Method for preparing composite micro powder from low-grade refractory iron ore

Abstract

The invention discloses a method for preparing composite micro powder from low-grade refractory iron ore, which comprises the following steps: crushing the low-grade refractory iron ore to a particle size range suitable for flotation, and removing gangue minerals with larger particles through screening to obtain ore to be treated; the method comprises the steps that ore to be treated is subjected to wet grinding, in the wet type ore grinding process, a flotation reagent is sprayed into the ore in the vertical direction, it is ensured that the reagent evenly covers ore particles, preliminary dissociation of gangue minerals and preliminary separation of phosphorus minerals are promoted, and ore pulp is obtained; the ore pulp is input into a flotation tank for flotation; and the flotation concentrate is further finely ground, and target composite micro powder with the particle size being 20-40 micrometers is obtained. Through the wet grinding and flotation combined process, the iron minerals, gangue minerals and phosphorus minerals are effectively separated by accurately controlling the dosage and concentration of the agents and matching with reasonable ore grinding time and temperature adjustment, and finally the composite micro powder is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of minerals, and in particular to a method for preparing composite micropowder from low-grade refractory iron ore. Background Art

[0002] The development and utilization of low-grade refractory iron ore is an important research direction in the current mining industry. With the increasing shortage of global iron ore resources, the supply of traditional high-grade iron ore has gradually decreased, and the development of low-grade ore has become an urgent issue to be solved. Low-grade refractory iron ore usually refers to ore with low iron mineral content, more gangue minerals and other impurities, and coarse mineral particles, which are difficult to be effectively separated by conventional beneficiation methods. The flotation and purification process of this type of ore has always been a technical problem in the mining industry.

[0003] Flotation is currently a common method for processing low-grade iron ore, but this method has a poor effect on the treatment of low-grade and difficult-to-select iron ore. The basic principle of flotation is to use the selective action of reagents to make mineral particles combine with bubbles and float to the surface of the liquid to form a foam layer, thereby achieving mineral separation. In low-grade ores, the physical and chemical properties of gangue minerals and iron minerals are relatively small, which makes it difficult to separate minerals during flotation. A large amount of flotation reagents is often required to enhance the interaction between the reagents and mineral particles. However, improper or uneven addition of reagents often leads to incomplete mineral separation and low recovery rate.

[0004] Wet grinding is an important part of the mineral processing process. Its role is to crush ore particles to a particle size suitable for flotation through grinding, and promote the dissociation of minerals. In the processing of low-grade iron ore, the spraying of reagents in the wet grinding stage is often carried out by the traditional uniform addition method, but the spraying rate and concentration of the reagents are not accurately controlled, which easily leads to the reagents failing to fully and evenly cover the ore particles, thereby affecting the dissociation effect of the minerals and the efficiency of the flotation process.

[0005] In the traditional wet grinding method, the contact time between the reagent and the mineral is short, and the reagent is not effective enough. Especially when dealing with difficult-to-separate ores, it is difficult to effectively separate gangue minerals and phosphate minerals from iron minerals, resulting in more impurities in the final flotation concentrate. Even if a stronger collector is used, it is still difficult to achieve the ideal separation effect, which seriously affects the recovery rate of the mineral and the quality of the concentrate.

[0006] The particle size of flotation concentrate is relatively large, and the particle size of flotation concentrate is an important indicator for evaluating the flotation effect. Large particle size not only affects the further purification of the mineral, but also reduces the efficiency of the subsequent smelting process. In the processing of low-grade and difficult-to-select iron ore, due to incomplete mineral dissociation and uneven action of reagents, the ore particles after flotation are relatively coarse and cannot meet the requirements of fine particle size and uniformity, resulting in a generally large particle size of the ore powder.

[0007] In addition, the minerals in low-grade iron ore are mostly fine particles. The traditional flotation method and grinding equipment cannot fully refine the ore particles, thus affecting the quality of the flotation concentrate. Fine-grained composite micropowders not only help improve the efficiency of subsequent smelting, but also enhance their applicability in industrial applications, such as metal powder metallurgy, environmentally friendly adsorption materials and other fields.

