阅读说明：本技术 微细粒铁矿物捕收剂和含碳酸盐铁矿石粗细异步浮选方法 (Fine-particle iron mineral collecting agent and coarse-fine asynchronous flotation method for carbonate-containing iron ore ) 是由 李文博 周立波 韩跃新 于 2021-08-30 设计创作，主要内容包括：本发明属于铁矿浮选领域,具体涉及一种微细粒铁矿物捕收剂,和使用该捕收剂对含碳酸盐铁矿石进行粗细异步浮选的方法。本发明针对含碳酸盐复杂难选铁矿中有用铁矿物嵌布粒度分布不均及含铁碳酸盐矿物易泥化的特点,针对不同粒级铁矿物开展不同的浮选工艺,在细粒级物料中添加微细粒铁矿物捕收剂,通过利用药剂结构中多极性亲固基在微细粒铁矿物表面进行选择性吸附,利用药剂结构中长烃链的疏水性能在高强度机械搅拌作用下形成疏水性铁矿物絮团,有助于提高微细粒铁矿物与气泡的碰撞概率,提高浮选作业回收率,显著降低微细粒铁矿物对粗粒铁矿物浮选行为的影响,降低矿泥罩盖,泡沫和水流夹带,提高浮选作业回收率和精矿质量,改善分选指标。(The invention belongs to the field of iron ore flotation, and particularly relates to a micro-fine particle iron mineral collecting agent and a method for performing coarse-fine asynchronous flotation on carbonate-containing iron ore by using the collecting agent. Aiming at the characteristics of uneven embedded particle size distribution of useful iron minerals and easy argillization of iron carbonate-containing minerals in carbonate-containing complex refractory iron ores, different flotation processes are carried out on different particle sizes of iron minerals, a micro-fine iron mineral collecting agent is added into a fine particle material, selective adsorption is carried out on the surface of the micro-fine iron minerals by utilizing a multi-polar hydrophilic solid base in a medicament structure, and hydrophobic iron mineral flocs are formed under the action of high-strength mechanical stirring by utilizing the hydrophobic property of a long hydrocarbon chain in the medicament structure, so that the method is beneficial to improving the collision probability of the micro-fine iron minerals and bubbles, improving the recovery rate of flotation operation, remarkably reducing the influence of the micro-fine iron minerals on the flotation behavior of the coarse iron minerals, reducing the cover of ore slime, improving the entrainment of foams and water flow, improving the recovery rate of the flotation operation and the quality of concentrates, and improving the separation indexes.)

1. A collecting agent for fine-particle iron minerals is characterized in that tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer is prepared by grafting copolymerization of tetradecyl trimethyl ammonium bromide and acrylic acid monomers.

2. The method of preparing a fine particle iron mineral collector of claim 1, comprising the steps of:

step A, adding tetradecyl trimethyl ammonium bromide into a reaction kettle, adding deionized water to prepare a solution with the mass concentration of 10% -20%, controlling the temperature to be 60-70 ℃, and stirring to dissolve the tetradecyl trimethyl ammonium bromide;

step B, cerium ammonium nitrate and potassium persulfate are mixed according to the mass ratio of (0.5-2): 1, adding the cerium ammonium nitrate and the potassium persulfate into a reaction kettle according to the total mass of 5-10% of the tetradecyl trimethyl ammonium bromide, introducing nitrogen into the solution in the reaction kettle, removing air, controlling the reaction temperature to be 55-65 ℃, and continuously reacting for 1-2 hours;

and C, controlling the reaction temperature to be 50-60 ℃, adding an acrylic monomer, wherein the acrylic monomer is prepared from the acrylic monomer and tetradecyl trimethyl ammonium bromide according to the mass ratio of (0.5-1): 1, and continuously reacting for 3-5 hours to obtain the micro-fine particle iron mineral collector.

3. The asynchronous flotation method for the coarse and fine iron ore containing carbonate is characterized by comprising the following steps:

step 1: grinding and magnetically separating the carbonate-containing iron ore to form mixed magnetic concentrate, and carrying out coarse-fine grading on the mixed magnetic concentrate to respectively obtain coarse-fraction mixed magnetic concentrate and fine-fraction mixed magnetic concentrate;

step 2: preparing a fine-grained mixed magnetic concentrate product subjected to coarse and fine classification into ore pulp, adding the fine-grained iron mineral collecting agent according to claim 1, adjusting the pH value and the stirring speed of the ore pulp, stirring, adding sodium oleate and second oil for size mixing, feeding the ore pulp subjected to size mixing into a flotation machine for direct flotation operation treatment of primary roughing, secondary concentration and secondary scavenging, and obtaining fine-grained material direct flotation concentrate and fine-grained material direct flotation tailings;

and step 3: performing reverse flotation operation on the coarse fraction mixed magnetic concentrate product after coarse and fine classification to obtain coarse fraction material reverse flotation concentrate and coarse fraction material reverse flotation tailings;

and 4, step 4: mixing the fine-fraction material direct flotation concentrate obtained in the step 2 and the coarse-fraction material reverse flotation concentrate obtained in the step 3 to obtain flotation final concentrate;

the steps 2 and 3 are not in sequence.

