CN113105253A

CN113105253A - Zirconium-silicon-chromium-based ladle drainage sand and preparation method thereof

Info

Publication number: CN113105253A
Application number: CN202110326856.8A
Authority: CN
Inventors: 李尚兵; 陈远清; 黄建军; 耿恒亮; 李艳梅; 马志军
Original assignee: Jiangsu Yonggang Group Co Ltd
Current assignee: Jiangsu Yonggang Group Co Ltd
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2021-07-13

Abstract

The invention discloses zirconium-silicon-chromium-based ladle drainage sand and a preparation method thereof, wherein the preparation method comprises the following steps: zircon sand, quartz sand, chromite sand and carbon black are mixed according to a certain weight ratio, and the mixture is mechanically stirred, sprayed, granulated, screened and cooled to obtain target drainage sand powder, wherein the obtained drainage sand contains 24-40% of ZrO₂27-37% of SiO₂10-20% of Cr₂O₃、1‑8％Al₂O₃、4‑16％Fe₂O₃And less than 0.5% H₂O, the refractoriness of the drainage sand is more than 1850 ℃, and the proportion of particles with the particle size of 0.1-1mm is controlled to be more than 98 percent. The drainage sand prepared by the method can fully and uniformly mix the raw materials, and solves the influence of segregation problem caused by non-uniform components on the self-opening rate, particularlyThe method improves the self-opening rate of the high-quality special steel ladle with the refining time of more than 3-8 hours, and avoids the influence on the quality of molten steel caused by later oxygen burning drainage.

Description

Zirconium-silicon-chromium-based ladle drainage sand and preparation method thereof

Technical Field

The invention belongs to the field of manufacturing of metallurgical refractory materials, and particularly relates to zirconium-silicon-chromium-based ladle drainage sand and a preparation method thereof.

Background

Most steel ladles in domestic steel plants mainly adopt high-chromium and siliceous drainage sands, but both the high-chromium and siliceous drainage sands have certain defects, such as low automatic casting rate due to more siliceous drainage sands, and huge negative effects caused by influencing the automatic casting rate. The high-chromium quicksand has better self-opening rate than siliceous material, but also has the problems of high cost and uneven and stable components.

The drainage sand is prepared by stirring and processing raw material fine powder, and sintering performance and fluidity are directly influenced by different material formulas, material granularity and the like. Steel making can meet the requirement of self-opening of steel ladles only by a proper flow guiding sand formula according to the time of receiving molten steel by the steel ladles, steel grades and the like, and steel factories pursue high self-opening rate, but the self-opening rate of the steel ladles is over 90 percent generally, part of the steel factories can reach about 95 percent, and the difficulty of improving the self-opening rate from 95 percent is high.

The drainage sand is filled in a water gap of the ladle, a thin sintered layer is generated on the surface layer of the drainage sand under the heat transfer action of molten steel, after the sliding plate of the ladle is opened, the non-sintered drainage sand in the water gap falls freely under the action of gravity, and simultaneously, the sintered layer of the drainage sand is crushed by the action of the static pressure of the molten steel, so that the molten steel flows out automatically (self-opening). The quality of the drainage sand mainly depends on the material, granularity, sintering performance and flow performance of the drainage sand, and the more reasonable the sintering performance of the drainage sand is, the higher the self-opening rate of the ladle is; the surface layer of the material for sintering the drainage sand is expected to be lightly sintered to prevent molten steel from permeating, and meanwhile, the strength of the sintered layer is not too high and can be broken by the static pressure of the molten steel to automatically open the flow.

For part of special steel enterprises, because the refining time of part of steel grades in a steel plant is about 3-8 hours, because the steel containing time of molten steel is long, a shell can be formed due to thick sintering layer and high strength of the drainage sand, so that the drainage sand can freely fall down and then seriously bridge the steel, the molten steel can not automatically flow out, and a ladle can not be opened by self. The ladle which is not opened by self needs oxygen burning and drainage treatment, which causes the pure molten steel to be polluted and influences the quality of the molten steel. In addition, because the diversion sand adopts the difference of bulk densities of materials such as ferrochromium ore powder and quartz powder, and is processed by adopting a traditional stirring mode, the segregation of material components is easy to occur, finally the diversion sand has the same formula in the actual use process, the self-opening difference of diversion sand of different batches is large, and the self-opening of a steel ladle is influenced.

Disclosure of Invention

Aiming at the problems that the refining time of special steel grades is long, the steel containing time is long, the self-opening rate of thick molten steel of a sintered layer of the drainage sand is difficult to increase by about 95 percent, and the self-opening is unstable in part of special steel plants, the invention provides the zirconium-silicon-chromium-based ladle drainage sand and a preparation method thereof by changing the material quality and the preparation method of the drainage sand.

The traditional chromium-based drainage sand is replaced by the zirconium-silicon-chromium material through iterative improvement, and the stirring and mixing preparation of the traditional stirrer at present is changed by adopting a spray granulation mode. The purposes of high refractoriness, uniform components, stable quality and high self-opening rate of the material are achieved.

