Flotation inhibitor and lime inhibition-free flotation method for high-sulfur lead-zinc ore

Abstract

The invention discloses a flotation inhibitor and a lime inhibition-free flotation method for high-sulfur lead zinc ore. The flotation inhibitor is zinc calcium pyrophosphate. The flotation method comprises the following steps: (1) crushing, screening and grinding the high-sulfur lead-zinc ore to obtain ore powder; (2) adding the ore powder and water into a flotation tank, stirring, and adding an inhibitor, a collecting agent and a foaming agent for flotation; the inhibitor is zinc calcium pyrophosphate. The flotation inhibitor has the effect of selectively inhibiting sphalerite and pyrite in the high-sulfur lead-zinc ore, the grade and the recovery rate of lead concentrate are improved, lime does not need to be added in the flotation process to inhibit the high-sulfur lead-zinc ore, and the flotation inhibitor has both environmental protection and economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of flotation and mineral processing technology, and particularly relates to a depressant and a flotation method for high-sulfur lead-zinc ore. Background Technology

[0002] Lead-zinc ore is an important strategic mineral resource with a wide range of applications, involving multiple key industries such as metallurgy, machinery, chemicals, electrical engineering, military, and light industry. With the rapid advancement of industrialization, the market demand for lead-zinc resources continues to grow, highlighting its strategic importance.

[0003] my country's lead-zinc mineral resources are mainly distributed in Yunnan, Inner Mongolia, Gansu, and Qinghai provinces, with reserves ranking among the world's largest. However, the resource endowment is complex, characterized by wide but uneven distribution, a scarcity of rich ores and a prevalence of poor ores, complex occurrence types, and diverse associated elements. High-sulfur lead-zinc ores, in particular, often contain large amounts of sphalerite and pyrite sulfides due to their high sulfur content, leading to significant difficulties in beneficiation and low recovery rates. Currently, my country still has room for improvement in the beneficiation and smelting technology of high-sulfur lead-zinc ores compared to some developed countries, and a large amount of resources remain underutilized. With the gradual depletion of easily processed lead-zinc mineral resources, high-sulfur lead-zinc ores have become a key focus of exploration and beneficiation efforts.

[0004] Traditional flotation processes for high-sulfur lead-zinc ores typically use zinc sulfate and lime as depressants. However, this method has significant drawbacks: on the one hand, it has low recovery rates and poor depressant selectivity, which can easily lead to excessive suppression of lead minerals and associated precious metals such as gold and silver; on the other hand, the highly alkaline slurry environment can affect the performance of frothers, resulting in lower concentrate grades and causing problems such as pipe scaling, high cost of recycled water treatment, and environmental pollution.

[0005] In order to break through the bottlenecks of traditional processes, it is urgent to develop a new type of environmentally friendly and efficient inhibitor and supporting flotation process. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a flotation inhibitor for high-sulfur lead-zinc ore and a flotation method for high-sulfur lead-zinc ore without lime inhibition. The flotation inhibitor has the effect of selectively inhibiting sphalerite and pyrite in high-sulfur lead-zinc ore, thereby improving the grade and recovery rate of lead concentrate. The flotation process does not require the addition of lime to inhibit high-sulfur lead-zinc ore, and has both environmental protection and economic benefits.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A flotation depressant for high-sulfur lead-zinc ore, wherein the flotation depressant is zinc calcium pyrophosphate.

[0008] Preferably, among the above-mentioned flotation inhibitors, the zinc calcium pyrophosphate is obtained by reacting pyrophosphate, zinc ions and calcium ions, and is in a colloidal state.

[0009] Preferably, among the above-mentioned flotation inhibitors, the chemical formula of the zinc calcium pyrophosphate is CaZnP2O7.

[0010] In the above-mentioned flotation inhibitors, preferably, the preparation method of zinc calcium pyrophosphate includes the following steps: stirring sodium pyrophosphate, zinc sulfate and calcium chloride under reaction conditions of pH 6.5-7.5, temperature 40-60℃ and stirring speed 200-400rpm for 2-4h to obtain a colloidal system dispersed in nanoparticles.

