A method for the flotation separation of sphalerite from pyrite with galena depression

Abstract

This invention discloses a flotation separation method for collecting galena and inhibiting sphalerite and pyrite, achieving efficient separation of galena from sphalerite and pyrite in a low-alkaline pulp environment, belonging to the field of mineral beneficiation technology. This invention uses N-hydroxyethylethylenediaminetriacetic acid as an inhibitor of sphalerite and pyrite at a low alkalinity of pH 7.5-9.5, and one or two of sodium diethyldithiocarbamate, sodium ethyl xanthate, and xylenol dithiophosphate as collectors for galena. Under low dosage conditions, it achieves simultaneous inhibition of sphalerite and pyrite and effective collection of galena, offering advantages of high efficiency, simple process, economy, and environmental friendliness. It is particularly suitable for silver-bearing, high-sulfur, low-grade lead-zinc ores and has broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology and relates to a flotation separation method for collecting galena and suppressing sphalerite and pyrite. Background Technology

[0002] In natural mineral deposits, lead and zinc often coexist in the form of sulfides, often accompanied by pyrite. Flotation is the primary method for achieving efficient separation of these minerals.

[0003] Lead and zinc are mainly extracted from lead-zinc sulfide ores. Valuable metallic minerals in lead-zinc sulfide ores are primarily galena, sphalerite, and pyrite, often accompanied by rare and precious metals such as gold and silver. Flotation separation processes mainly include: preferential flotation, mixed flotation, equal floatability flotation, and asynchronous flotation. The most common flotation process is preferential flotation, which sequentially floats different concentrate products based on the differences in the natural floatability of the minerals. Galena, sphalerite, and pyrite are recovered through a comprehensive process of zinc-sulfur flotation for lead—lead tailings sulfur flotation—zinc tailings sulfur flotation. This process commonly uses zinc sulfate, sodium sulfite, sodium cyanide, and sodium sulfide (1000-2000 g / t) as sphalerite depressants and lime as a pyrite depressant (pH 11-13, lime dosage 2000-6000 g / t). This process has several drawbacks: First, the complex types of reagents are not conducive to production operations, requiring the addition of 2 to 5 different reagents to inhibit sphalerite and pyrite. Second, the addition of some reagents is not environmentally friendly; some beneficiation plants add sodium sulfide, sodium cyanide, sodium cyanide-like substances, and lime, resulting in high operational risks and failing to meet environmental requirements. Third, production is prone to instability; the complex types of reagents added, and the tendency of lime to scale, clog pipes, and deposit in flotation cells, cause instability in the production process and affect normal production. Fourth, it is not conducive to the recovery of rare and precious metals from the ore; to achieve the flotation separation of galena and sphalerite from pyrite, a large amount of lime needs to be added in a high-alkali slurry environment, which easily leads to the inhibition and loss of rare and precious metals in the tailings, hindering comprehensive resource utilization.

[0004] Therefore, it is essential to develop efficient, environmentally friendly, and economically selective inhibitors to enable the inhibition of sphalerite and pyrite in low-alkali slurry flotation of galena, thus providing technical reserves for the comprehensive recovery and utilization of high-sulfur, silver-bearing, low-grade lead-zinc sulfide ores. Summary of the Invention

[0005] To address the current flotation separation problems in lead-zinc sulfide ores, the present invention aims to provide a flotation separation method for collecting galena to suppress sphalerite and pyrite, thereby achieving efficient separation of lead ore and sphalerite from the original pyrite in a low-alkali slurry environment and reducing unnecessary loss of rare and precious metals.

[0006] The technical solution adopted in this invention is as follows: A method for collecting galena and inhibiting the flotation separation of sphalerite and pyrite, comprising the following steps: (1) The raw ore is crushed, ground and then slurry is prepared to obtain the slurry to be flotated. The ore is ground to a thickness of -0.074 mm, accounting for 65% to 85%; (2) Add pH adjuster, sphalerite and pyrite inhibitor and galena collector to the slurry to be floated and carry out a roughing operation to obtain lead concentrate and zinc-containing sulfur tailings. The pH adjuster is one of sodium carbonate, sodium hydroxide, or calcium oxide, used to adjust the pH of the slurry to 7.5-9.5.

