ore pellet in Example 4

[0031]

[0032] The indexes of the green balls and the sintered balls prepared in Examples 1-4 are shown in Tables 5 and 6, respectively.

[0033] Table 5 Indexes of the green balls prepared in Examples 1-4

[0034]

[0035]

[0036] Table 6 Indexes of the sintered balls prepared in Examples 1-4

[0037]

[0038] As can be seen from Tables 5 and 6, with the change of the quicklime and the light-burned dolomite, the moisture control is not much different, the extreme difference of the green ball burst temperature is 25℃, and the difference is not obvious, and the sintering rate is good, all above 85%. The low-temperature reduction pulverization index of the magnesia pellets prepared by the method of the present application is good, all above 95%, the CaO content is about 1% higher than that of the original production of the acid pellets, 0.7%, and the MgO content is 0.6% higher than that of the original production of the acid pellets, 0.9%, the CaO and MgO contents are significantly improved, the compressive strength is as high as 2486N, meeting the requirement of ≥2000N, creating good conditions for the subsequent blast furnace to increase the proportion of the pellets.

Claims

1. A method for preparing a magnesium vanadium titanium base alkali extraction pellet, characterized in that, The target magnesium vanadium-titanium alkali extraction pellet is obtained by adding bentonite, light-burned dolomite and slaked lime to the concentrate after roller grinding, fully mixing the mixture to obtain a mixed material, atomizing water on the mixed material in a disc balling machine to obtain green balls, and controlling the final moisture content of the green balls at 8-9.5%, and then roasting the green balls in a belt roaster; wherein the concentrate includes vanadium-titanium concentrate and other concentrates, the proportions of the vanadium-titanium concentrate, the other concentrates, the bentonite, the light-burned dolomite and the slaked lime are 6-8%, 86.5-89%, 1-2%, 1.5-2% and 1.5-2% respectively; the vanadium-titanium concentrate contains TiO2≤12%, V2O5≥5% and has a balling index K≥0.35; the light-burned dolomite contains MgO≥27.00%, SiO2≤3.5% and has a content of-200 mesh≥85.00%; during the roasting, the thickness of the material layer is 380-430 mm during the preheating and cooling processes, the speed of the belt machine is 1.9 m / s-2.4 m / s, the temperature of the blast drying section is 150-280℃, the temperature of the exhaust drying section is 480-580℃, the preheating temperature is 600-850℃, the roasting temperature is 1180-1230℃, the temperature of the soaking section is 750-1100℃ and the temperature of the cooling section is 200-850℃.

2. The method for preparing magnesia vanadium titanium base alkaline extraction pellets according to claim 1, characterized in that, The slaked lime contains (CaO+MgO)≥65%, has no free water and has a content of-150 mesh≥85.00%.

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