A multi-metal ore dressing process suitable for low-grade associated lead, copper and zinc in iron tailings

Abstract

The invention relates to a beneficiation process for low-grade associated lead, copper and zinc polymetallics in iron ore tailings, comprising the following steps: (1) pre-screening the iron ore tailings slurry, and conveying the underscreen slurry to a beneficiation plant; (2) feeding the underscreen slurry into a grading system of the beneficiation plant, and the underflow enters a first-stage ball mill for ore grinding to obtain a grinding product and a grading overflow; the grinding product is returned to the grading system; a pH adjuster, a collector and a frother are added to the grading overflow, and the frother is fully stirred to produce a copper-lead-zinc mixed concentrate and a final tailing by flotation; (3) the copper-lead-zinc mixed concentrate is diluted with water and fed into a gravity separation device to produce a lead concentrate; the gravity separation tailings are regrinded to obtain a regrinded slurry; (4) the regrinded slurry is subjected to a coarse magnetic separation and a fine magnetic separation of a copper concentrate to produce a copper concentrate, coarse magnetic and fine magnetic tailings; (5) the coarse magnetic and fine magnetic tailings are directly used as a zinc concentrate after being combined; or the zinc concentrate is separated to produce a qualified zinc concentrate. The invention is environmentally friendly, efficient, low in cost and high in quality.

Description

Technical Field

[0001] The invention relates to the field of comprehensive utilization of tailings resources, and in particular to a beneficiation process suitable for low-grade associated lead, copper, and zinc polymetallics in iron tailings. Background Art

[0002] Some iron ore deposits are associated with a variety of valuable elements such as copper, lead, zinc, gold, and silver. These elements often cannot reach industrial grade, but after magnetic separation of iron concentrate, the associated valuable elements can generally be enriched. In addition, tailings reselection does not require mining, crushing, or even grinding operations, which greatly reduces costs and further reduces the economically usable grade.

[0003] However, there are major shortcomings in the re-selection of associated polymetallic ores. That is, since the mineral processing process often first conducts magnetic separation of iron concentrate, the grades of elements such as copper, lead, and zinc in the tailings fluctuate dramatically. In addition, due to the fluctuation of the iron grade of the original ore, the amount of tailings fluctuates further, which in turn makes subsequent flotation operations difficult and affects the quality of the concentrate. In addition, polymetallic sulfide ores often have structural characteristics such as dense symbiosis and complex embedding relationships, which has always been a problem that has plagued the mineral processing industry. In some iron-polymetallic ores, low-grade lead sulfide is often associated. Since its grade is relatively low compared to copper and zinc, the flotation method for selecting lead metal is complicated. If lead is not selected separately, the lead content in copper and zinc concentrates will exceed the standard, which will have an adverse impact on the operation of the beneficiation plant. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an environmentally friendly and efficient multi-metal beneficiation process suitable for beneficiating low-grade associated lead, copper and zinc in iron tailings.

[0005] In order to solve the above problems, the present invention discloses a process for beneficiating low-grade lead, copper and zinc polymetallic minerals from iron tailings, comprising the following steps:

[0006] ⑴ Feed the iron ore tailings slurry into the high-frequency vibrating screen for pre-screening, and discard the coarse particles on the screen as low-grade waste rock, and transport the slurry under the screen to the concentrator;

[0007] (2) The undersize pulp is fed to the classification system of the selection plant, and the underflow enters a ball mill for grinding operation to obtain grinding products and classification overflow respectively; the grinding products are returned to the classification system; the classification overflow is added with a pH adjuster to adjust the pH of the pulp to 9-11, and then a collector and a frother are added and fully stirred as the final selection material, and the flotation method is adopted to produce copper, lead and zinc mixed concentrate and final tailings through roughing, scavenging and concentrating operations;

[0008] (3) Adding water to dilute the copper-lead-zinc mixed concentrate to obtain a slurry with a concentration of 15-25%, and then feeding it into a gravity separation device to separate low-grade associated lead to produce lead concentrate; the gravity separation tailings enter the second-stage regrinding ball mill for regrinding to obtain a regrinded slurry;

