Flotation decalcifying agent for high-calcium magnesite and use method of flotation decalcifying agent

Abstract

The invention relates to the technical field of beneficiation of high-calcium low-grade magnesite, in particular to a flotation decalcification agent for high-calcium magnesite and a using method of the flotation decalcification agent. Aiming at the problems that magnesite and calcareous minerals are easy to inhibit synchronously during flotation and a traditional reagent is large in dosage and high in cost, the invention provides a novel flotation reagent which can inhibit the floatability of the calcareous minerals. The flotation reagent comprises an inhibitor, a collecting agent and a foaming agent, the inhibitor is methylglycine diacetic acid (MGDA) or trisodium methylglycine diacetate (MGDA-3Na), the collecting agent is sodium oleate, and the foaming agent is 2 # oil; 30 mg-300 mg of an inhibitor, 30 mg-180 mg of a collecting agent and 2 mg-7 mg of a foaming agent are correspondingly added into every 1 L of magnesite pulp; the low-calcium magnesite concentrate obtained by flotation comprises the following main components in percentage by mass: 46.0-48.5% of MgO, less than or equal to 0.4% of SiO2 and less than or equal to 0.8% of CaO; the recovery rate of the magnesite concentrate is 65%-90% by weight, and the recovery rate of MgO in the magnesite concentrate is 60%-80% by weight.

Description

Technical Field

[0001] The present invention relates to the technical field of beneficiation of high-calcium low-grade magnesite, and specifically relates to a flotation de-calcium agent for high-calcium magnesite and a method for using the same. Background Art

[0002] Magnesite is an important industrial mineral resource, which is widely used in refractory materials, metallurgical auxiliary materials and environmental protection fields. However, natural magnesite often coexists with calcareous minerals such as dolomite (CaMg(CO3)2). The presence of calcium impurities will significantly reduce its high-temperature performance and the purity of products. Therefore, flotation de-calcium is a key link in magnesite purification. In traditional flotation processes, water glass, starch or phosphate inhibitors are often used to selectively inhibit the floating of calcareous minerals. However, there are obvious limitations in practical applications: on the one hand, the surface physicochemical properties (such as the isoelectric point and solubility) of magnesite and calcareous minerals are highly similar, resulting in insufficient selectivity of conventional inhibitors, which is likely to cause synchronous inhibition of magnesite and calcareous minerals and reduce the recovery rate; on the other hand, traditional agents have large dosages and high costs, and some phosphorus-containing agents pose environmental risks, making it difficult to meet the requirements of green beneficiation. Therefore, developing a new type of inhibitor with high efficiency, environmental protection and both selective inhibition and mineral surface regulation functions is of great significance for improving the flotation de-calcium efficiency of magnesite, reducing the calcium content in concentrate and promoting the sustainable development of the industry. Summary of the Invention

[0003] Aiming at the above problems, the purpose of the present invention is to provide a flotation de-calcium agent for high-calcium magnesite and a method for using the same. During the flotation process of high-calcium magnesite, by adding the flotation agent of the present invention, the floatability of calcareous minerals can be inhibited, so as to remove the calcareous minerals in magnesite according to the floatability difference between magnesite and its impurity mineral dolomite, improve the flotation quality of magnesite, and provide a new agent for flotation de-calcium of high-calcium low-grade magnesite.

[0004] The flotation de-calcium agent for high-calcium magnesite described in the present invention includes an inhibitor, a collector and a foaming agent. The inhibitor is methylglycine diacetic acid (MGDA) or trisodium methylglycine diacetate (MGDA-3Na), which inhibits the floatability of calcareous minerals. The collector is sodium oleate, and the foaming agent is No. 2 oil;

[0005] For every 1 L of magnesite pulp, 30 mg to 300 mg of inhibitor, 30 mg to 180 mg of collector and 2 mg to 7 mg of foaming agent are added; preferably, for every 1 L of magnesite pulp, 150 mg of inhibitor and 100 mg of collector are added;

[0006] The mass concentration of magnesite powder in the magnesite pulp is 10% to 40%, and the mass of magnesite powder with a particle size < 74 μm accounts for 65% to 95% of the total mass of magnesite powder. The main components of magnesite and their mass percentages are as follows: MgO is 26% to 36%, CaO is 17% to 25%, and SiO2 is ≤ 0.8%.