[0011] In the above flotation inhibitors, preferably, the molar ratio of sodium pyrophosphate, zinc sulfate and calcium chloride is (1-2):(1-2):(1-2).

[0012] In the above-mentioned flotation inhibitors, preferably, the nanoparticles have a particle size of 30-50 nm.

[0013] In this invention, the preparation of zinc calcium pyrophosphate colloid involves a complexation-metathesis reaction under aqueous solution conditions. This is achieved by reacting acidic sodium pyrophosphate (Na₂H₂P₂O₇) with zinc sulfate (ZnSO₄) and calcium chloride (CaCl₂) in a molar ratio of (1-2):(1-2):(1-2) at a specific pH (6.5-7.5) and temperature (40-60°C) for a specific time (2-4 hours) and a specific rotation speed (200-400 rpm). The reaction forms a colloidal system dispersed as nanoparticles (30-50 nm). The process involves the coordination of pyrophosphate ions with metal ions and the dynamic equilibrium regulation of this reaction. This invention can produce a stable zinc calcium pyrophosphate colloid through reactions under specific conditions.

[0014] Zinc-calcium pyrophosphate colloids are strongly hydrophilic, coordinating and adsorbing with sphalerite and pyrite, thus retaining them in water and exerting an inhibitory effect. The Zn released from this colloid... 2+ With Ca 2+ It can selectively coordinate and adsorb sulfur ions on the surface of sphalerite and pyrite, making their surfaces hydrophilic, thereby effectively inhibiting the flotation of sphalerite and pyrite.

[0015] As a general technical concept, the present invention also provides a flotation method for high-sulfur lead-zinc ore without lime inhibition, comprising the following steps: (1) The high-sulfur lead-zinc ore is crushed, screened and ground to obtain ore powder; (2) Add the ore powder and water to the flotation cell, stir, and then add inhibitor, collector and frother for flotation; the inhibitor is the above-mentioned zinc calcium pyrophosphate.

[0016] In the above flotation method, preferably, the ore powder has a particle size of -200 mesh and a mass percentage of 60%-75%.

[0017] In the above flotation method, preferably, the amount of zinc calcium pyrophosphate added is 100-500 g / t of raw ore.

[0018] In the above flotation methods, preferably, no lime is added during the flotation process.

[0019] In the above flotation method, preferably, the collector is a mixture of 25# black powder, butyl xanthate and ethyl thiocyanate, and the frother is pine oil.

[0020] The zinc calcium pyrophosphate of this invention is prepared by reacting acidic sodium pyrophosphate, zinc sulfate, and calcium chloride in a molar ratio of (1-2):(1-2):(1-2) under specific conditions, and is in a colloidal state. The chemical reaction formula for preparing sodium pyrophosphate colloid is as follows: Na2H2P2O7+ZnSO4+CaCl2→CaZnP2O7.

[0021] The dissociation and interfacial property changes of the zinc calcium pyrophosphate colloid in the slurry of the present invention are as follows: the zinc calcium pyrophosphate colloid undergoes partial dissociation / ionization, releasing positively charged Zn. 2+ Ca 2+ Ions and negatively charged pyrophosphate (P2O7) 4- ) or its complexes. At the same time, the colloid itself contains a large number of hydrophilic groups, which gives it a strong hydration layer and hydrophilic interface properties. It can form a stable hydration layer at the mineral-solution interface and interact with the surface of sulfide minerals.

[0022] The selective inhibition mechanism of zinc calcium pyrophosphate colloid on sphalerite and pyrite in this invention is as follows: 1. Surface adsorption and hydrophilic layer formation: One is the Zn released by zinc calcium pyrophosphate colloid. 2+ Ca 2+ Sulfide ions (S₂) on the surface of zinc sphalerite (ZnS) and pyrite (FeS₂) can interact through coordination bonds or electrostatic interactions. 2- First, polysulfides / surface hydroxylated sulfur species combine to form a metal-sulfur coordination layer on the mineral surface; second, the zinc calcium pyrophosphate colloid itself and its dissociation products form a hydrophilic coating layer on the surface of sphalerite (ZnS) and pyrite (FeS2), which enhances the surface hydration and prevents the collector from adsorbing at the interface, thereby inhibiting the mineral flotation.