[0009] (4) the regrinded slurry enters the high gradient magnetic separator I for coarse magnetic separation of copper concentrate, and produces coarse magnetic copper concentrate and coarse magnetic tailings respectively; the coarse magnetic copper concentrate enters the high gradient magnetic separator II for fine magnetic separation, and produces copper concentrate and fine magnetic tailings respectively;

[0010] (5) The coarse magnetic tailings and the fine magnetic tailings are directly used as zinc concentrate after being combined; or the coarse magnetic tailings and the fine magnetic tailings are combined, water is added to dilute the slurry to obtain a concentration of 20-25%, and then the pH value is adjusted to 12-13 with lime, and then copper sulfate, collector and frother are added, and then the qualified zinc concentrate is produced after zinc roughing and zinc concentrating.

[0011] In the step (1), the mesh size of the high frequency vibrating screen is 1.2-2 mm.

[0012] The grading fineness adopted by the grading system in step (2) is -200 mesh 65%~85%.

[0013] In the step (2), the pH adjusting agent is lime.

[0014] In the step (2), the collector is prepared by mixing butyl xanthate and ethyl thiocyanate in a mass ratio of 2-4:0.5-1.

[0015] In the step (3), the re-grinding degree is -325 mesh 80% to 95%.

[0016] In the step (3), the gravity separation equipment is a spiral chute.

[0017] In step (4), the field strength of the high gradient magnetic separator I is 1.3-1.6T, and the field strength of the high gradient magnetic separator II is 1.2-1.4T.

[0018] In the step (5), the collecting agent is butyl xanthate and the foaming agent is 2# oil.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The present invention can remove coarse-grained low-grade waste rock in advance, and use flotation to separate copper, lead and zinc at the same time, and then use gravity separation to remove low-grade associated lead in advance, so as to avoid the influence of lead element on the quality of copper and zinc concentrates. The lead-removed tailings are separated into copper concentrate by magnetic separation. The whole separation process can greatly reduce or even completely avoid the use of harmful chemicals, thereby improving the quality of concentrate products and reducing the labor intensity of employees.

[0021] 2. The lead removal operation of the gravity separation of the present invention precedes the second-stage regrinding to avoid the loss of copper and zinc in the lead concentrate due to excessive grinding fineness.

[0022] 3. The present invention pre-screens and discards the iron tailings slurry to be selected in advance, so as to avoid the waste of low-grade waste rock on the equipment capacity of the dressing plant, and creatively adopts the comprehensive principle of "flotation pre-enrichment + gravity separation lead removal + magnetic separation copper removal + flotation zinc concentrate" to change the traditional technical solution of using a single flotation method to separate copper, lead and zinc, and avoids the influence of low-grade associated lead on the quality of copper and zinc concentrates while producing lead concentrate. At the same time, the magnetic separation method is used to select copper concentrate, which avoids the problem of concentrate quality fluctuation caused by changes in the grade and properties of the original ore to the greatest extent, can greatly reduce the difficulty of copper, lead and zinc separation, reduce the cost of mineral processing, protect the natural environment, and has good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0024] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0025] The present invention adopts an environmentally friendly public welfare scheme of flotation method to produce copper-lead-zinc mixed concentrate + spiral chute gravity separation to remove lead + high gradient magnetic separation of copper + flotation of zinc concentrate to separate and select the copper-lead-zinc mixed concentrate.

[0026] The invention is applicable to raw ores containing 0.2-0.8% copper, 0.1-0.4% lead and 0.5-2.0% zinc.

[0027] like Figure 1 As shown, a process for beneficiating low-grade associated lead, copper and zinc polymetallic minerals from iron tailings comprises the following steps:

[0028] ⑴ Feed the iron ore tailings slurry into the high-frequency vibrating screen for pre-screening, with a sieve hole size of 1.2~2mm, preferably 1.5mm. The coarse particles on the screen are discarded as low-grade waste rock, and the slurry under the screen is transported to the concentrator. This can reduce the amount of ore entering the concentrator, avoid low-grade waste rock wasting the concentrator equipment capacity and increase operating costs.

[0029] ⑵ The ore pulp under the screen is fed to the classification system of the selection plant, and the classification fineness is -200 mesh 65%~85%. The underflow enters a ball mill for grinding operation, and the grinding product and classification overflow are obtained respectively. The grinding product returns to the classification system.