[0007] The main components of the low-calcium magnesite concentrate obtained by flotation and their mass percentages are: MgO 46.0% to 48.5%, SiO2 ≤ 0.4%, and CaO ≤ 0.8%. The recovery rate of the magnesite concentrate is 65% to 90% by weight, and the recovery rate of MgO in the magnesite concentrate is 60% to 80% by weight.

[0008] The usage method of the high-calcium magnesite flotation de-calcification agent described in the present invention is as follows:

[0009] (1) Crushing ore: Crushing and screening high-calcium low-grade magnesite to obtain magnesite powder; the mass of magnesite powder with a particle size < 74 μm accounts for 65% to 95% of the total mass of magnesite powder.

[0010] The main components of the high-calcium low-grade magnesite and their mass percentages are: MgO 26% to 36%, CaO 17% to 25%, and SiO2 ≤ 0.8%.

[0011] (2) Preparing magnesite pulp: Placing the magnesite powder in a flotation device, adding deionized water to make a slurry, adding inhibitor MGDA or MGDA-3Na, and mixing evenly to carry out pulp conditioning to obtain magnesite pulp.

[0012] In the magnesite pulp: the mass concentration of magnesite powder is 10% to 40%; 30 mg to 300 mg of inhibitor MGDA or MGDA-3Na is added per 1 L of magnesite pulp.

[0013] (3) Positive flotation de-calcification: At room temperature, adding NaOH to the magnesite pulp, adjusting the pH value to 7.5 to 12.5, then adding collector sodium oleate and frother No. 2 oil, adding 30 mg to 180 mg of collector and 2 mg to 7 mg of frother per 1 L of magnesite pulp, stirring evenly, and then carrying out positive flotation roughing. After the roughing is completed, a low-calcium magnesite concentrate is obtained.

[0014] The main components of the low-calcium magnesite concentrate and their mass percentages are: MgO 46.0% to 48.5%, SiO2 ≤ 0.4%, and CaO ≤ 0.8%. The recovery rate of the low-calcium magnesite concentrate is 65% to 90% by weight, and the recovery rate of MgO in the low-calcium magnesite concentrate is 60% to 80% by weight.

[0015] In Step 1, the inhibitor is formulated into an aqueous solution with a concentration of 1.00 g / L to 3.00 g / L before use.

[0016] In Step 2, the flotation equipment is preferably a hanging cell flotation machine with a rotational speed of 1000 rpm to 2200 rpm.

[0017] In Step 2, it is preferred to add 150 mg of inhibitor MGDA and MGDA-3Na for every 1 L of magnesite pulp.

[0018] In Step 3, the pH value is preferably 11.

[0019] In Step 3, when adjusting the pH value, an aqueous NaOH solution with a mass fraction of 0.5% to 3% is preferably used.

[0020] In Step 3, it is preferred to add 100 mg of sodium oleate to every 1 L of magnesite pulp.

[0021] In Step 3, the collector sodium oleate is formulated into an aqueous solution for use, preferably an aqueous collector sodium oleate solution with a concentration of 1.00 g / L to 3.00 g / L. After adding the collector sodium oleate, a foaming agent is added, stirred evenly, and finally rough selective flotation is carried out.

[0022] In Step 3, the stirring rate is 1000 rpm to 2200 rpm, preferably 2000 rpm; the stirring time is 2 min to 5 min.

[0023] The high-calcium magnesite flotation de-calcium reagent adopted in the present invention, compared with the prior art, has the beneficial effects as follows:

[0024] 1. The novel inhibitors MGDA and MGDA-3Na have strong selective inhibition on calcium-containing minerals, simplify the flotation de-calcium process, make the flotation process more stable, the operation more convenient, and the novel inhibitors MGDA and MGDA-3Na are more environmentally friendly than other chemical inhibitors. Finally, magnesite concentrate with an MgO grade ≥ 46% and a recovery rate of 65% to 90% can be obtained.

[0025] 2. Compared with the prior art, the method of the present invention deals with ores with low grades and high CaO content in the raw ore; the obtained magnesite concentrate can reach MgO ≥ 46.00%, SiO2 ≤ 1.20%, and CaO ≤ 0.8%.