[0008] Reagent use and control. Currently, commonly used flotation reagents mainly include collectors, inhibitors and foaming agents. For low-grade iron ore, the selection of collectors and inhibitors is particularly critical. Cationic collectors (such as fatty acid compounds) and anionic inhibitors (such as xanthate) are widely used in flotation, but the control of their addition concentration, spraying rate and addition timing directly affects the separation effect and recovery rate of minerals. In the prior art, reagent concentration and addition method are mostly based on experience, lack of precise control, and often cannot provide stable effects during the flotation process.

[0009] The traditional reagent dosing method cannot accurately control the distribution of reagents, resulting in uneven reagent action, insufficient flotation separation of minerals, and low recovery rate. Especially in the wet grinding process, the spraying amount and concentration of reagents cannot usually be adjusted dynamically, so it is difficult to make corresponding adjustments according to the changes in the ore.

[0010] The existing technology has a series of problems in the flotation process of low-grade and difficult-to-select iron ore, such as uneven reagent addition, inaccurate reagent concentration control, and large flotation concentrate particle size, which leads to low recovery rate of low-grade ore and the quality of flotation concentrate cannot meet the needs of subsequent smelting or industrial application. Therefore, a new technology is needed to solve these problems, improve the recovery rate of low-grade and difficult-to-select iron ore, and ensure that the particle size of flotation concentrate is appropriate to meet the requirements of fine-grained micropowder in industrial production. Summary of the invention

[0011] The present invention provides a method for preparing composite micropowder from low-grade refractory iron ore, which uses a combined process of wet grinding and flotation, accurately controls the dosage and concentration of reagents, and coordinates reasonable grinding time and temperature regulation to effectively separate iron minerals, gangue minerals and phosphate minerals, and finally obtains composite micropowder with a particle size of 20 to 40 microns.

[0012] The technical solution adopted by the present invention is as follows: a method for preparing composite micropowder from low-grade refractory iron ore, the specific steps are as follows:

[0013] a) crushing low-grade refractory iron ore into a particle size range suitable for flotation, the particle size range is 100-150 mesh, and removing larger particles of gangue minerals by screening to obtain ore to be processed;

[0014] b) Wet grinding the ore to be processed. During the wet grinding process, the flotation reagent is sprayed into the ore through a reagent spraying device at a spraying speed of 1 to 5 kg per minute. The reagent is sprayed in a vertical direction to ensure that the reagent evenly covers the ore particles, promotes the initial dissociation of gangue minerals and the initial separation of phosphate minerals, and obtains ore pulp;

[0015] c) Inputting the slurry into the flotation tank, specifically comprising the following steps:

[0016] i. Evenly distribute the slurry in the flotation tank and start the bubble generator to generate bubbles with a diameter of 0.1 to 2 mm;

[0017] ii. Using the difference in hydrophilicity and hydrophobicity between the air bubbles and the particle surface, gangue minerals and phosphate minerals adhere to the air bubble surface and float to the foam layer, while iron minerals settle to the bottom of the tank;

[0018] iii. removing the foam layer containing gangue minerals and phosphate minerals through a scraping device to form tailings;

[0019] iv. collecting flotation concentrate containing iron minerals from the bottom of the tank;

[0020] d) The flotation concentrate is further finely ground using ethanol as a ball milling medium to obtain a target composite micro powder with a particle size of 20 to 40 microns.

[0021] Preferably, the flotation reagent is a mixture of a cationic collector and an anionic inhibitor in a ratio of 1:(0.5-2), the cationic collector is a fatty acid compound, the anionic inhibitor is a xanthate, and the concentration of the mixture of the cationic collector and the anionic inhibitor is 0.1-2.0 g / L.