4. The asynchronous flotation method for the thickness of the carbonate-containing iron ore according to the claim 3, wherein the thickness of the fine and fine fraction mixed magnetic concentrate obtained in the step 1 is classified, and the content of the fine fraction mixed magnetic concentrate with the granularity of-0.023 mm accounts for more than 85%.

5. The coarse and fine asynchronous flotation method for the carbonate-containing iron ore according to claim 3, wherein in the step 2, the mass fraction of the ore pulp is 30% -40%, the pH value of the ore pulp is adjusted to be 7.0-9.0, the dosage of the collecting agent for the fine iron ore is 200g/t per 100g/t of the mass of the ore sample, the dosage of sodium oleate is 50-100g/t per 50g/t of the mass of the ore sample, the dosage of the second oil is 1500-2000r/min per 1500-4 g/t of the mass of the ore sample, and the slurry mixing time is 3-5 min.

6. The coarse and fine asynchronous flotation method for the carbonate-containing iron ore according to the claim 3, wherein in the step 2, the primary roughing method is to feed the pulp after size mixing into a flotation machine for direct separation, and the flotation time is 3-5min, so as to obtain a coarse flotation concentrate and a coarse flotation tailing;

the twice concentration method comprises the steps of feeding the rough flotation concentrate into a concentration flotation machine for size mixing, sequentially adding sodium oleate and second oil, carrying out primary concentration after size mixing for 3-5min, and carrying out concentration on the concentrate subjected to primary concentration according to the same method as that of the primary concentration, namely secondary concentration; the dosage of the sodium oleate and the second oil which are carefully selected twice is half of the dosage of the medicament during rough selection;

the twice scavenging method is to directly perform once scavenging on the rough flotation tailings fed into the scavenging flotation machine, and performing scavenging on the tailings subjected to once scavenging again to obtain twice scavenging.

7. The coarse and fine asynchronous flotation method for the carbonate-containing iron ore according to the claim 3, wherein in the step 3, the reverse flotation operation is performed by the following method:

adding water into coarse-fraction mixed magnetic concentrate to adjust the mixed magnetic concentrate into ore pulp with the mass fraction of 30-40%, sequentially adding a pH regulator, an iron mineral inhibitor, a gangue mineral activator, a collecting agent and a foaming agent into the ore pulp, stirring and mixing the ore pulp, performing one-time roughing and one-time concentrating and two-time scavenging reverse flotation operation treatment, and finally obtaining coarse-fraction material reverse flotation concentrate and reverse flotation tailings.

8. The asynchronous flotation method for the thickness of the carbonate-containing iron ore according to the claim 7, wherein in the step 3, the pH regulator is sodium hydroxide, and the pH value of the ore pulp is controlled to be 11.00-11.50; the iron mineral inhibitor is causticized corn starch, and the using amount is 800-1200g/t according to the quality of the ore sample; the gangue mineral activating agent is lime or calcium chloride, and the dosage is 400-600g/t according to the quality of a mineral sample; the collecting agent is sodium oleate or other modified fatty acid reagents, and the dosage is 800g/t according to the mass of the ore sample; the foaming agent is No. two oil, and the dosage of the foaming agent is 30-60g/t of the mass of the ore sample.

9. The coarse and fine asynchronous flotation method for the carbonate-containing iron ore according to claim 7, wherein in the step 3, the primary roughing method is to feed the pulp after size mixing into a flotation machine for direct separation, and the flotation time is 3-5min, so as to obtain a coarse flotation concentrate and a coarse flotation tailing;

the primary concentration method comprises the steps of feeding the rough flotation concentrate into a concentration flotation machine for size mixing, sequentially adding sodium oleate and second oil, wherein the dosage of the sodium oleate and the second oil is half of the dosage of a roughing medicament, and performing primary concentration after 3-5min of size mixing;

the twice scavenging method is to directly perform once scavenging on the rough flotation tailings fed into the scavenging flotation machine, and performing scavenging on the tailings subjected to once scavenging again to obtain twice scavenging.