[0026] 3. The inhibitors MGDA (methylglycine diacetic acid) and MGDA-3Na (trisodium methylglycine diacetate) of the present invention are chelating agents with extremely strong calcium selectivity and are mainly used as surface metal ion complexing agents in industry. Since MGDA and MGDA-3Na can form hydrophilic chelates with calcium ions, they are used as inhibitors of dolomite in the flotation decalcification process of magnesite. The effects of the inhibitors MGDA and MGDA-3Na on the flotation of magnesite and dolomite are different, providing a new flotation reagent for the flotation decalcification of high-calcium and low-grade magnesite. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic flow chart of the flotation decalcification of high-calcium and low-grade magnesite of the present invention.

[0028] Figure 2 It is a diagram showing the change of the surface potential of minerals before and after the action of the inhibitor MGDA in Example 1; among them, (a) is the diagram of the change of the surface potential of magnesite, and (b) is the diagram of the change of the surface potential of dolomite.

[0029] Figure 3 It is an infrared spectrum diagram of MGDA and sodium oleate (NaOL) in Example 2.

[0030] Figure 4 It is an infrared spectrum diagram of different mineral surfaces before and after the action of MGDA and sodium oleate (NaOL) in Example 2; among them, (a) is the infrared spectrum diagram of the surface of magnesite, and (b) is the infrared spectrum diagram of the surface of dolomite. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments and the drawings. It should be noted that the embodiments described in the present invention are only used for further explanation and illustration, rather than limiting its application scope. Based on the present invention, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present invention.

[0032] In the following embodiments, the high-calcium and low-grade magnesite used is the magnesite in Dashiqiao, Liaoning. An X-ray fluorescence spectrometry instrument is used to analyze the elemental composition of the high-calcium and low-grade magnesite. Its main components and their mass percentages are: MgO is 32.72%, SiO2 is 0.27%, CaO is 17.25%, and the balance is CO2 and inevitable impurities. The inhibitor used is of analytical purity, the collector sodium oleate is of chemical purity, and the pH adjuster sodium hydroxide is of analytical purity. All the reagents used in the experiments are prepared into aqueous solutions with corresponding concentrations with deionized water for standby. The technological process of the flotation decalcification of magnesite is as Figure 1 shown.

[0033] Example 1

[0034] For every 1 L of magnesite pulp, 100 mg of inhibitor MGDA, 100 mg of collector, and 2.5 mg of frother are added. The mass concentration of magnesite powder in the magnesite pulp is 10%, and the mass of magnesite powder with a particle size < 74 μm accounts for 75% of the total mass of magnesite powder.

[0035] Step 1: Crush the ore material;

[0036] Crush and ball mill the high-calcium and low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 75% of the total mass of magnesite powder;

[0037] Step 2: Prepare magnesite pulp;

[0038] Place the magnesite powder in a hanging trough flotation machine, add deionized water to make a slurry, and add an inhibitor MGDA solution, and mix evenly to obtain magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 10%; for every 1 L of magnesite pulp, 100 mg of inhibitor MGDA is added, and the concentration of the inhibitor MGDA solution is 1.00 g / L;

[0039] Step 3: Positive flotation for de-calcium;

[0040] At room temperature, first add a 1% NaOH aqueous solution to the magnesite pulp, adjust the pH value to 11, stir for 2 min until the pulp is uniform, add an aqueous solution of collector sodium oleate with a concentration of 1.00 g / L, add 100 mg of sodium oleate for every 1 L of magnesite pulp, stir for 2 min, then add frother No. 2 oil, add 2.5 mg of frother for every 1 L of magnesite pulp, stir for 2 min, and finally conduct 3 min of positive flotation roughing. During the test process, set the rotational speed of the flotation machine to 2000 r / min, and a low-calcium magnesite concentrate is obtained after roughing.

[0041] Figure 2 Shows the change of the surface potential of minerals before and after the action of MGDA. From Figure 2 (a) and Figure 2 (b), it can be seen that when MGDA acts alone on the mineral surface, the potential change of dolomite is large, while that of magnesite is small; when MGDA and sodium oleate act on the mineral surface at the same time, the potential change of magnesite is large, while that of dolomite is small; this result shows that MGDA will selectively act on dolomite rather than magnesite.

[0042] In this embodiment, the main components and their mass percentages of the low-calcium magnesite concentrate are 46.26% MgO, 0.25% SiO2, and 0.78% CaO; the MgO in the low-calcium magnesite concentrate accounts for 68.25% of the total weight of MgO in the magnesite raw material.

