Oxidized pellet upgrading method
By wet mixing and strong mixing of iron concentrate in the slurry state, combined with the use of bentonite, the problem of insufficient mixing uniformity of pelletized materials is solved, and the uniformity of iron concentrate mineralization characteristics and the improvement of pellet performance is achieved, with significant quality improvement and consumption reduction effects.
Patent Information
- Application Number
- CN202411598979.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2025-04-25
AI Technical Summary
There is a problem of insufficient uniformity in the mixing of existing pellet pellet materials, which leads to unevenness in the subsequent materialization characteristics of pellet raw materials, making it difficult to achieve better mixed effects of pellet materials.
The new process of wet mixing and coupling of iron concentrate in the slurry state is adopted to further improve the uniformity of the mineralization characteristics of iron concentrate through primary wet mixing and secondary wet mixing, and bentonite is added to the strong mixing to further improve the uniformity of the spherical materials.
It significantly improves the uniformity and stability of physical and chemical characteristics of iron concentrate and pelletized materials, has obvious advantages in quality improvement and consumption reduction, simplifies the batching process of subsequent pellet production processes, reduces investment costs, and improves pellet performance indicators.
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Figure BDA0005127738240000051
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of iron and steel metallurgy pelletization process, and particularly relates to a quality improvement method for preparing oxidized pellets from iron ore concentrate. Background Art
[0002] At present, the technologies for improving the quality and reducing consumption of pellet production include optimizing ore blending and raw material pretreatment. Optimizing ore blending is based on the principle of complementary physical and chemical properties of iron concentrates. Iron concentrates with different characteristics are matched so that their comprehensive performance can meet the needs of pellet preparation. However, there is little research on this technology, and it is difficult to meet the needs of optimizing ore blending for iron concentrates with complex characteristics. Raw material pretreatment is aimed at the problem that the particle size, specific surface area, and reaction activity of iron concentrates are difficult to meet the needs of pellet preparation. Ball milling, high-pressure roller milling and other methods are used to pretreat iron concentrates to improve their balling, preheating, and roasting performance, but there are shortcomings such as large equipment investment and high operating costs. Therefore, the development of more suitable technologies for improving the quality and reducing consumption of pellet production is an important direction for future development.
[0003] Pellet production uses fine iron ore concentrate as the main raw material, and adds a small amount of binder, which is important for pellet preparation. Therefore, uniform mixing of materials in the pellet production process is crucial to the pellet preparation process. The uniformity of pelletizing material composition and particle size, as well as the uniform dispersion of moisture and binder, are conducive to reducing the ineffective binder in the pelletizing process, and have the potential to reduce the amount of binder used in pelletizing. The physical and chemical properties and performance indicators of different raw balls are more uniform, which is conducive to improving the performance indicators of subsequent preheated balls and roasted balls, and has important practical significance for achieving quality improvement and consumption reduction in the pellet production process.
[0004] At present, domestic and foreign pelletizing plants have equipped strong mixing equipment in the pelletizing workshop to improve the uniformity of pelletizing material mixing. The equipment is used to process the dry iron concentrate obtained after beneficiation, which has a good effect on improving the uniformity of material mixing. Due to the uneven physical and chemical properties of different types of iron concentrate raw materials produced in the beneficiation process, and the physical and chemical properties of the same type of iron concentrate produced at different times in the beneficiation process also fluctuate greatly, resulting in the uneven physical and chemical properties of subsequent pelletizing raw materials. Therefore, it is difficult to achieve a better mixing effect of pelletizing materials by relying solely on the mixer configured in the pelletizing workshop. Summary of the invention
[0005] The purpose of the present invention is to provide a method for improving the quality of oxidized pellets in order to solve the existing problems of pelletizing material mixing. The present invention constructs a new process of wet mixing of iron ore concentrate in a slurry state coupled with subsequent strong mixing, which improves the uniformity of the iron ore mineralization characteristics from the source and provides a new solution for improving the quality and reducing consumption in the pelletizing process.
