阅读说明：本技术 一种高碳酸盐铁矿石复合改性抑制剂及其制备、使用方法 (High-carbonate iron ore composite modified inhibitor and preparation and use methods thereof ) 是由 李文博 韩跃新 周立波 于 2021-08-30 设计创作，主要内容包括：本发明属于铁矿石反浮选抑制剂领域,主要涉及一种高碳酸盐铁矿石复合改性抑制剂及其制备、使用方法。本发明根据易泥化碳酸盐矿物的晶体化学性质和浮选行为研究,基于亲铁性高分子药剂的超分子缔合效应和桥联团聚性能,采用改性支链葡聚糖、改性聚丙烯酰胺及海藻酸钠等几种具有不同亲铁特征官能团和支链网状结构的改性药剂作为复合改性抑制剂。通过复合改性抑制剂的多效能作用,降低该类矿石中易泥化碳酸盐矿物对反浮选作业的影响,强化对易泥化碳酸盐铁矿物的抑制作用,减少细粒铁矿物在浮选过程中的水流及泡沫夹带,提高浮选回收率,改善分选指标。(The invention belongs to the field of iron ore reverse flotation inhibitors, and mainly relates to a high-carbonate iron ore composite modified inhibitor and preparation and use methods thereof. According to the research on the chemical properties and the flotation behavior of the crystals of the easily argillized carbonate minerals, based on the supermolecule association effect and the bridging agglomeration performance of the siderophilic high-molecular agents, the invention adopts several modified agents with different siderophilic characteristic functional groups and branched chain network structures, such as modified branched-chain glucan, modified polyacrylamide and sodium alginate, as composite modified inhibitors. Through the multi-effect action of the composite modified inhibitor, the influence of the easily argillable carbonate minerals in the ore on the reverse flotation operation is reduced, the inhibiting effect on the easily argillable carbonate iron minerals is strengthened, the water flow and foam entrainment of the fine iron minerals in the flotation process are reduced, the flotation recovery rate is improved, and the separation index is improved.)

1. The high-carbonate iron ore composite modified inhibitor is characterized by being prepared by mixing cross-linked polymers of branched glucan or/and modified glucan and sodium alginate with polyacrylamide or/and modified polyacrylamide.

2. The preparation method of the high carbonate iron ore composite modification inhibitor as claimed in claim 1, which is characterized by comprising the following steps:

step 1: mixing the branched-chain glucan or/and the modified glucan with sodium alginate to prepare a mixture solution, then adding glyoxal and sodium chloride, adjusting the pH value of the solution, reacting, and controlling the reaction temperature and the reaction time;

step 2: adding polyacrylamide or/and modified polyacrylamide after reaction, and uniformly mixing to obtain the high-carbonate iron ore composite modified inhibitor;

the preparation method of the modified glucan comprises the following steps:

step 1.1: carrying out causticization treatment on the branched-chain glucan in an alkaline solution, then adding propylene oxide and sodium chloroacetate for modification treatment, and controlling the reaction temperature and the reaction time of the modification treatment; after reaction, neutralizing, precipitating, filtering and drying to obtain modified glucan;

the preparation method of the modified acrylamide comprises the following steps:

step 1.2: mixing dry polyacrylamide and sodium hydroxide, adding water to prepare a polyacrylamide emulsion, adding the polyacrylamide emulsion into a reaction kettle, carrying out activation modification treatment by high-strength mechanical stirring, and controlling the reaction temperature and the reaction time; and neutralizing, precipitating, filtering and drying after the reaction to obtain the modified polyacrylamide.

3. The preparation method of the high carbonate iron ore complex modification inhibitor according to claim 2, wherein in the steps 1 and 2, the mass ratio of the used branched glucan or/and modified glucan, polyacrylamide or/and modified polyacrylamide and sodium alginate is (10-20): 1: (5-40) mixing.

4. The preparation method of the high carbonate iron ore composite modified inhibitor according to claim 2, wherein in the step 1, the mass concentration of the prepared mixture solution is 30-50%, and the addition amount of glyoxal and sodium chloride is 1-5% of the total mass of the branched glucan and/or the modified glucan and the sodium alginate respectively; regulating the pH value of the solution to 8.0-10.0, the reaction temperature to 70-80 ℃ and the reaction time to 1-2 h.