The technical purpose is achieved, the technical effect is achieved, and the invention is realized through the following technical scheme:

a zirconium-silicon-chromium-based ladle drainage sand is prepared from the following raw materials: zircon sand, quartz sand, chromite sand and carbon black, wherein the components of the zircon sand, the quartz sand, the chromite sand and the carbon black contain 24 to 40 percent of ZrO according to certain weight proportion₂27-37% of SiO₂10-20% of Cr₂O₃、1-8％Al₂O₃、4-16％Fe₂O₃Less than 0.5% H₂O and less than 0.5 percent of C, the refractoriness of the drainage sand is more than 1850 ℃, and the proportion of particles with the particle size of 0.1-1mm is controlled to be more than 98 percent.

As a further improvement of the invention, the granularity of the selected raw materials is 40-80 meshes;

the chromite sand comprises the following components in percentage by mass: cr (chromium) component₂O₃≥46％、Fe₂O₃≥27％，Al₂O₃≤15％，H₂O

＜1.0％；

The zircon sand is packed according to the mass percentageComprises the following components: ZrO (ZrO)₂≥66％，SiO₂≤33％，H₂O＜1.0％；

The quartz sand comprises the following components in percentage by mass: SiO 2₂≥95％、H₂O＜1.0％；

The carbon black comprises the following components: c is more than or equal to 95 percent.

As a further improvement of the invention, the zircon sand, the quartz sand, the chromite sand and the carbon black are mixed according to the following weight ratio: 40-50% of zircon sand, 23-27% of quartz sand, 25-35% of chromite sand and 0.5% of carbon black.

The invention also provides a preparation method of the zirconium-silicon-chromium-based ladle drainage sand, which comprises the following steps:

the materials are proportioned according to the raw material proportion in the zirconium-silicon-chromium-based ladle drainage sand;

premixing the raw materials by adopting mechanical stirring; and then, carrying out spray granulation, screening and cooling treatment on the mixed slurry in sequence to obtain the target drainage sand.

As a further improvement of the invention, the spray granulation adopts a spray gun with the diameter less than 0.4mm, and the slurry is sprayed into a spray tower with the temperature of 750 and 800 ℃.

As a further improvement of the invention, the slurry is at a pressure of 0.2MPa to 1MPa and at a pressure of 0.2m³/h-1m³The flow rate/h is injected into the spray tower.

As a further improvement of the invention, the exhaust temperature at the top of the spray tower is 150-200 ℃.

As a further improvement of the invention, the screening treatment adopts a square hole screen with the thickness of 0.1-1 mm.

The invention has the beneficial effects that: the drainage sand prepared by the method can fully and uniformly mix the raw materials, solves the influence of segregation problem caused by non-uniform components on the self-opening rate, especially improves the self-opening rate of the high-quality special steel ladle with the refining time of more than 3 hours, and avoids the influence on the quality of molten steel caused by later oxygen burning drainage.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

1. Raw material preparation

All the raw materials are 40-80 mesh in granularity, and the selected raw materials contain Cr as the main component of chromite sand₂O₃Content is not less than 46 percent and Fe₂O₃Content is more than or equal to 27 percent and Al₂O₃Content is less than or equal to 15%, granularity is 40-80 meshes, H₂O is less than 1.0 percent; quartz sand main component SiO₂Content is more than or equal to 95 percent, granularity is 40-80 meshes, H₂O is less than 1.0 percent; ZrO main component of zircon sand₂The content is more than or equal to 66 percent, and SiO is₂The content is less than or equal to 33 percent, the granularity is 40-80 meshes, H₂O is less than 1.0 percent, and the content of the carbon black main component C is more than or equal to 95 percent.

2. Raw material ratio

The examples were mixed in the proportions shown in Table 1.

Table 1: the raw material proportion (weight percentage%) of each example

Proportioning	Zircon sand	Quartz sand	Chromite sand	Carbon black
					Example 1	45	25	30	0.5
Example 2	40	25	35	0.5
					Example 3	50	25	25	0.5

3. Drainage sand production

The drainage sand is prepared by the processes of firstly preparing materials, then stirring and pulping, then spraying and granulating, and finally cooling and screening.

The raw materials are checked and accepted, the indexes such as components, granularity and moisture meet the requirements for reuse, and when the slurry is used, the raw materials are precisely weighed according to the proportion of the drainage sand, then weighed by a storage bin and placed into a slurry making container.

Secondly, fully stirring the slurry in a pulping container, adding 5 percent of water, and continuously stirring the mixture evenly to prepare the premixed slurry.

And then carrying out spray granulation on the premixed slurry. Adopting a spray gun with a nozzle diameter of 0.4mm, and performing spraying at a pressure of 0.2-1 MPa and a pressure of 0.2m³/h-1m³Spraying the mixed slurry into a spray tower at a flow speed of/h for granulation; the temperature in the spraying tower is stably controlled to be 800 ℃ at 750 through a blowing hot air system, the exhaust temperature at the top of the spraying tower is 200 ℃ at 150, so that the sprayed slurry mixed uniformly can be fully dried and pre-melted on the surface, and the components are more uniform and stable.