[0006] In order to achieve the purpose of the present invention, a technical solution is provided, which is a method for upgrading oxidized pellets, comprising the following steps:
[0007] 1) performing a first wet mixing on each type of concentrate slurry produced within a certain period of time in the beneficiation process to obtain each type of concentrate slurry after mixing;
[0008] The various types of concentrate pulps include flotation concentrate pulp, gravity concentration concentrate pulp, and magnetic concentration concentrate pulp. The various types of concentrate pulps after mixing include flotation concentrate pulp after mixing, gravity concentration concentrate pulp after mixing, and magnetic concentration concentrate pulp after mixing;
[0009] 2) according to the proportion of each type of concentrate required for subsequent oxidation pellet production, the mixed slurries of each type of concentrate obtained in 1) are introduced into a slurry stirring tank in proportion, and a second wet mixing is performed, and then a mixed concentrate is obtained after filtering; the water content of the mixed concentrate is the water content of the conventional concentrate;
[0010] (3) The mixed concentrate obtained in (1) is vigorously mixed with other additives to obtain a pelletizing material, and then oxidized pellets are prepared by conventional methods.
[0011] Preferably, the certain period of time in step 1) is no less than 3 days.
[0012] Preferably, in the first wet mixing in step 1), the mixing time is not less than 5 hours and the stirring slurry linear speed is not less than 10 m / min.
[0013] Preferably, the second wet mixing time in step 2) is not less than 10 h, and the stirring slurry linear speed is not less than 15 m / min.
[0014] Preferably, the intensive mixing time in step 3) is not less than 50 seconds.
[0015] Preferably, the additive in step 3) is bentonite, and the amount used is 0.8-1.2 wt % of the concentrate mass.
[0016] Preferably, the conventional method in step 3) is pelletizing, drying, preheating, calcining and cooling; preferably, the drying temperature is 250-400°C, the preheating temperature is 890-930°C, and the calcining temperature is 1200-1230°C.
[0017] The main innovative features of the present invention are:
[0018] (1) By using the technology provided by the present invention, a new process for enhancing the mixing of iron ore concentrate by wet mixing and coupling strong mixing of multiple types of concentrates is constructed. Compared with the conventional single strong mixing process, the mixing effect of the new process is greatly improved, and the physical and chemical properties of the iron ore concentrate and the pelletizing material after the addition of bonding are more uniform and stable, which has obvious advantages of improving quality and reducing consumption.
[0019] (2) By using the technology provided by the present invention, multiple types of iron ore concentrates produced in the beneficiation process are wet-mixed in a slurry state to obtain a mixed concentrate, which simplifies the batching process of the subsequent pelletizing production process and eliminates the need to separately configure different types of raw material bins. This reduces investment costs and is conducive to stabilizing the supply of iron ore concentrate raw materials.
[0020] (3) By adopting the technology provided by the present invention, multiple types of iron concentrates produced within a period of time are mixed separately in a slurry state, thereby achieving the uniformity of the mineralization characteristics of a single type of iron concentrate produced in different time periods, and then they are mixed in proportion according to the needs of subsequent pellet production and then mixed for a second time, thereby achieving the uniformity of the mineralization characteristics of the mixed iron concentrates produced in different time periods, which plays an important role in stabilizing the physical and chemical performance indicators of the pellets.
[0021] (4) By adopting the technology provided by the present invention, the mixing function of various types of iron ore concentrates is pre-placed in the slurry state for mixing, which greatly reduces the pressure of subsequent strong mixing on the mixing of the iron ore concentrates, and uses more mixing functions for the uniform dispersion of moisture and bonding, and helps to reduce invalid water and invalid bonding agents in the pellet production process, and is beneficial to improving the performance indicators and uniformity of green balls, preheated balls and roasted balls, thereby reducing production costs and energy consumption. DETAILED DESCRIPTION
[0022] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.
[0023] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The patent terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.
[0024] Unless otherwise specified, the various reagents and raw materials used in the present invention are commodities that can be purchased from the market or products that can be prepared by known methods.
