Method for direct flotation desilicication of magnesite by using inhibitor curdlan

Abstract

A method for applying an inhibitor curdlan to direct flotation desilicication of magnesite belongs to the technical field of direct flotation separation and purification of magnesite, and comprises the following steps: preparing a curdlan aqueous solution, crushing raw ore, and grinding the crushed raw ore to a proper size fraction to obtain ore pulp; the pH value of the ore pulp is adjusted, and a reverse flotation collecting agent is added for reverse flotation; and in-tank products obtained through reverse flotation are subjected to direct flotation, firstly, the pH value of ore pulp is adjusted, an inhibitor and a direct flotation collecting agent are sequentially added for roughing, in-tank products obtained through roughing are direct flotation tailings, and foam products obtained through three times of concentration of foam products obtained through roughing are flotation concentrates. The inhibitor curdlan has renewability and biodegradability, is relatively low in price, small in reagent usage amount and good in flotation separation effect, can greatly reduce the ore dressing cost and improve the ore dressing efficiency, and has huge advantages in wide application in the industry.

Description

Technical Field

[0001] The invention belongs to the technical field of positive flotation separation and purification of magnesite, and in particular relates to a method for using a depressant, curdlan, for positive flotation desiliconization of magnesite. Background Art

[0002] Magnesium, with the symbol Mg, is located in the third period and the second main group of the periodic table of chemical elements, with an atomic number of 12 and a relative atomic mass of 24g / mol. Magnesium is one of the elements that make up the earth, accounting for about 2.1% of the earth's crust and ranking eighth in element reserves. It also plays an important role in the lithosphere and the hydrosphere. Magnesium, magnesium alloys and magnesium materials are widely used in important fields such as refractory materials, military industry, medical treatment, automobiles, and food. As a metal with high chemical activity, it can only exist in the form of compounds in nature. Common magnesium-containing minerals with mining value include magnesite, brucite, dolomite, serpentine, etc.

[0003] Magnesite is a superior mineral resource in my country. Its proven reserves rank second in the world, second only to Russia. Its production and export volume rank first in the world. This determines that magnesite has become an important raw material for magnesium extraction. However, with the continuous exploitation of rich ore resources in recent years, magnesite resources have become increasingly "poor, fine and mixed", and it is more difficult to separate and purify magnesite from actual ores. At present, the commonly used method for processing magnesite in my country is flotation. The flotation method separates and purifies magnesite according to the difference in the surface properties of magnesite and gangue minerals. Among them, the gangue minerals associated with magnesite are mainly silicates and carbonates. The carbonate minerals are mainly dolomite, calcite, etc. The silicate minerals are mainly quartz, talc, serpentine, etc. The fusible silicate substances formed by these minerals will reduce the strength of refractory materials during the subsequent processing and calcination process. Therefore, it is imperative to take some measures to reduce silicon in production. In the actual ore flotation process, when the content of silicate minerals in magnesite ore is high, in line with the flotation principle of "easy first, difficult later, less float, more suppress", first use amine reagents to reverse float out a part of talc, serpentine, chlorite and other silicate minerals, and then use positive flotation to suppress gangue minerals to achieve the purpose of purifying magnesite. As the mineral properties of magnesite ore become more and more complex, the difficulty of sorting increases, and silicate gangue minerals are often difficult to be removed in one step in reverse flotation, and there is currently little research on silicon-containing mineral inhibitors in positive flotation.

[0004] In recent years, the research and development of new flotation agents has become an important direction in the development of the flotation field, and has made important contributions to the interaction between agent molecules and mineral surfaces, the purification of flotation concentrates, and the improvement of the economic benefits of ore dressing plants. Therefore, the inhibitor curdlan of the present invention has a practical guiding role in promoting the comprehensive utilization and development of low-grade magnesite. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for using a depressant, curdlan, in the direct flotation desiliconization of magnesite. The method utilizes the property that curdlan can be selectively adsorbed on the surface of talc in the raw ore in the form of chemical adsorption, so that the hydrophilicity of the talc surface is increased and the floatability is weakened, while the surface of the magnesite in the raw ore has no effect or a weak effect, and less adsorption is made on the surface of the magnesite, so that the floatability of the magnesite and the talc is greatly different. Therefore, curdlan is used as a depressant in the direct flotation process to achieve effective separation of the two ores.