[0023] 2. Regulation of surface charge and interfacial properties: One aspect is the regulation of charged ions (ZnS, FeS2, and ZnS) adsorbed on the surfaces of zinc sphalerite (ZnS) and pyrite (FeS2). 2+ Ca 2+ ) or pyrophosphate (P2O7)4- The zeta potential of mineral surfaces can be altered by the formation of hydrophilic layers and their complexes. This can change the surface charge of sphalerite and pyrite from strongly negative to positive or weakly negative, or increase the thickness of the double electric layer of sphalerite and pyrite, thereby enhancing electrostatic repulsion and reducing the probability of particle and bubble adhesion. Secondly, the formation of the hydrophilic layer significantly reduces the contact angle, weakens hydrophobic interactions, and further inhibits flotation.

[0024] 3. Selective adsorption: Firstly, Zn 2+ Ca has a stronger affinity for zinc sphalerite (ZnS) due to the ionic compatibility of the same metal ions. 2+ It readily forms stable bonds with the surface of pyrite (FeS2); secondly, in contrast, the surface of galena (PbS) readily bonds with Zn. 2+ Ca 2+ The interaction is weak, and the zinc calcium pyrophosphate colloid has low adsorption selectivity for it, thus preferentially inhibiting sphalerite and pyrite, achieving selective adsorption and ensuring the floatability of galena.

[0025] The flotation method of this invention is simple, low-cost, and consumes low amounts of reagents (the traditional lime method is weaker than the zinc calcium pyrophosphate colloid in adjusting electrical properties). It does not require the addition of lime to inhibit the surface of complex high-sulfur lead-zinc ores, has a fast mineralization rate, high inhibition efficiency, and is environmentally friendly. It can significantly remove sphalerite and pyrite from complex high-sulfur lead-zinc ores and improve the grade and recovery rate of lead concentrate.

[0026] Compared with the prior art, the advantages of the present invention are as follows: 1. The present invention provides a flotation depressant for high-sulfur lead-zinc ores. This depressant reduces or replaces the use of lime, mitigates the adverse effects of high pulp alkalinity on flotation, and selectively inhibits iron sulfide and zinc sulfide, avoiding unnecessary loss of valuable minerals. Specifically, zinc calcium pyrophosphate is used instead of zinc sulfate + lime as a depressant for flotation of high-sulfur lead-zinc ores, effectively reducing lime usage while significantly enhancing the inhibition of sphalerite and pyrite, improving the grade and recovery rate of lead ore in lead concentrate, and reducing the grade and recovery rate of zinc ore in lead concentrate.

[0027] 2. The flotation depressant and flotation method of the present invention for high-sulfur lead-zinc ore have low reagent consumption (conventional lime depressant consumption is 2-5 kg / t, while the depressant of the present invention has strong inhibitory effect on sphalerite and pyrite in high-sulfur lead-zinc ore, so the depressant consumption of the present invention is 0.1-0.5 kg / t, and the total flotation reagent consumption is reduced by 10-20 times). The process is simple, takes into account environmental friendliness and economic feasibility, and can improve the comprehensive resource recovery rate. It has important practical significance and application value for achieving efficient recovery of high-sulfur lead-zinc ore and promoting sustainable resource utilization. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The present invention relates to zinc calcium pyrophosphate and S. 2- and S - Coordination diagram.

[0030] Figure 2 This is a flotation process flow chart for Examples 1-5. Detailed Implementation

[0031] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0032] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0033] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0034] Example 1: In this embodiment, the flotation depressant for high-sulfur lead-zinc ore is a prepared calcium zinc pyrophosphate colloid with the chemical formula CaZnP2O7. It is produced by reacting sodium pyrophosphate, zinc sulfate, and calcium chloride under specific conditions and exists in a colloidal state. Its coordination diagram with the high-sulfur lead-zinc ore is shown below. Figure 1 As shown.

