A combined depressant for niobium mineral flotation and its preparation method and application

Abstract

The present application belongs to the technical field of mineral flotation, and particularly relates to a combined depressor for niobium mineral flotation and a preparation method and application thereof. The combined depressor for niobium mineral flotation is prepared from the following components in percentage by mass: 40-65% of sodium hexametaphosphate, 30-65% of sodium pyrophosphate and 20-55% of sodium sulfite, with a total of 100%. The combined depressor for niobium mineral flotation can effectively inhibit gangue minerals in the flotation process, has the advantages of high solubility, strong degradation capacity and good stability, and the obtained niobium concentrate has high grade and recovery rate of Nb2O5.

Description

Technical Field

[0001] This invention belongs to the field of mineral flotation technology, specifically relating to a combined inhibitor for niobium mineral flotation, its preparation method, and its application. Background Technology

[0002] The Bayan Obo mine is an important mineral resource base, with extremely rich niobium resources. The Nb element in the mine is mainly distributed in columbite, pyrochlore, columbite rutile and calcite, with distribution rates of 37.82%, 36.00%, 21.45% and 3.83%, respectively.

[0003] However, in the flotation process of niobium minerals in Bayan Obo, the poor floatability of niobium minerals and the weak inhibitory ability of existing depressants make it difficult to meet the requirements of efficient flotation. Moreover, the surface physicochemical properties of niobium minerals such as columbite are extremely similar to those of gangue minerals, which directly leads to their similar floatability, making flotation separation difficult. Therefore, based on the differences in mineral flotation behavior, developing a highly efficient and selective flotation inhibitor system has become a key path to achieve the enrichment and recovery of niobium mineral resources in Bayan Obo.

[0004] Currently, most depressants used in the flotation of niobium minerals are high-molecular-weight organic reagents. However, in the industrial flotation process of niobium minerals, these high-molecular-weight organic reagents have poor solubility and tend to agglomerate or precipitate in the slurry, resulting in uneven dispersion. This prevents the depressants from fully contacting the mineral surface. Furthermore, the effective concentration of these high-molecular-weight organic reagents is low, and their inhibition efficiency is unstable, resulting in a Nb₂O₅ grade that can only reach 4.38%, making it difficult to achieve efficient separation and recovery of niobium minerals from gangue minerals. Summary of the Invention

[0005] To address the technical problems of existing inhibitors having poor solubility, easy agglomeration, precipitation, and uneven dispersion in slurry, resulting in insufficient contact between the inhibitor and the mineral surface, as well as poor selectivity of the inhibitor for niobium minerals, this invention provides a combined inhibitor for niobium mineral flotation, its preparation method, and its application.

[0006] The first objective of this invention is to provide a combined depressant for the flotation of niobium minerals, which is prepared by mass percentage from the following components: 40%–65% sodium hexametaphosphate, 30%–65% sodium pyrophosphate, and 20%–55% sodium sulfite, totaling 100%.

[0007] It should be noted that sodium hexametaphosphate is a long-chain linear polyphosphate with multiple highly electronegative oxygen atoms, capable of simultaneously chelating multiple metal ions, such as Ca. 2+ Mg 2+ Fe 2+ and Fe 3+The chelating speed of sodium pyrophosphate is faster, but the structure is different; a layer of hydrophilic and stable metal-phosphate chelate layer is formed on the surface of gangue minerals by forming a chelate network with sodium pyrophosphate and sodium hexametaphosphate, so that the active sites are completely shielded, and the collector cannot adsorb the gangue minerals. Meanwhile, the sodium sulfite provides an alkaline environment, so that the chelation of sodium hexametaphosphate and sodium pyrophosphate is more stable; and through the reduction effect of sodium sulfite, high-valence metal ions are reduced to low-valence metal ions, which are more likely to form stable precipitates or chelates with phosphate ions.

