Process for recovering phosphorus, copper, precious metals from iron tailings and dry disposal of tailings

Abstract

A process for recovering phosphorus, copper, precious metals from iron ore tailings and dry tailings discharge, comprising: 1) the iron ore tailings are pumped to a cyclone, the underflow of the cyclone is fed to a ball mill for grinding, and the overflow is fed to flotation; 2) the flotation concentrate is fed to a Nelson concentrator for gravity separation, the Nelson concentrator concentrate contains gold, silver, platinum and palladium precious metals, and the tailings are copper concentrate; 3) the flotation tailings are fed to a vertical ring magnetic separator for magnetic separation, the magnetic separation concentrate is returned to the iron ore process for iron recovery, the vertical ring magnetic separation tailings are again subjected to flotation to obtain a phosphorus concentrate, the flotation tailings are fed to a high-efficiency thickener for thickening, and the thickened tailings are fed to a filter for filtration, and finally dry tailings discharge is achieved. The present application realizes the recovery of low-grade copper, phosphorus and precious metals in iron ore tailings, and at the same time realizes the dry discharge of tailings, i.e. no tailings pond is needed in the production process, and the safety hazards brought by the conventional tailings pond of the concentrator are eliminated.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and in particular relates to a process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal. Background Technology

[0002] With the rapid development of my country's steel industry, the development and utilization of iron ore mines has accelerated, resulting in a significant increase in the discharge of iron tailings and a large stockpile of tailings. Although the iron content in these tailings is relatively low, their reprocessing value is enormous.

[0003] Iron tailings are waste residues formed after iron ore is crushed, ground, and beneficiated. They are mainly composed of silicate minerals such as quartz, calcite, and amphibole. Two major characteristics of my country's iron ore resources are the abundance of low-grade ore and the coexistence of multiple components, resulting in large quantities of tailings and a significant amount of associated valuable components. Statistics show that approximately 3 tons of tailings are generated for every 1 ton of iron concentrate produced. The accumulation of large amounts of iron tailings not only occupies land and causes ecological damage, but also results in the ineffective utilization of valuable components, leading to resource waste to a certain extent. Therefore, finding suitable comprehensive utilization methods for iron tailings is urgently needed.

[0004] Currently, a relatively high proportion of iron tailings are used directly as building sand and gravel aggregates. This type of iron tailings resource utilization technology is simple and easy to implement, but compared with other comprehensive utilization methods, this method is difficult to significantly increase the added value of products, has a small market radius, and the economic advantages generated by the comprehensive utilization of iron tailings are not significant. Therefore, it is necessary to find ways to utilize iron tailings at a high value and achieve high-value utilization.

[0005] my country's iron tailings are diverse and complex in nature. Their composition and content vary depending on the origin and beneficiation process, but their chemical composition is generally similar. Furthermore, some minerals are associated minerals of iron. Extracting these associated minerals is of great significance for improving the comprehensive utilization rate of resources and realizing the secondary utilization of resources.

[0006] Iron tailings often contain associated minerals such as phosphorus, copper, and some precious metals. If only iron is processed during the beneficiation process, the remaining valuable minerals are discharged with the tailings, resulting in significant waste. Separating and fully utilizing the phosphorus, copper, and precious metals from iron tailings could yield substantial economic benefits. However, calcite in iron tailings significantly impacts the grade of phosphate concentrate, making it challenging to separate high-grade phosphate concentrate. Furthermore, there are currently no publicly available reports on the separation of copper and precious metals from iron tailings.

[0007] Furthermore, conventional technologies require the construction of tailings ponds for tailings discharge, which also wastes water resources. Summary of the Invention

[0008] The purpose of this invention is to provide a process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal. This process recovers low-grade copper, phosphorus, and precious metals from iron ore tailings and simultaneously dry-disposes the tailings, eliminating the need for tailings ponds during production and thus removing the safety hazards associated with conventional tailings ponds in concentrators.

[0009] To achieve the above objectives, the present invention employs the following technical solution:

[0010] A process for recovering phosphorus, copper, and precious metals from iron ore tailings and dry tailings disposal includes the following steps: After the iron ore tailings undergo flotation-magnetic separation-flotation to separate copper concentrate, precious metal concentrate, and phosphorus concentrate, the tailings are then subjected to dry tailings disposal.

