WO2020220380A1

WO2020220380A1 - Method for decalcification of magnesitewith reverse flotation by using eddha inhibitor

Info

Publication number: WO2020220380A1
Application number: PCT/CN2019/085487
Authority: WO
Inventors: 孙浩然; 印万忠; 唐远; 杨斌; 韩会丽; 姚金
Original assignee: 东北大学
Priority date: 2019-04-30
Filing date: 2019-05-05
Publication date: 2020-11-05
Also published as: CN110124851A; CN110124851B

Abstract

A method for decalcification of magnesite with reverse flotation by using an EDDHA inhibitor, belonging to the field of magnesite beneficiation and purification processes. In the method, high-calcium low-grade magnesite is crushed and ball-milled, and then water and an EDDHA inhibitor are added to adjust the pulp; the EDDHA inhibitor: magnesite pulp is (60 to 90) mg:1L in a solid-to-liquid ratio; and the mass concentration of the magnesite pulp is 10 to 30%. The pH value of the magnesite pulp is adjusted to10 - 12, and then sodium oleate is added for reverse flotation, rougher flotation and decalcification are performed so as to obtain a low-calcium magnesite concentrate. The recovery rate thereof is 70 to 85%, and the recovery rate of MgO in the low-calcium magnesite concentrate is 65 to 85%. The method uses the difference in the floatability of magnesite and impurity mineral dolomite in magnesite under the effect of an EDDHA inhibitor to remove calcium mineral in magnesite by means of reverse flotation, thereby improving the quality of magnesite and providing a new agent for beneficiation and decalcification of high-calcium low-grade magnesite.

Description

Method for decalcifying magnesite by reverse flotation using EDDHA inhibitor

Technical field

The invention relates to the technical field of magnesite beneficiation and purification technology, in particular to a method for decalcifying magnesite by reverse flotation using an EDDHA inhibitor.

Background technique

In the process of magnesite beneficiation and purification, reducing the content of CaO is the key to improving the quality of magnesite. CaO in magnesite is mainly contained in impurity mineral dolomite (CaMg(CO ₃ ) ₂ ). However, because dolomite and magnesite are both carbonate minerals, they have the same molecular structure and similar chemical properties, and the physical and chemical properties of calcium and magnesium ions are similar, resulting in the convergence of surface properties of magnesite and dolomite, increasing the flotation process. Difficulty of separating the author. At present, for the separation of magnesite and dolomite, most of the flotation methods of magnesite flotation, ie reverse flotation, are used to achieve the decalcification effect of magnesite flotation. Therefore, most of the regulators studied are for dolomite inhibition. There are few studies on magnesite inhibitors. EDDHA (N,N'-ethylbis(2-[2-hydroxyphenyl]glycine)) is a highly selective chelating agent for magnesium. At present, it is mainly used in the industry as additives for cosmetics and personal care products to control alkali The content of metal ions, but has not been used in beneficiation. Since EDDHA can form a hydrophilic chelate with magnesium ions, it can be used as an inhibitor of magnesite in the decalcification process of magnesite reverse flotation. Based on this, this technology has studied the effect of EDDHA on magnesite and dolomite. The influence of flotation provides a new inhibitor for the decalcification of low-grade magnesite ore.

Summary of the invention

technical problem

The solution to the problem

Technical solutions

The purpose of the present invention is to provide a method for decalcification of magnesite by reverse flotation using EDDHA inhibitor. The method relates to the application of EDDHA inhibitor in the decalcification of magnesite by reverse flotation, according to the specific EDDHA inhibitor dosage There is a difference in floatability between the impurity mineral dolomite in the lower magnesite and magnesite. The calcium minerals in the magnesite are removed by reverse flotation, and the quality of the magnesite is improved. The beneficiation and decalcification provide new agents.

In the present invention, an EDDHA inhibitor is used for reverse flotation decalcification of magnesite. In the decalcification process of magnesite reverse flotation, an EDDHA inhibitor is added; according to the solid-liquid ratio, the EDDHA inhibitor: magnesite Pulp=(60～90)mg:1L; the mass concentration of magnesite pulp is 10～30%.