[0035] The specific preparation method of zinc calcium pyrophosphate colloid includes the following steps: acidic sodium pyrophosphate (Na2H2P2O7) and zinc sulfate (ZnSO4) and calcium chloride (CaCl2) in a molar ratio of 1:1:1 undergo a complexation-metathesis reaction under heating and stirring at a specific pH (6.9) and temperature (55℃) for a specific time (3.5 hours) and a specific rotation speed (340 rpm) to form a colloidal system dispersed in nanoparticles (30-50 nm). The process involves the coordination of pyrophosphate ions with metal ions and the dynamic equilibrium regulation.

[0036] The flotation method for high-sulfur lead-zinc ore without lime inhibition in this embodiment includes the following steps: The sample used in the experiment was from a high-sulfur lead-zinc ore deposit in Australia. Its main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 2%, a zinc content of approximately 10%, and a sulfur content of approximately 30%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 75%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one rougher, two scavengers, and two cleaners to obtain lead concentrate. The experimental procedure is as follows: Figure 2 As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate (added as a colloid, the same in other examples) suppression flotation test: Roughing: Add 400 g / t of zinc calcium pyrophosphate, stir for 2 min, add 36 g / t of collector 1#, stir for 1 min, add 5 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 100 g / t of zinc calcium pyrophosphate, stir for 2 min, add 16 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 8 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 200 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Zinc sulfate + lime flotation inhibition test: Roughing: Add 4000 g / t lime, stir for 1 min; add 500 g / t zinc sulfate, stir for 1 min; add 36 g / t collector #1, stir for 1 min; add 5 g / t frother oil #2, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 16 g / t collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 8 g / t collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 300 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 100 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 1 below.

[0037] In this embodiment, collector 1# is a mixture of 25# black powder, butyl xanthate, and ethyl thiocyanate. Foaming agent 2# is pine oil.

[0038] Example 2: The flotation depressant for high-sulfur lead-zinc ore in this embodiment is a prepared zinc-calcium pyrophosphate colloid with the chemical formula CaZnP2O7. It is produced by reacting sodium pyrophosphate, zinc sulfate, and calcium chloride under specific conditions and exists in a colloidal state. The collector 1# and frother 2# for high-sulfur lead-zinc ore in this embodiment are the same as in Example 1.

[0039] The specific preparation method of zinc calcium pyrophosphate colloid includes the following steps: acidic sodium pyrophosphate (Na2H2P2O7) and zinc sulfate (ZnSO4) and calcium chloride (CaCl2) in a molar ratio of 1:2:1.5 undergo a complexation-metathesis reaction under heating and stirring at a specific pH (7.2) and temperature (60℃) for a specific time (3 hours) and a specific rotation speed (280 rpm) to form a colloidal system dispersed in nanoparticles (30-50 nm). The process involves the coordination of pyrophosphate ions with metal ions and the dynamic equilibrium regulation.

[0040] The flotation method for high-sulfur lead-zinc ore without lime inhibition in this embodiment includes the following steps: The sample used in the experiment was a high-sulfur lead-zinc ore from Xinjiang, whose main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 2.5%, a zinc content of approximately 5.3%, and a sulfur content of approximately 21.2%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 65%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one rougher, two scavengers, and two cleaners to obtain lead concentrate. The experimental procedure is as follows: Figure 2 As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate flotation inhibition test: Roughing: Add 500 g / t of zinc calcium pyrophosphate, stir for 2 min, add 40 g / t of collector 1#, stir for 1 min, add 8 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 200 g / t of zinc calcium pyrophosphate, stir for 2 min, add 20 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 10 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 300 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Zinc sulfate + lime flotation inhibition test: Roughing: Add 4500 g / t lime, stir for 1 min; add 600 g / t zinc sulfate, stir for 1 min; add 40 g / t collector #1, stir for 1 min; add 16 g / t frother oil #2, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 10 g / t collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 10 g / t collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 400 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 200 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 2 below.

