1. The method for evaluating and measuring the continuous crystallization performance of the iron ore powder is characterized by comprising the following steps of:

s1, carrying out briquetting operation by using iron ore powder to obtain a plurality of briquette blanks;

s2, taking two or more briquetting green bodies, superposing, and axially pressing to make the interfaces of the adjacent briquetting green bodies closely contact to obtain briquettes;

s3, roasting the briquette to obtain a briquette roasted body;

and S4, measuring the interface consolidation strength of the agglomerate roasted body, and characterizing the continuous crystallization performance of the iron ore powder according to the interface consolidation strength.

2. The method for evaluating and measuring the continuous crystallization performance of the iron ore powder as claimed in claim 1, wherein the specific manner for characterizing the continuous crystallization performance of the iron ore powder in step S4 is as follows: the continuous crystal strength of the iron ore powder is equal to the interface consolidation strength/the number of interfaces.

3. The method for evaluating and measuring the crystallization performance of the iron ore powder according to claim 1, wherein the iron ore powder in the step S1 is pretreated iron ore powder; the preprocessing content comprises the following steps: drying and grinding.

4. The method for evaluating and measuring the crystallization performance of the iron ore powder as claimed in claim 1, wherein the number of the agglomerates and the number of the agglomerate firing bodies are both 2-5;

the interface consolidation strength is the sum of all interface consolidation strengths of 2-5 briquette roasted bodies.

5. The method for evaluating and measuring the crystallization performance of the iron ore powder as claimed in claim 1, wherein the briquetting operation in the step S1 includes: taking a preset amount of iron ore powder, and pressing the iron ore powder into a cylinder under the pressure of 5-10 MPa.

6. The method for evaluating and measuring the crystallization performance of the iron ore powder as claimed in claim 5, wherein the diameter of the cylinder is 8-15 mm, and the height of the cylinder is 6-12 mm.

7. The method for evaluating and measuring the continuous crystallization performance of the iron ore powder according to claim 3, wherein the iron ore powder is hematite powder, magnetite powder, steelmaking sludge or iron-containing dust.

8. The method for evaluating and measuring the crystallization performance of the iron ore powder as claimed in claim 1, wherein the pressure for the axial pressing in step S2 is 5 to 10 MPa.

9. The method for evaluating and measuring the crystallization performance of the iron ore powder as claimed in claim 1, wherein the roasting conditions in step S3 are as follows: the roasting temperature is 1200-1300 ℃, the roasting time is 15-25 minutes, and the roasting atmosphere is air.

10. The method for evaluating and measuring the continuous crystallization performance of the iron ore powder according to claim 2, wherein the method further comprises the following steps:

and S5, calculating the continuous crystal strength of the unit area according to the continuous crystal strength and the interface area of the iron ore powder.

Background

The addition of acid pellets to high-alkalinity sinter ore has been a furnace burden structure commonly adopted by blast furnaces in China for a long time, and pellets are used as an important iron-containing furnace burden, have the advantages of high iron grade, good strength, uniform granularity, excellent metallurgical performance, more environment-friendly production process and the like, and are highly valued by iron-making workers. In recent years, the yield and the process equipment of the pellet ore in China are continuously developed, and particularly, the development of the melt type pellet, the magnesium pellet and the titanium-containing pellet ore is a hotspot of the research of universities and enterprises.

However, due to the diversity of iron ore raw materials in nature and the complexity of the existing forms of iron oxides in the iron ore powder, different iron ore powders show obvious differences in the process of preparing oxidized pellets. Besides the evaluation of the normal temperature characteristics such as chemical components, granularity composition, mineral characteristics and the like, the quantitative indexes for evaluating the high temperature performance of the iron ore powder for sintering are provided by the predecessors aiming at the sintering consolidation mechanism of the iron ore powder, and the quantitative indexes comprise assimilation performance, liquid phase flow performance, binding phase strength performance, calcium ferrite generation performance, crystal connection performance, high temperature bonding performance of adhesive powder/nuclear ore and the like, and the quantitative indexes provide new ideas and methods for optimizing ore blending for sintering and improving the quality of sintered ore. However, the high-temperature evaluation of the iron ore powder for pellet ore mainly continues to use the continuous crystallization performance of the iron ore powder in the sintering process, and the compressive strength of the briquette is used as the continuous crystallization strength of the pellet, so that the briquette is inevitably damaged when the compressive strength of the briquette is tested. The continuous crystallization performance of the iron ore powder refers to the continuous crystallization consolidation strength among minerals in the roasting process, namely the capability of combining mineral crystals into balls, the stronger the continuous crystallization capability is, the higher the compressive strength of the balls is, and the strength of the produced balls can be judged by comparing the continuous crystallization strengths of different concentrate powders under the same roasting condition. However, the existing method for determining the continuous crystal characteristics of the iron ore powder cannot accurately represent the continuous crystal strength of the iron ore powder, the determination method is influenced by the particle size of the iron ore powder and the experimental conditions such as the pressure in the sample preparation process, and the test belongs to destructive test and is not beneficial to the subsequent microscopic detection.