The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor of the present invention specifically includes the following steps:

Step 1: Grinding

The high-calcium low-grade magnesite is crushed and ball-milled to obtain magnesite powder; among them, the mass of magnesite powder less than 74μm accounts for 65-85% of the total mass of magnesite powder;

Step 2: Mix the pulp

Place the magnesite powder in the flotation equipment, add deionized water and EDDHA inhibitor solution, mix them evenly, and adjust the slurry to obtain the magnesite slurry; where, in the magnesite slurry, the mass concentration of the magnesite 10-30%; According to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry=(60～90)mg:1L;

Step 3: Reverse flotation decalcification

Add a strong alkali solution to the magnesite slurry at 20-35°C, adjust the pH to 10-12, and stir evenly to obtain a magnesite slurry with a pH of 10-12;

To the magnesite slurry with a pH value of 10-12, add the collector sodium oleate aqueous solution, stir it evenly, and then carry out reverse flotation and rough decalcification to obtain a low-calcium magnesite concentrate; Ratio, collector sodium oleate: magnesite slurry with pH value of 10-12=(100-140)mg:1L.

In the step 2, the flotation equipment is preferably a hanging trough flotation machine, with a rotation speed of 1700 to 1900 rpm, preferably 1800 rpm.

In the step 2, the configuration method of the EDDHA inhibitor solution is as follows: add NaOH to deionized water, adjust the pH to 10-12, obtain an aqueous solution with a pH of 10-12, and inhibit the solid powder EDDHA The agent is added to an aqueous solution with a pH of 10-12 and stirred until the EDDHA inhibitor is dissolved to obtain an EDDHA inhibitor solution; wherein the mass concentration of the EDDHA inhibitor solution is 1 to 5 g/L; the pH value is preferably 11.

In the step 2, the amount of the EDDHA inhibitor in the amount of the magnesite slurry is preferably 70 mg/L.

In the step 3, the strong alkali solution is preferably a NaOH solution, more preferably an aqueous NaOH solution with a mass concentration of 1 to 5%.

In the step 3, the pH value is preferably 11.

In the step 3, the stirring speed is 1700-1900 rpm.

In the step 3, in the reverse flotation rough decalcification, the speed of the flotation machine is preferably 1800 rpm.

In the step 3, the aqueous sodium oleate solution of the collector is preferably an aqueous sodium oleate solution with a molar concentration of 0.01 to 0.05 mol/L.

In the step 3, the amount of the collector sodium oleate in the amount of the magnesite slurry is preferably 120 mg/L.

In the step 3, the stirring is uniform, and the time is 2-5 min.

In the step 3, after adding the collector sodium oleate, add the foaming agent, stir evenly, and finally carry out the reverse flotation and rough decalcification. The foaming agent is preferably No. 2 oil. Liquid ratio, No. 2 oil: magnesite slurry = (4 ~ 6) mg: 1L.

In the step 3, the rough selection by reverse flotation takes 3 to 5 minutes.

In the above method, the main components of the high-calcium low-grade magnesite are as follows: MgO is 25 to 35.5%, CaO is 18 to 25%, SiO ₂ is 0 to 0.5%, and the balance is impurities.

In the above method, after reverse flotation, the main components of the low-calcium magnesite concentrate obtained by mass percentage are: MgO 47.5-48.5%, SiO ₂ ≤0.3%, CaO≤0.6%, and the balance is impurities.

After reverse flotation in the above method, the recovery rate of the low-calcium magnesite concentrate obtained is 70-85% by mass percentage, and the recovery rate of MgO in the low-calcium magnesite concentrate is 65-85% by mass percentage.

The method of the present invention for decalcification by reverse flotation of magnesite using EDDHA inhibitor has the main mechanism of action: EDDHA inhibitor has strong selectivity and can chelate with the magnesium ions on the surface of magnesite to produce Chelate, reduce the adsorption amount of sodium oleate on the surface of magnesite and inhibit the uplift of magnesite, but it has weak chelating effect on the calcium ion on the surface of dolomite, so it has little effect on the uplift of dolomite, thus realizing magnesite Reverse flotation decalcification of ore, and the principle is proved by means of dynamic potential, contact angle, XPS and infrared spectroscopy.

The beneficial effects of the invention

Beneficial effect

Compared with the prior art, the method for decalcifying magnesite by reverse flotation using EDDHA inhibitor of the present invention has the following beneficial effects:

The present invention develops the use of a new EDDHA inhibitor, and develops a beneficiation process for decalcification by reverse flotation of magnesite. Because the new EDDHA inhibitor has strong selective inhibition on magnesium-containing minerals, it shortens and simplifies the flotation process. The selective decalcification process makes the flotation process run more smoothly and the operation is easier. Finally, magnesite concentrate with MgO grade greater than 47% and MgO recovery rate of 65-85% can be obtained.