[0041] Example 3: The flotation depressant used in this embodiment for high-sulfur lead-zinc ore is the same as in Example 1, and the collector 1# and frother 2# used are also the same as in Example 1.

[0042] The flotation method for high-sulfur lead-zinc ore without lime inhibition in this embodiment includes the following steps: The sample used in the experiment was from a high-sulfur lead-zinc ore deposit in Mongolia. Its main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 1.8%, a zinc content of approximately 6.2%, and a sulfur content of approximately 18.5%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 70%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one rougher, two scavengers, and two cleaners to obtain lead concentrate. The experimental procedure is as follows: Figure 2 As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate flotation inhibition test: Roughing: Add 500 g / t of zinc calcium pyrophosphate, stir for 2 min, add 30 g / t of collector 1#, stir for 1 min, add 8 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 300 g / t of zinc calcium pyrophosphate, stir for 2 min, add 16 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 8 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 300 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Zinc sulfate + lime flotation inhibition test: Roughing: Add 5500 g / t lime, stir for 1 min; add 800 g / t zinc sulfate, stir for 1 min; add 30 g / t collector #1, stir for 1 min; add 16 g / t frother oil #2, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 8 g / t collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 8 g / t collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 400 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 200 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 3 below.

[0043] Example 4: The flotation depressant used in this embodiment for high-sulfur lead-zinc ore is the same as in Example 1, and the collector 1# and frother 2# used are also the same as in Example 1.

[0044] The flotation method for high-sulfur lead-zinc ore without lime inhibition in this embodiment includes the following steps: The sample used in the experiment was from a high-sulfur lead-zinc ore deposit in Inner Mongolia. Its main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 0.9%, a zinc content of approximately 3.8%, and a sulfur content of approximately 16%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 70%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one roughing step, two scavenging steps, and two cleaning steps to obtain lead concentrate. The experimental procedure is as follows: Figure 2As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate flotation inhibition test: Roughing: Add 300 g / t of zinc calcium pyrophosphate, stir for 2 min, add 30 g / t of collector 1#, stir for 1 min, add 5 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 100 g / t of zinc calcium pyrophosphate, stir for 2 min, add 12 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 6 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 150 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Zinc sulfate + lime flotation inhibition test: Roughing: Add 3500 g / t lime, stir for 1 min; add 400 g / t zinc sulfate, stir for 1 min; add 30 g / t collector #1, stir for 1 min; add 10 g / t frother oil #2, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 6 g / t collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 6 g / t collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 200 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 100 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 4 below.

[0045] Example 5: The flotation depressant used in this embodiment for high-sulfur lead-zinc ore is the same as in Example 1, and the collector 1# and frother 2# used are also the same as in Example 1.

[0046] The flotation method for high-sulfur lead-zinc ore without lime inhibition in this embodiment includes the following steps: The sample used in the experiment was from a high-sulfur lead-zinc ore deposit in Guangxi. Its main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 1.3%, a zinc content of approximately 3.5%, and a sulfur content of approximately 25%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 60%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one rougher, two scavengers, and two cleaners to obtain lead concentrate. The experimental procedure is as follows: Figure 2As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate flotation inhibition test: Roughing: Add 250 g / t of zinc calcium pyrophosphate, stir for 2 min, add 24 g / t of collector 1#, stir for 1 min, add 5 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 100 g / t of zinc calcium pyrophosphate, stir for 2 min, add 12 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 4 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 100 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Zinc sulfate + lime flotation inhibition test: Roughing: Add 3000 g / t lime, stir for 1 min; add 300 g / t zinc sulfate, stir for 1 min; add 24 g / t collector #1, stir for 1 min; add 5 g / t frother oil #2, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 12 g / t collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 4 g / t collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 200 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 100 g / t zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 5 below.