[0007] The inhibitor for sphalerite and pyrite is N-hydroxyethylethylenediaminetriacetic acid, used at a dosage of 100~300 g / t, and has the following structure:

[0008] It has the following ball-and-stick model:

[0009] The galena collector is one or two of sodium diethyldithiocarbamate, sodium ethyl xanthate, and xylenol dithiophosphate, and the dosage of the galena collector is 30~60g / t.

[0010] The raw ore is a silver-bearing, high-sulfur, low-grade lead-zinc sulfide ore.

[0011] The beneficial effects and advantages of the present invention are as follows: (1) The sphalerite and pyrite inhibitor N-hydroxyethylethylenediaminetriacetic acid described in this invention can selectively inhibit sphalerite and pyrite. N-hydroxyethylethylenediaminetriacetic acid reacts with the exposed Zn²⁺ sites on the surface of sphalerite and the iron oxide layer or surface lattice iron ions on the surface of pyrite to generate a hydrophilic chelate film, which prevents sphalerite and pyrite from interacting with the collector, thereby achieving mineral inhibition. N-hydroxyethylethylenediaminetriacetic acid has a weak effect on galvanite because the Pb²⁺ ion radius is large and the stability constant of the complex formed with Pb²⁺ is much smaller than that of Fe³⁺ and Zn²⁺.

[0012] (2) The present invention can achieve simultaneous and efficient inhibition of sphalerite and pyrite under neutral to weakly alkaline conditions (pH 7.5-9.5), reducing the amount of pH adjusters such as lime, reducing the risk of pipe scaling, and avoiding the inhibition of galena and rare precious metals in a high-alkaline slurry environment.

[0013] (3) The reagent of the present invention is simplified. Existing technologies can often only solve the single problem of "zinc inhibition" and "sulfur inhibition". The present invention achieves dual inhibition of sphalerite and pyrite with only one reagent through the synergistic chelating effect of N-hydroxyethyl ethylenediamine triacetic acid.

[0014] (4) This invention enables the separation of lead and zinc sulfur in a low-alkali slurry environment, which can effectively reduce the amount of activator required for subsequent flotation of zinc sulfide and pyrite minerals, and reduce production costs. Attached Figure Description

[0015] Figure 1 This is a flowchart of the flotation separation test of the present invention. Detailed Implementation

[0016] The present invention will be further described below with reference to embodiments and accompanying drawings, but this does not limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0017] The invention will be further illustrated below with specific implementation examples: Example 1

[0018] Take a lead-zinc sulfide mine in a certain area of ​​Qinghai as an example.

[0019] Properties of the raw ore: The ore contains 1.55% Pb, 1.90% Zn, 16.72% S, and 26 g / t Ag. Lead is found as an independent mineral in galena, zinc is found as an independent mineral in sphalerite, sulfur is mainly found in pyrrhotite, followed by pyrite, and silver is found as mechanical inclusions or isomorphous inclusions in galena. The main gangue minerals are quartz, followed by calcite and sulphite, etc.

[0020] The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite in this embodiment is carried out according to the following steps: (1) First stage of grinding: Add 500g of crushed ore and water to the mill at a solid-liquid ratio of 1:1, grind to a fineness of -0.074mm to 65%, and obtain the slurry to be floated; (2) Place the above slurry sample into the flotation machine, add 500g / t of lime to the slurry to be floated to adjust the pH of the slurry to 7.5, add 100g / t of N-hydroxyethyl ethylenediamine triacetic acid, an inhibitor of sphalerite and pyrite, and stir for 3min, add 50g / t of xylenol dithiophosphate, a flotation collector for galena, and stir for 2min, and aerate and skim for 4min to obtain lead crude concentrate and tailings.

[0021] Comparative Example 1: The other conditions and operations of this comparative example are the same as those of Example 1, except that the inhibitors used are changed. In this comparative example, 500 g / t of zinc sulfate and 1500 g / t of lime are added as inhibitors to obtain lead concentrate and tailings with zinc sulfate and lime as inhibitors.