[0022] Preferably, the flotation reagent also includes an organic acid reagent for use in the phosphorus removal process. The organic acid reagent is hydrofluoric acid or sulfuric acid, and the concentration of the organic acid reagent is 0.5-2.0 g / L.

[0023] Preferably, the wet grinding adopts a wet ball mill, and the dosage, concentration and grinding time of the reagent are dynamically adjusted during the wet grinding process, specifically including:

[0024] a) In the initial stage, the reagent concentration is 0.5-1.0 g / L and the grinding time is 20-30 minutes to ensure the initial dissociation of gangue minerals and phosphate minerals;

[0025] b) In the intermediate stage, the reagent concentration is 1.0-1.5 g / L and the grinding time is 30-40 minutes, which further promotes the separation of gangue minerals and the removal of phosphate minerals;

[0026] c) In the later stage, the reagent concentration is 1.5-2.0 g / L and the grinding time is 40-50 minutes to ensure the complete separation of gangue minerals and the thorough removal of phosphate minerals.

[0027] Preferably, the pH value of the liquid phase in the flotation cell is controlled between 4 and 5 to optimize the removal effect of phosphate minerals and ensure the recovery rate of flotation concentrate.

[0028] Preferably, ethanol is used as a ball milling medium in the fine grinding process to improve the grinding efficiency.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. Improve the efficiency of mineral separation: By dynamically adjusting the dosage and concentration of the reagent, the gangue minerals and phosphate minerals can be effectively separated, thereby improving the recovery rate of iron minerals.

[0031] 2. Improve the quality of composite micropowders: Accurately control the reagent concentration and grinding time in wet grinding to make the particle size distribution of composite micropowders more uniform and suitable for various industrial applications.

[0032] 3. Optimize the reagent dosing method: The reagent spraying device can ensure that the reagent evenly covers the ore and ensure the high efficiency of the mineral dissociation and separation process.

[0033] 4. Strong flexibility and applicability: This method is not only suitable for low-grade and difficult-to-select iron ore, but can also be applied to the efficient beneficiation and recycling of other mineral resources, and has broad industrial application prospects.

[0034] 5. Energy saving and environmental protection: Through reasonable grinding process and reagent use, the mineral processing efficiency is improved, and energy consumption and environmental pollution are reduced. DETAILED DESCRIPTION

[0035] The present invention provides a method for preparing composite micropowder from low-grade refractory iron ore, comprising the following steps:

[0036] a) crushing low-grade refractory iron ore into a particle size range suitable for flotation, the particle size range is 100-150 mesh, and removing larger particles of gangue minerals by screening to obtain ore to be processed;

[0037] b) Wet grinding the ore to be processed. During the wet grinding process, the flotation reagent is sprayed into the ore through a reagent spraying device at a spraying speed of 1 to 5 kg per minute. The reagent is sprayed in a vertical direction to ensure that the reagent evenly covers the ore particles, promotes the initial dissociation of gangue minerals and the initial separation of phosphate minerals, and obtains ore pulp;

[0038] In a specific embodiment, the flotation reagent is a mixture of a cationic collector and an anionic depressant in a ratio of 1:(0.5-2), the cationic collector is a fatty acid compound, the anionic depressant is a xanthate, and the concentration of the mixture of the cationic collector and the anionic depressant is 0.1-2.0 g / L.

[0039] In a specific embodiment, the flotation reagent also includes an organic acid reagent for phosphorus removal. The organic acid reagent is hydrofluoric acid or sulfuric acid. The concentration of the organic acid reagent is 0.5-2.0 g / L.

[0040] In a specific embodiment, the wet grinding uses a wet ball mill, and the amount, concentration and grinding time of the reagent are dynamically adjusted during the wet grinding process, specifically including:

[0041] a) In the initial stage, the reagent concentration is 0.5-1.0 g / L and the grinding time is 20-30 minutes to ensure the initial dissociation of gangue minerals and phosphate minerals;

[0042] b) In the intermediate stage, the reagent concentration is 1.0-1.5 g / L and the grinding time is 30-40 minutes, which further promotes the separation of gangue minerals and the removal of phosphate minerals;

[0043] c) In the later stage, the reagent concentration is 1.5-2.0 g / L and the grinding time is 40-50 minutes to ensure the complete separation of gangue minerals and the thorough removal of phosphate minerals.