5. The method for preparing the hypercarbonate iron ore complex modification inhibitor according to claim 2, wherein in step 1.1, the mass ratio of the branched glucan to the propylene oxide and the mass ratio of the branched glucan to the propylene oxide chloroacetic acid are (4-6): 1 and (3-5) 1, controlling the reaction temperature of the modification treatment to be 50-70 ℃ and controlling the reaction time to be 3-5 h.

6. The preparation method of the high-carbonate iron ore composite modification inhibitor according to claim 2, wherein in the step 1.2, polyacrylamide and sodium hydroxide are mixed according to a mass ratio of 0.5:1-2:1, the mass concentration of the prepared polyacrylamide emulsion is 60% -80%, the reaction temperature is controlled at 85-95 ℃, and the reaction time is controlled at 4-6 h.

7. The use method of the high carbonate iron ore composite modification inhibitor according to claim 1, is characterized by comprising the following steps:

and stirring and mixing the mixed magnetic concentrate obtained by magnetic separation of the high-carbonate iron ore to obtain ore pulp with the mass concentration of 30-45%, sequentially adding an ore pulp pH value regulator, the high-carbonate iron ore composite modification inhibitor, a gangue mineral activating agent, a collecting agent and a foaming agent, fully mixing the pulp, and feeding the pulp into a flotation machine for reverse flotation operation to obtain an iron concentrate product.

8. The use method of the high carbonate iron ore composite modification inhibitor according to claim 7, characterized in that:

the ore pulp pH value regulator is sodium hydroxide and is adjusted to a pH value of 11.0-12.0; the adding amount of the high-carbonate iron ore composite modification inhibitor is 500-800g/t of the mass of the ore sample according to the solid content of the polymer in the high-carbonate iron ore composite modification inhibitor; the gangue mineral activating agent is lime or calcium chloride, and the adding amount is 800g/t of 400-one of the ore sample quality; the collecting agent is sodium oleate, and the adding amount is 500-800g/t according to the mass of the ore sample; the foaming agent is No. two oil, and the adding amount is 30-50g/t according to the mass of the ore sample.

9. The use method of the high carbonate iron ore composite modification inhibitor according to claim 7, characterized in that: in the reverse flotation operation, one-time reverse flotation roughing, two-time fine separation and two-time scavenging are sequentially carried out.

10. The use method of the high carbonate iron ore composite modification inhibitor according to claim 9, characterized in that:

the parameters of the primary reverse flotation roughing are as follows: the roughing time is 4-6 min;

the two-time selection parameters are as follows: adding a gangue mineral activating agent and a collecting agent, wherein the dosage of the gangue mineral activating agent is 400-400 g/t, the dosage of the collecting agent is 200-400g/t, the pH value of ore pulp is controlled to be 11.0-12.0, and the concentration time is 3-4 min;

the two-time scavenging parameters are as follows: controlling the pH value of the ore pulp to be 11.0-12.0, adding no other medicament, and scavenging for 3-4 min.

Technical Field

The invention belongs to the field of iron ore reverse flotation inhibitors, and mainly relates to a high-carbonate iron ore composite modified inhibitor and preparation and use methods thereof.

Background

With the continuous acceleration of the industrialized and modernized construction process of China, the demand of domestic iron and steel enterprises for iron ores is increased year by year, and as the domestic iron ore resources have the characteristics of 'poor, fine and miscellaneous', and the mining and smelting costs are high, the external dependence of the iron ores is always over 85% for many years, and the healthy development of the domestic iron and steel enterprises and the national economy is severely restricted, so that the high-efficiency development and utilization of the domestic complex refractory iron ores are enhanced, the self-sufficiency of the iron ores is improved, the external dependence of the domestic iron ores can be relieved to a certain extent, and the method has important practical significance for the sustainable development of the resources and the healthy development of the national economy.

