A collector for flotation separation of calcium-magnesium carbonate minerals and its application

Abstract

The application discloses a collector for flotation separation of calcium-magnesium carbonate minerals and application thereof, and the collector comprises potassium cetyl phosphate and monohydric alcohol. The collector has a better effect on the separation of magnesite and calcium carbonate minerals associated therewith. Compared with a conventional sodium oleate collector scheme, the collector has a better selective flotation separation effect, a fast flotation rate and good foam performance, and is favorable for development of a reasonable magnesite flotation separation technology and realization of quality improvement and impurity reduction of low-quality calcium-containing magnesite.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbonate mineral flotation separation, and particularly relates to a collector for calcium-magnesium carbonate mineral flotation separation and application thereof. BACKGROUND

[0002] The industrial magnesite ore that can be directly used usually does not contain obvious impurities, but as the social production and life demand intensifies, the exploitation amount of magnesite ore gradually increases, causing the high-quality magnesite ore resources to be increasingly exhausted. The impurity components of the industrial magnesite ore will affect the properties of the downstream magnesium-containing products to different degrees, and therefore, it is necessary to improve the magnesite ore raw material quality through a series of sorting processes before subsequent processing such as smelting and calcination, and fully and reasonably utilizing the medium and low grade magnesite resources will become an important way to solve the magnesium ore resource supply and demand contradiction. The associated calcium-containing gangue minerals in the industrial magnesite ore are mainly carbonate minerals such as dolomite and calcite, and the low-grade magnesite ore with high calcium content cannot be directly used for the production of refractory materials and must be subjected to pre-decalcification treatment. The flotation method is an effective means to realize the enrichment and purification of the calcium-containing magnesite ore, and the collector is a key factor affecting the flotation separation effect, and therefore, it is of theoretical and practical significance to carry out research on high-efficiency collectors for calcium-magnesium carbonate mineral flotation separation.

[0003] The magnesite, dolomite and calcite are all alkaline earth metal carbonate minerals, have similar crystal structure and surface chemical properties, and only differ in the lattice ions of the three minerals. Although there is such a difference in the mineral surface of the magnesite, dolomite and calcite, the properties of the calcium and magnesium elements are also very similar, and can be mutually replaced to a certain extent to exhibit isomorphism, so that the various properties of the above three minerals are very similar, thereby causing the difficulty in selective separation of the three minerals.

[0004] The related art has the disadvantages of complex preparation before experiment, high requirement for environmental acidity and alkalinity, and weak selectivity of magnesite flotation, and therefore, new technical ideas are urgently needed for the separation of the three minerals. SUMMARY

[0005] Therefore, the present application provides a collector for calcium-magnesium carbonate mineral flotation separation and application thereof, which can realize the quality improvement and impurity reduction of low-quality calcium-containing magnesite ore and has strong selectivity for magnesite flotation.

[0006] To achieve the above technical purposes, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a collector for calcium-magnesium carbonate mineral flotation separation, which comprises potassium cetyl phosphate and monohydric alcohol.

[0008] Preferably, the molar ratio of the potassium cetyl phosphate to the monohydric alcohol is 5-25:75-95.

[0009] Preferably, the molar ratio of the potassium cetyl phosphate to the monohydric alcohol is 20:80.

[0010] Preferably, the monohydric alcohol comprises one or more of n-butanol, n-pentanol, n-hexanol, n-octanol and iso-octanol.

[0011] In a second aspect, the application provides a use of a collector for calcium-magnesium carbonate minerals in floatation separation of magnesite from its associated calcium carbonate minerals.

[0012] Preferably, the specific use comprises the following steps:

[0013] S1. Adding deionized water to a magnesite sample to be floated, and stirring and mixing to obtain a slurry;

[0014] S2. Adjusting the pH value of the slurry to 5-11, and after uniform stirring, adding the collector to obtain a mixture;

[0015] S3. Stirring the mixture, and passing a constant flow rate of air to perform floatation and bubble scraping to obtain a magnesite concentrate.

[0016] Preferably, the concentration of the slurry is 5-35%.

[0017] Preferably, the concentration of the collector is 20-120 mg / L.

[0018] Preferably, the concentration of the collector is 60 mg / L.

[0019] Preferably, the floatation in step S3 is positive floatation.

[0020] The application has the following beneficial effects: the collector of the application can improve the difference in floatation behavior of calcium-magnesium carbonate minerals, and can selectively and stably adsorb on the surface of magnesite, so that the floatation separation effect of magnesite from calcium carbonate minerals is good; the addition of monohydric alcohol in the application improves the foam performance of the floatation system while reducing the cost, in addition, the calcium-magnesium carbonate mineral floatation separation process of the application is simple and has certain industrial value. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a floatation separation process flowchart of the application;

[0022] Figure 2 is a comparison chart of the collector of the application and the comparative example on the recovery rate of magnesite under different collector concentrations;

[0023] Figure 3A comparison chart of the recovery rate of magnesite under different pH conditions for the collector of the present solution and the comparative example. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0025] The main calcium-containing gangue minerals associated with industrial magnesite ore are carbonate minerals such as dolomite and calcite. It is difficult to achieve selective separation of the three due to the similar chemical properties of the crystal surfaces of magnesite, dolomite and calcite. In view of this technical problem, the present application provides a collector for flotation separation of calcium-magnesium carbonate minerals, which comprises potassium cetyl phosphate and a monohydric alcohol.