[0006] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0007] S1. Prepare a curdlan glue solution: add deionized water to the curdlan glue, heat and stir in a constant temperature water bath, then add sodium hydroxide and stir until completely dissolved to obtain a curdlan glue solution;

[0008] S2. Grinding: crushing the raw ore and grinding it to a suitable particle size to obtain ore pulp;

[0009] S3. Reverse flotation: adjust the pH value of the slurry, add reverse flotation collector, obtain the in-tank product and foam product, the foam product is the reverse flotation tailings;

[0010] S4. Direct flotation: The in-tank product obtained from reverse flotation is subjected to direct flotation. After adjusting the pH value of the slurry, inhibitors and forward flotation collectors are added in sequence for roughing to obtain in-tank products and foam products. The in-tank product is the forward flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained from the primary concentration is returned to the roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained from the secondary concentration is returned to the primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained from the tertiary concentration is returned to the secondary concentration, and the obtained foam product is flotation concentrate, i.e., magnesite concentrate.

[0011] in:

[0012] In the step S1, the mass ratio of curdlan to sodium hydroxide is (5-10):1, the heating temperature under the condition of a constant temperature water bath is 80-90° C., and the mass concentration of the obtained curdlan solution is 0.5%-2%.

[0013] In step S2, the ore has a MgO content of 40.1% to 42.9%, a SiO2 content of 2.1% to 4.5%, a CaO content of 0.09% to 0.3%, a FeO content of 0.04% to 0.2%, and an Al2O3 content of 0.02% to 0.3%, calculated by mass fraction.

[0014] In step S2, the raw ore is ground to a particle size of -0.074 mm, accounting for 65% to 80%, and the slurry concentration is 30% to 40%.

[0015] In step S3, hydrochloric acid solution and sodium hydroxide solution are used to adjust the pH value of the pulp during the reverse flotation process, and the pH value is maintained at 5-7, and the pH is kept constant during the dosing process.

[0016] In the step S3, the dosage of the reverse flotation collector is 70-120 g per ton of ore, selected from one of ether amine solution, dodecylamine solution and LKD solution, and the mass concentration is 1%-3%.

[0017] In step S4, the pulp concentration in the positive flotation process is 30% to 40%; the pH value of the pulp is adjusted by using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid and sodium hydroxide solutions is 0.1% to 5%; the pH value is maintained at 10 to 11.5 in the roughing and tertiary cleaning processes, and the pH value is kept constant during the dosing process.

[0018] In step S4, the dosage of the collector in the roughing process of the positive flotation is 1000-1400 g per ton of ore, and the collector is selected from one of sodium oleate solution, hexadecyl phosphate solution, hydroxamic acid solution and sodium oleate / benzohydroxamic acid solution, and the mass concentration is 1%-3%.

[0019] In step S4, the inhibitor for the roughing of the positive flotation is a curdlan solution, which is added at a rate of 100 to 150 g per ton of ore, and no reagent is added in the three selection processes of the positive flotation.

[0020] In the step S4, the MgO content in the magnesite concentrate is 46.12% to 47.48% by mass, the SiO2 content is 0.09% to 0.98% by mass, and the MgO recovery rate is 36.87% to 38.21%.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The inhibitor curdlan selected in the present invention is renewable and biodegradable, can be safely used in food processing, and is an environmentally friendly flotation agent.

[0023] 2. The inhibitor curdlan selected in the present invention is relatively cheap, which greatly reduces the cost of mineral processing and has great advantages in being widely used in industry.

[0024] 3. The depressant curdlan selected in the present invention has a small dosage in the flotation separation process of magnesite and a good flotation separation effect, which can improve the ore dressing efficiency.

[0025] 4. The inhibitor curdlan used in the present invention has a strong adsorption effect on talc and can occupy the action sites of sodium oleate on the surface of talc, so it has a good separation effect in the flotation separation of magnesite and talc. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A process flow chart of using a depressant, curdlan, for positive flotation desiliconization of magnesite according to the present invention. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the examples, but the examples are not intended to limit the technical solutions of the present invention. The test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0028] In order to better explain the present invention, the main contents of the present invention are further explained below in conjunction with specific laboratory examples, but the contents of the present invention are not limited to the following examples.