High carbonate iron ore is a refractory iron ore with complex mineral composition and distribution relationship. At present, the complex and difficult-to-separate ores are usually subjected to a combined process of weak magnetic separation, strong magnetic separation and reverse flotation, but because carbonate minerals such as iron dolomite, calcite and siderite contained in the ores are low in mohs hardness and easy to argillize in an ore grinding process, a large amount of fine mud minerals are generated and dispersed in ore pulp, and because the mineral particles have high specific surface area and surface energy, fine mud covers are generated in a flotation process, and the problems of surface conversion, flotation foam entrainment and the like are caused, so that the problems of poor selectivity of flotation reagents, low flotation recovery rate and large reagent dosage are caused, and the separation environment is seriously deteriorated. Due to the lack of effective separation technology and suitable flotation reagents, many of the carbonate-containing iron ores in China are mainly stockpiled for a long time. According to statistics, about 100 million of iron ores are stockpiled in the Anshan Liaoning area every year, and the total stockpiling amount exceeds 2000 million.

In addition, because the traditional iron ore reverse flotation inhibitor usually adopts natural polysaccharide starch medicaments extracted from grain crops such as corn, wheat, potato, cassava and the like, and because the natural starch medicaments have single structures, do not contain characteristic functional groups, and have poor medicament selectivity and expansion performance, a large amount of medicaments need to be added in the using process, a large amount of waste of the grain crops is caused, the waste is not beneficial to the food supply safety in China, and the development of national economy is also not beneficial, so the development of the high-efficiency inhibitor suitable for the separation of the carbonate-containing hematite has important practical significance.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation and use method of a magnetic hematite mixed high carbonate iron ore composite modified inhibitor, aiming at solving the problem of high-efficiency recycling of high-carbonate complex refractory iron ores, reducing the influence of easily argillized carbonate minerals in the ores on reverse flotation operation, strengthening the inhibition effect on the easily argillized carbonate iron minerals, reducing the water flow and foam entrainment of fine iron minerals (mainly micro-fine carbonate iron minerals) in the flotation process, improving the flotation recovery rate and improving the separation index through the multi-efficiency effect of the composite modified inhibitor.

The invention adopts the following technical scheme:

a compound modified inhibitor of iron ore with high carbonate content is prepared from branched-chain dextran or/and modified dextran (branched-chain dextran, or modified dextran, or their mixture), cross-linked polymer of sodium alginate, and polyacrylamide or/and modified polyacrylamide (polyacrylamide, or modified polyacrylamide, or their mixture).

The preparation method of the modified glucan comprises the following steps: carrying out causticization treatment on the branched-chain glucan in an alkaline solution, then adding epoxypropane and sodium chloroacetate for modification treatment, and controlling the reaction temperature and the reaction time; and after reaction, neutralizing, precipitating, filtering and drying to obtain the modified glucan with the characteristic iron-philic functional group. The mass ratio of the branched-chain glucan to the epoxypropane to the chloroacetic acid is (4-6): 1 and (3-5) 1, controlling the reaction temperature to be 50-70 ℃ and the reaction time to be 3-5 h. For neutralization, for example, a 10% oxalic acid solution may be used.

The modified glucan is characterized in that more polar functional groups with hydrophilicity and hydrophilicity are further introduced into glucan, after the modified glucan is prepared into a composite modified inhibitor, the polar functional groups with hydrophilicity and hydrophilicity are subjected to competitive adsorption with a flotation collector and an activator through supermolecular association in the reverse flotation process, so that an active site of a micro-fine carbonate iron mineral is subjected to adsorption covering, the micro-fine carbonate iron mineral is fully inhibited, the selectivity of a flotation reagent is improved, the consumption of the flotation collector and the activator is reduced, and the recovery rate of iron is improved. The structural schematic diagram of the modified glucan is shown in figure 1.

The preparation method of the modified polyacrylamide comprises the following steps: mixing polyacrylamide and sodium hydroxide according to a certain proportion, adding a proper amount of water to prepare a polyacrylamide emulsion with a certain concentration, adding the polyacrylamide emulsion into a reaction kettle, carrying out activation modification treatment by high-strength mechanical stirring, and controlling the reaction temperature and the reaction time; and neutralizing, precipitating, filtering and drying after the reaction to obtain the modified polyacrylamide. Wherein, the polyacrylamide and the sodium hydroxide are mixed according to the mass ratio of 0.5:1-2:1, the mass concentration of the prepared polyacrylamide emulsion is 60-80%, the reaction temperature is controlled at 85-95 ℃, and the reaction time is controlled at 4-6 h. For neutralization, for example, a 10% oxalic acid solution may be used.