[0008] Both sodium hexametaphosphate and sodium pyrophosphate can dissociate a large number of negative ions in water, and these multivalent negative ions can be strongly adsorbed on the surface of all solid particles in the ore slurry. Strong electrostatic repulsion is generated between the solid particles, thereby effectively preventing the gangue fine mud from being adsorbed on the surface of the target mineral, i.e., fine mud cover; and preventing the mineral particles from agglomerating. This makes the ore slurry system maintain a stable and uniform dispersion state.

[0009] A second object of the present application is to provide a preparation method of a combined inhibitor for niobium mineral flotation, comprising the following steps:

[0010] Sodium sulfite is dissolved in water at 35-40 DEG C to provide an alkaline environment; then sodium hexametaphosphate and sodium pyrophosphate are added in sequence, so that the pH is stabilized at 10-11.5, to form a chelate network, thereby obtaining the combined inhibitor.

[0011] Preferably, the temperature for mixing sodium hexametaphosphate and sodium pyrophosphate is 35-40 DEG C. In the present application, sodium sulfite is first dissolved in water to obtain a sodium sulfite aqueous solution; under stirring, sodium hexametaphosphate is added to avoid the formation of a gel by the local high concentration of sodium hexametaphosphate, and then sodium pyrophosphate is added, and the pH is adjusted to 10-11.5 to form a chelate network, thereby obtaining the combined inhibitor.

[0012] Preferably, the mass concentration of the combined inhibitor for niobium mineral flotation is 3-15 wt.%.

[0013] A third object of the present application is to provide the application of the combined inhibitor for niobium mineral flotation in the flotation of niobium minerals.

[0014] Preferably, the combined inhibitor is used as a gangue mineral inhibitor for the flotation separation of niobium minerals.

[0015] Preferably, the flotation separation method is as follows:

[0016] The niobium crude ore is ground and prepared into an ore slurry by adding water, and the pH is adjusted to 7.0-8.5; the reagent is added to the ore slurry, and after flotation, the niobium concentrate is obtained.

[0017] Preferably, the specific flotation process is as follows:

[0018] The reagent is added into the ore pulp, and after rough separation, a rough separation concentrate is obtained; the rough separation concentrate is adjusted to an ore pulp, and after first separation, a first separation concentrate is obtained; the first separation concentrate is adjusted to an ore pulp, and after second separation, a niobium concentrate is obtained.

[0019] Preferably, the reagent used in the flotation is a combined depressant, a collector and a frother; wherein the amount of the combined depressant is 0.2 kg / t to 1 kg / t, the amount of the collector is 0.5 kg / t to 4 kg / t, and the amount of the frother is 20 g / t to 80 g / t, per ton of niobium minerals.

[0020] Preferably, the temperature of the flotation is 45 DEG C to 55 DEG C.

[0021] Preferably, the collector is a hydroxamic acid reagent, and the hydroxamic acid collector is one of octyl hydroxamic acid, benzyl hydroxamic acid and naphthyl methyl hydroxamic acid; the mass concentration of the collector is 2wt.% to 10wt.%.

[0022] Preferably, the frother is No. 2 oil.

[0023] Preferably, the proportion of the particle size less than 0.074 mm in the niobium raw ore is 90% to 95%, and the mass concentration of the ore pulp is 30wt.% to 55wt.%.

[0024] Preferably, the mass concentration of the rough separation concentrate adjusted to the ore pulp is 30wt.% to 50wt.%; and the mass concentration of the first separation concentrate adjusted to the ore pulp is 20wt.% to 45wt.%.