Technical Field

The invention belongs to the field of iron ore flotation, and particularly relates to a micro-fine particle iron mineral collecting agent and a method for performing coarse-fine asynchronous flotation on carbonate-containing iron ore by using the collecting agent.

Background

The symbiotic relationship between useful minerals and gangue minerals in the carbonate-containing iron ores is complex, and the carbonate-containing iron ores belong to one of complex and refractory iron ores. Because the ore contains a large amount of easily argillized iron carbonate minerals with low mohs hardness, a large amount of fine-particle slime is formed in the ore grinding process, the slime has high specific surface area and surface energy, so that slime covering, surface conversion and the like are easily generated in the reverse flotation process of the iron ore, and the slime is adhered to the surfaces of coarse useful iron minerals and gangue minerals, so that the useful minerals and the gangue minerals cannot be effectively separated. In addition, because the micro-fine particle minerals are easy to generate bubbles and water flow entrainment in the reverse flotation process, a large amount of micro-fine particle iron minerals are lost into tailings, and the surface energy of the micro-fine particle iron minerals is larger, the using amount of flotation reagents can be obviously increased, and the production cost is increased. Research results show that when the siderite content in the ore exceeds 3%, the flotation index can be seriously deteriorated, and even the phenomenon of no separation of fine tailings occurs.

Because the carbonate-containing iron ore has the characteristic of uneven distribution of the disseminated particle size and the fineness, and the conventional strong magnetic separation and reverse flotation process is difficult to efficiently recover the iron minerals with the fine particle size, a large amount of useful minerals are lost into tailings, for example, although a relatively advanced step flotation process is adopted in a Dongshan sintering plant, the separation index is greatly improved compared with the original conventional anion reverse flotation process, because a large amount of hematite and siderite minerals with fine particles in the ore cannot be effectively recycled, a large amount of useful iron minerals are lost in the separation process, the iron grade of the comprehensive tailings reaches over 17 percent, the resource is greatly wasted, and meanwhile, the tailing stock is remarkably increased, so that serious environmental and social problems are brought, therefore, further research work is needed for the technology for strengthening and recycling the iron minerals with fine particles in the iron ore.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a micro-fine particle iron mineral collecting agent, a preparation method thereof and a method for performing coarse-fine asynchronous flotation on carbonate-containing maghemia mixed iron ore by using the micro-fine particle iron mineral collecting agent, and aims to solve the problem of efficient recycling of complex and difficultly-separated carbonate-containing lean iron ore.

The specific scheme of the invention is as follows:

a hydrophobic multi-polar-group micro-fine particle iron mineral collector is a tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer prepared by graft copolymerization of tetradecyl trimethyl ammonium bromide and acrylic acid monomers.

The preparation method of the micro-fine particle iron mineral collector comprises the following steps:

step A, adding a certain amount of tetradecyl trimethyl ammonium bromide into a reaction kettle, then adding deionized water to prepare a solution with the mass concentration of 10% -20%, controlling the temperature to be 60-70 ℃, and stirring to fully dissolve the tetradecyl trimethyl ammonium bromide;

step B, cerium ammonium nitrate and potassium persulfate are mixed according to the mass ratio of (0.5-2): 1, adding the cerium ammonium nitrate and the potassium persulfate into a reaction kettle according to the total mass of 5-10% of the tetradecyl trimethyl ammonium bromide, introducing nitrogen into the solution in the reaction kettle, removing air, controlling the reaction temperature to be 55-65 ℃, and continuously reacting for 1-2 hours;

and C, controlling the reaction temperature to be 50-60 ℃, then adding an acrylic monomer, wherein the acrylic monomer is prepared from the acrylic monomer and tetradecyl trimethyl ammonium bromide according to the mass ratio of (0.5-1): 1, and continuously reacting for 3-5 hours to obtain a tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer with a grafting rate of more than 80%, namely the micro-fine particle iron mineral collecting agent.

The grafting process of the tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer is as follows:

the micro-fine particle iron mineral collecting agent has a selective adsorption effect on iron minerals, particularly micro-fine particle iron minerals, a plurality of polar hydrophilic and solid groups such as carboxyl in the structure can be selectively adsorbed on the surfaces of the micro-fine particle iron minerals, then hydrophobic iron mineral floccules can be formed under the action of high-strength mechanical stirring due to the hydrophobic effect of long hydrocarbon chains in the structure, and the micro-fine particle iron minerals can be separated from the hydrophobic iron mineral floccules through direct flotation operation.