Modification of polyacrylamide can hydrolyze amide groups into iron-philic carboxyl functional groups, so that the selectivity of the medicament is improved, and electrostatic repulsion is formed due to electronegativity of carboxyl groups, so that curled high-molecular chains of polyacrylamide can be fully stretched, the chances of collision and adsorption of the high-molecular chains with fine particles are greatly increased, and the adsorption effect of the polyacrylamide is fully exerted. The structural formula of the obtained modified polyacrylamide is shown as follows:

the preparation method of the high-carbonate iron ore composite modified inhibitor comprises the following steps:

step 1: mixing the branched-chain glucan or/and the modified glucan with sodium alginate to prepare a mixture solution, then adding glyoxal and sodium chloride, adjusting the pH value of the solution, reacting, and controlling the reaction temperature and the reaction time;

step 2: and adding polyacrylamide or/and modified polyacrylamide after the reaction, and uniformly mixing to obtain the high-carbonate iron ore composite modified inhibitor. The high-carbonate iron ore composite modification inhibitor can be prepared into an aqueous solution with a certain concentration, such as 5-8% mass concentration for use.

Branched glucan or/and modified glucan, polyacrylamide or/and modified polyacrylamide and sodium alginate according to the mass ratio (10-20): 1: (5-40). In the step 1, the mass concentration of the prepared mixture solution is 30-50%, and the adding amount of glyoxal and sodium chloride is 1-5% of the total mass of the branched glucan or/and the modified glucan and the sodium alginate respectively. The reaction pH value is 8.0-10.0, the reaction temperature is 70-80 ℃, and the reaction time is 1-2 h.

Through the steps, the branched chains of the glucan or/and the modified glucan and the sodium alginate are crosslinked with each other through glyoxal to form a net structure, and then the net structure is mixed with polyacrylamide or/and modified polyacrylamide to form the composite modified inhibitor. The micro-fine carbonate iron minerals in the high-carbonate iron ore are subjected to bridging agglomeration by utilizing the branched chain network structure of the composite modified inhibitor, so that the apparent particle size of carbonate iron mineral particles is increased, water flow and foam entrainment of the carbonate iron minerals in the reverse flotation process are reduced, and the flotation recovery rate is improved.

The invention also provides a use method of the high-carbonate iron ore composite modified inhibitor, which comprises the following steps:

and (3) carrying out magnetic separation on the high-carbonate iron ore to prepare mixed magnetic concentrate. Stirring and size mixing the mixed magnetic concentrate to obtain ore pulp with the mass concentration of 30-45%, sequentially adding an ore pulp pH value regulator, the high-carbonate iron ore composite modified inhibitor, the gangue mineral activator, the collecting agent and the foaming agent, fully mixing the pulp, feeding the pulp into a flotation machine for reverse flotation operation, and sequentially carrying out primary reverse flotation roughing, secondary fine concentration and secondary scavenging in the reverse flotation operation to finally obtain a qualified iron concentrate product.

In the method, the pH value regulator of the ore pulp is sodium hydroxide and is adjusted to 11.0-12.0; the adding amount of the high carbonate iron ore composite modification inhibitor is 500-800g/t of the mass of the ore sample according to the solid content of the polymer in the high carbonate iron ore composite modification inhibitor; the gangue mineral activating agent is lime or calcium chloride, and the adding amount is 800g/t of 400-one of the ore sample quality; the collecting agent is sodium oleate, and the adding amount is 500-800g/t according to the mass of the ore sample; the foaming agent is No. two oil, and the adding amount is 30-50g/t according to the mass of the ore sample.

In the method, the parameters of the primary reverse flotation roughing are as follows: the roughing time is 4-6 min.

In the method, the two-time selection parameters are as follows: the dosage of the gangue mineral activating agent is 400-600g/t, the dosage of the collecting agent is 200-400g/t, the pH value of the ore pulp is controlled to be 11.0-12.0, and the concentration time is 3-4 min.

In the method, the two-time scavenging parameters are as follows: controlling the pH value of the ore pulp to be 11.0-12.0, adding no other medicament, and scavenging for 3-4 min.

In the method, the iron grade of the qualified iron ore concentrate product is 66.5-67.2%, and the iron recovery rate is 86.3-90.5%.