[0043] Example 2

[0044] For every 1 L of magnesite pulp, 200 mg of inhibitor MGDA, 100 mg of collector, and 2.5 mg of frother are added. The mass concentration of magnesite powder in the magnesite pulp is 10%, and the mass of magnesite powder with a particle size < 74 μm accounts for 75% of the total mass of magnesite powder.

[0045] Step 1: Crushing the ore material;

[0046] The high-calcium low-grade magnesite raw material is crushed and ball-milled to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 75% of the total mass of magnesite powder.

[0047] Step 2: Preparing magnesite pulp;

[0048] The magnesite powder is placed in a hanging-cell flotation machine, deionized water is added to make a slurry, and an inhibitor MGDA solution is added and mixed evenly to obtain magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 10%; for every 1 L of magnesite pulp, 200 mg of inhibitor MGDA is added, and the concentration of the inhibitor MGDA solution is 1.00 g / L.

[0049] Step 3: Forward flotation for de-calcification;

[0050] At room temperature, first, an aqueous NaOH solution with a mass fraction of 1.0% is added to the magnesite pulp, the pH value is adjusted to 8, stirred for 2 min until the pulp is uniform, an aqueous collector sodium oleate solution with a concentration of 1.00 g / L is added, 100 mg of sodium oleate is added for every 1 L of magnesite pulp, stirred for 2 min, then frother No. 2 oil is added, 2.5 mg of frother is added for every 1 L of magnesite pulp, stirred for 2 min, and finally, 3 min of forward flotation roughing is carried out. During the test process, the rotational speed of the flotation machine is set at 2000 r / min, and low-calcium magnesite concentrate is obtained after roughing.

[0051] Figure 3 The infrared spectra of MGDA and sodium oleate. Figure 4 The infrared spectra of the mineral surface before and after the action of MGDA and sodium oleate. From Figure 4 (a), it can be seen that there is no characteristic peak of MGDA generated on the surface of magnesite in the presence of MGDA, and there is no obvious shift in the peak position of magnesite, but there is a characteristic peak of sodium oleate generated on the surface of magnesite when sodium oleate acts alone or when sodium oleate and MGDA act simultaneously; from Figure 4(b) It can be seen that when MGDA exists alone, characteristic peaks of MGDA are generated on the surface of dolomite, and the peak positions and intensities of dolomite change significantly. When sodium oleate acts alone, characteristic peaks of sodium oleate are generated on the surface of dolomite. However, when sodium oleate and MGDA act simultaneously, only characteristic peaks of MGDA are generated on the surface of dolomite, indicating the selective adsorption of MGDA.

[0052] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are 46.75% MgO, 0.35% SiO2, and 0.68% CaO; the MgO in the low-calcium magnesite concentrate accounts for 69.36% of the total weight of MgO in the magnesite raw material.

[0053] Example 3

[0054] For every 1 L of magnesite pulp, 160 mg of inhibitor MGDA, 100 mg of collector, and 2.5 mg of foaming agent are added. The mass concentration of magnesite powder in the magnesite pulp is 10%, and the mass of magnesite powder with a particle size < 74 μm accounts for 75% of the total mass of magnesite powder.

[0055] Step 1: Crush the ore material;

[0056] Crush and ball-mill the high-calcium low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 75% of the total mass of magnesite powder.

[0057] Step 2: Prepare the magnesite pulp;

[0058] Place the magnesite powder in a hanging-cell flotation machine, add deionized water to make a slurry, and add an inhibitor MGDA solution, and mix evenly to obtain the magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 10%; for every 1 L of magnesite pulp, 160 mg of inhibitor MGDA is added, and the concentration of the inhibitor MGDA solution is 1.00 g / L.

[0059] Step 3: Positive flotation for calcium removal;

[0060] At room temperature, first add a 1% NaOH aqueous solution by mass to the magnesite pulp, adjust the pH value to 11, stir for 2 min until the pulp is uniform, add an aqueous solution of collector sodium oleate with a concentration of 1.00 g / L, add 100 mg of sodium oleate for every 1 L of magnesite pulp, stir for 2 min, then add foaming agent No. 2 oil, add 2.5 mg of foaming agent for every 1 L of magnesite pulp, stir for 2 min, and finally conduct 3 min of positive flotation roughing. During the test process, set the rotational speed of the flotation machine at 2000 r / min. After roughing, a low-calcium magnesite concentrate is obtained.

[0061] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are as follows: MgO is 48.13%, SiO2 is 0.19%, and CaO is 0.62%; the MgO in the low-calcium magnesite concentrate accounts for 69.36% of the total weight of MgO in the magnesite raw material.