[0030] Lime is added as a pH adjuster to the overflow of the classification to adjust the pH of the pulp to 9-11, preferably 10-10.5. Then 30-60g / t of collector and 20-50g / t of frother are added and fully stirred as the final selected material. The flotation method is used to produce copper-lead-zinc mixed concentrate and final tailings through roughing, scavenging and concentrating operations.

[0031] Wherein: the collector is prepared by butyl xanthate and ethyl thiocyanate in a mass ratio (g / g) of 2~4:0.5~1, and preferably butyl xanthate:ethyl thiocyanate=3:1.

[0032] The foaming agent is 2# oil.

[0033] ⑶ Add water to dilute the copper-lead-zinc mixed concentrate to obtain a slurry with a concentration of 15-25%, and then feed it into the gravity separation equipment, which is a spiral chute. The low-grade associated lead is separated to produce lead concentrate; the gravity separation tailings enter the second-stage regrinding ball mill for regrinding to obtain the regrinded slurry with a regrinding fineness of -325 mesh 80%-95%, so that the copper and zinc minerals can be fully dissociated.

[0034] (4) The regrinding slurry enters the high gradient magnetic separator I with a field strength of 1.3~1.6T for coarse magnetic separation of copper concentrate, and produces coarse magnetic copper concentrate and coarse magnetic tailings respectively; the coarse magnetic copper concentrate enters the high gradient magnetic separator II with a field strength of 1.2~1.4T for fine magnetic operation, and produces copper concentrate and fine magnetic tailings respectively.

[0035] ⑸ When the zinc grade of the product after the coarse magnetic tailings and the fine magnetic tailings are combined is greater than 42%, the coarse magnetic tailings and the fine magnetic tailings are directly used as zinc concentrate after being combined; or the coarse magnetic tailings and the fine magnetic tailings are combined, water is added to dilute the slurry to obtain a concentration of 20~25%, and then the pH is adjusted to 12~13 with lime, and then 50~100g / t copper sulfate, 20~50g / t collector, and 10~30g / t frother are added, and then qualified zinc concentrate is produced after zinc roughing and zinc concentrating.

[0036] Among them: the collector is butyl xanthate and the foaming agent is 2# oil.

[0037] Example 1 A beneficiation process for low-grade associated lead, copper, and zinc polymetallic minerals in iron tailings, comprising the following steps:

[0038] ⑴ 100kg of iron ore tailings pulp is fed into a high-frequency vibrating screen for pre-screening, and the screen size is 1.5mm. The coarse particles on the screen are discarded as low-grade waste rock, and the 92kg of pulp under the screen is transported to the concentrator. This can reduce the amount of ore entering the concentrator, avoid low-grade waste rock, waste the concentrator equipment capacity and increase operating costs.

[0039] (2) The ore pulp under the screen is fed to the classification system of the selection plant, and the classification fineness is -200 mesh 75%. The underflow enters the first stage ball mill for grinding operation, and 52kg of grinding products and 40kg of classification overflow are obtained respectively. The grinding products are returned to the classification system.

[0040] Lime was added as pH adjuster to the overflow of the classification to adjust the pH of the pulp to 10. Then 60g / t collector and 30g / t frother were added and stirred thoroughly, and 4.46kg of copper-lead-zinc mixed concentrate and 87.68kg of final tailings were produced after 1 roughing, 2 scavenging and 3 concentrating operations.

[0041] ⑶ The copper-lead-zinc mixed concentrate is diluted with water to obtain a slurry with a concentration of 20%, which is then fed into the gravity separation equipment to separate low-grade associated lead, producing 0.25kg of lead concentrate; 4.21kg of gravity separation tailings enter the second-stage regrinding ball mill for regrinding, and the regrinding fineness is -325 mesh 85%, so that the copper and zinc minerals can be fully dissociated.

[0042] (4) The regrinding pulp enters the high gradient magnetic separator I with a field strength of 1.4T for coarse magnetic separation of copper concentrate, producing 1.78kg of coarse magnetic copper concentrate and 2.43kg of coarse magnetic tailings respectively; the coarse magnetic copper concentrate enters the high gradient magnetic separator II with a field strength of 1.3T for fine magnetic operation, producing 1.52kg of copper concentrate and 0.26kg of fine magnetic tailings respectively. The coarse magnetic tailings and fine magnetic tailings are combined for zinc concentrate separation.

