Slow-release inhibitor for high-magnesium sulfide mineral flotation and application thereof

Abstract

Disclosed are a slow-release inhibitor for high-magnesium sulfide mineral flotation and an application thereof, where the inhibitor is a nano colloidal particle of an alkaline earth fluoride such as CaF.sub.2 and BaF.sub.2 or a highly-reactive natural alkaline earth metal mineral powder. When applied to the flotation separation of a high-magnesium sulfide ore, the inhibitor can slowly release F ions to preferentially form a MgF.sub.2 layer on the magnesium-containing mineral surface, which provides a structure similar to MgF.sub.2 on a surface of oxidized gangue minerals such as magnesium oxide, changing surface electrical property of the magnesium-containing mineral, inhibiting heterogeneous coagulation of magnesium-containing minerals and sulfide ores due to electrostatic attraction and reducing entrainment, enveloping and agglomeration of gangue minerals to efficiently inhibit the flotation of oxidized gangue minerals such as magnesium oxide.

Claims

1. A method of separating a high-magnesium sulfide ore, comprising: mixing alkaline earth metal fluoride in the form of a nano alkaline earth fluoride colloidal particle or in the form of a natural alkaline earth metal mineral with the high-magnesium sulfide mineral to produce an ore pulp; stirring the ore pulp under 1,200-3,000 rpm for 5-30 min; and introducing a collector to obtain a flotation system.

2. The method of claim 1, wherein a mass ratio of the nano alkaline earth fluoride colloidal particle or the natural alkaline earth metal mineral to the high-magnesium sulfide mineral is 1:10-500; and a pulping time is 5-30 min.

3. The method of claim 1, wherein a concentration of the ore pulp in the flotation is controlled at 30%-40%, and a pH of the flotation system is controlled to 7-9.

4. The method of claim 1, wherein the nano alkaline earth fluoride colloidal particle or the natural alkaline earth metal mineral is used in combination with at least one of acidified sodium silicate, sodium hexametaphosphate, starch and tannin.

5. The method of claim 1, wherein the collector is selected from the group consisting of copper sulfide, cobalt sulfide and nickel sulfide.

6. A method of separating a high-magnesium sulfide ore, comprising: mixing alkaline earth metal fluoride in the form of a nano alkaline earth fluoride colloidal particle or in the form of a natural alkaline earth metal mineral with the high-magnesium sulfide mineral to produce an ore pulp; stirring the ore pulp under 1,200-3,000 rpm for 5-30 min; and introducing a collector to obtain a flotation system; wherein the high-magnesium sulfide ore comprises at least one magnesium-containing gangue mineral selected from magnesite, serpentine, talc, olivine, pyroxene, hornblende, biotite, chlorite, vermiculite, montmorillonite and illite, and at least one metal sulfide ore selected from nickel sulfide mineral, cobalt sulfide mineral and copper sulfide mineral.

7. The method of claim 5, wherein a mass ratio of the nano alkaline earth fluoride colloidal particle or the natural alkaline earth metal mineral to the high-magnesium sulfide mineral is 1:10-500; and a pulping time is 5-30 min.

8. The method of claim 5, wherein the nano alkaline earth fluoride colloidal particle or the natural alkaline earth metal mineral is used in combination with at least one of acidified sodium silicate, sodium hexametaphosphate, starch and tannin.

9. The method of claim 6, wherein the collector is selected from the group consisting of copper sulfide, cobalt sulfide and nickel sulfide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow chart showing the mineral processing according to a first embodiment of the invention.

(2) FIG. 2 is a flow chart showing the mineral processing according to a second embodiment of the invention.

(3) FIG. 3 is a flow chart showing the mineral processing according to a third embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

(4) The invention will be further illustrated below with reference to the embodiments, and is not limited thereto.

Example 1

(5) Naturally pure fluorite minerals were ground to amorphous state (−2 μm) for the flotation of a nickel-copper sulfide ore. The multi-element analysis results of the nickel-copper sulfide ore were shown in Table 1, and it can be observed that gangue minerals of the ore mainly included oxides such as MgO, SiO.sub.2 and Al.sub.2O.sub.3. As shown in FIG. 1, an ore dressing method including a combination of grinding, magnetic separation, one roughing and one scavenging was employed herein according to characteristics of the ore, where diethyldithiocarbamate was used as a collector, a natural fluorite particle with an amorphous surface was used as an inhibitor, and BK205 was used as a foaming agent. After added with the inhibitor, the flotation system was pulped under stirring at 1,500 rpm for 10 min. After the flotation separation, a grade and a recovery rate of concentrate nickel were 4.24% and 73.21%, respectively; a grade and a recovery rate of concentrate copper were 0.82% and 69.13%, respectively; and a grade of magnesium oxide in the concentrate was significantly reduced to 3.37%. Therefore, based on the above process, the flotation separation of the nickel-copper sulfide ore and magnesium oxide was achieved.