[0011] 1) Iron tailings are pumped to a hydrocyclone, the underflow from the hydrocyclone is fed to a ball mill for grinding, and the overflow from the hydrocyclone enters the flotation process;

[0012] 2) The flotation concentrate is fed to the Nelson concentrator for gravity separation. The Nelson concentrator concentrate contains precious metals such as gold, silver, platinum, and palladium, and the tailings are copper concentrate.

[0013] 3) The flotation tailings enter the vertical ring magnetic separator for magnetic separation. The magnetic concentrate is returned to the iron beneficiation process for iron recovery. The vertical ring magnetic separation tailings are floated again to obtain phosphate concentrate. The flotation tailings enter the high-efficiency thickener for concentration. After concentration, the tailings enter the filter for filtration, and finally the tailings are dry discharged.

[0014] The iron tailings concentration is 40%–45%; the fineness is -0.074 mm, accounting for 45%–48%; and the overflow fineness of the hydrocyclone is -0.074 mm, accounting for 60%–65%.

[0015] The flotation process in step 2) above includes one roughing, four cleaning, and two sweeping.

[0016] The reagent system for roughing copper is as follows: 180-200 g / t of butyl xanthate and 2500-2800 g / t of lime. The reagent system for secondary cleaning copper is as follows: 500-600 g / t of lime. The reagent system for tertiary cleaning copper is as follows: 100-120 g / t of diesel oil. 60-80 g / t of butyl xanthate is added during the primary scavenging stage of copper selection.

[0017] The flotation process in step 3) above includes one roughing, three cleaning, and one sweeping.

[0018] The reagent system for phosphorus roughing is as follows: collector 300-350 g / t; sodium carbonate 1500-1800 g / t; water glass 800-1000 g / t. The reagent system for primary phosphorus cleaning is as follows: sodium carbonate 600-900 g / t. The reagent system for secondary phosphorus cleaning is as follows: sodium carbonate 100-200 g / t. The reagent system for scavenging phosphorus is as follows: collector 50-70 g / t. The tailings from scavenging phosphorus are then concentrated in a high-efficiency thickener, with overflow water concentration ≤0.05%, filtrate concentration ≤0.2%, and dry tailings moisture content ≤8%.

[0019] The collector is MES: oxidized paraffin soap = (8~10): 1, by weight.

[0020] The conditions for gravity separation of precious metals using a Nelson concentrator are: water flow rate of 3–3.5 L / min and relative centrifugal force (RCF) of 85–95 G. The force of the vertical ring magnetic separator in step 3) above is 0.6–0.65 T.

[0021] The final concentrate product specifications are as follows: copper grade ≥18%, phosphorus grade ≥32%, gold grade ≥110g / t, silver grade ≥260g / t, platinum grade ≥60g / t, and palladium grade ≥140g / t.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) The present invention can realize the recovery of ultra-low grade phosphorus in iron ore tailings.

[0024] (2) Among them, calcite has a significant impact on the grade of phosphate concentrate. The present invention selects a reasonable reagent system to separate phosphate concentrate from calcite and ensure the grade of phosphate concentrate.

[0025] (3) This invention utilizes the Nelson gravity separation method to recover copper and precious metals.

[0026] (4) The present invention filters the tailings to achieve dry tailings discharge and water reuse. Attached Figure Description

[0027] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are merely illustrative and are not intended to limit the present invention.

[0029] See Figure 1 A process for recovering phosphorus, copper, and precious metals from iron ore tailings and dry tailings disposal, wherein the iron ore tailings undergo flotation-magnetic separation-flotation to separate copper concentrate, precious metal concentrate, and phosphorus concentrate, and the tailings are then subjected to dry tailings disposal, specifically including the following steps:

[0030] 1) Iron tailings are pumped to a hydrocyclone, the underflow from the hydrocyclone is fed to a ball mill for grinding, and the overflow from the hydrocyclone enters the flotation process;

[0031] 2) The flotation concentrate is fed to the Nelson concentrator for gravity separation. The Nelson concentrator concentrate contains precious metals such as gold, silver, platinum, and palladium, and the tailings are copper concentrate.