[0047] Comparative Example 1: The flotation inhibitor for high-sulfur lead-zinc ore in this comparative example was prepared by directly adding a mixture of calcium oxide, zinc sulfate, and sodium pyrophosphate powder in a molar ratio of 1:1:1, and its inhibitory effect was compared with that of the zinc-calcium pyrophosphate colloid prepared under specific conditions in Example 1. The collector 1# and frother 2# used were the same as in Example 1.

[0048] The comparative example of a flotation method for high-sulfur lead-zinc ore without lime inhibition includes the following steps: The sample used in the experiment was from a high-sulfur lead-zinc ore deposit in Australia. Its main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 2%, a zinc content of approximately 10%, and a sulfur content of approximately 30%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 75%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one rougher, two scavengers, and two cleaners to obtain lead concentrate. The experimental procedure is as follows: Figure 2As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate flotation inhibition test: Roughing: Add 400 g / t of zinc calcium pyrophosphate, stir for 2 min, add 36 g / t of collector 1#, stir for 1 min, add 5 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 100 g / t of zinc calcium pyrophosphate, stir for 2 min, add 16 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 8 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 200 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Calcium oxide + zinc sulfate + sodium pyrophosphate flotation inhibition test: Roughing: Add 400 g / t of calcium oxide, stir for 1 min; add 400 g / t of zinc sulfate, stir for 1 min; add 400 g / t of sodium pyrophosphate, stir for 1 min; add 36 g / t of collector #1, stir for 1 min; add 5 g / t of frother #2 oil, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 16 g / t of collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 8 g / t of collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 300 g / t of zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 100 g / t of zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 6 below.

[0049] Comparative Example 2: The flotation inhibitor for high-sulfur lead-zinc ore in this comparative example was prepared by directly adding a mixture of calcium chloride, zinc sulfate, and sodium pyrophosphate powder in a molar ratio of 1:2:1.5, and compared with the inhibition effect of the zinc-calcium pyrophosphate colloid prepared under specific conditions in Example 2. The collector 1# and frother 2# used were also the same as in Example 2.

[0050] The comparative example of a flotation method for high-sulfur lead-zinc ore without lime inhibition includes the following steps: The sample used in the experiment was a high-sulfur lead-zinc ore from Xinjiang, whose main components were lead, zinc, sphalerite, and pyrite, with a lead content of approximately 2.5%, a zinc content of approximately 5.3%, and a sulfur content of approximately 21.2%. The ore sample was crushed and ground to a pulp sample with a -200 mesh content of approximately 65%. Flotation was carried out in a mechanically stirred flotation machine. The operating procedure was designed as follows: two sets of experiments were conducted, with a closed-loop circulation process of one rougher, two scavengers, and two cleaners to obtain lead concentrate. The experimental procedure is as follows: Figure 2As shown, the experimental parameters are as described in 1 and 2. 1. Zinc calcium pyrophosphate flotation inhibition test: Roughing: Add 500 g / t of zinc calcium pyrophosphate, stir for 2 min, add 40 g / t of collector 1#, stir for 1 min, add 8 g / t of frother 2# oil, stir for 1 min, and skim the bubbles for 3 min; Scavenging 1: Add 200 g / t of zinc calcium pyrophosphate, stir for 2 min, add 20 g / t of collector 1#, stir for 1 min, and skim the bubbles for 2 min; Scavenging 2: Add 10 g / t of collector 1#, stir for 1 min, and skim the bubbles for 1 min; Cleaning 1: Add 300 g / t of zinc calcium pyrophosphate, stir for 1 min, and skim the bubbles for 3 min; Cleaning 2: Stir for 1 min and skim the bubbles for 2 min to obtain lead concentrate. 2. Calcium chloride + zinc sulfate + sodium pyrophosphate flotation inhibition test: Roughing: Add 500 g / t of calcium chloride, stir for 1 min; add 1000 g / t of zinc sulfate, stir for 1 min; add 750 g / t of sodium pyrophosphate, stir for 1 min; add 40 g / t of collector #1, stir for 1 min; add 16 g / t of frother #2 oil, stir for 1 min, and skim off the bubbles for 3 min; Scavenging 1: Add 10 g / t of collector #1, stir for 1 min, and skim off the bubbles for 2 min; Scavenging 2: Add 10 g / t of collector #1, stir for 1 min, and skim off the bubbles for 1 min; Cleaning 1: Add 400 g / t of zinc sulfate, stir for 1 min, and skim off the bubbles for 3 min; Cleaning 2: Add 200 g / t of zinc sulfate, stir for 1 min, and skim off the bubbles for 2 min to obtain lead concentrate. The test results are shown in Table 7 below.