[0062] Example 4

[0063] For every 1 L of magnesite pulp, 260 mg of inhibitor MGDA, 100 mg of collector, and 2 mg of frother are added. The mass concentration of magnesite powder in the magnesite pulp is 10%, and the mass of magnesite powder with a particle size < 74 μm accounts for 75% of the total mass of magnesite powder.

[0064] Step 1: Crush the ore material;

[0065] Crush and ball-mill the high-calcium low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 75% of the total mass of magnesite powder.

[0066] Step 2: Prepare magnesite pulp;

[0067] Place the magnesite powder in a hanging-cell flotation machine, add deionized water to make a slurry, and add an inhibitor MGDA solution, and mix evenly to obtain magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 10%; for every 1 L of magnesite pulp, 260 mg of inhibitor MGDA is added, and the concentration of the inhibitor MGDA solution is 1.00 g / L.

[0068] Step 3: Positive flotation for calcium removal;

[0069] At room temperature, first add an aqueous NaOH solution with a mass fraction of 1.0% to the magnesite pulp, adjust the pH value to 11, stir for 2 min until the pulp is uniform, add an aqueous collector sodium oleate solution with a concentration of 1.00 g / L, add 100 mg of sodium oleate for every 1 L of magnesite pulp, stir for 2 min, then add frother No. 2 oil, add 2 mg of frother for every 1 L of magnesite pulp, stir for 2 min, and finally conduct 3 min of positive flotation roughing. During the test process, set the rotational speed of the flotation machine at 2000 r / min, and low-calcium magnesite concentrate is obtained after roughing.

[0070] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are as follows: MgO is 47.85%, SiO2 is 0.32%, and CaO is 0.5%; the MgO in the low-calcium magnesite concentrate accounts for 74.59% of the total weight of MgO in the magnesite raw material.

[0071] Example 5

[0072] For every 1 L of magnesite pulp, 150 mg of inhibitor MGDA, 100 mg of collector, and 2 mg of foaming agent are added. The mass concentration of magnesite powder in the magnesite pulp is 20%, and the mass of magnesite powder with a particle size < 74 μm accounts for 80% of the total mass of magnesite powder.

[0073] Step 1: Crush the ore material;

[0074] The high-calcium low-grade magnesite raw material is crushed and ball-milled to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 80% of the total mass of magnesite powder.

[0075] Step 2: Prepare magnesite pulp;

[0076] The magnesite powder is placed in a hanging trough flotation machine, deionized water is added to make a slurry, and an inhibitor MGDA solution is added and mixed evenly to obtain magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 20%; for every 1 L of magnesite pulp, 150 mg of inhibitor MGDA is added, and the concentration of the inhibitor MGDA solution is 1.00 g / L.

[0077] Step 3: Positive flotation for calcium removal;

[0078] At room temperature, first add a 1% NaOH aqueous solution by mass to the magnesite pulp, adjust the pH value to 11, stir for 2 min until the pulp is uniform, add an aqueous solution of collector sodium oleate with a concentration of 1.00 g / L, add 100 mg of sodium oleate for every 1 L of magnesite pulp, stir for 2 min, then add foaming agent No. 2 oil, add 2 mg of foaming agent for every 1 L of magnesite pulp, stir for 2 min, and finally conduct 3 min of positive flotation roughing. During the test process, set the rotational speed of the flotation machine at 2000 r / min. After roughing, a low-calcium magnesite concentrate is obtained.

[0079] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are 47.95% for MgO, 0.33% for SiO2, and 0.6% for CaO; the MgO in the low-calcium magnesite concentrate accounts for 72.55% of the total weight of MgO in the magnesite raw material.

[0080] Example 6

[0081] For every 1 L of magnesite pulp, 150 mg of inhibitor MGDA, 100 mg of collector, and 2 mg of foaming agent are added. The mass concentration of magnesite powder in the magnesite pulp is 20%, and the mass of magnesite powder with a particle size < 74 μm accounts for 80% of the total mass of magnesite powder.

[0082] Step 1: Crush the ore material;

[0083] Crush and ball-mill the high-calcium low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 80% of the total mass of magnesite powder.