[0043] ⑸ The coarse magnetic tailings and the fine magnetic tailings are combined, and water is added to dilute the slurry to obtain a concentration of 21%. The pH value is adjusted to 12 with lime, and then 50g / t copper sulfate, 30g / t collector, and 10g / t frother are added. After one zinc roughing and two zinc concentrations, 1.52kg of qualified zinc concentrate is produced.

[0044] In this embodiment, when the original ore contains 0.43% copper, 0.26% lead and 1.08% zinc, a gravity-selected lead concentrate with a lead grade of 46.21%, 1.92% copper and 2.76% zinc, a magnetic-selected copper concentrate with a copper grade of 22.36%, 1.67% lead and 4.38% zinc, and a flotation zinc concentrate with a zinc grade of 44.83%, 0.77% copper and 3.52% lead can be obtained respectively, and the comprehensive copper, lead and zinc recoveries are 88.53%, 47.24% and 64.81%, respectively.

[0045] Example 2 A process for beneficiating low-grade associated lead, copper and zinc polymetallic minerals from iron tailings, comprising the following steps:

[0046] ⑴ 100kg of iron ore tailings pulp is fed into a high-frequency vibrating screen for pre-screening, and the screen size is 2.0mm. The coarse particles on the screen are discarded as low-grade waste rock, and the 96kg of slurry under the screen is transported to the concentrator. This can reduce the amount of ore entering the concentrator, avoid low-grade waste rock, waste the concentrator equipment capacity and increase operating costs.

[0047] (2) The slurry under the screen is fed to the classification system of the selection plant, and the classification fineness is -200 mesh 65%. The underflow enters the first stage ball mill for grinding operation, and 61kg of grinding products and 35kg of classification overflow are obtained respectively. The grinding products are returned to the classification system.

[0048] Lime was added as pH adjuster to adjust the pH of the pulp to 9.5 in the overflow of the classification. Then 40g / t collector and 20g / t frother were added and stirred thoroughly, and 4.98kg of copper-lead-zinc mixed concentrate and 91.02kg of final tailings were produced after 2 roughing operations, 1 scavenging operation and 2 concentrating operations.

[0049] ⑶ The copper-lead-zinc mixed concentrate is diluted with water to obtain a slurry with a concentration of 25%, which is then fed into the gravity separation equipment to separate low-grade associated lead, producing 0.35kg of lead concentrate; 4.63kg of gravity separation tailings enter the second-stage regrinding ball mill for regrinding, and the regrinding fineness is -325 mesh 90%, so that the copper and zinc minerals can be fully dissociated.

[0050] (4) The regrinding slurry enters the high gradient magnetic separator I with a field strength of 1.6T for coarse magnetic separation of copper concentrate, producing 2.57kg of coarse magnetic copper concentrate and 2.06kg of coarse magnetic tailings; the coarse magnetic copper concentrate enters the high gradient magnetic separator II with a field strength of 1.4T for fine magnetic operation, producing 2.21kg of copper concentrate and 0.36kg of fine magnetic tailings.

[0051] ⑸ The coarse magnetic tailings and the fine magnetic tailings are combined and directly output as zinc concentrate.

[0052] In this embodiment, when the original ore contains 0.56% copper, 0.32% lead and 1.64% zinc, a gravity-selected lead concentrate with a lead grade of 50.33%, 1.56% copper and 3.45% zinc, a magnetic-selected copper concentrate with a copper grade of 21.38%, 0.96% lead and 5.67% zinc, and a flotation zinc concentrate with a zinc grade of 46.21%, 1.05% copper and 2.50% lead can be obtained respectively, and the comprehensive copper, lead and zinc recoveries are 87.68%, 57.55% and 70.63%, respectively.

