Beneficiation method for recovering iron ore concentrate from superfine hematite mud

Abstract

The invention discloses a beneficiation method for recovering iron ore concentrate from superfine hematite mud, which comprises the following steps: carrying out strong magnetic roughing on the superfine hematite mud to obtain strong magnetic roughed iron ore concentrate, and discharging strong magnetic roughed tailings; the strong magnetic roughing tailings are subjected to open-circuit strong magnetic scavenging twice, and first strong magnetic scavenging concentrate and second strong magnetic scavenging concentrate are obtained respectively; the strong magnetic roughing iron ore concentrate, the strong magnetic scavenging concentrate 1 and the strong magnetic scavenging concentrate 2 are combined and then fed into reverse flotation roughing operation, and the reverse flotation roughing operation is one-time roughing and three-time open-circuit scavenging. According to the method, full-open-flow fine sorting is adopted in strong magnetic separation and reverse flotation, strong magnetic roughing and scavenging bulk concentrates are subjected to flotation, reverse roughing and scavenging concentrates are combined into total concentrates, under the condition that it is guaranteed that the iron grade of the iron concentrates is larger than 63.0%, the iron ore concentrate recovery rate is increased to the maximum extent, the full-flow recovery rate is 72% or above, and the iron ore concentrate recovery rate is increased to the maximum extent. The contradiction between improvement of the iron ore concentrate grade and great reduction of the recovery rate is solved to the maximum extent, and an unexpected technical effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of iron ore beneficiation, and specifically relates to a beneficiation method for recovering iron concentrate from ultrafine hematite mud, and is particularly suitable for processing ultrafine hematite mud with a TFe grade of 45% to 50% and a particle size of -0.030 mm and a content of 80% to 90%. Background Art

[0002] my country is one of the countries with the widest distribution and largest reserves of hematite in the world. Hematite accounts for a considerable proportion of iron ore resources. Compared with magnetite, hematite has finer particle size, higher mud content and greater difficulty in mineral processing.

[0003] With the continuous development and utilization of iron ore resources, the characteristics of iron ore "poor, fine and mixed" are becoming more and more prominent. In order to select iron concentrate for industrial application, the ore needs to be ground very finely to achieve the monomer dissociation of useful minerals, and a lot of "secondary ore mud" will be produced in the process. At present, many mining companies need to grind iron ore to below 44μm, which leads to the appearance of many fine-grained ores with a particle size of -20μm or even -10μm. Due to their light weight and large specific surface area, fine-grained ores will consume too much flotation reagents during flotation, and are prone to heterogeneous agglomeration and being "entrained" into the tailings. It is difficult to achieve the recovery of fine-grained minerals with existing methods, which seriously affects the flotation indicators.

[0004] After grinding and classification of hematite ore, desliming and flotation are carried out. The removed sludge has high grade, but it cannot be recycled due to its fine particle size. In order to reduce its impact on flotation indicators, many companies directly discard it as tailings, resulting in a waste of resources. At present, there are only the following ways to utilize iron tailings:

[0005] (1) Recovery of valuable elements in iron tailings, i.e., tailings reselection, but the yield of recovered concentrate is low and a large amount of remaining tailings still needs to be processed;

[0006] (2) After magnetization roasting or deep reduction, some iron concentrate or reduced iron powder is obtained, but the energy consumption and cost are high, it is difficult to implement in industry, and there is pressure on environmental protection;

[0007] (3) The demand for aerated concrete blocks is not strong, and it is difficult to sell them after production;

[0008] (4) Microbial leaching to recover iron is not only costly but also has a small processing capacity and serious environmental pollution, making it even more difficult to achieve in industry. Summary of the invention

[0009] The object of the present invention is to provide a beneficiation method for recovering iron concentrate from ultra-fine hematite mud, which has high iron recovery rate, high grade of iron concentrate, low beneficiation cost and is easy to be applied on a large scale industrially, aiming at the technical problem that it is difficult to recover the discarded ultra-fine hematite in tailings at present.

[0010] To achieve the above object of the present invention, a beneficiation method for recovering iron concentrate from ultra-fine hematite mud is provided. It is used to process ultra-fine hematite mud with a TFe grade of 45% - 50%, a particle size of -0.030mm particle size fraction content of 80% - 90%, and a proportion of SiO2 in gangue minerals greater than 80%. It is implemented by the following processes and steps:

[0011] S1 Strong magnetic roughing of ultra-fine hematite mud

[0012] Perform strong magnetic roughing on the ultra-fine hematite mud to obtain strong magnetic roughing iron concentrate and discharge the strong magnetic roughing tailings.

[0013] S2 Strong magnetic scavenging of strong magnetic roughing tailings

[0014] Perform strong magnetic scavenging on the strong magnetic roughing tailings discharged in step S1. The strong magnetic scavenging is two-stage open-circuit scavenging, namely strong magnetic scavenging 1 and strong magnetic scavenging 2, to obtain strong magnetic scavenging 1 concentrate and strong magnetic scavenging 2 concentrate respectively, and discard the strong magnetic scavenging 2 tailings.

[0015] S3 Reverse flotation roughing

[0016] Merge the strong magnetic roughing iron concentrate, strong magnetic scavenging 1 concentrate and strong magnetic scavenging 2 concentrate obtained in step S1 and step S2, and feed them into the reverse flotation roughing operation. The reverse flotation roughing operation uses sodium hydroxide as the pH regulator, corn starch as the iron mineral inhibitor, and dodecylamine as the collector to obtain reverse flotation roughing iron concentrate (bottom part of the cell) and discharge the reverse flotation roughing tailings (foam part).