[0084] Step 2: Prepare magnesite pulp;

[0085] Place the magnesite powder in a hanging trough flotation machine, add deionized water to make a slurry, and add an inhibitor MGDA solution, and mix evenly to obtain magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 20%; 150 mg of inhibitor MGDA is added per 1 L of magnesite pulp, and the concentration of the inhibitor MGDA solution is 1.00 g / L.

[0086] Step 3: Positive flotation for calcium removal;

[0087] At room temperature, first add a 1% NaOH aqueous solution by mass to the magnesite pulp, adjust the pH value to 11.0, stir for 2 min until the pulp is uniform, add an aqueous solution of collector sodium oleate with a concentration of 1.00 g / L, add 100 mg of sodium oleate per 1 L of magnesite pulp, stir for 2 min, then add frother No. 2 oil, add 2 mg of frother per 1 L of magnesite pulp, stir for 2 min, and finally conduct 3 min of roughing in positive flotation. During the test process, set the rotational speed of the flotation machine to 2000 r / min, and obtain low-calcium magnesite concentrate after roughing.

[0088] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are 47.15% for MgO, 0.31% for SiO2, and 0.69% for CaO; the MgO in the low-calcium magnesite concentrate accounts for 75.15% of the total weight of MgO in the magnesite raw material.

[0089] Example 7

[0090] 150 mg of inhibitor MGDA-3Na, 100 mg of collector, and 2 mg of frother are added per 1 L of magnesite pulp. The mass concentration of magnesite powder in the magnesite pulp is 20%, and the mass of magnesite powder with a particle size < 74 μm accounts for 80% of the total mass of magnesite powder.

[0091] Step 1: Crush the ore;

[0092] Crush and ball-mill the high-calcium low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 80% of the total mass of magnesite powder.

[0093] Step 2: Prepare magnesite pulp;

[0094] Put magnesite powder into a hanging trough flotation machine, add deionized water to make a slurry, and add an inhibitor MGDA-3Na solution, mix evenly to obtain magnesite ore pulp; among them, the mass concentration of magnesite in the magnesite ore pulp is 20%; for every 1 L of magnesite ore pulp, 150 mg of inhibitor MGDA-3Na is added, and the concentration of the inhibitor MGDA-3Na solution is 2.00 g / L;

[0095] Step 3: Positive flotation for de-calcium;

[0096] At room temperature, first add a 1% NaOH aqueous solution to the magnesite ore pulp, adjust the pH value to 11.0, stir for 2 min until the pulp is uniform, add an aqueous solution of collector sodium oleate with a concentration of 1.00 g / L, add 100 mg of sodium oleate for every 1 L of magnesite ore pulp, stir for 2 min, then add foaming agent No. 2 oil, add 2 mg of foaming agent for every 1 L of magnesite ore pulp, stir for 2 min, and finally conduct 3 min of positive flotation roughing. During the test process, set the rotational speed of the flotation machine at 1600 r / min, and obtain low-calcium magnesite concentrate after roughing.

[0097] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are 47.88% for MgO, 0.29% for SiO2, and 0.75% for CaO; the MgO in the low-calcium magnesite concentrate accounts for 74.24% of the total weight of MgO in the magnesite raw material.

[0098] Example 8

[0099] For every 1 L of magnesite ore pulp, 150 mg of inhibitor MGDA-3Na, 100 mg of collector, and 3 mg of foaming agent are added. The mass concentration of magnesite powder in the magnesite ore pulp is 20%, and the mass of magnesite powder with a particle size <74 μm accounts for 80% of the total mass of magnesite powder.

[0100] Step 1: Crushing ore materials;

[0101] Crush and ball mill the high-calcium low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 80% of the total mass of magnesite powder;

[0102] Step 2: Preparing magnesite ore pulp;

[0103] Put magnesite powder into a hanging trough flotation machine, add deionized water to make a slurry, and add an inhibitor MGDA-3Na solution, mix evenly to obtain magnesite ore pulp; among them, the mass concentration of magnesite in the magnesite ore pulp is 20%; for every 1 L of magnesite ore pulp, 150 mg of inhibitor MGDA-3Na is added, and the concentration of the inhibitor MGDA-3Na solution is 2.00 g / L;

[0104] Step 3: Positive flotation for de-calcium;

[0105] At room temperature, first add an aqueous NaOH solution with a mass fraction of 1.5% to the magnesite pulp. After adjusting the pH value to 9, stir for 2 min until the pulp is uniform. Then add an aqueous solution of sodium oleate as a collector with a concentration of 1.00 g / L. Add 100 mg of sodium oleate for every 1 L of magnesite pulp, and stir for 2 min. Then add No. 2 oil as a frother, add 3 mg of frother for every 1 L of magnesite pulp, and stir for 2 min. Finally, conduct rough flotation for 3 min. During the test process, set the rotational speed of the flotation machine at 2000 r / min. After rough flotation, a low-calcium magnesite concentrate is obtained.