[0029] Example 1

[0030] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 42.83%, the content of SiO2 is 3.76%, the content of CaO is 0.23%, the content of FeO is 0.06%, and the content of Al2O3 is 0.15%.

[0031] A method for using a depressant, curdlan, for the direct flotation desiliconization of magnesite, the process flow chart of which is as follows: Figure 1 As shown, the specific steps include:

[0032] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0033] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0034] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector etheramine solution with a mass concentration of 1% is added, and the dosage is 70g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0035] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, the pH value of the pulp is adjusted to 10 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor, curdlan aqueous solution, and a positive flotation collector, sodium oleate solution, are added in sequence for roughing, the mass concentration of the inhibitor, curdlan, is 1%, and the dosage is 120g per ton of ore; the mass concentration of the positive flotation collector, sodium oleate, is 1%, and the dosage is 1000g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by primary concentration is returned to roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by secondary concentration is returned to primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by tertiary concentration is returned to secondary concentration, and the obtained foam product is flotation concentrate, i.e., magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0036] The obtained magnesite concentrate has a MgO content of 47.48%, a SiO2 content of 0.13% and a MgO recovery rate of 38.21% by mass.

[0037] Example 2

[0038] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 41.79%, the content of SiO2 is 3.45%, the content of CaO is 0.15%, the content of FeO is 0.11%, and the content of Al2O3 is 0.27%.

[0039] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0040] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0041] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0042] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector dodecylamine solution with a mass concentration of 1% is added, and the dosage is 95g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0043] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, the pH value of the pulp is adjusted to 10 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor, curdlan aqueous solution, and a positive flotation collector, hexadecyl phosphate solution, are added in sequence for roughing, the mass concentration of the inhibitor curdlan is 1%, and the dosage is 140g per ton of ore, and the mass concentration of the positive flotation collector hexadecyl phosphate is 1%, and the dosage is 1200g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by primary concentration is returned to roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by secondary concentration is returned to primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by tertiary concentration is returned to secondary concentration, and the obtained foam product is flotation concentrate, i.e., magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0044] The obtained magnesite concentrate has a MgO content of 47.32%, a SiO2 content of 0.15% and a MgO recovery rate of 37.99% by mass.

[0045] Example 3

[0046] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 41.35%, the content of SiO2 is 3.54%, the content of CaO is 0.09%, the content of FeO is 0.04%, and the content of Al2O3 is 0.16%.

[0047] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0048] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0049] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0050] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector LKD solution with a mass concentration of 1% is added, and the dosage is 120g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0051] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, hydrochloric acid solution and sodium hydroxide solution are used to adjust the pulp pH value to 10, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor curdlan aqueous solution and a positive flotation collector hydroxamic acid solution are added in sequence for roughing, the mass concentration of the inhibitor curdlan is 1%, and the dosage is 120g per ton of ore, and the mass concentration of the positive flotation collector hydroxamic acid is 1%, and the dosage is 1100g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by the primary concentration is returned to the roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by the secondary concentration is returned to the primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by the tertiary concentration is returned to the secondary concentration, and the obtained foam product is a flotation concentrate, i.e., a magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0052] The obtained magnesite concentrate has a MgO content of 47.12%, a SiO2 content of 0.23% and a MgO recovery rate of 36.87% by mass.

[0053] Example 4

[0054] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 41.28%, the content of SiO2 is 4.33%, the content of CaO is 0.20%, the content of FeO is 0.11%, and the content of Al2O3 is 0.05%.