The invention takes high carbonate iron ore, such as high carbonate maghemite mixed iron ore in Liaoning area as raw material, and particularly aims at the mixed magnetic concentrate sample obtained after magnetic separation treatment, and adopts the high carbonate iron ore composite modified inhibitor to carry out anion reverse flotation treatment, so as to obtain qualified iron concentrate products. According to the research of the crystal chemical property and the flotation behavior of the easily argillized carbonate mineral, based on the supermolecule association effect and the bridging agglomeration performance of the siderophilic high-molecular medicament, the invention adopts several modified medicaments with different siderophilic characteristic functional groups and branched chain net structures, such as modified branched-chain glucan, modified polyacrylamide, sodium alginate and the like as composite modified inhibitors, firstly, a large amount of siderophilic hydrophilic polar functional groups in the high-molecular structure of the composite modified inhibitor are utilized to generate competitive adsorption with a flotation collector and an activator through supermolecule association, so as to carry out adsorption covering on active sites of the micro-fine carbonate iron mineral, fully inhibit the micro-fine carbonate iron mineral, improve the selectivity of the flotation medicament, reduce the consumption of the collector and a gangue mineral activator during flotation, and simultaneously, carry out bridging agglomeration on the micro-fine carbonate iron mineral by utilizing the branched chain net structure of the composite modified inhibitor, the apparent particle size of carbonate iron mineral particles is increased, the water flow and foam entrainment of the carbonate iron mineral in the reverse flotation process are reduced, and the flotation recovery rate is improved. And stirring and mixing the mixed magnetic concentrate sample obtained after magnetic separation treatment, adjusting the pH value of ore pulp, sequentially adding a composite modified inhibitor, an activating agent, a collecting agent and a foaming agent, and then performing reverse flotation operation treatment on the mixed magnetic concentrate by adopting a one-coarse two-fine two-sweep flotation process to finally obtain a qualified iron concentrate product (the iron grade is more than or equal to 65 percent, and the iron recovery rate is more than or equal to 85 percent).

Drawings

FIG. 1 is a schematic diagram of the structure of modified glucan according to the present invention.

FIG. 2 is a flow chart of the reverse flotation process of the mixed magnetic concentrate in the embodiment of the invention.

Detailed Description

Example 1

Taking high-carbonate iron ore mixed magnetic concentrate of a Liaoning Dongshan sintering plant as a flotation raw material, wherein the granularity analysis result of the high-carbonate iron ore mixed magnetic concentrate is that the ore is 85.22 percent with the granularity of-0.038 mm, the TFe grade in an ore sample is 50.64 percent, and SiO is₂The content of the iron carbonate-containing mineral is 30.32 percent and the content of the iron carbonate-containing mineral is 8.19 percent. The flow chart of the reverse flotation process of the high carbonate mixed magnetic concentrate is shown in figure 2, and the specific implementation steps are as follows:

1) carrying out causticization treatment on the branched-chain glucan in an alkaline solution, and then respectively setting the mass ratio of the branched-chain glucan to propylene oxide and chloroacetic acid in a reaction kettle as 4: mixing the components in a ratio of 1 to 3:1, controlling the reaction temperature to be 65 ℃, taking out after reacting for 3 hours, neutralizing, precipitating, filtering and drying the modified glucan for later use;

2) mixing polyacrylamide and sodium hydroxide according to a ratio of 0.5:1, adding a proper amount of water to prepare an emulsion with the mass concentration of the polyacrylamide being 60%, adding the emulsion into a reaction kettle, carrying out activation modification treatment by high-strength mechanical stirring, controlling the reaction temperature to be 85 ℃, reacting for 4 hours to obtain modified polyacrylamide, neutralizing, precipitating, filtering and drying the modified polyacrylamide for later use;

3) mixing modified glucan and sodium alginate, adding water to prepare a 30% mixture solution, then adding glyoxal and sodium chloride, adjusting the pH value of the solution to 8.0, reacting, and controlling the reaction temperature to be 70 ℃ and the reaction time to be 1 h; adding modified polyacrylamide after reaction, and uniformly mixing to obtain the high-carbonate iron ore composite modified inhibitor; and the high carbonate iron ore composite modification inhibitor is prepared into a 5% aqueous solution for later use.