[0106] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate are 47.49% MgO, 0.36% SiO2, and 0.71% CaO; the MgO in the low-calcium magnesite concentrate accounts for 68.35% of the total weight of MgO in the magnesite raw material.

[0107] Example 9

[0108] Add 80 mg of inhibitor MGDA-3Na, 100 mg of collector, and 4 mg of frother for every 1 L of magnesite pulp. The mass concentration of magnesite powder in the magnesite pulp is 20%, and the mass of magnesite powder with a particle size < 74 μm accounts for 80% of the total mass of magnesite powder.

[0109] Step 1: Crush the ore material;

[0110] Crush and ball-mill the high-calcium low-grade magnesite raw material to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounts for 80% of the total mass of magnesite powder.

[0111] Step 2: Prepare the magnesite pulp;

[0112] Place the magnesite powder in a hanging-cell flotation machine, add deionized water to make a slurry, and add an MGDA-3Na solution as an inhibitor. Mix evenly to obtain the magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp is 20%; add 80 mg of inhibitor MGDA-3Na for every 1 L of magnesite pulp, and the concentration of the MGDA-3Na solution is 1.00 g / L.

[0113] Step 3: Remove calcium by direct flotation;

[0114] At room temperature, first, an aqueous NaOH solution with a mass fraction of 1.0% was added to the magnesite pulp. After adjusting the pH value to 9, it was stirred for 2 min until the pulp was uniform. Then, an aqueous solution of sodium oleate as a collector with a concentration of 1.00 g / L was added, with 100 mg of sodium oleate added per 1 L of magnesite pulp, and it was stirred for 2 min. Then, No. 2 oil as a frother was added, with 4 mg of frother added per 1 L of magnesite pulp, and it was stirred for 2 min. Finally, rough flotation was carried out for 3 min. During the test process, the rotational speed of the flotation machine was set at 1800 r / min, and a low-calcium magnesite concentrate was obtained after rough flotation.

[0115] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate were 47.21% for MgO, 0.11% for SiO2, and 0.59% for CaO; the MgO in the low-calcium magnesite concentrate accounted for 78.34% of the total weight of MgO in the magnesite raw material.

[0116] Example 10

[0117] 250 mg of inhibitor MGDA-3Na, 100 mg of collector, and 3 mg of frother were added per 1 L of magnesite pulp. The mass concentration of magnesite powder in the magnesite pulp was 20%, and the mass of magnesite powder with a particle size <74 μm accounted for 80% of the total mass of magnesite powder.

[0118] Step 1: Crushing the ore material;

[0119] The high-calcium low-grade magnesite raw material was crushed and ball-milled to obtain magnesite powder; the mass of magnesite powder with a particle size less than 74 μm accounted for 80% of the total mass of magnesite powder.

[0120] Step 2: Preparing the magnesite pulp;

[0121] The magnesite powder was placed in a hanging-cell flotation machine, deionized water was added to make a slurry, and an MGDA-3Na solution as an inhibitor was added, and they were mixed evenly to obtain the magnesite pulp; among them, the mass concentration of magnesite in the magnesite pulp was 20%; 250 mg of inhibitor MGDA-3Na was added per 1 L of magnesite pulp, and the concentration of the inhibitor MGDA-3Na solution was 1.00 g / L.

[0122] Step 3: Positive flotation for calcium removal;

[0123] At room temperature, first, an aqueous NaOH solution with a mass fraction of 1% was added to the magnesite pulp. After adjusting the pH value to 9, it was stirred for 2 minutes until the pulp was uniform. Then, an aqueous solution of sodium oleate collector with a concentration of 1.00 g / L was added, with 100 mg of sodium oleate added per 1 L of magnesite pulp, and it was stirred for 2 minutes. Next, No. 2 oil foaming agent was added, with 3 mg of foaming agent added per 1 L of magnesite pulp, and it was stirred for 2 minutes. Finally, positive flotation roughing was carried out for 3 minutes. During the test process, the rotational speed of the flotation machine was set at 1800 r / min, and a low-calcium magnesite concentrate was obtained after roughing.