[0044] c) Inputting the slurry into the flotation tank, specifically comprising the following steps:

[0045] i. Evenly distribute the slurry in the flotation tank and start the bubble generator to generate bubbles with a diameter of 0.1 to 2 mm;

[0046] ii. Using the difference in hydrophilicity and hydrophobicity between the air bubbles and the particle surface, gangue minerals and phosphate minerals adhere to the air bubble surface and float to the foam layer, while iron minerals settle to the bottom of the tank;

[0047] iii. removing the foam layer containing gangue minerals and phosphate minerals through a scraping device to form tailings;

[0048] iv. collecting flotation concentrate containing iron minerals from the bottom of the tank;

[0049] In a specific embodiment, the pH value of the liquid phase in the flotation cell is controlled between 4 and 5 to optimize the removal effect of phosphate minerals and ensure the recovery rate of flotation concentrate.

[0050] d) The flotation concentrate is further finely ground to obtain target composite micro powder with a particle size of 20 to 40 microns.

[0051] In a specific embodiment, ethanol is used as a ball milling medium in the fine grinding process to improve the grinding efficiency.

[0052] The present invention is further described in detail below with reference to specific embodiments.

[0053] The embodiments of the present invention require the following equipment:

[0054] a) a crusher, used to crush low-grade refractory iron ore into a particle size range suitable for flotation, wherein the crusher can adjust the particle size;

[0055] b) Wet ball mill, used to grind ore to appropriate particle size;

[0056] c) a flotation cell, used for separating the ore pulp into flotation concentrate and tailings, the flotation cell comprising a bubble generating device and a bubble scraping device;

[0057] d) Reagent spraying device, used to spray flotation reagent into the ore pulp in the wet ball mill, with the spraying direction being vertical.

[0058] Example 1

[0059] The low-grade refractory iron ore is crushed to 120 mesh and processed by a wet ball mill. The wet grinding stage is divided into three stages of reagent spraying:

[0060] Initial stage: the concentration of the reagent is 0.8g / L, the spraying rate is 2 kg per minute, and the grinding time is 20 minutes. Intermediate stage: the concentration of the reagent is 1.2g / L, the spraying rate is 3 kg per minute, and the grinding time is 30 minutes. Late stage: the concentration of the reagent is 1.5g / L, the spraying rate is 4 kg per minute, and the grinding time is 40 minutes.

[0061] The bubble diameter used in the flotation stage was 1 mm, and the final flotation concentrate recovery rate was 92%, and the particle size of the composite micropowder was 25 microns.

[0062] Example 2

[0063] The low-grade refractory iron ore is crushed to 150 mesh and processed by a wet ball mill. The wet grinding stage is divided into three stages of reagent spraying:

[0064] Initial stage: reagent concentration is 0.9g / L, spraying rate is 2.5kg / min, and grinding time is 22 minutes. Intermediate stage: reagent concentration is 1.3g / L, spraying rate is 3kg / min, and grinding time is 32 minutes. Late stage: reagent concentration is 1.8g / L, spraying rate is 4kg / min, and grinding time is 42 minutes.

[0065] Bubbles with a diameter of 1.5 mm were used in the flotation process, with a final recovery of 89% and a composite micropowder particle size of 30 microns.

[0066] Example 3

[0067] The low-grade refractory iron ore is crushed to 100 mesh and processed by a wet ball mill. The wet grinding stage is divided into three stages of reagent spraying:

[0068] Initial stage: reagent concentration is 1.0g / L, spraying rate is 3 kg per minute, and grinding time is 25 minutes. Intermediate stage: reagent concentration is 1.4g / L, spraying rate is 3.5 kg per minute, and grinding time is 35 minutes. Late stage: reagent concentration is 1.6g / L, spraying rate is 4 kg per minute, and grinding time is 45 minutes.