The modified glucan, the modified polyacrylamide and the sodium alginate are added into a reaction kettle according to the mass ratio of 10:1:10, and the glyoxal and the sodium chloride are added into the reaction kettle according to 1% of the total mass of the modified glucan and the sodium alginate for reaction.

4) As shown in fig. 2, the obtained high carbonate mixed magnetic concentrate is stirred and slurried to a slurry with a mass concentration of 35%, and then: adjusting the pH value of the ore pulp to 11.0 by using an ore pulp pH value regulator sodium hydroxide; adding the composite modified inhibitor, wherein the dosage (calculated according to the solid content of the polymer of the composite modified inhibitor) is 500 g/t; the dosage of the activator lime is 400 g/t; the using amount of collecting agent sodium oleate is 800 g/t; the amount of the foaming agent No. two oil is 30 g/t. And performing a reverse flotation roughing test after 3min of size mixing, wherein the roughing time is 5 min. Carrying out concentration twice on the roughed concentrate, wherein the using amount of an activator lime is 400g/t, the using amount of a collecting agent sodium oleate is 500g/t, the pH value of ore pulp is controlled to be 11.50, and the concentration time is 3min, so as to obtain the final reverse flotation concentrate; and (4) carrying out scavenging on the rougher tailings twice, controlling the pH value of the ore pulp to be 11.50, and carrying out scavenging for 3min to obtain the reverse flotation final tailings.

The iron grade of the concentrate finally obtained by the method is 66.5%, the iron recovery rate is 90.5%, and the results of primary calculation of technical and economic indexes show that compared with the conventional reverse flotation process of the high-carbonate iron ore mixed magnetic concentrate, the method can increase the iron concentrate yield by 50.84 ten thousand t each year, reduce the tailing discharge by 16.75 ten thousand t, reduce the sodium oleate consumption of a collecting agent by 560t, reduce the lime consumption of an activating agent by 520t, increase the iron grade of the concentrate by 2.55 percentage points, increase the iron recovery rate by 12.68 percentage points, and increase the economic benefit by about 4.89 million yuan each year.

Example 2

The raw materials and the method are basically the same as example 1, except that the modification of the branched glucan and the polyacrylamide in the steps 1) and 2) is not performed, and the branched glucan and the polyacrylamide are directly used in the step 3) instead of the modified glucan and the modified polyacrylamide, respectively.

By adopting the method of the embodiment, the iron grade of the concentrate is 65.2%, the iron recovery rate is 84.56%, and the results of the primary calculation of technical and economic indexes show that compared with the embodiment 1, the iron grade of the flotation concentrate is reduced by 1.3%, and the iron recovery rate is reduced by 5.94%.

Comparative example 3

The raw material and the method are basically the same as example 1, and the difference is that the inhibitor is a mixture of branched-chain glucan and sodium alginate according to the mass ratio of 1:1, the dosage of the inhibitor is 1000g/t, the dosage of the collector before rough concentration is 1000g/t, the dosage of the activator is 550g/t, and finally iron ore concentrate is obtained, and through detection, the iron grade is 63.95%, and the iron recovery rate is 82.82%.

Comparative example 4

The raw material treatment and the method are basically the same as example 1, and the difference is that a mixture of branched-chain glucan, polyacrylamide and sodium alginate in a mass ratio of 10:1:10 is adopted, the using amount of the inhibitor is 1200g/t, the using amount of the collecting agent before rough concentration is 1000g/t, and the using amount of the activating agent is 650g/t, so that iron ore concentrate is finally obtained, and through detection, the iron grade is 64.95%, and the iron recovery rate is 82.56%.