[0032] 3) The flotation tailings enter the vertical ring magnetic separator for magnetic separation. The magnetic concentrate is returned to the iron beneficiation process for iron recovery. The vertical ring magnetic separation tailings are floated again to obtain phosphate concentrate. The flotation tailings enter the high-efficiency thickener for concentration. After concentration, the tailings enter the filter for filtration, and finally the tailings are dry discharged.

[0033] The iron tailings concentration is 40%–45%; the fineness is -0.074 mm, accounting for 45%–48%; and the overflow fineness of the hydrocyclone is -0.074 mm, accounting for 60%–65%.

[0034] The flotation process in step 2) above includes one roughing, four cleaning, and two sweeping.

[0035] The reagent system for roughing copper is as follows: 180-200 g / t of butyl xanthate and 2500-2800 g / t of lime. The reagent system for secondary cleaning copper is as follows: 500-600 g / t of lime. The reagent system for tertiary cleaning copper is as follows: 100-120 g / t of diesel oil. 60-80 g / t of butyl xanthate is added during the primary scavenging stage of copper selection.

[0036] The flotation process in step 3) above includes one roughing, three cleaning, and one sweeping.

[0037] The reagent system for phosphorus roughing is as follows: collector 300-350 g / t; sodium carbonate 1500-1800 g / t; water glass 800-1000 g / t. The reagent system for primary phosphorus cleaning is as follows: sodium carbonate 600-900 g / t. The reagent system for secondary phosphorus cleaning is as follows: sodium carbonate 100-200 g / t. The reagent system for scavenging phosphorus is as follows: collector 50-70 g / t. The tailings from scavenging phosphorus are then concentrated in a high-efficiency thickener, with overflow water concentration ≤0.05%, filtrate concentration ≤0.2%, and dry tailings moisture content ≤8%.

[0038] The collector is MES: oxidized paraffin soap = (8~10): 1, by weight.

[0039] The conditions for gravity separation of precious metals in the Nelson concentrator are: water supply 3-3.5 L / min and relative centrifugal force (RCF) 85-95 G.

[0040] The electric field strength of the vertical ring magnetic separator in step 3) above is 0.6~0.65T.

[0041] The final concentrate product specifications are as follows: copper grade ≥18%, phosphorus grade ≥32%, gold grade ≥110g / t, silver grade ≥260g / t, platinum grade ≥60g / t, and palladium grade ≥140g / t.

[0042] Example 1:

[0043] A process for recovering phosphorus, copper, and precious metals from iron ore tailings and dry tailings disposal includes the following steps: After the iron ore tailings undergo flotation-magnetic separation-flotation to separate copper concentrate, precious metal concentrate, and phosphorus concentrate, the tailings are then subjected to dry tailings disposal.

[0044] 1) The iron tailings are pumped to a hydrocyclone, the underflow from the hydrocyclone is fed to a ball mill for grinding, and the overflow from the hydrocyclone enters the flotation process; the iron tailings concentration is 43%; the fineness is -0.074mm, accounting for 47%; the overflow fineness from the hydrocyclone is -0.074mm, accounting for 64%.

[0045] 2) The flotation concentrate is fed to the Nelson concentrator for gravity separation. The Nelson concentrator concentrate contains precious metals such as gold, silver, platinum, and palladium, and the tailings are copper concentrate. The flotation operation includes one roughing, four cleaning, and two scavenging.

[0046] The reagent system for copper roughing is as follows: 190 g / t butyl xanthate and 2600 g / t lime. The reagent system for copper secondary cleaning is as follows: 550 g / t lime. The reagent system for copper tertiary cleaning is as follows: 110 g / t diesel oil. 70 g / t butyl xanthate is added during the first copper scavenging stage.

[0047] 3) Flotation tailings are fed into a vertical ring magnetic separator for magnetic separation. The magnetic concentrate is returned to the iron ore beneficiation process for iron recovery. The vertical ring magnetic separation tailings are then subjected to flotation again to obtain phosphate concentrate. The flotation tailings are then fed into a high-efficiency thickener for concentration. After concentration, the tailings are filtered and finally discharged dry. The flotation operation includes one roughing, three cleaning, and one scavenging.