Compared with the prior art, the method of the present invention has a low grade of ore processed and a high content of CaO in the raw ore; the obtained magnesite concentrate can reach the special standard of the metallurgical industry (YB321-81), that is, 47.00% of MgO, SiO ₂ ≤0.30%, CaO≤0.8%.

Brief description of the drawings

Description of the drawings

Fig. 1 is a schematic flow diagram of the method for decalcification of magnesite by reverse flotation using EDDHA inhibitor in Example 1 of the present invention.

Figure 2 is an XRD pattern of the raw material magnesite of the present invention.

Fig. 3 is a comparison diagram of infrared spectra of the present invention using EDDHA inhibitor for reverse flotation decalcification of magnesite and comparison analysis of blank samples.

Fig. 4 is a comparison diagram of infrared spectra of the present invention using EDDHA inhibitors for dolomite reverse flotation decalcification and blank samples for comparative analysis.

Invention embodiment

Embodiments of the invention

The present invention will be further described in detail below in conjunction with the embodiments.

In the present invention, unless otherwise specified, solution refers to its aqueous solution, and concentration refers to its mass concentration.

In the following examples, the high-calcium and low-grade magnesite used is Shuidonggou magnesite in Kuandian, Liaoning. The elemental composition of the high-calcium and low-grade magnesite is analyzed by X-ray fluorescence spectrometry. The main components are The mass percentages are: MgO is 33.58%, SiO ₂ is 0.27%, and CaO is 15.17%; the balance is CO ₂ and unavoidable impurities. The XRD pattern is shown in Figure 2. The EDDHA inhibitor used is analytical grade, its CAS: 1170-02-1, the collector sodium oleate is chemically pure, and sodium hydroxide is analytically pure. The EDDHA inhibitor used in the experiment was dissolved and prepared with deionized water with a pH of 11, and the rest of the reagents were prepared with neutral deionized water to prepare an aqueous solution of corresponding concentration for later use.

Example 1

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor. The schematic diagram of the process is shown in Figure 1, and includes the following steps:

Step 1: Grinding

The high-calcium and low-grade magnesite raw materials are crushed and ball milled to obtain magnesite powder; among them, the magnesite powder with a size of less than 74 μm accounts for 65% of the total magnesite powder mass;

Step 2: Mix the pulp

Place magnesite powder with a particle size of less than 74μm and account for 65% of the total mass of magnesite powder in a hanging trough flotation machine, and add deionized water and EDDHA inhibitor. Among them, according to the solid-liquid ratio, EDDHA inhibitor : Magnesite slurry=60mg:1L, mix it evenly, and adjust the slurry to obtain magnesite slurry; wherein the mass concentration of magnesite in the magnesite slurry is 10%;

Step 3: Reverse flotation decalcification

At room temperature, first add 1% NaOH aqueous solution with a mass concentration of 1% to the magnesite slurry, adjust the pH to 11, and stir for 2 minutes until the slurry is uniform to obtain a magnesite slurry with a pH of 11;

To the magnesite slurry with a pH value of 11, first add an aqueous solution of sodium oleate as a collector with a molar concentration of 0.05 mol/L, where the sodium oleate accounts for 100 mg/L of the magnesite slurry, and stir for 2 minutes , And then add the foaming agent No. 2 oil, the amount of No. 2 oil added to the magnesite slurry is 5mg/L, stir for 2 minutes, and finally carry out 3 minutes reverse flotation roughing to obtain low calcium magnesite concentrate and tailings. During the test, set the speed of the flotation machine to 1700r/min.

In this embodiment, the main components of the low calcium magnesite concentrate are MgO 47.5%, SiO ₂ 0.05%, and CaO 0.29% by mass percentage; the MgO in the low calcium magnesite concentrate accounts for the total MgO in the raw material 67.25% of the quality.

In this example, infrared spectroscopy detection was performed on sodium oleate, EDDHA inhibitor, magnesite pure mineral, magnesite pure mineral + sodium oleate, and magnesite pure mineral + EDDHA inhibitor + sodium oleate. .