[0025] Compared with the prior art, the present application has the following technical effects:

[0026] The present application utilizes the fact that sodium hexametaphosphate and sodium pyrophosphate dissociate a large number of negative ions in water and are adsorbed on the surface of all solid particles in the ore pulp. Strong electrostatic repulsion is generated between the solid particles, effectively preventing gangue fine mud from being adsorbed on the surface of the target mineral and the mineral particles from being aggregated; the ore pulp system is kept in a stable and uniform dispersed state; the poor solubility of the high-molecular organic reagent, the easy aggregation, precipitation and uneven dispersion of the high-molecular organic reagent in the ore pulp, and the poor selectivity of the high-molecular organic reagent to the niobium mineral are solved. At the same time, under the action of sodium sulfite, a strong chelating network is formed by sodium pyrophosphate and sodium hexametaphosphate, so that the activated metal ions on the surface of the gangue mineral are strongly chelated and reduced, thereby forming a hydrophilic and stable chelating layer on the surface of the gangue mineral, shielding the active sites on the surface of the gangue mineral and weakening the adsorption of the collector to the gangue mineral; the poor selectivity of the high-molecular organic reagent to the niobium mineral is solved.

[0027] The new inhibitor for inhibiting vein stone minerals in Baiyunebo mine provided by the application can meet the needs of various flotation processes for Baiyunebo vein stone minerals when carrying out niobium flotation operation. Therefore, the combined inhibitor agent can efficiently improve the flotation efficiency of Baiyunebo niobium minerals.

[0028] The combined inhibitor of the application has strong inhibition ability to vein stone minerals and good stability; when applied to the flotation separation production process of Baiyunebo tailings, the combined inhibitor can improve the selectivity of niobium minerals in the flotation separation process, and has the advantages of environmental friendliness, easy degradation, reduction of inhibitor dosage, strong solubility and non-toxic, harmless and non-polluted mineral processing wastewater, thereby reducing the flotation production cost of niobium minerals. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the technical solutions of the application and implement the same, the application will be further described below in combination with specific embodiments.

[0030] In the description of the application, unless otherwise specified, all reagents used are commercially available, and all methods used are conventional techniques in the art.

[0031] Example 1

[0032] A combined inhibitor for niobium mineral flotation is prepared from the following components in mass percentage: 50% sodium hexametaphosphate, 30% sodium pyrophosphate and 20% sodium sulfite, with a total of 100%.

[0033] The combined inhibitor is prepared by the following method:

[0034] 2g of sodium sulfite is dissolved in 250mL of water, stirred at 35℃ for 5min to provide an alkaline environment of the solution, to obtain a sodium sulfite aqueous solution.

[0035] 5g of sodium hexametaphosphate is slowly added to the sodium sulfite aqueous solution under stirring at 35℃, stirred for 5min to avoid the formation of a local high concentration of sodium hexametaphosphate to form a gel, and then 3g of sodium pyrophosphate is added, stirred for 5min to stabilize the pH at 11, to obtain the combined inhibitor.

[0036] Example 2

[0037] A combined inhibitor is prepared from the following components in mass percentage: 40% sodium hexametaphosphate, 35% sodium pyrophosphate and 25% sodium sulfite, with a total of 100%.

[0038] The combined inhibitor is prepared by the following method:

[0039] 2.5g of sodium sulfite is dissolved in 250mL of water, stirred at 40℃ for 10min to provide an alkaline environment of the solution, to obtain a sodium sulfite aqueous solution.

[0040] Slowly add 4 g of sodium hexametaphosphate into the aqueous sodium sulfite solution under stirring at 40℃, and stir for 10 min to avoid the formation of colloids due to the local high concentration of sodium hexametaphosphate; then add 3.5 g of sodium pyrophosphate, and stir for 10 min to stabilize the pH at 10, to obtain the combined inhibitor.

[0041] Comparative Example 1

[0042] A combined inhibitor is prepared from the following components in mass percentage: 65% of sodium hexametaphosphate and 35% of sodium pyrophosphate, with a total of 100%.

[0043] The combined inhibitor is prepared by the following method:

[0044] Slowly add 6.5 g of sodium hexametaphosphate into 250 mL of water, and stir for 10 min at 35℃, then add 3.5 g of sodium pyrophosphate, and stir for 10 min to stabilize the pH at 10, to obtain the combined inhibitor.