Based on the chemical properties and flotation behaviors of the micro-fine iron mineral crystals in the carbonate-containing iron ore, the invention also provides a coarse-fine asynchronous flotation method of the carbonate-containing iron ore, which specifically comprises the following steps:

step 1, carrying out ore grinding and magnetic separation on carbonate-containing iron ore to form mixed magnetic concentrate, and carrying out coarse-fine grading on the mixed magnetic concentrate to respectively obtain coarse-fraction mixed magnetic concentrate and fine-fraction mixed magnetic concentrate;

wherein, the thickness is graded, the granularity of the fine fraction mixed magnetic concentrate after grading is-0.023 mm, the content of the fine fraction mixed magnetic concentrate is more than 85 percent, and the rest is the coarse fraction mixed magnetic concentrate.

Step 2, preparing the fine-fraction mixed magnetic concentrate products after coarse and fine classification into ore pulp with the mass fraction of 30% -40%, adding a certain amount of the fine-fraction iron mineral collecting agent, adjusting the pH value and the stirring speed of the ore pulp, forming hydrophobic flocs by high-intensity stirring, adding a small amount of sodium oleate and second oil after stirring for a certain time (3-5min), performing size mixing, and feeding the ore pulp after size mixing into a flotation machine for performing direct flotation operation treatment of primary roughing, secondary concentration and secondary scavenging to obtain fine-fraction material direct flotation concentrate and fine-fraction material direct flotation tailings;

the chemical dosage of the micro-fine particle iron mineral collecting agent (referring to the dosage of the tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer) is 100-200g/t according to the mass of a mineral sample;

the pH value of the ore pulp is 7.0-9.0;

the stirring speed is 1500-;

the dosage of the sodium oleate is 50-100g/t according to the mass of the ore sample;

the dosage of the second oil is 30-50g/t according to the mass of the ore sample.

The primary roughing method comprises the steps of feeding pulp after size mixing into a flotation machine for direct sorting, wherein the flotation time is 3-5min, coarse flotation concentrate and coarse flotation tailings are obtained, the secondary concentration method comprises the steps of feeding the coarse flotation concentrate into a concentration flotation machine for size mixing, sequentially adding sodium oleate and second oil, performing primary concentration after 3-5min of size mixing, and performing concentration again according to the same method to obtain secondary concentration; the dosage of the two-time selection sodium oleate and the second oil is half of that of the crude selection medicament. The twice scavenging method is to directly perform once scavenging on the rough flotation tailings fed into the scavenging flotation machine, and performing scavenging on the tailings subjected to once scavenging again to obtain twice scavenging.

And 2, adding a micro-fine iron mineral collecting agent with selective adsorption on iron minerals into the fine-fraction mixed magnetic concentrate, selectively adsorbing the micro-fine iron mineral on the surface of the micro-fine iron mineral by utilizing a multi-polar hydrophilic solid base in a medicament structure, forming hydrophobic iron mineral flocs under the action of high-strength mechanical stirring by virtue of the hydrophobic action of a long hydrocarbon chain in the medicament structure, and separating out the micro-fine iron mineral through the positive flotation operation.

And 3, performing reverse flotation on the coarse fraction mixed magnetic concentrate product subjected to coarse and fine classification to obtain coarse fraction material reverse flotation concentrate and coarse fraction material reverse flotation tailings. The reverse flotation process can adopt the existing general reverse flotation process, and concretely can adopt the following method:

adding water into coarse-fraction mixed magnetic concentrate to adjust the mixed magnetic concentrate into ore pulp with the mass fraction of 30-40%, sequentially adding a pH regulator, an iron mineral inhibitor, a gangue mineral activator, a collecting agent and a foaming agent into the ore pulp, stirring and mixing the ore pulp, performing one-time roughing and one-time concentrating and two-time scavenging reverse flotation operation treatment, and finally obtaining coarse-fraction material reverse flotation concentrate and reverse flotation tailings.