The infrared spectrum comparison chart is shown in Figure 3. From Figure 3, it can be concluded that in the infrared spectrum of sodium oleate, the peaks at 2924.31 cm ^-1 and 2853.26 cm ^-1 are the characteristic peaks of sodium oleate, indicating the carbon chain The stretching vibration absorption peaks of mesomethyl-CH ₃ and methylene-CH ₂ , when only sodium oleate is added, magnesite has stronger new spectra around 2928cm ^-1 and 2859cm ^-1 The characteristic peaks correspond to the methyl-CH _{3 of} sodium oleate and the stretching vibration absorption peaks of methylene-CH ₂ , and the peak positions have a blue shift of about 5 cm ^-1 , indicating that sodium oleate is in the diamond Chemical adsorption occurred on the surface of magnesite. When EDDHA inhibitor and sodium oleate were added, the magnesite had no obvious changes compared to its own map, indicating that the addition of EDDHA inhibitor inhibited the adsorption of sodium oleate on the surface of magnesite.

In this embodiment, infrared spectroscopy detection was performed on sodium oleate, EDDHA inhibitor, pure dolomite mineral, pure dolomite mineral + sodium oleate, and pure dolomite mineral + EDDHA inhibitor + sodium oleate.

The infrared spectrum comparison chart is shown in Figure 4. From Figure 4, it can be concluded that when only sodium oleate is added, dolomite has stronger new characteristic peaks at 2928 cm ^-1 and 2859 cm ^-1 compared to its own spectrum. It shows that sodium oleate is chemically adsorbed on the surface of dolomite. When EDDHA inhibitor and sodium oleate are added, the spectrum of dolomite has no obvious change compared with the dolomite pure mineral + sodium oleate. It shows that the EDDHA inhibitor is added. It has little effect on the adsorption of sodium oleate on the surface of dolomite.

In summary, it can be proved that adding EDDHA inhibitor can have a better effect on decalcification of magnesite by reverse flotation.

Example 2

Step 1: Grinding

The high-calcium low-grade magnesite raw materials are crushed and ball milled to obtain magnesite powder; among them, magnesite powder with a size of less than 74μm accounts for 75% of the total magnesite powder;

Step 2: Mix the pulp

Place magnesite powder with a particle size of less than 74μm and account for 75% of the total magnesite powder in a hanging trough flotation machine, add deionized water and EDDHA inhibitor, among which, according to the solid-liquid ratio, EDDHA inhibitor : Magnesite slurry=70mg:1L, and mix it evenly, and adjust the slurry to obtain magnesite slurry; wherein the mass concentration of magnesite in the magnesite slurry is 15%;

Step 3: Reverse flotation decalcification

At room temperature, first add a 2% NaOH aqueous solution with a mass concentration to the magnesite slurry, adjust the pH to 12, and stir for 2 minutes until the slurry is uniform to obtain a magnesite slurry with a pH of 12;

To the magnesite slurry with a pH of 12, first add an aqueous solution of sodium oleate as a collector with a molar concentration of 0.05 mol/L, where the sodium oleate accounts for 110 mg/L of the magnesite slurry, and stir for 2 minutes , And then add foaming agent No. 2 oil, the amount of No. 2 oil added accounts for 6mg/L of magnesite slurry, stir for 2min, and finally carry out 3min reverse flotation roughing to obtain low calcium magnesite concentrate and tailings. During the test, set the flotation machine speed to 1800r/min.

In this embodiment, the main components of the low-calcium magnesite concentrate are 48.30% by mass of MgO, 0.24% of SiO ₂ and 0.51% of CaO; the MgO in the low-calcium magnesite concentrate accounts for the total MgO in the raw material. 68.25% of the quality.

Example 3

Step 1: Grinding

The high-calcium and low-grade magnesite raw materials are crushed and ball milled to obtain magnesite powder; among them, the magnesite powder with a particle size of less than 74μm accounts for 85% of the total magnesite powder;

Step 2: Mix the pulp

Place the magnesite powder with a particle size of less than 74μm and account for 85% of the total magnesite powder in a hanging trough flotation machine, add deionized water and EDDHA inhibitor, among which, according to the solid-liquid ratio, EDDHA inhibitor : Magnesite slurry=80mg:1L, and mix it evenly, and adjust the slurry to obtain magnesite slurry; wherein the mass concentration of magnesite in the magnesite slurry is 20%;