[0053] Example 3 A process for beneficiating low-grade lead, copper and zinc polymetallic minerals from iron tailings, comprising the following steps:

[0054] ⑴ 100kg of iron ore tailings pulp is fed into a high-frequency vibrating screen for pre-screening, and the screen size is 1.2mm. The coarse particles on the screen are discarded as low-grade waste rock, and the 90kg of pulp under the screen is transported to the concentrator. This can reduce the amount of ore entering the concentrator, avoid low-grade waste rock wasting the concentrator equipment capacity and increase operating costs.

[0055] (2) The slurry under the screen is fed to the classification system of the selection plant, and the classification fineness is -200 mesh 80%. The underflow enters the first stage ball mill for grinding operation, and 58kg of grinding products and 32kg of classification overflow are obtained respectively. The grinding products are returned to the classification system.

[0056] Lime was added as pH adjuster to adjust the pH of the pulp to 10.5 in the overflow of the classification. Then 40g / t collector and 30g / t frother were added and stirred thoroughly, and 4.01kg of copper-lead-zinc mixed concentrate and 85.99kg of final tailings were produced after 1 roughing, 2 scavenging and 2 concentrating operations.

[0057] ⑶ The copper-lead-zinc mixed concentrate is diluted with water to obtain a slurry with a concentration of 15%, which is then fed into the gravity separation equipment to separate low-grade associated lead, producing 0.47kg of lead concentrate; 3.54kg of gravity separation tailings enter the second-stage regrinding ball mill for regrinding, and the regrinding fineness is -325 mesh 80%, so that the copper and zinc minerals can be fully dissociated.

[0058] (4) The regrinding pulp enters the high gradient magnetic separator I with a field strength of 1.5T for coarse magnetic separation of copper concentrate, producing 2.69kg of coarse magnetic copper concentrate and 0.85kg of coarse magnetic tailings respectively; the coarse magnetic copper concentrate enters the high gradient magnetic separator II with a field strength of 1.2T for fine magnetic operation, producing 2.33kg of copper concentrate and 0.36kg of fine magnetic tailings respectively. The coarse magnetic tailings and fine magnetic tailings are combined for zinc concentrate separation.

[0059] ⑸ The coarse magnetic tailings and the fine magnetic tailings are combined, water is added to dilute the slurry to obtain a concentration of 25%, and then the pH is adjusted to 11 with lime. Then, 70g / t copper sulfate, 50g / t collector, and 30g / t frother are added, and after one zinc roughing and one zinc concentration, 0.99kg of qualified zinc concentrate is produced.

[0060] In this embodiment, when the original ore contains 0.67% copper, 0.38% lead and 0.82% zinc, a gravity-selected lead concentrate with a lead grade of 49.76%, 1.14% copper and 3.76% zinc, a magnetic-selected copper concentrate with a copper grade of 23.42%, 1.08% lead and 3.85% zinc, and a flotation zinc concentrate with a zinc grade of 42.66%, 1.27% copper and 4.35% lead can be obtained respectively, and the comprehensive copper, lead and zinc recoveries are 89.68%, 68.43% and 57.57%, respectively.

[0061] Example 4 A process for beneficiating low-grade lead, copper and zinc polymetallic minerals from iron tailings, comprising the following steps:

[0062] ⑴ 100kg of iron ore tailings pulp is fed into a high-frequency vibrating screen for pre-screening, and the screen size is 1.8mm. The coarse particles on the screen are discarded as low-grade waste rock, and the 95kg of pulp under the screen is transported to the concentrator. This can reduce the amount of ore entering the concentrator, avoid low-grade waste rock wasting the concentrator equipment capacity and increase operating costs.

[0063] (2) The slurry under the screen is fed to the classification system of the selection plant, and the classification fineness is -200 mesh 85%. The underflow enters the first stage ball mill for grinding operation, and 61kg of grinding products and 34kg of classification overflow are obtained respectively. The grinding products are returned to the classification system.

[0064] Lime was added as pH adjuster to the overflow of the classification to adjust the pH of the pulp to 11. Then 50g / t collector and 20g / t frother were added and stirred thoroughly, and 2.06kg of copper-lead-zinc mixed concentrate and 92.94kg of final tailings were produced after 1 roughing, 1 scavenging and 2 concentrating operations.