The pH regulator is sodium hydroxide, and the pH value of ore pulp is controlled to be 11.00-11.50;

the iron mineral inhibitor is causticized corn starch, and the using amount is 800-1200g/t according to the quality of the ore sample;

the gangue mineral activating agent is lime or calcium chloride, and the dosage is 400-600g/t according to the quality of a mineral sample;

the collecting agent is sodium oleate and other modified fatty acid medicaments, and the dosage is 800g/t according to the mass of the ore sample;

the foaming agent is No. two oil, and the dosage of the foaming agent is 30-60g/t of the mass of the ore sample;

the primary roughing method comprises the steps of feeding pulp after size mixing into a flotation machine for direct sorting, wherein the flotation time is 3-5min, and coarse flotation concentrate and coarse flotation tailings are obtained; the twice scavenging method is to directly perform once scavenging on the rough flotation tailings fed into the scavenging flotation machine, and performing scavenging on the tailings subjected to once scavenging again to obtain twice scavenging.

And 3, performing reverse flotation operation, namely performing concentrate extraction and desilicification treatment on the classified coarse fraction mixed magnetic concentrate by adopting a reverse flotation process to obtain a reverse flotation iron concentrate product.

And 4, mixing the fine-fraction material forward flotation concentrate obtained in the step 2 and the coarse-fraction material reverse flotation concentrate obtained in the step 3 to obtain final flotation concentrate.

In the method, the step 2 and the step 3 are two separated relatively independent steps, the sequence is not limited, the quality of the ore sample in the step 2 refers to the quality of the mixed magnetic concentrate in a fine fraction, and the quality of the ore sample in the step 3 refers to the quality of the mixed magnetic concentrate in a coarse fraction.

The invention has the beneficial effects that: aiming at the characteristics of uneven distribution of useful iron minerals in the carbonate-containing complex refractory iron ore and easy argillization of iron carbonate-containing minerals, the invention carries out different flotation processes aiming at different size grades of iron minerals by carrying out coarse and fine grading operation treatment on the mixed magnetic concentrate, thereby enhancing the recycling of the micro-fine iron minerals and improving the separation index. The novel hydrophobic multi-polar-group high-molecular micro-fine particle iron mineral collecting agent is added into fine-grained materials, selective adsorption is carried out on the surface of a micro-fine particle iron mineral by utilizing a multi-polar hydrophilic solid base in a medicament structure, hydrophobic iron mineral flocs are formed under the action of high-strength mechanical stirring by utilizing the hydrophobic property of a long hydrocarbon chain in the medicament structure, the collision probability of the micro-fine particle iron mineral and bubbles is favorably improved, the flotation operation recovery rate is improved, meanwhile, the influence of the micro-fine particle iron mineral on the flotation behavior of the coarse particle iron mineral can be remarkably reduced through a coarse and fine classification asynchronous flotation process, a slime cover cap is reduced, foam and water flow entrainment are carried, the flotation operation recovery rate and the concentrate quality are improved, and the separation index is improved.

Drawings

FIG. 1 is a process flow chart of a coarse-fine asynchronous flotation method for carbonate-containing maghemia mixed iron ore in the embodiment of the invention.

Detailed Description

Example 1

The mixed magnetic concentrate product of carbonate-containing magnetite-hematite mixed iron ore is obtained after ore grinding-magnetic separation treatment of Anshan Liaoning, wherein the sample granularity is-0.038 mm and accounts for more than 78.53%, the TFe grade in the ore sample is 40.30%, and SiO is₂The content of the carbonate minerals is 48.56 percent, the content of other elements is 11.14 percent, and the carbonate minerals mainly comprise siderite and iron dolomite; the content of carbonate minerals is 8.65 percent, and the content of siderite is 5.84 percent. The process flow chart of the magnetic hematite mixed iron ore coarse-fine asynchronous flotation method is shown in figure 1, and the specific implementation steps are as follows:

(1) carrying out coarse and fine grading on a mixed magnetic concentrate sample after grinding and magnetic separation treatment on the carbonate-containing iron ore, wherein the grading granularity is-0.023 mm and accounts for 87.64%, and respectively obtaining a coarse fraction mixed magnetic concentrate sample and a fine fraction mixed magnetic concentrate sample;

(2) adding 2kg of tetradecyl trimethyl ammonium bromide into a reaction kettle, adding deionized water to prepare a solution with the concentration of 10%, controlling the temperature to be 60 ℃, and stirring to fully dissolve the tetradecyl trimethyl ammonium bromide; cerium ammonium nitrate and potassium persulfate are mixed according to the mass ratio of 0.5: 1, adding cerium ammonium nitrate and potassium persulfate into a reaction kettle according to the mass ratio of 5% of tetradecyl trimethyl ammonium bromide, introducing nitrogen into the solution in the reaction kettle, removing air, controlling the reaction temperature to be 60 ℃, continuing to react for 1h, controlling the reaction temperature to be 60 ℃, then adding an acrylic monomer, wherein the acrylic monomer and the tetradecyl trimethyl ammonium bromide are added according to the mass ratio of 0.5: 1, continuously reacting for 3 hours to obtain a tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer with a grafting rate of 83.2 percent; the reaction can be expressed as:

(3) preparing the fine-fraction mixed magnetic concentrate products after coarse and fine classification into ore pulp with the mass fraction of 30-40% in a stirring barrel, adding 100g/t of tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer according to the mass of an ore sample, adjusting the pH value of the ore pulp to 7.5, stirring the ore pulp at the stirring speed of 1600r/min, stirring at high strength to enable fine-particle iron minerals to form hydrophobic flocs, stirring for 5min, adding 50g/t of sodium oleate and 30g/t of second oil for respective size mixing for 3min, feeding the pulp after size mixing into a flotation machine for one-coarse-two-fine-two-sweep positive flotation operation treatment to obtain fine-fraction material positive flotation concentrate and positive flotation tailings;

(4) preparing the coarse fraction mixed magnetic concentrate product after coarse and fine classification into ore pulp with the mass fraction of 30-40%, adding sodium hydroxide to adjust the pH value of the ore pulp to 11.0, then adding 1000g/t of causticized corn starch, 400g/t of lime, 600g/t of sodium oleate and 30g/t of second oil according to the mass of an ore sample, stirring and pulping, respectively pulping for 3min, and then carrying out reverse flotation operation treatment of one coarse step and one fine step, thus finally obtaining coarse fraction material reverse flotation concentrate and reverse flotation tailings.

(5) And (4) mixing the fine-fraction material direct flotation concentrate obtained in the step (3) and the coarse-fraction material reverse flotation concentrate obtained in the step (4) to obtain flotation final concentrate.

The iron grade of the concentrate finally obtained by the method is 66.5%, the iron recovery rate is 91.74%, and the results of the primary accounting of technical and economic indexes show that compared with the conventional reverse flotation process of the mixed magnetic concentrate, the method can increase the iron concentrate yield by 32.67 ten thousand t each year, reduce the tailing discharge by 18.24 thousand t, increase the iron grade of the concentrate by 1.21 percentage points, improve the iron recovery rate by 9.68 percentage points, and increase the economic benefit by about 2.78 million yuan each year.

Comparative example 2

The difference of the processed raw materials from the example 1 is that only the conventional reverse flotation process of the mixed magnetic concentrate is adopted, and finally the iron concentrate is obtained, the iron grade is 65.29% and the iron recovery rate is 80.06% through detection.

Example 3

Taking a carbonate-containing magnetic hematite mixed magnetic concentrate product which is processed by ore grinding-magnetic separation operation on Anshan Liaoning, wherein the sample granularity is-0.038 mm and accounts for more than 80.65%, the TFe grade in the ore sample is 44.78%, the SiO2 content is 43.76%, the content of other elements is 11.46%, and the carbonate mineral mainly comprises siderite and iron dolomite; the content of carbonate minerals is 7.65 percent, and the content of siderite is 4.43 percent. The process flow chart of the magnetic hematite mixed iron ore coarse-fine asynchronous flotation method is shown in figure 1, and the specific implementation steps are as follows:

(1) carrying out coarse and fine classification on a mixed magnetic concentrate sample after grinding and magnetic separation treatment on carbonate-containing iron ore, wherein the classification granularity is-0.023 mm and accounts for 86.75 percent, and respectively obtaining a coarse fraction mixed magnetic concentrate sample and a fine fraction mixed magnetic concentrate sample;

(2) adding 2.5kg of tetradecyl trimethyl ammonium bromide into a reaction kettle, adding deionized water to prepare a solution with the concentration of 15%, controlling the temperature to be 65 ℃, and stirring to fully dissolve the tetradecyl trimethyl ammonium bromide; cerium ammonium nitrate and potassium persulfate are mixed according to the mass ratio of 1: 1, adding cerium ammonium nitrate and potassium persulfate into a reaction kettle according to the total mass of 7% of tetradecyl trimethyl ammonium bromide, introducing nitrogen into the solution in the reaction kettle, removing air, controlling the reaction temperature to be 55 ℃, continuing to react for 1.5h, controlling the reaction temperature to be 50 ℃, then adding an acrylic monomer, wherein the mass ratio of the acrylic monomer to the tetradecyl trimethyl ammonium bromide is 0.5: 1, continuously reacting for 4 hours to obtain a tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer with a grafting rate of 88.56%;