Step 3: Reverse flotation decalcification

At room temperature, first add a 3% NaOH aqueous solution with a mass concentration to the magnesite slurry, adjust the pH to 10, and stir for 2 minutes until the slurry is uniform to obtain a magnesite slurry with a pH of 10;

To the magnesite slurry with a pH of 10, first add an aqueous solution of sodium oleate with a molar concentration of 0.05 mol/L as a collector, where the sodium oleate accounts for 110 mg/L of the magnesite slurry, and stir for 2 minutes , And then add the foaming agent No. 2 oil, the amount of No. 2 oil added accounts for 4mg/L of the magnesite slurry, stir for 2 minutes, and finally carry out 3 minutes reverse flotation roughing to obtain low calcium magnesite concentrate and tailings. During the test, set the speed of the flotation machine to 1900r/min.

In this embodiment, the main components of the low-calcium magnesite concentrate are as follows: MgO is 48.5%, SiO ₂ is 0.12%, and CaO is 0.19% by mass percentage; the MgO in the low-calcium magnesite concentrate accounts for the total MgO in the raw material 76.25% of the quality.

Example 4

Step 1: Grinding

Step 2: Mix the pulp

Place magnesite powder with a particle size of less than 74μm and account for 75% of the total magnesite powder in a hanging trough flotation machine, add deionized water and EDDHA inhibitor, among which, according to the solid-liquid ratio, EDDHA inhibitor : Magnesite slurry=90mg:1L, mix it evenly, and adjust the slurry to obtain magnesite slurry; wherein the mass concentration of magnesite in the magnesite slurry is 30%;

Step 3: Reverse flotation decalcification

At room temperature, first add a 4% NaOH aqueous solution with a mass concentration of 4% to the magnesite slurry, adjust the pH to 11, and stir for 2 minutes until the slurry is uniform to obtain a magnesite slurry with a pH of 11;

To the magnesite slurry with a pH value of 11, first add an aqueous solution of sodium oleate as a collector with a molar concentration of 0.05 mol/L, in which the sodium oleate accounts for 130 mg/L of the magnesite slurry, and stir for 2 minutes , And then add the foaming agent No. 2 oil, the amount of No. 2 oil added accounts for 4mg/L of the magnesite slurry, stir for 2 minutes, and finally carry out 3 minutes reverse flotation roughing to obtain low calcium magnesite concentrate and tailings. During the test, set the speed of the flotation machine to 1700r/min.

In this example, the main components of the low-calcium magnesite concentrate are 48.15% by mass of MgO, 0.03% of SiO ₂ and 0.43% of CaO; the MgO in the low-calcium magnesite concentrate accounts for the total MgO in the raw material. 74.69% of the quality.

Example 5

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor, same as Example 1, except that, according to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry = 70mg:1L, the resulting low calcium The main components of magnesite concentrate are 48.23% of MgO, 0.03% of SiO ₂ and 0.09% of CaO according to the mass percentage; MgO in the low-calcium magnesite concentrate accounts for 68.74% of the total mass of MgO in the raw material.

Example 6

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor is the same as Example 1, except that according to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry = 80mg:1L, and the resulting low calcium The main components of magnesite concentrate are 48.23% of MgO, 0.21% of SiO ₂ and 0.47% of CaO according to the mass percentage; MgO in the low-calcium magnesite concentrate accounts for 69.25% of the total mass of MgO in the raw material.

Example 7

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor, same as Example 1, except that, according to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry = 90mg:1L, the resulting low calcium magnesite concentrate main components by mass percent of MgO 48.41%, SiO ₂ of 0.11%, CaO 0.07%; MgO concentrate magnesite low calcium accounted for 74.26% of the total mass of the raw material of MgO.

Example 8

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor is the same as in Example 2, except that according to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry = 90mg:1L, the resulting low calcium The main components of magnesite concentrate are 47.91% of MgO, 0.21% of SiO ₂ and 0.57% of CaO in terms of mass percentage; MgO in the low-calcium magnesite concentrate accounts for 73.16% of the total mass of MgO in the raw material.

Example 9

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor, same as Example 3, the difference is that according to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry = 90mg:1L, the resulting low calcium magnesite concentrate main components by mass percent of MgO 48.51%, SiO ₂ of 0.30%, CaO 0.07%; MgO concentrate magnesite low calcium accounted for 74.26% of the total mass of the raw material of MgO.