[0045] Comparative Example 2

[0046] A combined inhibitor is prepared from the following components in mass percentage: 60% of sodium hexametaphosphate and 40% of sodium pyrophosphate.

[0047] The combined inhibitor is prepared by the following method:

[0048] Slowly add 6 g of sodium hexametaphosphate into 250 mL of water, and stir for 10 min at 35℃, then add 4 g of sodium pyrophosphate, and stir for 10 min to stabilize the pH at 10, to obtain the combined inhibitor.

[0049] Application Example 1

[0050] The niobium raw ore used in this application example is a tailing from the dilution of the Baiyunebo production workshop, and the mineral composition of the niobium raw ore is shown in Table 1; the content of Nb2O5 is determined to be 0.3%.

[0051] The combined inhibitor prepared in Example 1 is used for flotation, and the specific flotation method is as follows:

[0052] The niobium raw ore is ground to a particle size of less than 0.074 mm, accounting for 91.25%, then water is added to prepare a slurry with a mass concentration of 45 wt.%, and the temperature is raised to 50℃, the pH is adjusted to 7.5, and stirred for 4 min. The reagents are added for flotation, with a dosage of 1 ton of niobium raw ore.

[0053] Coarse selection: 0.8 kg / t of the combined depressant was added to the ore slurry and stirred for 3 min; 3 kg / t of octylhydroxamic acid was added and the pH was adjusted to 7.5, and stirred for 3 min; 60 g / t of No. 2 oil was added and stirred for 3 min; then air flotation was carried out for 5 min, to obtain a froth product on the tank as the coarse selection concentrate, and a product at the tank bottom as the coarse selection tailings, i.e. the niobium tailings.

[0054] First selection: the coarse selection concentrate was adjusted to an ore slurry with a mass concentration of 35 wt.%, and stirred for 2 min; 0.6 kg / t of the combined depressant was added and stirred for 3 min; 2 kg / t of octylhydroxamic acid was added and the pH was adjusted to 7.5, and stirred for 3 min; 40 g / t of No. 2 oil was added and stirred for 3 min; then air flotation was carried out for 5 min, to obtain a froth product on the tank as the first selection concentrate; and a product at the tank bottom as the first selection tailings.

[0055] Second selection: the first selection concentrate was adjusted to an ore slurry with a mass concentration of 25 wt.%, and stirred for 2 min; 0.3 kg / t of the combined depressant was added and stirred for 3 min; 1 kg / t of octylhydroxamic acid was added and the pH was adjusted to 7.5, and stirred for 3 min; 20 g / t of No. 2 oil was added and stirred for 4 min; then air flotation was carried out for 5 min, to obtain a froth product on the tank as the second selection concentrate, i.e. the niobium concentrate; and a product at the tank bottom as the second selection tailings.

[0056] The first selection tailings and the second selection tailings were combined and returned as the coarse selection feed; and the above coarse selection, first selection and second selection were repeated until the yield and the grade value of Nb2O5 of the product after the first selection tailings and the second selection tailings were combined changed by no more than 5%.

[0057] Application Comparative Example 1

[0058] The niobium raw ore used in the application comparative example was a tailings from a rare ore selection, taken from the Baiyunebo production workshop, and the mineral composition of the niobium raw ore is shown in Table 1; the content of Nb2O5 was determined to be 0.3%.

[0059] Sodium hexametaphosphate was used as the depressant for flotation, and the specific flotation method referred to the method of application example 1, and the niobium concentrate was obtained through coarse selection, first selection and second selection; wherein the reagent dosages of the coarse selection, first selection and second selection were the same as those of application example 1.

[0060] As shown in Table 1, compared with the flotation process using only sodium hexametaphosphate as the depressant, the combined depressant prepared by application example 1 had a significant inhibitory effect on the gangue minerals such as magnetite / hematite, aegirine, fluorite, barite and quartz; thus indicating that the combined depressant prepared by application example 1 had a significant inhibitory effect on the gangue minerals, and efficiently improved the inhibitory ability on the gangue minerals of Baiyunebo.