(3) preparing the fine-fraction mixed magnetic concentrate products after coarse and fine classification into ore pulp with the mass fraction of 30% -40% in a stirring barrel, adding 150g/t of tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer according to the mass of an ore sample, adjusting the pH value of the ore pulp to 8.0, stirring the ore pulp at the stirring speed of 1800r/min, stirring at high strength to enable fine-particle iron minerals to form hydrophobic flocs, stirring for 5min, then adding 80g/t of sodium oleate and 50g/t of second oil for respective size mixing for 3min, feeding the pulp after size mixing into a flotation machine for one-coarse-two-fine-fraction positive flotation operation treatment, and obtaining fine-fraction material positive flotation concentrate and positive flotation tailings;

(4) preparing the coarse fraction mixed magnetic concentrate product after coarse and fine classification into ore pulp with the mass fraction of 30-40%, adding sodium hydroxide to adjust the pH value of the ore pulp to 11.5, then adding 800g/t of causticized corn starch, 500g/t of lime, 650g/t of sodium oleate and 50g/t of second oil according to the mass of an ore sample, stirring and size mixing, respectively size mixing for 3min, and then performing one-coarse-one-fine two-sweep reverse flotation operation treatment to finally obtain coarse fraction material reverse flotation concentrate and reverse flotation tailings.

(5) And (4) mixing the fine-fraction material direct flotation concentrate obtained in the step (3) and the coarse-fraction material reverse flotation concentrate obtained in the step (4) to obtain flotation final concentrate.

The iron grade of the concentrate finally obtained by the method is 66.43%, the iron recovery rate is 90.74%, and the results of the primary calculation of technical and economic indexes show that compared with the conventional reverse flotation process of the mixed magnetic concentrate, the method can increase the iron concentrate yield by 28.67 kilotons every year, reduce the tailing discharge by 16.24 kilotons, increase the iron grade of the concentrate by 1.07 percentage point, increase the iron recovery rate by 8.32 percentage points, and increase the economic benefit by about 2.56 million yuan every year.

Comparative example 4

The difference between the processed raw materials and the example 3 lies in that the iron concentrate is finally obtained by only adopting the conventional reverse flotation process of the mixed magnetic concentrate, and the detection shows that the iron grade is 65.36% and the iron recovery rate is 82.42%.

Comparative example 5

The processing materials and processes were the same as in example 3 except that tetradecyltrimethylammonium bromide was replaced with dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, and octadecyltrimethylammonium bromide, respectively, and the tests showed that the iron grades were 65.28%, 65.21%, and 64.86%, and the iron recovery rates were 88.59%, 87.37%, and 82.68%, respectively. In the mechanism, when the ferric ammonium bromide is dodecyl trimethyl ammonium bromide, the hydrophobic agglomeration performance of the micro-fine iron mineral is poor due to the short hydrophobic alkyl chain, so that the iron recovery rate cannot be effectively improved, and when the ferric ammonium bromide is hexadecyl trimethyl ammonium bromide or octadecyl trimethyl ammonium bromide, the acrylic acid is not easy to polymerize due to the long hydrophobic alkyl chain, so that the medicament cannot generate an adsorption effect on the surface of the iron mineral, and the iron recovery rate cannot be effectively improved.

Example 6

Taking a carbonate-containing magnetic hematite mixed magnetic concentrate product processed by ore grinding-magnetic separation operation in Anshan Liaoning, wherein the sample granularity is-0.038 mm and accounts for more than 86.78%, the TFe grade in the ore sample is 48.71%, the SiO2 content is 43.89%, the content of other elements is 7.40%, and the carbonate mineral mainly comprises siderite and iron dolomite; the content of carbonate minerals is 8.69 percent, and the content of siderite is 5.34 percent. The process flow chart of the magnetic hematite mixed iron ore coarse-fine asynchronous flotation method is shown in figure 1, and the specific implementation steps are as follows:

(1) carrying out coarse and fine grading on a mixed magnetic concentrate sample after grinding and magnetic separation treatment on the carbonate-containing iron ore, wherein the grading granularity is-0.023 mm and accounts for 85.24%, and respectively obtaining a coarse fraction mixed magnetic concentrate sample and a fine fraction mixed magnetic concentrate sample;