[0065] ⑶ The copper-lead-zinc mixed concentrate is diluted with water to obtain a slurry with a concentration of 23%, which is then fed into the gravity separation equipment to separate low-grade associated lead, producing 0.29kg of lead concentrate; 1.77kg of gravity separation tailings enter the second-stage regrinding ball mill for regrinding, and the regrinding fineness is -325 mesh 95%, so that the copper and zinc minerals can be fully dissociated.

[0066] (4) The regrinding pulp enters the high gradient magnetic separator I with a field strength of 1.4T for coarse magnetic separation of copper concentrate, producing 0.97kg of coarse magnetic copper concentrate and 0.80kg of coarse magnetic tailings respectively; the coarse magnetic copper concentrate enters the high gradient magnetic separator II with a field strength of 1.2T for fine magnetic operation, producing 0.83kg of copper concentrate and 0.14kg of fine magnetic tailings respectively. The coarse magnetic tailings and fine magnetic tailings are combined for zinc concentrate separation.

[0067] (5) The coarse magnetic tailings and the fine magnetic tailings are combined, water is added to dilute the slurry to obtain a 24% concentration, and then the pH is adjusted to 12.5 with lime. Then, 50g / t copper sulfate, 40g / t collector, and 25g / t frother are added, and after one zinc roughing and three zinc concentrations, 0.81kg of qualified zinc concentrate is produced.

[0068] In this embodiment, when the original ore contains 0.23% copper, 0.20% lead and 0.55% zinc, a gravity-selected lead concentrate with a lead grade of 45.71%, 0.87% copper and 2.98% zinc, a magnetic-selected copper concentrate with a copper grade of 20.47%, 1.84% lead and 4.28% zinc, and a flotation zinc concentrate with a zinc grade of 41.43%, 1.45% copper and 3.62% lead can be obtained respectively, and the comprehensive copper, lead and zinc recoveries are 79.41%, 69.36% and 64.62%, respectively.

Claims

1. A process for beneficiating low-grade lead, copper and zinc polymetallic minerals from iron tailings, comprising the following steps: (1) Feed the iron ore tailings slurry into the high-frequency vibrating screen for pre-screening, discard the coarse particles on the screen as low-grade waste rock, and transport the slurry under the screen to the concentrator; the mesh size of the high-frequency vibrating screen is 1.2~2mm; (2) The undersize pulp is fed to the classification system of the selection plant, and the bottom flow enters a ball mill for grinding operation to obtain grinding products and classification overflow respectively; the grinding products are returned to the classification system; the classification overflow is added with a pH adjuster to adjust the pH of the pulp to 9-11, and then a collector and a frother are added and fully stirred as the final selection material, and the flotation method is adopted to produce copper, lead and zinc mixed concentrate and final tailings through roughing, scavenging and concentrating operations; the classification fineness adopted by the classification system is -200 mesh 65%-85%; the pH adjuster is lime; the collector is prepared by butyl xanthate and ethyl thiocyanate in a mass ratio of 2-4:0.5-1; ⑶ The copper-lead-zinc mixed concentrate is diluted with water to obtain a slurry with a concentration of 15-25%, and then fed into a gravity separation device to separate low-grade associated lead to produce lead concentrate; the gravity separation tailings enter the second-stage regrinding ball mill for regrinding to obtain regrinded slurry; the regrinding fineness is -325 mesh 80%-95%; the gravity separation equipment is a spiral chute; (4) The regrinded slurry enters the high gradient magnetic separator I for coarse magnetic separation of copper concentrate, and produces coarse magnetic copper concentrate and coarse magnetic tailings respectively; the coarse magnetic copper concentrate enters the high gradient magnetic separator II for fine magnetic operation, and produces copper concentrate and fine magnetic tailings respectively; the field strength of the high gradient magnetic separator I is 1.3~1.6T, and the field strength of the high gradient magnetic separator II is 1.2~1.4T; (5) The coarse magnetic tailings and the fine magnetic tailings are combined, water is added to dilute the slurry to obtain a concentration of 20-25%, and then the pH is adjusted to 12-13 with lime, and then copper sulfate, a collector and a frother are added, and then zinc roughing and zinc concentrating are carried out to produce qualified zinc concentrate; the collector is butyl xanthate and the frother is 2# oil.

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