(6) TABLE-US-00001 TABLE 1 Multi-element analysis of a raw sulfide ore Element Ni Cu Co Fe S MgO SiO.sub.2 Al.sub.2O.sub.3 Content 0.63 0.14 0.03 7.75 3.60 23.95 42.82 2.17 (%)

(7) In order to verify the significance of the stirring time after the addition of the inhibitor, comparative tests merely varying in stirring times were carried out, and the results were shown in Table 2. It can be concluded that a shorter stirring time will lead to incomplete dissolution of the amorphous pure mineral inhibitor and surface conversion reaction, resulting in poor inhibition and low recovery rate. In the case that the stirring time reached 10 min, the recovery rates of nickel and copper overall tended to be stable with some small fluctuations.

(8) TABLE-US-00002 TABLE 2 Testing results at different stirring time Time (min) 3 5 10 15 30 Nickel recovery 52.13 66.45 73.21 74.36 74.02 rate (%) Copper recover 46.55 59.34 69.13 69.75 70.17 rate (%)

Example 2

(9) 30 g of calcite fluoride and 20 g of sodium oleate were added to 100 mL of water and reacted at 150° C. and 10 MPa in a high-pressure reactor for 1 h to produce a nano colloid inhibitor for the flotation of a raw ore in Jinchuan No. 1 mining area. The raw ore was subjected to a mineral processing sequentially including a grinding, one roughing and one scavenging to produce a rough concentrate, which was then treated by re-grinding and re-beneficiation. Grades of nickel, copper and magnesium oxide before and after the mineral processing were shown in Table 3. A combination of xanthate and dithiophosphate was used as a flotation collector, the nano calcium fluoride colloid was used as an inhibitor, and 2# oil was used as a foaming agent. After added with the inhibitor, the flotation system was stirred at 1,600 rpm for 5 min. It can be observed that through the mineral processing shown in FIG. 2, in the ore concentrate, the nickel grade was increased from 1.63% to 6.61% and the recovery rate of nickel reached 80.04%; the copper grade was increased from 0.91% to 2.86% and the recovery rate of copper reached 76.55%; while the magnesium oxide grade was reduced from 21.55% to 5.64%.

(10) TABLE-US-00003 TABLE 3 Analysis of a raw ore and ore concentrate in Jinchuan No. 1 mining area Grade of Grade of Recovery raw ore (%) ore concentrate (%) rate % Ni 1.63 6.04 80.04 Cu 0.91 2.86 76.55 MgO 21.55 5.64 —

Example 3

(11) 20 g of barium fluoride and 10 g of sodium dodecyl sulfate were added to 50 mL of water and reacted at 200° C. and 10 MPa in a high-pressure reactor for 0.5 h to produce a nano colloid inhibitor for the flotation of a raw ore in Jinchuan No. 2 mining area. The component and multi-element analysis results of the raw ore were shown in Tables 4 and 5. A combination of Z-200 and diethyldithiocarbamate was employed as a collector, the nano barium fluoride colloid was used as the inhibitor, and 2# oil was used as a foaming agent. The flotation system was further added with acidified water glass. After added with the inhibitor, the flotation system was stirred at 1,500 rpm for 5 min. A sequentially closed-circuit mineral processing including a grinding, a magnetic separation, a roughing, a concentrating and a scavenging was employed and shown in FIG. 3. Using the collector and inhibitor, a grade and a recovery rate of concentrate nickel were 7.02% and 82.41%, respectively; a grade and a recovery rate of concentrate copper were 3.17% and 79.08%, respectively; a content of magnesium oxide in the ore concentrate was significantly reduced to 6.18%. Therefore, an effective flotation separation of sulfide ores such as nickel-copper sulfide and oxide ores such as magnesium oxide was achieved by the inhibitor in the invention.

(12) TABLE-US-00004 TABLE 4 Component analysis of a raw ore in Jinchuan No. 2 mining area Mineral Pyrrhotite Pentlandite Chalcopyrite Valleriite Pyrite Serpentine Olivine Content % 10.55 4.35 2.83 0.62 0.63 37.45 12.71 Mineral Pyroxene Amphibole Talc Chlorite Mica Carbonate Iron oxide Content % 16.26 4.73 0.96 1.85 0.82 0.97 5.21

(13) TABLE-US-00005 TABLE 5 Multi-element analysis of the raw ore in Jinchuan No. 2 mining area Element Ni Co Cu Fe S MgO SiO.sub.2 Content % 1.70 0.043 1.16 16.67 6.27 27.81 28.15

(14) In order to further demonstrate the significant effect of the stirring strength on the function of the inhibitor, comparative tests merely varying in stirring strengths were carried out, and the results were shown in Table 6. It can be observed that the recovery rates of nickel and copper would be affected when the stirring intensity was too strong or too weak. As the stirring strength increased, the recovery rate was first increased and then decreased, and a peak value occurred at 1,500 rpm. The surface conversion would be incomplete when the stirring was too weak, while the inhibitor would be desorbed when the stirring was too strong, both of which had an effect on the flotation to a certain extent. Therefore, the slow-release inhibitor for the high-magnesium sulfide mineral flotation provided herein should be preferably employed in a certain range of stirring strength.

(15) TABLE-US-00006 TABLE 6 Testing results at different stirring strengths Stirring strength (rmp) 1000 1200 1500 2000 3000 Nickel recovery 64.89 75.58 82.41 80.94 72.33 rate (%) Copper recovery 60.73 71.37 79.08 76.25 67.19 rate (%)