(2) adding 2kg of tetradecyl trimethyl ammonium bromide into a reaction kettle, adding deionized water to prepare a solution with the concentration of 20%, controlling the temperature to be 70 ℃, and stirring to fully dissolve the tetradecyl trimethyl ammonium bromide; cerium ammonium nitrate and potassium persulfate are mixed according to the mass ratio of 2: 1, adding cerium ammonium nitrate and potassium persulfate into a reaction kettle according to the total mass of 10% of the mass of tetradecyl trimethyl ammonium bromide, introducing nitrogen into the solution in the reaction kettle, removing air, controlling the reaction temperature to be 65 ℃, continuing to react for 2 hours, controlling the reaction temperature to be 60 ℃, then adding an acrylic monomer, wherein the acrylic monomer and the tetradecyl trimethyl ammonium bromide are added according to the mass ratio of 1: 1, continuously reacting for 5 hours to obtain a tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer with a grafting rate of 87.65 percent;

(3) preparing the fine-fraction mixed magnetic concentrate products after coarse and fine classification into ore pulp with the mass fraction of 30-40% in a stirring barrel, adding 200g/t of tetradecyl trimethyl ammonium bromide-acrylic acid graft polymer according to the mass of an ore sample, adjusting the pH value of the ore pulp to 9.0, stirring the ore pulp at the stirring speed of 1600r/min, stirring at high strength to enable fine-particle iron minerals to form hydrophobic flocs, stirring for 5min, then adding 100g/t of sodium oleate and 50g/t of second oil for respective size mixing for 3min, feeding the pulp after size mixing into a flotation machine for one-coarse-two-fine-fraction positive flotation operation treatment, and obtaining fine-fraction material positive flotation concentrate and positive flotation tailings;

(4) preparing the coarse fraction mixed magnetic concentrate product after coarse and fine classification into ore pulp with the mass fraction of 30-40%, adding sodium hydroxide to adjust the pH value of the ore pulp to 11.50, then adding 1200g/t of causticized corn starch, 600g/t of lime, 600g/t of sodium oleate and 30g/t of second oil according to the mass of an ore sample, stirring and pulping, respectively pulping for 3min, then carrying out one-coarse-one-fine two-sweep reverse flotation operation treatment, and finally obtaining coarse fraction material reverse flotation concentrate and reverse flotation tailings.

(5) And (4) mixing the fine-fraction material direct flotation concentrate obtained in the step (3) and the coarse-fraction material reverse flotation concentrate obtained in the step (4) to obtain flotation final concentrate.

The iron grade of the concentrate finally obtained by the method is 66.38%, the iron recovery rate is 93.29%, and the results of the primary accounting of technical and economic indexes show that compared with the conventional reverse flotation process of the mixed magnetic concentrate, the method can increase the iron concentrate yield by 26.67 ten thousand t each year, reduce the tailing discharge by 17.86 ten thousand t, increase the iron grade of the concentrate by 1.24 percent, improve the iron recovery rate by 9.04 percent and increase the economic benefit by about 3.02 million yuan each year.

Comparative example 7

The processing raw material is the same as that in example 6, except that the conventional reverse flotation process of the mixed magnetic concentrate is only adopted, and finally the iron concentrate is obtained, and the detection shows that the iron grade is 65.14% and the iron recovery rate is 82.25%.

Comparative example 8

The raw materials and the process were treated as in example 6, except that tetradecyltrimethylammonium bromide was replaced with dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, and octadecyltrimethylammonium bromide, respectively, and the tests showed that the iron grades were 65.34%, 65.28%, and 64.84%, and the iron recovery rates were 88.59%, 86.56%, and 84.31%, respectively. In the mechanism, when the ferric ammonium bromide is dodecyl trimethyl ammonium bromide, the hydrophobic agglomeration performance of the micro-fine iron mineral is poor due to the short hydrophobic alkyl chain, so that the iron recovery rate cannot be effectively improved, and when the ferric ammonium bromide is hexadecyl trimethyl ammonium bromide or octadecyl trimethyl ammonium bromide, the acrylic acid is not easy to polymerize due to the long hydrophobic alkyl chain, so that the medicament cannot generate an adsorption effect on the surface of the iron mineral, and the iron recovery rate cannot be effectively improved.

Comparative example 9

The processing raw material and the process are the same as example 2, except that acrylic acid is replaced by acrylamide or acrylonitrile with the same mass, and the iron grade is 64.83% and the iron recovery rate is 87.65% through detection. In the mechanism, carboxyl in acrylic acid can form a stable chelate with iron atoms on the surface of iron minerals, and acrylamide, acrylonitrile and the iron atoms cannot form the stable chelate with the iron atoms, so that the medicament cannot generate an adsorption effect on the surface of the iron minerals, and the iron recovery rate cannot be effectively improved.