[0055] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0056] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0057] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0058] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector etheramine solution with a mass concentration of 1% is added, and the dosage is 70g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0059] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, hydrochloric acid solution and sodium hydroxide solution are used to adjust the pulp pH value to 10, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor curdlan aqueous solution and a positive flotation collector sodium oleate / benzohydroxamic acid solution are added in sequence for roughing, the mass concentration of the inhibitor curdlan is 1%, and the dosage is 125g per ton of ore, and the mass concentration of the positive flotation collector sodium oleate / benzohydroxamic acid is 1%, and the dosage is 700g / 300g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by the primary concentration is returned to the roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by the secondary concentration is returned to the primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by the tertiary concentration is returned to the secondary concentration, and the obtained foam product is a flotation concentrate, i.e., a magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0060] The obtained magnesite concentrate has a MgO content of 47.38%, a SiO2 content of 0.09% and a MgO recovery rate of 37.57% by mass.

[0061] Example 5

[0062] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 41.22%, the content of SiO2 is 4.12%, the content of CaO is 0.20%, the content of FeO is 0.09%, and the content of Al2O3 is 0.15%.

[0063] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0064] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0065] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0066] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector dodecylamine solution with a mass concentration of 1% is added, and the dosage is 95g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0067] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, hydrochloric acid solution and sodium hydroxide solution are used to adjust the pulp pH value to 10, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor curdlan aqueous solution and a positive flotation collector sodium oleate / benzohydroxamic acid solution are added in sequence for roughing, the mass concentration of the inhibitor curdlan is 1%, and the dosage is 150g per ton of ore, and the mass concentration of the positive flotation collector sodium oleate / benzohydroxamic acid is 1%, and the dosage is 750g / 400g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by the primary concentration is returned to the roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by the secondary concentration is returned to the primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by the tertiary concentration is returned to the secondary concentration, and the obtained foam product is a flotation concentrate, i.e., a magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0068] The obtained magnesite concentrate has a MgO content of 47.43%, a SiO2 content of 0.16% and a MgO recovery rate of 37.81% by mass.

[0069] Example 6

[0070] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 40.97%, the content of SiO2 is 4.05%, the content of CaO is 0.11%, the content of FeO is 0.09%, and the content of Al2O3 is 0.02%.

[0071] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0072] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0073] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0074] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector LKD solution with a mass concentration of 1% is added, and the dosage is 120g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0075] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, hydrochloric acid solution and sodium hydroxide solution are used to adjust the pulp pH value to 10, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor curdlan aqueous solution and a positive flotation collector sodium oleate / benzohydroxamic acid solution are added in sequence for roughing, the mass concentration of the inhibitor curdlan is 1%, and the dosage is 110g per ton of ore, and the mass concentration of the positive flotation collector sodium oleate / benzohydroxamic acid is 1%, and the dosage is 900g / 200g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by the primary concentration is returned to the roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by the secondary concentration is returned to the primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by the tertiary concentration is returned to the secondary concentration, and the obtained foam product is a flotation concentrate, i.e., a magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0076] The obtained magnesite concentrate has a MgO content of 46.98%, a SiO2 content of 0.18% and a MgO recovery rate of 37.13% by mass.

[0077] Example 7

[0078] The composition of the raw ore used in this embodiment is calculated by mass fraction, and the content of MgO is 40.27%, the content of SiO2 is 3.62%, the content of CaO is 0.12%, the content of FeO is 0.08%, and the content of Al2O3 is 0.04%.

[0079] A method for using a depressant, curdlan, for direct flotation desiliconization of magnesite, specifically comprising the following steps:

[0080] S1. Prepare a curdlan solution: weigh 1 g of curdlan and 0.2 g of sodium hydroxide, place the weighed curdlan in a small beaker, add deionized water, heat to 80 ° C in a constant temperature water bath and stir, then add the weighed sodium hydroxide, stir until the curdlan is completely dissolved, and adjust the solution to a 1% curdlan solution;

[0081] S2. Grinding: After the raw ore is crushed, it is ground to a particle size of -0.074 mm, accounting for 69%, and the obtained pulp concentration is 40%, and reverse flotation is performed;

[0082] S3. Reverse flotation: The pH value of the pulp is adjusted to 6 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid solution and the sodium hydroxide solution is 1%; then, a reverse flotation collector etheramine solution with a mass concentration of 1% is added, and the dosage is 70g per ton of ore. During the dosing process, the pH is kept constant to obtain a tank product and a foam product, and the foam product is the reverse flotation tailings;