[0061] Table 1 Mineral composition of the niobium concentrate obtained after flotation of the application example 1 and the application comparative example 1

[0062]

[0063] As can be seen from Table 2, after flotation using the combined depressant prepared in the example 1, the grade of Nb2O5 in the niobium concentrate product obtained is 5.80%, and the recovery rate is 37.04%. Compared with the single depressant sodium hexametaphosphate, the grade of niobium concentrate obtained after flotation is 2.11%, which is increased by 3.69%. Thus, it is shown that the combined depressant prepared in the example can significantly improve the grade of niobium concentrate after flotation.

[0064] Table 2 Flotation results of the application example 1 and the application comparative example 1

[0065]

[0066] Application example 2

[0067] The niobium raw ore used in the application example is a blocky niobium-containing ore taken from the west mining area of Baiyunebo. The mineral composition of the niobium raw ore is shown in Table 3; the content of Nb2O5 is 0.109% as determined.

[0068] The combined depressant prepared in the example 2 is used for flotation, and the specific flotation method is as follows:

[0069] The niobium raw ore is ground to a particle size of 200 mesh accounting for 92.23%, and then water is added to prepare a slurry with a mass concentration of 45wt.%, and the temperature is increased to 50℃, the pH is adjusted to 8.0, and the stirring is performed for 3min. The reagents are added for flotation, with 0.7kg / t of the combined depressant per ton of the niobium raw ore.

[0070] Coarse selection: 0.7kg / t of the combined depressant is added to the slurry, and stirring is performed for 3min; 2kg / t of octylhydroxamic acid is added, and the pH is adjusted to 7.5, and stirring is performed for 3min; 40g / t of No.2 oil is added, and stirring is performed for 3min; then air flotation is performed for 5min, and the foam product on the tank is the coarse concentrate, and the product at the bottom of the tank is the coarse tailings, i.e. the niobium tailings.

[0071] First selection: the coarse concentrate is adjusted to a slurry with a mass concentration of 35wt.%, and stirring is performed for 2min; 0.5g / t of the combined depressant is added, and stirring is performed for 3min; 1kg / t of octylhydroxamic acid is added, and the pH is adjusted to 7.5, and stirring is performed for 3min; 30g / t of No.2 oil is added, and stirring is performed for 2-4min; then air flotation is performed for 5min, and the foam product on the tank is the first selection concentrate; and the product at the bottom of the tank is the first selection tailings.

[0072] Second cleaning: the first cleaning concentrate was adjusted to a mass concentration of 25 wt.% of the slurry, stirred for 2 min; 0.3 kg / t of the combined depressant was added, stirred for 3 min; 0.5 kg / t of octylhydroxamic acid was added, and the pH was adjusted to 7.5, stirred for 3 min; 20 g / t of No. 2 oil was added, stirred for 3 min; then air flotation was carried out for 5 min, to obtain the second cleaning concentrate, i.e. the niobium concentrate, as the tank top foam product; and the tank bottom product was the second cleaning tailings.

[0073] The first cleaning tailings were returned as the roughing feed, and the second cleaning tailings were returned as the primary cleaning feed; and the above-mentioned roughing, first cleaning and second cleaning were repeated.

[0074] Application Comparative Example 2

[0075] The niobium raw ore used in the application comparative example was the same as that of application example 2, and the flotation was carried out using the combined depressant prepared in comparative example 2, and the specific flotation method referred to the flotation method of application example 2. After roughing, first cleaning and second cleaning, the niobium concentrate was obtained; wherein the dosages of the reagents in the roughing, first cleaning and second cleaning were the same as those of application example 2.