[0069] The flotation stage uses bubbles with a diameter of 0.8 mm, the flotation concentrate recovery rate is 94%, and the composite micropowder particle size is 28 microns.

[0070] Example 4

[0071] The low-grade refractory iron ore is crushed to 140 mesh and processed by a wet ball mill. The wet grinding stage is divided into three stages of reagent spraying:

[0072] Initial stage: reagent concentration is 1.0g / L, spraying rate is 2.5kg / min, and grinding time is 28 minutes. Intermediate stage: reagent concentration is 1.4g / L, spraying rate is 3kg / min, and grinding time is 38 minutes. Late stage: reagent concentration is 1.7g / L, spraying rate is 3.5kg / min, and grinding time is 48 minutes.

[0073] The flotation process used bubbles of 1.2 mm diameter, with a recovery rate of 91% and a composite micropowder particle size of 26 microns.

[0074] Example 5

[0075] The low-grade refractory iron ore is crushed to 130 mesh and processed by a wet ball mill. The wet grinding stage reagent spraying is divided into three stages:

[0076] Initial stage: reagent concentration is 1.1g / L, spraying rate is 3 kg per minute, and grinding time is 30 minutes. Intermediate stage: reagent concentration is 1.5g / L, spraying rate is 3.5 kg per minute, and grinding time is 40 minutes. Late stage: reagent concentration is 1.8g / L, spraying rate is 4 kg per minute, and grinding time is 50 minutes.

[0077] The bubble diameter used in the flotation stage was 1.0 mm, the recovery rate was 93%, and the particle size of the composite micropowder was 27 microns.

[0078] Comparative Example 1

[0079] Instead of spraying wet grinding reagents, conventional reagents were directly added to the flotation tank, with a reagent concentration of 0.8 g / L and a recovery rate of 80% after flotation. The final composite micropowder particle size was 50 microns, which was a poor effect.

[0080] Comparative Example 2

[0081] Wet grinding reagent spraying was used, but the reagent concentration was 2.0g / L throughout the process. The addition concentration and rate were too high, resulting in excessive reagents during the flotation process, and the flotation effect was poor, with a recovery rate of 76%. The particle size of the composite micropowder was 70 microns, which was too large and not suitable for delicate applications.

[0082] Table 1

[0083] Example / Comparative Example Recovery rate (%) Composite micro powder particle size (μm) Example 1 92 25 Example 2 89 30 Example 3 94 28 Example 4 91 26 Example 5 93 27 Comparative Example 1 80 50 Comparative Example 2 76 70

[0084] It can be seen from Table 1 that the recovery rates in the embodiments are generally high, ranging from 89% to 94%, while the recovery rates of the comparative examples are 80% (Comparative Example 1) and 76% (Comparative Example 2), respectively. This shows that the separation effect of iron ore can be significantly improved by the method provided by the present invention, especially by accurately controlling the spraying mode, concentration and grinding time of the reagent during wet grinding, thereby improving the recovery rate of flotation concentrate. In contrast, the reagent addition mode and concentration control in the traditional method are not accurate enough, resulting in low recovery efficiency. The particle size of the composite micropowder in the embodiments is generally small, ranging from 25 microns to 30 microns. These particle sizes are suitable for subsequent smelting treatment or industrial applications (such as metal powder metallurgy and environmentally friendly adsorption materials), and fine particles help to increase the surface area and reactivity of the material. The particle size of the composite micropowder in the comparative example is larger, 50 microns (Comparative Example 1) and 70 microns (Comparative Example 2), respectively. Larger particle size not only affects the subsequent processing efficiency, but also may cause product quality to not meet the requirements, limiting its use in fine applications.