[0083] S4. Direct flotation: The in-tank product obtained by reverse flotation is subjected to direct flotation, and the pulp concentration is 33%. First, the pH value of the pulp is adjusted to 10 using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of hydrochloric acid and sodium hydroxide solution is 1%; then, an inhibitor, curdlan aqueous solution, and a positive flotation collector, hexadecyl phosphate solution, are added in sequence for roughing, the mass concentration of the inhibitor curdlan is 1%, and the dosage is 105g per ton of ore, and the mass concentration of the positive flotation collector hexadecyl phosphate is 1%, and the dosage is 1300g per ton of ore, to obtain an in-tank product and a foam product, the in-tank product is the positive flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained by primary concentration is returned to roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained by secondary concentration is returned to primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained by tertiary concentration is returned to secondary concentration, and the obtained foam product is flotation concentrate, i.e., magnesite concentrate. The pH value was kept at 10 during the roughing and tertiary cleaning processes, and the pH value was kept constant during the dosing process. No reagents were added during the tertiary cleaning processes of positive flotation.

[0084] The obtained magnesite concentrate has a MgO content of 46.85%, a SiO2 content of 0.10% and a MgO recovery rate of 37.34% by mass.

[0085] Comparative Example 1

[0086] The flotation process is the same as that in Example 1, and the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH value is 6, the etheramine dosage is 70 g / t, the forward flotation pH value is 9, 1500 g / t of sodium carbonate, 1200 g / t of water glass, 180 g / t of sodium hexametaphosphate, and 1200 g / t of sodium oleate are added in the roughing, and the MgO content of the obtained magnesite concentrate is 46.55%, the SiO2 content is 0.35%, and the MgO recovery rate is 36.99%.

[0087] Comparative Example 2

[0088] The flotation process is the same as that in Example 1, and the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH is 6, the dosage of dodecylamine is 95 g / t, the forward flotation pH is 10, 900 g / t carboxymethyl cellulose and 1000 g / t hexadecyl phosphate are added in the roughing, and the MgO content of the obtained magnesite concentrate is 47.01%, the SiO2 content is 0.88%, and the MgO recovery rate is 37.21%.

[0089] Comparative Example 3

[0090] The flotation process is the same as that in Example 1, except that the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH value is 6, the LKD dosage is 120 g / t, the forward flotation pH value is 10, 1000 g / t of water glass, 150 g / t of sodium hexametaphosphate, and 1400 g / t of hydroxamic acid are added in the roughing, and the MgO content of the obtained magnesite concentrate is 46.79%, the SiO2 content is 0.27%, and the MgO recovery rate is 36.94%.

[0091] Comparative Example 4

[0092] The flotation process is the same as that in Example 1, and the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH is 6, the etheramine dosage is 70 g / t, the forward flotation pH is 10, 850 g / t of water glass, 130 g / t of sodium hexametaphosphate, 900 g / t and 250 g / t of sodium oleate / benzohydroxamic acid are added in the roughing, and the MgO content of the obtained magnesite concentrate is 46.22%, the SiO2 content is 0.45%, and the MgO recovery rate is 37.12%.

[0093] Comparative Example 5

[0094] The flotation process is the same as that in Example 1, and the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH is 6, the dosage of dodecylamine is 95 g / t, the forward flotation pH is 10, 850 g / t of sodium alginate, 700 g / t and 200 g / t of sodium oleate / benzohydroxamic acid are added in the roughing, and the MgO content of the obtained magnesite concentrate is 46.84%, the SiO2 content is 0.78%, and the MgO recovery rate is 37.24%.

[0095] Comparative Example 6

[0096] The flotation process is the same as that in Example 1, except that the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH is 6, the LKD dosage is 120 g / t, the forward flotation pH is 10, 1100 g / t of water glass, 200 g / t of sodium alginate, 750 g / t and 150 g / t of sodium oleate / benzohydroxamic acid are added in the roughing, and the MgO content of the obtained magnesite concentrate is 46.12%, the SiO2 content is 0.49%, and the MgO recovery rate is 36.88%.