[0025] Example 1
[0026] A method for improving the quality of oxidized pellets, wherein the flotation concentrate, magnetic concentrate and gravity concentrate produced in the beneficiation process within 4 days are wet mixed in the slurry state for 6 hours and the stirring slurry line speed is 12 m / min; then the mixed flotation concentrate, mixed magnetic concentrate and mixed gravity concentrate obtained after the wet mixing are wet mixed for a second time according to the dry basis mass percentage of 20%:60%:20% for 12 hours and the stirring slurry line speed is 15 m / min, and the mixed concentrate is obtained after filtration. Bentonite with a mass of 1.1 wt% of the mixed concentrate is added to the mixed concentrate, and after strong mixing in a strong mixer for 55 seconds, the pellets are obtained through balling (moisture content of balling 8.0%), drying (exhaust drying temperature 270°C, blast drying temperature 350°C), preheating (temperature 900°C), and roasting (roasting temperature 1210°C). The performance indicators of green balls, preheated balls and roasted balls are shown in Table 1.
[0027] Example 2
[0028] A method for improving the quality of oxidized pellets, wherein the flotation concentrate, magnetic concentrate and gravity concentrate produced within 5 days of the beneficiation process are wet mixed in the slurry state for one time, the wet mixing time is 6 hours, and the stirring slurry line speed is 12m / min; then the mixed flotation concentrate, mixed magnetic concentrate and mixed gravity concentrate obtained after the one wet mixing are wet mixed for a second time according to the dry basis mass percentage of 20%:60%:20%, the mixing time is 12 hours, the stirring slurry line speed is 15m / min, and the mixed concentrate is obtained after filtration. Bentonite with a mass of 1.03wt% of the mixed concentrate is added to the mixed concentrate, and after strong mixing for 60s in a strong mixer, the pellets are obtained through balling (moisture content of balling 7.9%), drying (exhaust drying temperature 270℃, blast drying temperature 350℃), preheating (temperature 900℃), and roasting (roasting temperature 1210℃). The performance indicators of green balls, preheated balls and roasted balls are shown in Table 1.
[0029] Example 3
[0030] A method for improving the quality of oxidized pellets, wherein the flotation concentrate, magnetic separation concentrate and gravity separation concentrate produced within 7 days of the beneficiation process are wet mixed in the slurry state for one time, the wet mixing time is 6 hours, and the stirring slurry line speed is 12m / min; then the mixed flotation concentrate, mixed magnetic separation concentrate and mixed gravity separation concentrate obtained after the one wet mixing are wet mixed for a second time according to the dry basis mass percentage of 20%:60%:20%, the mixing time is 12 hours, the stirring slurry line speed is 15m / min, and the mixed concentrate is obtained after filtering. Bentonite with a mass of 1.00wt% of the mixed concentrate is added to the mixed concentrate, and after strong mixing for 65s in a strong mixer, the pellets are obtained through balling (moisture content of balling 7.84%), drying (exhaust drying temperature 270℃, blast drying temperature 350℃), preheating (temperature 900℃), and roasting (roasting temperature 1210℃). The performance indicators of green balls, preheated balls and roasted balls are shown in Table 1.
[0031] Comparative Example 1 (Benchmark Solution)
[0032] A method for mixing oxidized pellets, wherein the flotation concentrate, magnetic concentrate and gravity concentrate produced by the beneficiation process are mixed according to the dry basis mass percentage of 20%:60%:20%, 1.2wt% of bentonite is added, and then a strong mixer is used for strong mixing, and the mixing time is 60s. After pelletizing (moisture content of pelletizing is 8.1%), drying (air extraction drying temperature is 270°C, blast drying temperature is 350°C), preheating (temperature is 900°C), and roasting (roasting temperature is 1210°C), pellets are obtained. The performance indicators of green balls, preheated balls and roasted balls are shown in Table 1.
[0033] Comparative Example 2
[0034] A method for mixing oxidized pellets, wherein the flotation concentrate, magnetic concentrate and gravity concentrate produced in the ore dressing process within one day are wet mixed in the slurry state for one time, the wet mixing time is 6 hours, and the stirring slurry line speed is 12m / min; then the mixed flotation concentrate, mixed magnetic concentrate and mixed gravity concentrate obtained after the one wet mixing are wet mixed for a second time according to the dry basis mass percentage of 20%:60%:20%, the mixing time is 12 hours, the stirring slurry line speed is 15m / min, and the mixed concentrate is obtained after filtration, 1.1wt% bentonite is added, and then a strong mixer is used for strong mixing, and the mixing time is 55s. After balling (balling water content 8.0%), drying (exhaust drying temperature 270℃, blast drying temperature 350℃), preheating (temperature 900℃), roasting (roasting temperature 1210℃), pellets are obtained. The performance indicators of raw balls, preheated balls and roasted balls are shown in Table 1.