[0022] Comparative Example 2: The other conditions and operations of this comparative example are the same as those of Example 1, except that no sphalerite and pyrite inhibitors are added in this comparative example, resulting in lead concentrate and tailings without inhibitors.

[0023] The results of Example 1 and Comparative Examples 1 and 2 are as follows:

[0024]

[0025] As shown in the table, comparing the experimental indicators under three conditions—with the inhibitor of this invention, the traditional inhibitor, and without the inhibitor—the zinc loss rate in lead concentrate was lowest at 11.45% using the inhibitor of this invention, followed by 15.11% with the traditional inhibitor, and highest at 47.08% without the inhibitor. This indicates that the inhibitor of this invention has the best inhibitory effect on sphalerite during galena flotation. The lead grade in the lead concentrate obtained using the inhibitor of this invention was highest at 28.03%, followed by 25.52% with the traditional inhibitor, and lowest without the inhibitor, indicating that the inhibitor of this invention has a better inhibitory effect on pyrite. The silver recovery rate in the lead concentrate obtained using the inhibitor of this invention was about 3 percentage points higher than that obtained with the traditional inhibitor, indicating that the traditional inhibitor is more favorable for silver recovery. In summary, the inhibitor of this invention can achieve the inhibition of sphalerite and pyrite during galena flotation under very low dosage conditions, with minimal impact on silver-bearing minerals. Example 2

[0026] Take a lead-zinc sulfide mine in a certain area of ​​Yunnan as an example.

[0027] Properties of the raw ore: The ore contains 2.65% Pb, 3.99% Zn, 21.23% S, and 65.77 g / t Ag. Lead is found as an independent mineral in galena, zinc is found as an independent mineral in sphalerite, sulfur is mainly found in pyrite, and silver is mainly found in argentite, and secondarily in galena as mechanical inclusions or isomorphous inclusions. The main gangue minerals are calcite and quartz, followed by basalt, mica, etc.

[0028] The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite in this embodiment is carried out according to the following steps: (1) First stage of grinding: Add 500g of ore and water to the mill at a solid-liquid ratio of 1:1, grind to a fineness of -0.074mm to 75%, and obtain the slurry to be floated; (2) Add 400 g / t of sodium hydroxide to the slurry to be floated to adjust the pH of the slurry to 8, add 200 g / t of N-hydroxyethyl ethylenediamine triacetic acid (NH3) inhibitors for sphalerite and pyrite and stir for 3 min, add 60 g / t of sodium ethyl xanthate and sodium diethyl dithiocarbamate (1:1 ratio) flotation collectors for galena and stir for 2 min, aerate and skim for 4 min to obtain lead crude concentrate and tailings with N-hydroxyethyl ethylenediamine triacetic acid as inhibitor.

[0029] Comparative Example 2-1: The other conditions of this comparative example are the same as those of Example 2, except that the inhibitors used are different. In this comparative example, 1000 g / t of zinc sulfate and 1800 g / t of lime are added as inhibitors to obtain lead concentrate and tailings with zinc sulfate and lime as inhibitors.

[0030] Comparative Example 2-2: The other conditions of this comparative example are the same as those of Example 2, except that sphalerite and pyrite inhibitors are not added, resulting in lead concentrate and tailings without inhibitors.

[0031] The results of Example 2 and the two comparative examples are shown in the table below:

[0032]

[0033] As shown in the table, comparing the experimental indicators under three conditions—with the addition of the inhibitor of this invention, the traditional inhibitor, and without the addition of the inhibitor—the zinc loss rate in the lead concentrate was lowest (8.55%) with the inhibitor of this invention, followed by the traditional inhibitor, and highest without the inhibitor, indicating that the inhibitor of this invention has the best inhibitory effect on sphalerite during the flotation of galena. The lead grade in the lead concentrate obtained using the inhibitor of this invention was highest (31.51%), followed by the traditional inhibitor (24.35%), and lowest without the inhibitor, indicating that the inhibitor of this invention has a good inhibitory effect on pyrite. The silver recovery rate in the lead concentrate obtained using the inhibitor of this invention was similar to that without the inhibitor, and both were higher than those using the traditional inhibitor, indicating that the traditional inhibitor has an inhibitory effect on silver, while the inhibitor of this invention has no significant inhibitory effect on silver-bearing minerals. In summary, the inhibitor of this invention can achieve the inhibition of sphalerite and pyrite during the flotation of galena at very low dosages, with minimal impact on silver-bearing minerals. Example 3

[0034] Take a lead-zinc sulfide mine in a certain area of ​​Guizhou as an example.