[0026] The inventors of the present application have unexpectedly found that using a monohydric fatty alcohol mixed with potassium cetyl phosphate as a selective collector for magnesite can achieve efficient separation of magnesite. The monohydric fatty alcohol not only improves the foam performance of the flotation system, but also has a significant cost advantage compared to using high-priced potassium cetyl phosphate alone as a collector. Potassium cetyl phosphate also has a strong effect on the calcium ions on the surface of dolomite and calcite, can quickly bind to the calcium on the surface of dolomite and calcite and make it settle in the solution, reducing the number of active sites on the surface of dolomite and calcite and affecting their floating effect. This makes potassium cetyl phosphate have a high collection efficiency for magnesite and basically not collect dolomite and calcite, which helps to directly improve the flotation separation effect of magnesite and calcium-containing carbonate minerals.

[0027] In some embodiments, the molar ratio of potassium cetyl phosphate to monohydric alcohol is 5-25:75-95.

[0028] In some embodiments, the molar ratio of potassium cetyl phosphate to monohydric alcohol is 20:80.

[0029] In some embodiments, the monohydric alcohol includes one or more of n-butanol, n-pentanol, n-hexanol, n-octanol and isooctanol.

[0030] In addition, the present application provides a collector for flotation separation of calcium-magnesium carbonate minerals for use in flotation separation of magnesite concentrate and its associated calcium-containing carbonate minerals. The flotation separation includes the following steps:

[0031] As Figure 1As shown, under normal temperature conditions, the magnesite sample to be floated and deionized water are added to the flotation tube, stirred at 900-1200 rpm for 1-3 min, mixed uniformly, and a slurry with a concentration of 5-35% is obtained; the pH value of the slurry is adjusted to be in the range of 5-11 by introducing hydrochloric acid, sodium hydroxide or sodium carbonate solution; after stirring for 1-3 min, a collector with a concentration of 20-120 mg / L is introduced into the flotation tube; after stirring for 1-3 min again, constant flow of air is introduced and the flotation scraping is started, and the products obtained after the flotation process are the foam product and the in-tank product, wherein the foam product is the desired magnesite concentrate, and the in-tank product is the tailings.

[0032] Specifically, the flotation in step S3 is positive flotation, and the objects of the positive flotation are magnesite, dolomite and calcite, which can be carried out by using a device for positive flotation of ores.

[0033] As used herein, the "magnesite sample to be floated" is an industrial magnesite ore, i.e., a mixed ore sample containing magnesite, dolomite or calcite. In order to illustrate the effect of the collector and its flotation scheme on the selective separation of magnesite, in the following examples, the magnesite sample to be floated is a mixture of natural magnesite, dolomite and calcite ores with high purity obtained by hand picking, wherein the magnesite and dolomite are taken from Anshan area in Liaoning Province, and the calcite is taken from Changsha area in Hunan Province. The ore sample is crushed to -2 mm, then the three single minerals are quickly dry ground to -150 μm by a ceramic ball mill, and finally, -150+75 μm, -75+45 μm and -45+25 μm products are sieved out by a Tyler standard sieve and stored in a desiccator for flotation test. The purity of magnesite, dolomite and calcite is 98.03%, 97.68% and 98.41%, respectively.

[0034] Example 1

[0035] A flotation separation method of calcium-magnesium carbonate minerals, comprising the following steps:

[0036] Under normal temperature conditions, 5 parts of the above-mentioned magnesite sample to be floated and deionized water are added to the flotation tube, stirred at 1100 rpm for 2 min, mixed uniformly, and a slurry with a concentration of 25% is obtained; under the condition of pH 6, a collector with a concentration of 20 mg / L, 40 mg / L, 60 mg / L, 80 mg / L or 100 mg / L is introduced into the flotation tube, wherein the collector is n-octanol and potassium cetyl phosphate with a molar ratio of 25:75; after stirring for 2 min again, constant flow of air is introduced and the flotation scraping is started, the air flow rate is set to 35 ml / min, the flotation scraping duration is 3 min, the concentrate is scraped to the concentrate basin with the foam, and the tailings remain in the flotation tank.

[0037] Example 2

[0038] A method for the flotation separation of calcium-magnesium carbonate minerals, comprising the steps of:

[0039] A method for the flotation separation of calcium-magnesium carbonate minerals, comprising the steps of:

[0040] Example 3

[0041] A method for the flotation separation of calcium-magnesium carbonate minerals, comprising the steps of:

[0042] Comparative Example 1

[0043] A method for the flotation separation of calcium-magnesium carbonate minerals, comprising the steps of:

[0044] Comparative Example 2

[0045] A method for the flotation separation of calcium-magnesium carbonate minerals, comprising the steps of:

[0046] Comparative Example 3

[0047] A method for the flotation separation of calcium-magnesium carbonate minerals, comprising the steps of:

[0048] Comparative Example 4

[0049] A method for flotation separation of calcium-magnesium carbonate minerals, other steps are the same as example 2, the difference is that the collector used is dodecyl phosphate.