[0085] The method of the present invention effectively improves the mineral recovery rate in the flotation process and optimizes the particle size distribution of the micropowder. Compared with the traditional method, the embodiment not only improves the resource recovery efficiency by finely controlling the parameters of each link, but also ensures the high-quality performance of the composite micropowder, and has significant industrial application prospects. The low recovery rate and large composite micropowder particle size of the comparative example show that the traditional method has certain limitations in mineral separation and micropowder preparation, and it is difficult to meet the needs of efficient mineral processing and industrial application.

[0086] The composite micropowder provided by the present invention is suitable for subsequent smelting treatment, or used as a recycling material for industrial applications, such as metal powder metallurgy and environmentally friendly adsorption materials.

[0087] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for preparing composite micropowder from low-grade refractory iron ore, characterized in that: The following steps are involved: a) crushing low-grade refractory iron ore into a particle size range suitable for flotation, the particle size range is 100-150 mesh, and removing larger particles of gangue minerals by screening to obtain ore to be processed; b) Wet grinding the ore to be processed. During the wet grinding process, the flotation reagent is sprayed into the ore through a reagent spraying device at a spraying speed of 1 to 5 kg per minute. The reagent is sprayed in a vertical direction to ensure that the reagent evenly covers the ore particles, promotes the initial dissociation of gangue minerals and the initial separation of phosphate minerals, and obtains ore pulp; c) Inputting the slurry into the flotation tank, specifically comprising the following steps: i. Evenly distribute the slurry in the flotation tank and start the bubble generator to generate bubbles with a diameter of 0.1 to 2 mm; ii. Using the difference in hydrophilicity and hydrophobicity between the air bubbles and the particle surface, gangue minerals and phosphate minerals adhere to the air bubble surface and float to the foam layer, while iron minerals settle to the bottom of the tank; iii. removing the foam layer containing gangue minerals and phosphate minerals through a scraping device to form tailings; iv. collecting flotation concentrate containing iron minerals from the bottom of the tank; d) The flotation concentrate is further finely ground to obtain target composite micro powder with a particle size of 20 to 40 microns.

2. The method for preparing composite micropowder from low-grade refractory iron ore according to claim 1, characterized in that: The flotation reagent is a mixture of a cationic collector and an anionic inhibitor in a ratio of 1:(0.5-2), the cationic collector is a fatty acid compound, the anionic inhibitor is a xanthate, and the concentration of the mixture of the cationic collector and the anionic inhibitor is 0.1-2.0 g / L.

3. The method for preparing composite micropowder from low-grade refractory iron ore according to claim 1, characterized in that: The flotation reagent also includes an organic acid reagent, which is used in the phosphorus removal process. The organic acid reagent is hydrofluoric acid or sulfuric acid, and the concentration of the organic acid reagent is 0.5-2.0 g / L.

4. The method for preparing composite micropowder from low-grade refractory iron ore according to claim 1, characterized in that: The wet grinding adopts a wet ball mill, and the dosage, concentration and grinding time of the reagent are dynamically adjusted during the wet grinding process, specifically including: a) In the initial stage, the reagent concentration is 0.5-1.0 g / L and the grinding time is 20-30 minutes to ensure the initial dissociation of gangue minerals and phosphate minerals; b) In the intermediate stage, the reagent concentration is 1.0-1.5 g / L and the grinding time is 30-40 minutes, which further promotes the separation of gangue minerals and the removal of phosphate minerals; c) In the later stage, the reagent concentration is 1.5-2.0 g / L and the grinding time is 40-50 minutes to ensure the complete separation of gangue minerals and the thorough removal of phosphate minerals.

5. The method for preparing composite micropowder from low-grade refractory iron ore according to claim 1, characterized in that: The pH value of the liquid phase in the flotation tank is controlled between 4 and 5 to optimize the removal effect of phosphate minerals and ensure the recovery rate of flotation concentrate.

6. The method for preparing composite micropowder from low-grade refractory iron ore according to claim 1, characterized in that: In the fine grinding process, ethanol is used as a ball milling medium to improve the grinding efficiency.