Example 5

Taking high-carbonate iron ore mixed magnetic concentrate of a Liaoning Dongshan sintering plant as a flotation raw material, wherein the granularity analysis result of the high-carbonate iron ore mixed magnetic concentrate is that the ore is 88.36 percent with the granularity of-0.038 mm, the TFe grade in an ore sample is 54.21 percent, and SiO is₂The content of the iron carbonate-containing mineral is 35.32 percent, and the content of the iron carbonate-containing mineral is 10.58 percent. The flow chart of the reverse flotation process of the high carbonate mixed magnetic concentrate is shown in figure 2, and the specific implementation steps are as follows:

1) carrying out causticization treatment on the branched-chain glucan in an alkaline solution, and then respectively setting the mass ratio of the branched-chain glucan to propylene oxide and chloroacetic acid in a reaction kettle as 5: mixing the components in a ratio of 1 to 4.5:1, controlling the reaction temperature at 70 ℃, taking out after 5 hours of reaction, neutralizing, precipitating, filtering and drying the modified glucan for later use;

2) mixing polyacrylamide and sodium hydroxide according to a ratio of 0.7:1, adding a proper amount of water to prepare emulsion with the mass concentration of the polyacrylamide being 75%, adding the emulsion into a reaction kettle, carrying out activation modification treatment by high-strength mechanical stirring, controlling the reaction temperature to be 90 ℃, reacting for 5 hours to obtain modified polyacrylamide, neutralizing, precipitating, filtering and drying the modified polyacrylamide for later use;

3) mixing modified glucan and sodium alginate, adding water to prepare a 40% mixture solution, then adding glyoxal and sodium chloride, adjusting the pH value of the solution to 9.0, reacting, and controlling the reaction temperature to be 75 ℃ and the reaction time to be 1.5 h; adding modified polyacrylamide after reaction, and uniformly mixing to obtain the high-carbonate iron ore composite modified inhibitor; and preparing the high carbonate iron ore composite modified inhibitor into a 7% aqueous solution for later use.

The modified glucan, the modified polyacrylamide and the sodium alginate are added into a reaction kettle according to the mass ratio of 15:1:10, and the glyoxal and the sodium chloride are added into the reaction kettle according to 3% of the total mass of the modified glucan and the sodium alginate for reaction.

4) Stirring and mixing the obtained high carbonate mixed magnetic concentrate to obtain slurry with the mass concentration of 40%, and sequentially adding: adjusting the pH value of the ore pulp to 11.5 by using an ore pulp pH value regulator sodium hydroxide; adding the composite modified inhibitor, wherein the dosage (calculated according to the solid content of the polymer of the composite modified inhibitor) is 600 g/t; the dosage of the activating agent lime is 550 g/t; the using amount of collecting agent sodium oleate is 500 g/t; the amount of the foaming agent No. two oil is 35 g/t. And performing a reverse flotation roughing test after 3min of size mixing, wherein the roughing time is 5 min. Carrying out concentration twice on the roughed concentrate, wherein the using amount of an activator lime is 500g/t, the using amount of a collecting agent sodium oleate is 250g/t, the pH value of ore pulp is controlled to be 11.50, and the concentration time is 3min, so as to obtain the final reverse flotation concentrate; and (4) carrying out scavenging on the rougher tailings twice, controlling the pH value of the ore pulp to be 11.50, and carrying out scavenging for 3min to obtain the reverse flotation final tailings.

The concentrate iron grade finally obtained by the method is 66.82%, the iron recovery rate is 88.69%, and the results of the primary calculation of technical and economic indexes show that compared with the conventional reverse flotation process of the high-carbonate iron ore mixed magnetic concentrate, the method can increase the iron concentrate yield by 45.65 ten thousand tons per year, reduce the tailing discharge by 20.38 thousand tons, reduce the sodium oleate consumption of a collecting agent by 380 tons, reduce the lime consumption of an activating agent by 430 tons, increase the iron grade of the concentrate by 1.78 percents, improve the iron recovery rate by 10.32 percents, and increase the economic benefit by about 4.56 million yuan per year.

Comparative example 6

The raw material and the method are basically the same as those in example 6, except that the inhibitor is only a mixture of modified glucan and polyacrylamide in a mass ratio of 15:1, the dosage of the inhibitor is 1100g/t, the dosage of the collector before roughing is 1050g/t, and the dosage of the activator is 800g/t, and finally iron ore concentrate is obtained, and through detection, the iron grade is 65.48%, and the iron recovery rate is 78.37%.