[0035] Properties of the raw ore: The ore contains 1.80% Pb, 6.12% Zn, 26.11% S, and 45.24 g / t Ag. Lead is found as an independent mineral in galena, zinc is found as an independent mineral in sphalerite, sulfur is mainly found in pyrite, and silver is mainly found as mechanical inclusions or isomorphous inclusions in galena. The main gangue minerals are calcite and quartz, followed by garnet, chlorite, and mica.

[0036] The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite in this embodiment is carried out according to the following steps: (1) First stage of grinding: Add 500g of ore and water to the mill at a solid-liquid ratio of 1:1, grind to a fineness of -0.074mm to 80%, and obtain the slurry to be flotated; (2) Place the above slurry sample into the flotation machine, add 200g / t of sodium carbonate and 100g / t of sodium hydroxide to the slurry to be floated to adjust the pH of the slurry to 7.5, add 300g / t of N-hydroxyethyl ethylenediamine triacetic acid (NEDTA) as a inhibitor for sphalerite and pyrite and stir for 3min, add 60g / t of sodium diethyl dithiocarbamate and sodium ethyl xanthate as flotation collectors at a ratio of 1:1 and stir for 2min, aerate and skim for 4min to obtain lead rough concentrate and tailings with NEDTA as an inhibitor.

[0037] Comparative Example 3-1: The other conditions and operations of this comparative example are the same as those of Example 1, except that only the inhibitor used is changed. In this comparative example, zinc sulfate 1500g / t + sodium sulfite 500g + lime 2000g / t are added to obtain zinc sulfate, sodium sulfite and lime as inhibitors for lead concentrate and tailings.

[0038] Comparative Example 3-2: The other conditions and operations of this comparative example are the same as those of Example 1, except that sphalerite and pyrite inhibitors are not added, resulting in lead concentrate and tailings without inhibitors.

[0039] The results of Example 3 and the two comparative examples are as follows:

[0040]

[0041] As shown in the table, comparing the experimental indicators under three conditions—with the addition of the inhibitor of this invention, the traditional inhibitor, and without the addition of the inhibitor—the zinc loss rate in the lead concentrate was lowest at 6.89% using the inhibitor of this invention, followed by 9.21% with the traditional inhibitor, and highest at 44.49% without the inhibitor. This indicates that the inhibitor of this invention has the best inhibitory effect on sphalerite during the flotation of galena. The lead grade in the lead concentrate obtained using the inhibitor of this invention was highest at 26.21%, followed by 22.45% with the traditional inhibitor, and lowest without the inhibitor, indicating that the inhibitor of this invention has a good inhibitory effect on pyrite. The silver recovery rate in the lead concentrate obtained using the inhibitor of this invention was similar to that without the inhibitor, and both were higher than those obtained using the traditional inhibitor, indicating that the traditional inhibitor has an inhibitory effect on silver, while the inhibitor of this invention has a smaller inhibitory effect on silver-bearing minerals. In summary, the inhibitor of this invention can achieve the inhibition of sphalerite and pyrite during the flotation of galena at very low dosages, with minimal impact on silver-bearing minerals. Example 4

[0042] Take a lead-zinc sulfide mine in a certain area of ​​Hunan Province as an example.

[0043] Properties of the raw ore: The raw ore contains 2.63% Pb, 2.88% Zn, 16.26% S, and 85.17 g / t Ag. Lead is found as an independent mineral in galena, zinc is found as an independent mineral in sphalerite, sulfur is mainly found in pyrite, silver is mainly found in argentite, and a small amount is found in galena as mechanical inclusions or isomorphous inclusions. The main gangue minerals are quartz, followed by calcite, andradite, barite, and mica.