And finally, cooling and screening, namely screening by adopting a 0.1-1mm square-hole screen after natural cooling on a production line, and controlling the water content discharged from the tower to be less than or equal to 0.05%. And packaging, marking and warehousing after the granularity, the temperature and the components meet the requirements. The packaging bag is sealed by double-layer packaging with an inner film bag, and the inside of the packaging bag is a small 10kg moisture-proof packaging with a kraft paper bag.

Corresponding to examples 1-3, the products prepared are labeled Y1-Y3.

4. Physical and chemical indexes of prepared drainage sand

Table 2: drainage sand Y1-Y3 physicochemical index

Species of

ZrO₂％

SiO₂％

Cr₂O₃％

Al₂O₃％

Fe₂O₃％

H₂O％

C％

Refractoriness degree C

Particle size mm

Y1

28-36

27-35

10-18

1-6

6-14

＜0.5

＞1850

0.1-1＞98％

Y2

24-32

25-33

12-20

3-8

8-16

＜0.5

＞1850

0.1-1＞98％

Y3

32-40

29-37

8-16

1-5

4-12

＜0.5

＞1850

0.1-1＞98％

The zirconium-silicon-chromium-based ladle drainage sand prepared by the method has two advantages, firstly, the material of the drainage sand has higher refractoriness than that of the traditional chromium-based drainage sand by introducing a zirconium material, and the problem of no self-opening caused by over-thick sintered layer after the ladle is added is prevented; compared with the traditional stirring and mixing mode, the drainage sand disclosed by the invention has the advantages that the components are uniform and consistent, and the quality is more stable by adopting a spray granulation mode.

5. Practical application condition of drainage sand

Table 3: application of drainage sand Y1-Y3 prepared in different embodiments and application conditions for manufacturing different steel grades

Wherein Y1 is suitable for 100-150 ton ladles, and the molten steel is refined by LF and VD for 3-5 hours; y2 is suitable for the special steel product of 50-100 tons of steel ladles, molten steel is refined for 2-4 hours by LF, VD; y3 is suitable for 100-150 ton ladles, and the molten steel is refined by LF and VD for 4-8 hours.

The three typical drainage sands prepared by the invention can achieve the using effect of stability and over 99.5 percent of self-opening rate when used on steel grades such as carbon structural steel, low alloy steel, alloy structural steel, high alloy steel and the like under the condition that the average using amount of the drainage sands on a steel ladle of 50-150 tons in a certain steel mill is 0.35 kg/ton.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The zirconium-silicon-chromium-based ladle drainage sand is characterized in that: comprises the following raw materials: zircon sand, quartz sand, chromite sand and carbon black, wherein the components of the zircon sand, the quartz sand, the chromite sand and the carbon black contain 24 to 40 percent of ZrO according to certain weight proportion₂27-37% of SiO₂10-20% of Cr₂O₃、1-8％Al₂O₃、4-16％Fe₂O₃Less than 0.5% H₂Drainage sands of O and less than 0.5% C, said drainageThe refractoriness of the quicksand is more than 1850 ℃, and the proportion of particles with the particle size of 0.1-1mm is controlled to be more than 98%.

2. The zirconium-silicon-chromium-based ladle drainage sand of claim 1, which is characterized in that: the granularity of the selected raw materials is 40-80 meshes;

the chromite sand comprises the following components in percentage by mass: cr (chromium) component₂O₃≥46％、Fe₂O₃≥27％，Al₂O₃≤15％，H₂O＜1.0％；

The zircon sand comprises the following components in percentage by mass: ZrO (ZrO)₂≥66％，SiO₂≤33％，H₂O＜1.0％；

3. The zirconium-silicon-chromium-based ladle drainage sand of claim 2, which is characterized in that: the zircon sand, the quartz sand, the chromite sand and the carbon black are mixed according to the following weight ratio: 40-50% of zircon sand, 23-27% of quartz sand, 25-35% of chromite sand and 0.5% of carbon black.

4. The preparation method of the zirconium-silicon-chromium-based ladle drainage sand is characterized by comprising the following steps of:

the raw materials are proportioned according to the raw materials in the zirconium-silicon-chromium-based ladle drainage sand of any one of claims 1 to 3;

5. The method of claim 4, wherein: the spray granulation adopts a spray gun with the diameter less than 0.4mm to spray the slurry into a spray tower with the temperature of 750 and 800 ℃.

6. The method of claim 5, wherein: the slurry is under the air pressure of 0.2MPa-1MPa and the air pressure is 0.2m³/h-1m³The flow rate/h is injected into the spray tower.

7. The method of claim 5, wherein: the exhaust temperature at the top of the spray tower is 150-200 ℃.

8. The method of claim 4, wherein: the screening treatment adopts a square hole screen with 0.1-1 mm.