[0124] In this example, the main components and their mass percentages of the low-calcium magnesite concentrate were 47.95% of MgO, 0.19% of SiO2, and 0.68% of CaO; the MgO in the low-calcium magnesite concentrate accounted for 74.68% of the total weight of MgO in the magnesite raw material.

Claims

1. A high calcium magnesite flotation decalcification agent, characterized in that: The method comprises the following contents: the flotation decalcification agent comprises an inhibitor, a collector and a frother; the inhibitor comprises methylglycine diacetic acid (MGDA) or methylglycine diacetic acid trisodium (MGDA-3Na), which inhibits the floatability of calcium minerals; the collector is sodium oleate, and the frother is No. 2 oil; For every 1L of magnesite slurry, 30mg-300mg of inhibitor, 30mg-180mg of collector and 2mg-7mg of foaming agent are added; the mass concentration of magnesite powder in the magnesite slurry is 10%-40%, and the mass of magnesite powder with a particle size of less than 74μm accounts for 65%-95% of the total mass of magnesite powder. The main components of the high-calcium magnesite and their mass percentages are as follows: MgO 26%-36%, CaO 17%-25%, SiO2≤0.8%; the main components of the low-calcium magnesite concentrate obtained by flotation and their mass percentages are: MgO 46.0%-48.5%, SiO2≤0.4%, CaO≤0.8%; the recovery rate of the magnesite concentrate is 65%-90% by weight, and the recovery rate of MgO in the magnesite concentrate is 60%-80% by weight.

2. A high calcium magnesite flotation decalcification agent according to claim 1, characterized in that: 150 mg of inhibitor was added for every 1L of magnesite slurry.

3. A high calcium magnesite flotation decalcification agent according to claim 1, characterized in that: 100 mg of collector was added for every 1L of magnesite slurry.

4. The method for using the flotation decalcification agent according to any one of claims 1 to 3, characterized in that: Includes the following: (1) Crushing ore: crushing and screening high-calcium low-grade magnesite to obtain magnesite powder; the mass of magnesite powder with a particle size of less than 74 μm accounts for 65% to 95% of the total mass of magnesite powder; The main components of the high-calcium low-grade magnesite and their mass percentages are: MgO 26% to 36%, CaO 17% to 25%, SiO2 ≤ 0.8%; (2) Preparing magnesite slurry: placing magnesite powder in a flotation device, adding deionized water to make a slurry, and adding an inhibitor to perform slurry adjustment to obtain magnesite slurry; In the magnesite slurry: the mass concentration of magnesite powder is 10% to 40%; 30 mg to 300 mg of inhibitor is added for every 1 L of magnesite slurry; (3) Direct flotation decalcification: NaOH is added to the magnesite slurry to adjust the pH value to 7.5-12.5, and then a collector and a frother are added. For every 1L of magnesite slurry, 30mg-180mg of collector and 2mg-7mg of frother are added. Direct flotation roughing is performed to obtain a low-calcium magnesite concentrate after roughing. The main components of the magnesite concentrate and their mass percentages are: MgO 46.0% to 48.5%, SiO2≤0.4%, CaO≤0.8%; the recovery rate of the magnesite concentrate is 65% to 90% by weight, and the recovery rate of MgO in the magnesite concentrate is 60% to 80% by weight.

5. The method for using the flotation decalcification agent according to claim 4, characterized in that: The inhibitor in step (1) is prepared into an aqueous solution with a concentration of 1.00 g / L to 3.00 g / L before use.

6. The method for using the flotation decalcification agent according to claim 4, characterized in that: In step (2), 150 mg of inhibitor is added to every 1 L of magnesite slurry; the flotation equipment is a hanging trough flotation machine.

7. The method for using the flotation decalcification agent according to claim 4, characterized in that: The pH value in step (3) is 11; when adjusting the pH value, a NaOH aqueous solution with a mass fraction of 0.5% to 3% is used.

8. The method for using the flotation decalcification agent according to claim 4, characterized in that: In step (3), 100 mg of collector is added to every 1 L of magnesite slurry; the collector is prepared into a concentration of 1.00 g / L to 3.00 g / L aqueous solution for use.

9. The method for using the flotation decalcification agent according to claim 4, characterized in that: The stirring rate of the rough selection in step 3 is 1000rpm~2200rpm, and the stirring time is 2min~5min.

Images