[0097] Comparative Example 7

[0098] The flotation process is the same as that in Example 1, and the reagent system is as follows: grinding to a particle size of -0.074 mm accounts for 69%, the reverse flotation pH is 6, the etheramine dosage is 70 g / t, the forward flotation pH is 10, 950 g / t sodium alginate and 1100 g / t hexadecyl phosphate are added in the roughing, and the MgO content of the obtained magnesite concentrate is 46.51%, the SiO2 content is 0.98%, and the MgO recovery rate is 37.14%.

Claims

1. A method for using a depressant, curdlan, for the direct flotation desiliconization of magnesite, characterized in that: The specific steps include: S1. Prepare a curdlan glue solution: add deionized water to the curdlan glue, heat and stir in a constant temperature water bath, then add sodium hydroxide and stir until completely dissolved to obtain a curdlan glue solution; S2. Grinding: crushing the raw ore and grinding it to a suitable particle size to obtain ore pulp; S3. Reverse flotation: adjust the pH value of the slurry, add reverse flotation collector, obtain the in-tank product and foam product, the foam product is the reverse flotation tailings; S4. Direct flotation: The in-tank product obtained from reverse flotation is subjected to direct flotation. After adjusting the pH value of the slurry, inhibitors and forward flotation collectors are added in sequence for roughing to obtain in-tank products and foam products. The in-tank product is the forward flotation tailings, and the foam product is subjected to primary concentration; the in-tank product obtained from the primary concentration is returned to the roughing, and the obtained foam product is subjected to secondary concentration; the in-tank product obtained from the secondary concentration is returned to the primary concentration, and the obtained foam product is subjected to tertiary concentration; the in-tank product obtained from the tertiary concentration is returned to the secondary concentration, and the obtained foam product is flotation concentrate, i.e., magnesite concentrate.

2. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In the step S1, the mass ratio of curdlan to sodium hydroxide is (5-10):1, the heating temperature under the condition of a constant temperature water bath is 80-90° C., and the mass concentration of the obtained curdlan solution is 0.5%-2%.

3. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In step S2, the ore has a MgO content of 40.1% to 42.9%, a SiO2 content of 2.1% to 4.5%, a CaO content of 0.09% to 0.3%, a FeO content of 0.04% to 0.2%, and an Al2O3 content of 0.02% to 0.3%, calculated by mass fraction.

4. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In step S2, the raw ore is ground to a particle size of -0.074 mm, accounting for 65% to 80%, and the slurry concentration is 30% to 40%.

5. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In step S3, hydrochloric acid solution and sodium hydroxide solution are used to adjust the pH value of the pulp during the reverse flotation process, and the pH value is maintained at 5-7, and the pH is kept constant during the dosing process.

6. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In the step S3, the dosage of the reverse flotation collector is 70-120 g per ton of ore, selected from one of ether amine solution, dodecylamine solution and LKD solution, and the mass concentration is 1%-3%.

7. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In step S4, the pulp concentration in the positive flotation process is 30% to 40%; the pH value of the pulp is adjusted by using hydrochloric acid solution and sodium hydroxide solution, and the mass concentration of the hydrochloric acid and sodium hydroxide solutions is 0.1% to 5%; the pH value is maintained at 10 to 11.5 in the roughing and tertiary cleaning processes, and the pH value is kept constant during the dosing process.

8. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In step S4, the dosage of the collector in the roughing process of the positive flotation is 1000-1400 g per ton of ore, and the collector is selected from one of sodium oleate solution, hexadecyl phosphate solution, hydroxamic acid solution and sodium oleate / benzohydroxamic acid solution, and the mass concentration is 1%-3%.

9. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In step S4, the inhibitor for the roughing of the positive flotation is a curdlan solution, which is added at a rate of 100 to 150 g per ton of ore, and no reagent is added in the three selection processes of the positive flotation.

10. The method for using a depressant, curdlan, for direct flotation desiliconization of magnesite according to claim 1, characterized in that: In the step S4, the MgO content in the magnesite concentrate is 46.12% to 47.48% by mass, the SiO2 content is 0.09% to 0.98% by mass, and the MgO recovery rate is 36.87% to 38.21%.

Images