Example 7

Taking high-carbonate iron ore mixed magnetic concentrate of a Liaoning Dongshan sintering plant as a flotation raw material, wherein the granularity analysis result of the high-carbonate iron ore mixed magnetic concentrate is that-0.038 mm accounts for 82.25%, the TFe grade in an ore sample is 57.23%, and SiO is₂The content of the iron carbonate-containing mineral is 30.83 percent, and the content of the iron carbonate-containing mineral is 9.58 percent. The flow chart of the reverse flotation process of the high carbonate mixed magnetic concentrate is shown in figure 2, and the specific implementation steps are as follows:

1) carrying out causticization treatment on the branched-chain glucan in an alkaline solution, and then respectively setting the mass ratio of the branched-chain glucan to propylene oxide and chloroacetic acid in a reaction kettle as 6: mixing the components in a ratio of 1 to 5:1, controlling the reaction temperature at 70 ℃, taking out after reacting for 4 hours, neutralizing, precipitating, filtering and drying the modified glucan for later use;

2) mixing polyacrylamide and sodium hydroxide according to a ratio of 1:1, adding a proper amount of water to prepare emulsion with the mass concentration of the polyacrylamide being 75%, adding the emulsion into a reaction kettle, carrying out activation modification treatment by high-strength mechanical stirring, controlling the reaction temperature to be 95 ℃, obtaining modified polyacrylamide after reacting for 4 hours, neutralizing the modified polyacrylamide, precipitating, filtering and drying for later use;

3) mixing modified glucan and sodium alginate, adding water to prepare a 50% mixture solution, then adding glyoxal and sodium chloride, adjusting the pH value of the solution to 10.0, reacting, and controlling the reaction temperature to be 80 ℃ and the reaction time to be 2 hours; adding modified polyacrylamide after reaction, and uniformly mixing to obtain the high-carbonate iron ore composite modified inhibitor; and the high carbonate iron ore composite modification inhibitor is prepared into an aqueous solution with the concentration of 8% for later use.

The modified glucan, the modified polyacrylamide and the sodium alginate are added into a reaction kettle according to the mass ratio of 20:1:10, and the glyoxal and the sodium chloride are added into the reaction kettle according to 5% of the total mass of the modified glucan and the sodium alginate for reaction.

4) Stirring and mixing the obtained high carbonate mixed magnetic concentrate to obtain slurry with the mass concentration of 40%, and sequentially adding: adjusting the pH value of the ore pulp to 11.5 by using an ore pulp pH value regulator sodium hydroxide; adding the composite modified inhibitor, wherein the dosage (calculated according to the solid content of the polymer of the composite modified inhibitor) is 800 g/t; the dosage of the activating agent lime is 550 g/t; the using amount of collecting agent sodium oleate is 600 g/t; the dosage of the foaming agent No. two oil is 40 g/t. And performing a reverse flotation roughing test after 3min of size mixing, wherein the roughing time is 5 min. Carrying out concentration twice on the roughed concentrate, wherein the using amount of an activator lime is 600g/t, the using amount of a collecting agent sodium oleate is 350g/t, the pH value of ore pulp is controlled to be 11.50, and the concentration time is 3min, so as to obtain the final reverse flotation concentrate; and (4) carrying out scavenging on the rougher tailings twice, controlling the pH value of the ore pulp to be 11.50, and carrying out scavenging for 3min to obtain the reverse flotation final tailings.

The iron grade of the concentrate finally obtained by the method is 67.20%, the iron recovery rate is 86.30%, and the results of the primary calculation of technical and economic indexes show that compared with the conventional reverse flotation process of the high-carbonate iron ore mixed magnetic concentrate, the method can increase the iron concentrate yield by 41.80 ten thousand t each year, reduce the tailing discharge by 22.35 ten thousand t, reduce the sodium oleate consumption of a collecting agent by 480t, reduce the lime consumption of an activating agent by 530t, increase the iron grade of the concentrate by 1.58 percentage points, increase the iron recovery rate by 11.26 percentage points, and increase the economic benefit by about 4.38 million yuan each year.

Comparative example 8

The raw material treatment and the method are basically the same as example 1, and the difference is that the mixture of sodium alginate and polyacrylamide in a mass ratio of 10:1 is adopted as the inhibitor, the using amount of the inhibitor is 1200g/t, the using amount of the collector before rough concentration is 1000g/t, and the using amount of the activator is 750g/t, so that iron ore concentrate is finally obtained, and through detection, the iron grade is 65.62%, and the iron recovery rate is 75.04%.