[0050] Test and evaluation

[0051] The concentrates and tailings obtained from examples 1-2 and comparative examples 1-4 are filtered, dried, weighed, and mixed with the magnesite, dolomite, or calcite ore sample to be processed. The grade of the concentrate is detected by the ammonium molybdate volumetric method (GB / T 223.61-1988), and the recovery rate is calculated. The results are as follows:

[0052] Figure 2 The flotation recovery rates of the mixed ore samples containing magnesite, dolomite, or calcite under different reagent dosages for example 1. The flotation collector in this case is the "inventive flotation reagent" marked in the figure, and the flotation tests are all carried out at a pH of 6.

[0053] From Figure 2 It can be seen that within the tested reagent dosage range, the inventive flotation collector has stronger selective collection ability for magnesite, and almost no collection for dolomite and calcite, which means that using the inventive flotation collector alone can efficiently separate magnesite from dolomite and calcite. As the reagent concentration increases from 0 to 80 mol / L, the recovery rate of the inventive flotation collector for magnesite increases significantly, up to 96%, while the recovery rates for dolomite and calcite are both about 2%, with a difference of 94%. This indicates that as the reagent dosage increases, the collection ability of the inventive flotation collector for dolomite and calcite does not improve significantly, and the best separation effect for magnesite and dolomite or calcite is achieved at a reagent dosage of 60 mol / L, so 60 mol / L is selected as the preferred reagent dosage for subsequent experiments and tests. Comparative example 2 can collect both magnesite and dolomite, and has stronger collection ability for dolomite, while the recovery rates of magnesite and dolomite are not significantly different, and the recovery rates of the two are very similar within the entire tested reagent dosage range, so the collector in comparative example 2 cannot achieve efficient separation of magnesite and dolomite or calcite.

[0054] Figure 3 The recovery rates of the mixed ore samples containing magnesite, dolomite, or calcite under different pH values for example 2. The flotation collector in this case is the "inventive flotation reagent" marked in the figure, and the flotation tests are all carried out at a collector concentration of 60 mg / L.

[0055] From Figure 3It can be seen that in the range of slurry pH value 5-11, the flotation recovery rate of the flotation collector of the present application for magnesite is kept at a high level of 90% or above, but the dolomite and calcite are basically not floated. When the slurry natural pH value (about 6.8) is approached, the flotation recovery rate of magnesite reaches the highest. Therefore, in the whole pH value range, the flotation collector of the present application has good selectivity for magnesite. The collector in Comparative Example 2 reaches the best recovery rate difference at pH value 6, but still not as good as any recovery rate difference of the flotation collector of the present application in the whole pH value range.

[0056] The above results show that compared with sodium oleate, the dodecyl phosphate ester has stronger action with calcium on the surface of dolomite, and the dodecyl phosphate ester adsorbed on the calcium on the surface of dolomite can achieve better collecting effect on dolomite. Due to the different arrangement of calcium ions on the surface of magnesite and dolomite, there is a difference in the collecting effect between magnesite and dolomite, but this difference is not enough to achieve the purpose of ideal flotation separation of magnesite and dolomite, and an inhibitor such as water glass needs to be added again to effectively enhance the selectivity of dodecyl phosphate ester for the action of magnesite and dolomite, while the collector of the present application can achieve high-efficiency separation of magnesite in one step.

[0057] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any change or replacement easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered in the protection scope of the present application.

Claims

1. A collector for the flotation separation of calcium and magnesium carbonate minerals, characterised in that, The potassium cetyl phosphate ester includes monohydric alcohol; the flotation is positive flotation, the object of the flotation is magnesite and its associated calcium carbonate mineral; the molar ratio of the potassium cetyl phosphate ester and the monohydric alcohol is 20:80; the monohydric alcohol is n-octanol. The associated calcium carbonate mineral is one or more of dolomite or calcite.

2. Use of a collector for flotation separation of calcium-magnesium carbonate minerals according to claim 1.

3. Use according to claim 2, characterized in that, The specific application steps are as follows: S1. Add deionized water to the magnesite sample to be floated, mix by stirring, and obtain a slurry; S2. Adjust the pH value of the slurry to 5-11, stir uniformly, then add the collector to obtain a mixture; S3. Stir the mixture and pass a constant flow rate of air to perform flotation and bubble scraping, and obtain a magnesite concentrate.

4. Use according to claim 3, characterized in that, The concentration of the slurry is 5-35%.

5. Use according to claim 3, characterized in that, The concentration of the collector is 20-120 mg / L.

6. Use according to claim 3, characterized in that, The concentration of the collector is 60 mg / L.

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