[0076] Table 3 Mineral composition of the niobium concentrate obtained after flotation in application example 2 and application comparative example 2

[0077]

[0078] As shown in Table 2, compared with the flotation using the combined depressant prepared from sodium hexametaphosphate and sodium pyrophosphate, the combined depressant prepared in application example 2 had a significant inhibitory effect on the gangue minerals such as iron dolomite, phlogopite, calcite, biotite and pyrite in the flotation process, which fully proved that the combined flotation reagent prepared in application example 1 had a significant inhibitory effect on the gangue minerals.

[0079] Table 4 Flotation results of application example 2 and application comparative example 2

[0080]

[0081] As can be seen from Table 4, after flotation using the combined depressant prepared in application example 2, the grade of Nb2O5 in the obtained niobium concentrate product reached 1.585%, and the recovery rate reached 23.90%; compared with the combined depressant prepared from sodium hexametaphosphate and sodium pyrophosphate, the grade of the obtained niobium concentrate after flotation was 0.86%, which was increased by 3.69%. This indicates that the combined depressant prepared in this example can significantly improve the grade of the niobium concentrate after flotation.

[0082] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure without departing from the spirit and scope of the application. Accordingly, it is intended that the appended claims include all such modifications and variations as fall within the scope of the present application.

[0083] It is apparent that those skilled in the art can make various changes and modifications to the application without departing from the spirit and scope of the application. It is therefore intended that the present application cover all such changes and modifications that are within its scope.

Claims

1. A combined depressant for niobium mineral flotation, characterized in that, It is prepared by mass percentage from the following components: sodium hexametaphosphate 40%–65%, sodium pyrophosphate 30%–65%, and sodium sulfite 20%–55%, totaling 100%; The combined inhibitor was prepared by dissolving sodium sulfite in water at 35°C to 40°C to provide an alkaline environment; then sodium hexametaphosphate and sodium pyrophosphate were added sequentially to stabilize the pH at 10 to 11.5 to form a chelate network, thus obtaining the combined inhibitor.

2. The application of the combined depressant of claim 1 for niobium mineral flotation in niobium mineral flotation, characterized in that, The combined inhibitor is used as a gangue mineral inhibitor for the flotation separation of niobium minerals.

3. The application of the combined depressant for niobium mineral flotation according to claim 2 in niobium mineral flotation, characterized in that, The flotation separation method is as follows: The niobium ore was ground, mixed with water to form a slurry, and the pH was adjusted to 7.0–8.

5. Reagents are added to the slurry, and after flotation, niobium concentrate is obtained.

4. The application of the combined depressant for niobium mineral flotation according to claim 3 in niobium mineral flotation, characterized in that, The specific flotation process is as follows: Add reagents to the slurry, and after roughing, obtain rough concentrate; The rough concentrate is adjusted to the slurry, and after the first cleaning process, the first clean concentrate is obtained. The first-selected concentrate was added to the slurry, and after a second selection, niobium concentrate was obtained.

5. The application of the combined depressant for niobium mineral flotation according to claim 3 in niobium mineral flotation, characterized in that, The reagents used in flotation are a combination of depressants, collectors, and frothers; among them, the dosage of the combination depressant is 0.2 kg / t to 1 kg / t, the dosage of the collector is 0.5 kg / t to 4 kg / t, and the dosage of the frother is 20 g / t to 80 g / t, based on each ton of niobium mineral.

6. The application of the combined inhibitor according to claim 3 in the flotation of niobium minerals, characterized in that, The flotation temperature is 45℃~55℃.

7. The application of the combined inhibitor according to claim 5 in the flotation of niobium minerals, characterized in that, The collector is a hydroxamic acid derivative with a mass concentration of 2 wt.% to 10 wt.%; the foaming agent is No. 2 oil.

8. The application of the combined inhibitor according to claim 3 in the flotation of niobium minerals, characterized in that, The proportion of particles smaller than 0.074 mm in the niobium ore is 90% to 95%, and the mass concentration of the slurry is 30 wt.% to 55 wt.%.

Images