[0051] Table 1: Test Results of Example 1

[0052] Table 2: Test Results of Example 2

[0053] Table 3: Test Results of Example 3

[0054] Table 4: Test Results of Example 4

[0055] Table 5: Test Results of Example 5

[0056] Table 6: Experimental Results of Comparative Example 1

[0057] Table 7: Experimental Results of Comparative Example 2

[0058] In Examples 1-5, Test Group 1 is the flotation process of the present invention. The grade and recovery rate of lead minerals in lead concentrate are much higher than those in Test Group 2, which is a conventional flotation process. The grade and recovery rate of zinc minerals in lead concentrate are lower than those in Test Group 2, which is a conventional flotation process. Furthermore, the depressant used in the flotation process of the present invention is significantly smaller.

[0059] In Comparative Examples 1-2, Experimental Group 1, which uses zinc calcium pyrophosphate colloid prepared under specific conditions as an inhibitor in the flotation process of this invention, showed significantly higher grades and recoveries of lead minerals in the lead concentrate compared to Experimental Group 2, which uses calcium oxide or calcium oxide, zinc sulfate, and sodium pyrophosphate powders directly mixed in a molar ratio as inhibitors. The grades and recoveries of zinc minerals in the lead concentrate were lower than those in Experimental Group 2, which uses calcium oxide or calcium chloride, zinc sulfate, and sodium pyrophosphate powders directly mixed in a molar ratio as inhibitors. Furthermore, the total amount of inhibitor used in the flotation process of this invention is significantly smaller.

Claims

1. A flotation depressant for high-sulfur lead-zinc ores, characterized in that, The flotation depressant is calcium zinc pyrophosphate.

2. The floatation depressant according to claim 1, characterized in that, The calcium zinc pyrophosphate is obtained by the reaction of pyrophosphate, zinc ions and calcium ions, and is in a colloidal state.

3. The floatation inhibitor according to claim 2, characterized in that, The chemical formula of the calcium zinc pyrophosphate is CaZnP2O7.

4. The floatation depressant according to claim 2, characterized in that, The preparation method of the calcium zinc pyrophosphate comprises the following steps: stirring sodium pyrophosphate, zinc sulfate and calcium chloride under the reaction conditions that the pH value is 6.5-7.5, the temperature is 40-60℃, and the stirring speed is 200-400 rpm for 2-4 h, and obtaining a colloidal system dispersed with nanoparticles.

5. The floatation depressant according to claim 4, characterized in that, The molar ratio of the sodium pyrophosphate, the zinc sulfate and the calcium chloride is (1-2):(1-2):(1-2).

6. The floatation depressant according to claim 4, characterized in that, The particle size of the nanoparticles is 30-50 nm.

7. A method of lime-free depression flotation of high-sulfur lead-zinc ore, characterized by, The method comprises the following steps: (1) obtaining ore powder by crushing, screening and grinding high-sulfur lead-zinc ore; (2) adding the ore powder and water into a flotation tank, stirring, and then adding a depressant, a collector and a frother for flotation; the depressant is the calcium zinc pyrophosphate according to any one of claims 1-6.

8. The flotation method according to claim 7, characterized in that, The particle size of the ore powder is 60%-75% of the mass percentage of-200 mesh.

9. The flotation method according to claim 7, characterized in that, The adding amount of the calcium zinc pyrophosphate is 100-500 g / t of raw ore.

10. The flotation method according to claim 7, characterized in that, No lime is added in the flotation process.

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