Therefore, there is a need to develop a new method for evaluating and measuring the continuous crystallization performance of iron ore powder to overcome the shortcomings of the prior art, so as to solve or alleviate one or more of the above problems.

Disclosure of Invention

In view of the above, the invention provides a method for evaluating and measuring the continuous crystallization performance of iron ore powder, which defines the strength of continuous crystallization between interfaces of briquettes after roasting as the continuous crystallization capability of iron ore powder, can nondestructively detect the continuous crystallization strength of the iron ore powder after roasting, and is not affected by the pressure of ore powder particles and the pressure in the sample preparation process.

The invention provides a method for evaluating and measuring the continuous crystallization performance of iron ore powder, which is characterized by comprising the following steps of:

s1, carrying out briquetting operation by using iron ore powder to obtain a plurality of briquette blanks;

s2, taking two or more briquetting green bodies, superposing, and axially pressing to make the interfaces of the adjacent briquetting green bodies closely contact to obtain briquettes;

s3, roasting the briquette to obtain a briquette roasted body;

and S4, measuring the interface consolidation strength of the agglomerate roasted body, and characterizing the continuous crystallization performance of the iron ore powder according to the interface consolidation strength.

In the foregoing aspect and any possible implementation manner, a specific manner for characterizing the continuous crystallization performance of the iron ore powder in step S4 is further provided as follows: the continuous crystal strength of the iron ore powder is equal to the interface consolidation strength/the number of interfaces.

In the aspect and any possible implementation manner described above, there is further provided an implementation manner, in which the iron ore powder in step S1 is pretreated iron ore powder; the preprocessing content comprises the following steps: drying and grinding.

The above aspects and any possible implementation manner further provide an implementation manner, and the number of the briquettes and the briquette roasted body is 2-5;

the interface consolidation strength is the sum of all interface consolidation strengths of 2-5 briquette roasted bodies.

The above-mentioned aspect and any possible implementation manner further provide an implementation manner, and the specific content of the blocking operation in step S1 includes: taking a preset amount of iron ore powder, and pressing the iron ore powder into a cylinder under the pressure of 5-10 MPa.

The above aspect and any possible implementation manner further provide an implementation manner, wherein the diameter of the cylinder is 8-15 mm, and the height of the cylinder is 6-12 mm.

The above aspects and any possible implementations further provide an implementation in which the iron ore powder is hematite powder, magnetite powder, steelmaking sludge, or iron-containing dust.

The above aspect and any possible implementation manner further provide an implementation manner, and the pressure of the axial pressing in the step S2 is 5 to 10 MPa.

In the above aspect and any possible implementation manner, there is further provided an implementation manner, in step S3, the baking conditions are: the roasting temperature is 1200-1300 ℃, the roasting time is 15-25 minutes, and the roasting atmosphere is air.

The above-described aspects and any possible implementation further provide an implementation, and the steps of the method further include:

and S5, calculating the continuous crystal strength of the unit area according to the continuous crystal strength and the interface area of the iron ore powder.

Compared with the prior art, one of the technical schemes has the following advantages or beneficial effects: the strength of the continuous crystals between the interfaces of the briquettes after roasting is defined as the continuous crystal capability of the iron ore powder, namely the continuous crystal strength of the shear stress iron ore powder between the briquettes is measured, the continuous crystal strength of the roasted iron ore powder can be detected in a nondestructive mode, the crushing damage to a roasting test is avoided, and a sample after the strength measurement can be further detected;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: the method is not influenced by mineral powder particles and pressure in the sample preparation process, and the measured strength can more accurately reflect the continuous crystallization capacity of the iron ore powder; in the prior art, in a mode of adopting the compressive strength of a pressing block as the continuous crystal strength, the measured compressive strength comprises the continuous crystal capability and the compressive capability of the material, so that a large error exists, and the consolidation strength of the interface of the method is basically equal to the continuous crystal capability, so that the continuous crystal capability of the iron ore powder can be more accurately reflected;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: the prepared sample can effectively expose the continuous crystal section of the mineral powder after strength detection, and is beneficial to the next step of microscopic detection of the continuous crystal section;

another technical scheme in the above technical scheme has the following advantages or beneficial effects: the method provides theoretical basis and practical experience for preferentially selecting the types of the iron ore powder and optimizing ore proportioning of the pellet ore, and provides necessary technical support for further systematically and finely researching the high-temperature behavior and various reactions of the iron ore powder in the high-temperature roasting process.

Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a flow chart of a method for evaluating and measuring the performance of iron ore powder continuous crystallization according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of single compact pressing provided by one embodiment of the present invention;

FIG. 3 is a schematic view of an interface between compact compacts provided by an embodiment of the present invention;

FIG. 4 is a graph showing the measurement of the intergranular strength of the interface after firing of the briquette according to one embodiment of the present invention.

Detailed Description

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Aiming at the defects of the prior art, the invention provides a method for measuring the continuous crystal strength of iron ore powder, which can detect the continuous crystal strength of the roasted iron ore powder and is not influenced by the pressure of ore powder particles and a sample pressing process.