[0048] The reagent system for the roughing of phosphorus is as follows: collector 330 g / t; sodium carbonate 1600 g / t; water glass 900 g / t; the reagent system for the primary cleaning of phosphorus is as follows: sodium carbonate 800 g / t; the reagent system for the secondary cleaning of phosphorus is as follows: sodium carbonate 200 g / t; the reagent system for the scavenging of phosphorus is as follows: collector 60 g / t; the tailings from the scavenging of phosphorus are fed into a high-efficiency thickener for concentration, with an overflow water concentration of 0.05%; a filtrate concentration of 0.2%; and a dry tailings moisture content of 8%.

[0049] The collector used was MES: oxidized paraffin soap = 9:1, by weight.

[0050] The conditions for gravity separation of precious metals in the Nelson concentrator are: water supply 3.4 L / min and relative centrifugal force (RCF) 90 G.

[0051] The strength of the vertical ring magnetic separator is 0.65T.

[0052] Iron tailings ore beneficiation: copper grade 0.05%, phosphorus grade 0.68%, gold grade 0.02 g / t, silver grade 0.41 g / t, platinum grade 0.085 g / t, palladium grade 0.69 g / t

[0053] The final concentrate grades were: copper 18.54%, phosphorus 32.04%, gold 123.76 g / t, silver 284.53 g / t, platinum 69.12 g / t, and palladium 153.4 g / t.

[0054] The mineral processing results data of Example 1 are shown in Table 1.

[0055] Table 1

[0056]

[0057] Implementation Case 2:

[0058] A process for recovering phosphorus, copper, and precious metals from iron ore tailings and dry tailings disposal includes the following steps: After the iron ore tailings undergo flotation-magnetic separation-flotation to separate copper concentrate, precious metal concentrate, and phosphorus concentrate, the tailings are then subjected to dry tailings disposal.

[0059] 1) The iron tailings are pumped to a hydrocyclone, the underflow from the hydrocyclone is fed to a ball mill for grinding, and the overflow from the hydrocyclone enters the flotation process; the iron tailings concentration is 45%; the fineness is -0.074mm, accounting for 48%; the overflow fineness from the hydrocyclone is -0.074mm, accounting for 65%.

[0060] 2) The flotation concentrate is fed to the Nelson concentrator for gravity separation. The Nelson concentrator concentrate contains precious metals such as gold, silver, platinum, and palladium, and the tailings are copper concentrate. The flotation operation includes one roughing, four cleaning, and two scavenging.

[0061] The reagent system for rough copper selection is as follows: 200 g / t butyl xanthate; 2500 g / t lime; the reagent system for secondary copper cleaning is as follows: 600 g / t lime; the reagent system for tertiary copper cleaning is as follows: 120 g / t diesel oil; and 60 g / t butyl xanthate is added during the primary copper scavenging stage.

[0062] 3) Flotation tailings are fed into a vertical ring magnetic separator for magnetic separation. The magnetic concentrate is returned to the iron ore beneficiation process for iron recovery. The vertical ring magnetic separation tailings are then subjected to flotation again to obtain phosphate concentrate. The flotation tailings are then fed into a high-efficiency thickener for concentration. After concentration, the tailings are filtered and finally discharged dry. The flotation operation includes one roughing, three cleaning, and one scavenging.

[0063] The reagent system for phosphorus roughing is as follows: collector 300-350 g / t; sodium carbonate 1600 g / t; water glass 1000 g / t; the reagent system for primary phosphorus cleaning is as follows: sodium carbonate 700 g / t; the reagent system for secondary phosphorus cleaning is as follows: sodium carbonate 150 g / t; the reagent system for scavenging phosphorus is as follows: collector 50-70 g / t; the tailings from scavenging phosphorus are fed into a high-efficiency thickener for concentration, with an overflow water concentration of 0.04%; a filtrate concentration of 0.1%; and a dry tailings moisture content of 6%.

[0064] The collector used was MES: oxidized paraffin soap = 8:1, by weight.