[0044] The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite in this embodiment is carried out according to the following steps: (1) First stage of grinding: Add 500g of ore and water to the mill at a solid-liquid ratio of 1:1, grind to a fineness of -0.074mm to 70%, and obtain the slurry to be flotated; (2) Place the above slurry sample into a flotation machine, add 200g / t of lime and 200g / t of sodium carbonate to the slurry to be floated to adjust the pH of the slurry to 9.5, add 170g / t of N-hydroxyethyl ethylenediamine triacetic acid (NEDTA) as a inhibitor for sphalerite and pyrite and stir for 3 min, add 50g / t of sodium diethyldithiocarbamate (DITC) as a flotation collector for galena and stir for 2 min, and aerate and skim for 4 min to obtain lead crude concentrate and tailings with NEDTA as an inhibitor.

[0045] Comparative Example 4-1: The other conditions and operations of this comparative example are the same as those of Example 1, except that the inhibitor used is changed. In this comparative example, (zinc sulfate 1000g / t + sodium sulfite 500g + lime 1800g / t) are added to obtain lead concentrate and tailings as inhibitors using zinc sulfate, sodium sulfite and lime.

[0046] Comparative Example 4-2: The other conditions and operations of this comparative example are the same as those of Example 1, except that no sphalerite and pyrite inhibitors are added in this comparative example, resulting in lead concentrate and tailings without inhibitors.

[0047] The results of Example 4 and the two comparative examples are as follows:

[0048]

[0049] As shown in the table, comparing the experimental indicators under three conditions—with the inhibitor of this invention, the traditional inhibitor, and without the inhibitor—the zinc loss rate in lead concentrate was lowest at 11.56% using the inhibitor of this invention, followed by 18.60% with the traditional inhibitor, and highest at 61.33% without the inhibitor. This indicates that the inhibitor of this invention has the best inhibitory effect on sphalerite during galena flotation. The lead grade in the lead concentrate obtained using the inhibitor of this invention was highest at 32.21%, followed by 30.11% with the traditional inhibitor, and lowest at only 10.73% without the inhibitor, indicating that the inhibitor of this invention has a good inhibitory effect on pyrite. The silver recovery rate in the lead concentrate obtained using the inhibitor of this invention was similar to that without the inhibitor, and both were higher than those obtained using the traditional inhibitor, indicating that the traditional inhibitor has an inhibitory effect on silver, while the inhibitor of this invention has a smaller inhibitory effect on silver-bearing minerals. In summary, the inhibitor of this invention can achieve the inhibition of sphalerite and pyrite during galena flotation under very low dosage conditions, with minimal impact on silver-bearing minerals.

Claims

1. A method for collecting galena and suppressing the flotation separation of sphalerite and pyrite, characterized in that... Follow these steps: (1) The raw ore is crushed, ground and then mixed to obtain the slurry to be floated; (2) Add pH adjuster, sphalerite and pyrite inhibitor and galena collector to the slurry to be floated and carry out a roughing operation to obtain lead concentrate and zinc-containing sulfur tailings. The inhibitor for sphalerite and pyrite is N-hydroxyethylethylenediaminetriacetic acid, which has the following structure: ； The galena collector is one or two of sodium diethyldithiocarbamate, sodium ethyl xanthate, and xylenol dithiophosphate.

2. The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite according to claim 1, characterized in that: Step (1) Grind the ore to -0.074 mm, which accounts for 65% to 85%.

3. The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite according to claim 1, characterized in that: In step (2), the pH adjuster is one of sodium carbonate, sodium hydroxide, or calcium oxide, which adjusts the pH of the slurry to 7.5-9.

5.

4. The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite according to claim 1, characterized in that: The dosage of N-hydroxyethylethylenediaminetriacetic acid, an inhibitor for sphalerite and pyrite, is 100~300 g / t.

5. The method for collecting galena and suppressing the flotation separation of sphalerite and pyrite according to claim 1, characterized in that: The dosage of the galena collector is 30~60g / t.

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