A method for measuring the continuous crystallization performance of iron ore powder is disclosed, as shown in figure 1, the method defines the strength of continuous crystallization among interfaces of briquettes after roasting as the continuous crystallization capacity of the iron ore powder, namely measuring the shear stress among the briquettes to evaluate the continuous crystallization performance of the iron ore powder, and comprises the following measuring steps:

firstly, a certain amount of iron ore powder is taken and dried in an oven at 100-150 ℃ for 3-5 hours, and bulk water in the ore powder is removed;

the iron ore powder refers to all iron-containing materials for pelletizing and agglomeration, and can be hematite powder, magnetite powder, steelmaking sludge, iron-containing dust and the like;

secondly, placing the iron ore powder in a mortar for light grinding for a period of time, which can be 5 minutes, so that the ore powder is fully and uniformly mixed, hardening generated in the drying process is eliminated, and the particle size distribution of the ore powder is more uniform;

thirdly, weighing 9 parts of 5g of uniformly mixed iron ore powder, and pressing the iron ore powder into 9 cylindrical briquettes by a sample press under the pressure of 10 MPa; according to specific conditions, the number of the agglomerates, the weight of each part of iron ore powder and the briquetting strength can be changed;

the pressure for pressing the block masses in the third step can be 5-10 MPa, the diameter of the block masses is 8-15 mm, and the height of the block masses is 6-12 mm;

fourthly, dividing 9 lumps into 3 parts, stacking every three cylindrical lumps to form two contact surfaces, and axially pressurizing the three lumps through a sample pressing machine to enable the interfaces to be in close contact;

the number of samples for preparing the roasted blocks in the fourth step can be 2-5, and the number of generated interfaces is 1-4; in order to make the interface contact more compact, the pressure applied to the agglomerate is 5-10 MPa;

fifthly, placing the pressed briquette into a high-temperature furnace for roasting for a period of time, taking out the sample, and cooling the sample to room temperature in the air;

roasting the briquette in the fifth step at 1200-1300 ℃, wherein the roasting time is 15-25 minutes, and the atmosphere in the roasting process is air;

sixthly, measuring the consolidation strength of the interface between the blocks by using a shear stress tester, namely the continuous crystal strength of the iron ore powder, and simultaneously calculating the continuous crystal strength in unit area;

and step six, defining the shear stress of a single interface as the continuous crystal strength of the iron ore powder, and simultaneously calculating the continuous crystal strength in unit area.

The first embodiment is as follows: and (3) determining the crystallization performance of the iron ore powder:

drying a certain amount of iron ore powder in an oven at 100 ℃ for 3 hours to remove bulk water in the ore powder; then, placing the dried iron ore powder in a mortar for lightly grinding for 5 minutes to fully and uniformly mix the ore powder, eliminating hardening generated in the drying process and simultaneously enabling the particle size distribution of the ore powder to be more uniform; weighing 9 parts of 5g of uniformly mixed iron ore powder, pressing the iron ore powder into 9 cylindrical briquettes (shown in figure 2) with the diameter of 10mm and the height of 8mm by a press machine under the pressure of 10 MPa; dividing the 9 lumps into 3 portions eachThree cylindrical briquettes formed two contact surfaces, and the three briquettes were pressurized by a sample press at a pressure of 5MPa to make the interfaces in close contact (as shown in fig. 3). And (3) placing the pressed briquette into a high-temperature furnace for roasting for a period of time, taking out the sample, and cooling to room temperature in air. The consolidation strength between the briquettes (as shown in FIG. 4) was measured by a shear stress tester as τ (the consolidation strength τ is the sum of the consolidation strengths at all interfaces), and the floor area of the compacted sample was A. The calculation formula for defining the continuous crystal strength and the continuous crystal strength per unit area is as follows, the measured continuous crystal strength of the iron ore powder is shown in table 1, the average consolidation strength tau of the ore powder obtained by 3 times of tests is 2242N, and the continuous crystal strength F is_L1121N, A78.5 mm²Unit area continuous grain strength F_AIs 7.140N/mm²。

Strength of intergranular phase F_L：F_Lτ/2; (2 in τ/2 is the number of interfaces, and can also be represented by n, the value of n is a positive integer)

Strength per unit area of continuous crystal F_A：F_A＝τ/(2A)。

TABLE 1 actually measured data of iron ore powder continuous crystallization property

Numbering	τ	FL	A	FA
					Briquette 1	2250	1125	78.5	7.165
Briquette 2	2230	1115	78.5	7.102
					Briquette 3	2246	1123	78.5	7.153

TABLE 2 mean data of continuous crystallization property of iron ore powder

Numbering	τ	FL	A	FA
					Briquette	2242	1121	78.5	7.140

The evaluation and measurement method for the continuous crystallization performance of the iron ore powder provided by the embodiment of the application is described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The protection scope of the present application shall be subject to the definitions of the appended claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.