[0035] Comparative Example 3
[0036] A method for mixing oxidized pellets, wherein the flotation concentrate, magnetic concentrate and gravity concentrate produced in the ore dressing process within 4 days are wet mixed in the slurry state, the wet mixing time is 4 hours, and the stirring slurry line speed is 9 m / min; then the mixed flotation concentrate, mixed magnetic concentrate and mixed gravity concentrate obtained after the wet mixing are wet mixed in a second time according to the dry basis mass percentage of 20%:60%:20%, the mixing time is 9 hours, and the stirring slurry line speed is 14 m / min, and the mixed concentrate is obtained after filtration, 1.1wt% of bentonite is added, and then a strong mixer is used for strong mixing, and the mixing time is 55s. After balling (balling water content 8.0%), drying (exhaust drying temperature 270℃, blast drying temperature 350℃), preheating (temperature 900℃), roasting (roasting temperature 1210℃), pellets are obtained. The performance indicators of raw balls, preheated balls and roasted balls are shown in Table 1.
[0037] Table 1 Pellet performance indexes
[0038]
[0039] It can be seen from the data of the examples and comparative examples that the pellet performance indexes are also improved after the uniformity of the materials is improved. This indicates that the uniformity of the pelletizing material composition and particle size as well as the uniform dispersion of water and binder are conducive to reducing the ineffective binder in the pelletizing process, and have the potential to reduce the amount of binder used in pelletizing. Moreover, the physical and chemical properties and performance indexes of different raw balls are more uniform, which is conducive to improving the performance indexes of subsequent preheated balls and roasted balls, and has important practical significance for improving the quality and reducing consumption in the pelletizing production process.
Claims
1. A method for upgrading oxidized pellets, characterized in that: The following steps are involved: 1) performing a first wet mixing on each type of concentrate slurry produced within a certain period of time in the beneficiation process to obtain each type of concentrate slurry after mixing; The various types of concentrate pulps include flotation concentrate pulp, gravity concentration concentrate pulp, and magnetic concentration concentrate pulp. The various types of concentrate pulps after mixing include flotation concentrate pulp after mixing, gravity concentration concentrate pulp after mixing, and magnetic concentration concentrate pulp after mixing; 2) according to the ratio of each type of concentrate required for subsequent oxidation pellet production, the mixed slurries of each type of concentrate obtained in 1) are introduced into a slurry stirring tank in proportion, and a second wet mixing is performed, and then a mixed concentrate is obtained after filtering; 3) The mixed concentrate obtained in 2) is vigorously mixed with other additives to obtain a pelletizing material, and then oxidized pellets are prepared by conventional methods.
2. The method for upgrading oxidized pellets according to claim 1, characterized in that: The certain period of time in step 1) is no less than 3 days.
3. The method for upgrading oxidized pellets according to claim 1, characterized in that: In the first wet mixing in step 1), the mixing time is not less than 5 hours and the stirring slurry linear speed is not less than 10 m / min.
4. The method for upgrading oxidized pellets according to claim 1, characterized in that: The second wet mixing time in step 2) is not less than 10 hours, and the stirring slurry linear speed is not less than 15 m / min.
5. The method for upgrading oxidized pellets according to claim 1, characterized in that: The intensive mixing time in step 3) is not less than 50 seconds.
6. The method for upgrading oxidized pellets according to claim 1, characterized in that: The additive in step 3) is bentonite, and the amount used is 0.8-1.2 wt% of the concentrate mass.
7. The method for upgrading oxidized pellets according to claim 1, characterized in that: The conventional method in step 3) is pelletizing, drying, preheating, roasting and cooling.
8. The method for upgrading oxidized pellets according to claim 7, characterized in that: The drying temperature is 250-400°C, the preheating temperature is 890-930°C, and the calcination temperature is 1200-1230°C.