Example 10

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor, same as Example 4, the difference is that according to the solid-to-liquid ratio, EDDHA inhibitor: magnesite pulp = 80mg:1L, the resulting low calcium The main components of magnesite concentrate are 47.61% of MgO, 0.29% of SiO ₂ and 0.38% of CaO according to the mass percentage; MgO in the low-calcium magnesite concentrate accounts for 73.62% of the total mass of MgO in the raw material.

Example 11

A method for decalcification of magnesite by reverse flotation using EDDHA inhibitor. Same as Example 1, except that no foaming agent No. 2 oil is added, the main components of low calcium magnesite concentrate are obtained by quality The percentages are 47.51% for MgO, 0.29% for SiO ₂ and 0.57% for CaO; MgO in the low-calcium magnesite concentrate accounts for 65.2% of the total mass of MgO in the raw material.

Claims

A method for decalcifying magnesite by reverse flotation using an EDDHA inhibitor, characterized in that, during the decalcification process of magnesite reverse flotation, an EDDHA inhibitor is added; according to the solid-liquid ratio, the EDDHA inhibitor: magnesite Ore slurry=(60～90)mg:1L; the mass concentration of magnesite slurry is 10～30%.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1, characterized in that it comprises the following steps:

Step 1: Grinding

The high-calcium low-grade magnesite is crushed and ball-milled to obtain magnesite powder; among them, the mass of magnesite powder less than 74μm accounts for 65-85% of the total mass of magnesite powder;

Step 2: Mix the pulp

Place the magnesite powder in the flotation equipment, add deionized water and EDDHA inhibitor solution, mix them evenly, and adjust the slurry to obtain the magnesite slurry; where, in the magnesite slurry, the mass concentration of the magnesite 10-30%; According to the solid-liquid ratio, EDDHA inhibitor: magnesite slurry = (60-90) mg:1L;

Step 3: Reverse flotation decalcification

Add a strong alkali solution to the magnesite slurry at 20-35°C, adjust the pH to 10-12, and stir evenly to obtain a magnesite slurry with a pH of 10-12;

To the magnesite slurry with a pH value of 10-12, add the collector sodium oleate aqueous solution, stir it evenly, and then carry out reverse flotation and rough decalcification to obtain a low-calcium magnesite concentrate; The ratio, the collector sodium oleate: magnesite slurry with a pH of 10-12 = (100-140) mg:1L.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the step 2, the flotation equipment is a hanging trough flotation machine, Its speed is 1700～1900rpm.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the step 2, the EDDHA inhibitor solution is configured as follows: Add NaOH to deionized water and adjust the pH to 10-12 to obtain an aqueous solution with a pH of 10-12. Add the solid powder EDDHA inhibitor to the aqueous solution with a pH of 10-12, and stir until the EDDHA inhibitor is dissolved to obtain EDDHA inhibitor solution; wherein the mass concentration of the EDDHA inhibitor solution is 1～5g/L.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the step 3, the strong alkali solution has a mass concentration of 1 to 5%的NaOH aqueous solution.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the step 3, the stirring speed is 1700-1900 rpm.
The method for decalcification of magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the step 3, the sodium oleate aqueous solution of the collector has a molar concentration of 0.01～0.05mol/L sodium oleate aqueous solution.
The method for decalcification of magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the step 3, after adding the collector sodium oleate, then adding foaming The foaming agent is No. 2 oil, and according to the solid-liquid ratio, No. 2 oil: magnesite slurry = (4-6) mg:1L.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the method, the high-calcium low-grade magnesite has the main components The mass percentages are as follows: MgO is 25 to 35.5%, CaO is 18 to 25%, SiO 2 is 0 to 0.5%, and the balance is impurities.
The method for decalcification of magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the method, in the above method, the low-calcium magnesite obtained after reverse flotation The main components of the concentrate are as follows by mass percentage: MgO 47.5～48.5%, SiO 2 ≤0.3%, CaO≤0.6%, and the remainder is impurities.
The method for decalcifying magnesite by reverse flotation using EDDHA inhibitor according to claim 1 or 2, characterized in that, in the method, after reverse flotation, the low calcium magnesite concentrate obtained The recovery rate is 70-85% by mass percentage, and the recovery rate of MgO in the low-calcium magnesite concentrate is 65-85% by mass percentage.