[0065] The conditions for gravity separation of precious metals in the Nelson concentrator are: water supply 3.5 L / min and relative centrifugal force (RCF) 90 G.

[0066] The strength of the vertical ring magnetic separator is 0.65T.

[0067] In the iron tailings ore beneficiation: copper grade 0.045%, phosphorus grade 0.64%, gold grade 0.018 g / t, silver grade 0.43 g / t, platinum grade 0.081 g / t, palladium grade 0.62 g / t

[0068] The final concentrate grades were: copper 18.21%, phosphorus 32.56%, gold 115.46 g / t, silver 266.72 g / t, platinum 64.35 g / t, and palladium 143.8 g / t.

[0069] The mineral processing results data for Example 2 are shown in Table 2.

[0070] Table 2

[0071]

Claims

1. A process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal, characterized in that, After iron ore tailings undergo flotation-magnetic separation-flotation to separate copper concentrate, precious metal concentrate, and phosphate concentrate, the tailings are then subjected to dry tailings disposal, which specifically includes the following steps: 1) The tailings from the iron ore beneficiation process are fed to a hydrocyclone, the underflow from the hydrocyclone is fed to a ball mill for grinding, and the overflow from the hydrocyclone is fed into the flotation process; 2) The flotation concentrate is fed to the Nelson concentrator for gravity separation. The Nelson concentrator concentrate contains precious metals such as gold, silver, platinum, and palladium, and the tailings are copper concentrate. 3) The flotation tailings are fed into a magnetic separator for magnetic separation. The magnetic concentrate is returned to the iron ore beneficiation process for iron recovery. The magnetic tailings are then subjected to flotation again to obtain phosphate concentrate. The flotation tailings are fed into a high-efficiency thickener for concentration. After concentration, the tailings are filtered by a filter to achieve dry tailings discharge. The iron ore tailings concentration is 40%–45%; the fineness is -0.074mm, accounting for 45%–48%; the hydrocyclone overflow fineness is -0.074mm, accounting for 60%–65%. The reagent system for roughing copper selection is as follows: 180-200 g / t of butyl xanthate and 2500-2800 g / t of lime. The reagent system for secondary cleaning copper selection is as follows: 500-600 g / t of lime. The reagent system for tertiary cleaning copper selection is as follows: 100-120 g / t of diesel oil. 60-80 g / t of butyl xanthate is added during the primary scavenging stage of copper selection. The reagent system for phosphorus roughing is as follows: collector 300-350 g / t; sodium carbonate 1500-1800 g / t; water glass 800-1000 g / t; the reagent system for primary phosphorus cleaning is as follows: sodium carbonate 600-900 g / t; the reagent system for secondary phosphorus cleaning is as follows: sodium carbonate 100-200 g / t; the reagent system for scavenging phosphorus is as follows: collector 50-70 g / t. The tailings from the phosphorus scavenging process are then concentrated in a high-efficiency thickener, with overflow water concentration ≤0.05%, filtrate concentration ≤0.2%, and dry tailings moisture content ≤8%.

2. The process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal according to claim 1, characterized in that, The flotation process in step 2) above includes one roughing, four cleaning, and two sweeping.

3. The process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal according to claim 1, characterized in that, The flotation process in step 3) above includes one roughing, three cleaning, and one sweeping.

4. The process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal according to claim 1, characterized in that, The collector is MES: oxidized paraffin soap = (8-10): 1, by weight.

5. The process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal according to claim 1, characterized in that, The conditions for gravity separation of precious metals using the Nelson concentrator are: water supply of 3-3.5 L / min and relative centrifugal force of 85-95 G.

6. The process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal according to claim 1, characterized in that, The magnetic separator in step 3) above is a vertical ring magnetic separator with a field strength of 0.6 to 0.65 T.

7. The process for recovering phosphorus, copper, and precious metals from iron ore tailings and for dry tailings disposal according to claim 1, characterized in that, The final concentrate product specifications are as follows: copper grade ≥18%, phosphorus grade ≥32%, gold grade ≥110g / t, silver grade ≥260g / t, platinum grade ≥60g / t, and palladium grade ≥140g / t.

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