[0017] S4 Reverse flotation scavenging of reverse flotation roughing tailings

[0018] Feed the reverse flotation roughing tailings discharged in step S3 into the reverse flotation scavenging operation without adding drugs. The reverse flotation scavenging operation is three-stage open-circuit scavenging, namely reverse flotation scavenging 1, reverse flotation scavenging 2 and reverse flotation scavenging 3, to obtain reverse flotation scavenging 1 concentrate (bottom part of the cell), reverse flotation scavenging 2 concentrate (bottom part of the cell) and reverse flotation scavenging 3 concentrate (bottom part of the cell) respectively, and discard the reverse flotation scavenging 3 tailings (foam part). The reverse flotation roughing iron concentrate obtained in step S3 and reverse flotation scavenging 1 concentrate, reverse flotation scavenging 2 concentrate and reverse flotation scavenging 3 concentrate are merged into the final iron concentrate. The final iron concentrate has a TFe grade > 63.0% and an Fe recovery rate > 72.0%. The strong magnetic scavenging 2 tailings discarded in step S2 and the reverse flotation scavenging 3 tailings are merged into the total tailings.

[0019] Preferably, the magnetic separation equipment used in the strong magnetic rough selection in step S1 and the strong magnetic scavenging in step S2 is the Slon vertical ring pulsating high-gradient magnetic separator. The magnetic field intensity in both the strong magnetic rough selection and the strong magnetic scavenging is between 1.35 T and 1.50 T, and the magnetic field intensities in the strong magnetic rough selection and the strong magnetic scavenging are the same.

[0020] Preferably, in step S3, the dosage of sodium hydroxide as the pH adjuster is 300 - 500 g / t, the dosage of corn starch as the inhibitor is 300 - 500 g / t, and the dosage of dodecylamine as the collector is 100 - 200 g / t; the addition amounts of all the above agents are converted to the dry ore amount of the flotation feed.

[0021] Furthermore, in step S3, by adjusting the dosage of the agent added in the reverse flotation rough selection operation and the time of the reverse flotation rough selection operation, the TFe grade in the reverse flotation rough selection iron concentrate is controlled between 63.5% and 64.5%; in step S4, by adjusting the operation time of the first reverse flotation scavenging, the TFe grade of the concentrate of the first reverse flotation scavenging is controlled between 61.0% and 62.0%; by adjusting the operation time of the second reverse flotation scavenging, the TFe grade of the concentrate of the second reverse flotation scavenging is controlled between 60.7% and 61.3%; by adjusting the operation time of the third reverse flotation scavenging, the TFe grade of the concentrate of the third reverse flotation scavenging is controlled between 57.5% and 58.5%.

[0022] Furthermore, the magnetic field intensity in both the strong magnetic rough selection in step S1 and the strong magnetic scavenging in step S2 is 1.4 T.

[0023] The specific values of the above parameters such as the magnetic field intensity and the dosage of the agent can all be determined according to the ore properties based on the results of laboratory tests.

[0024] Compared with the prior art, the beneficiation method for recovering iron concentrate from ultrafine hematite mud of the present invention has the following advantages:

[0025] ① The ultrafine hematite mud is subjected to strong magnetic separation. Through one rough selection and two scavengings, a magnetic separation mixed concentrate with an iron grade of more than 58.0% is obtained. The same magnetic field intensity as that in the strong magnetic rough selection is used in the two scavengings. The iron grades of the concentrates of the first strong magnetic scavenging and the second strong magnetic scavenging are only slightly lower than that of the concentrate of the strong magnetic rough selection, while the iron grade of the tailings is significantly reduced, greatly improving the recovery rate of the magnetic separation mixed concentrate and achieving an unexpected technical effect.

[0026] ② Considering the fineness of the materials treated by reverse flotation, the flotation process of the present invention adopts a full open - circuit process, which avoids the influence of middlings return on the separation indexes, is conducive to the stability of the beneficiation process flow, and is also more convenient for on - site operation adjustment in production. By adjusting the dosage of reagents and the operation time of the reverse roughing flotation operation, the TFe grade in the reverse roughing iron concentrate is controlled; by adjusting the operation time of the first reverse scavenging flotation, the TFe grade of the first reverse scavenging concentrate is controlled; by adjusting the operation time of the second reverse scavenging flotation, the TFe grade of the second reverse scavenging concentrate is controlled; and by adjusting the operation time of the third reverse scavenging flotation, the TFe grade of the third reverse scavenging concentrate is controlled.

[0027] ③ The reverse flotation adopts a full open - circuit process for fine separation. The scavenging concentrate and the roughing concentrate are combined into the total concentrate. Under the condition of ensuring that the iron grade of the iron concentrate is greater than 63.0%, the recovery rate of the iron concentrate is maximized. The recovery rate of the flotation operation is as high as over 87.0%, which largely solves the contradiction between increasing the iron grade of the iron concentrate and the significant reduction of the recovery rate of the iron concentrate, achieving an unexpected technical effect.

[0028] ④ The present invention obtains an iron concentrate with a yield of more than 50% from ultra - fine hematite mud, turning waste into treasure, and is expected to have significant economic, social and environmental benefits.

[0029] It should be noted that although the present invention seems simple, it has achieved unexpected technical effects and is a breakthrough in the beneficiation technology for recovering iron concentrate from ultra - fine hematite mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 FIG. is the principle process flow chart of a beneficiation method for recovering iron concentrate from ultra - fine hematite mud according to the present invention.

[0031] Figure 2 FIG. is the full - process mass and quality flow chart of an embodiment of a beneficiation method for recovering iron concentrate from ultra - fine hematite mud according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] To further describe the present invention, the following further elaborates on a beneficiation method for recovering iron concentrate from ultra - fine hematite mud according to the present invention with reference to the drawings and embodiments. It should be noted that any modifications, equivalent replacements, improvements, etc. made within the technical concept and principles of the present invention shall be included within the protection scope of the present invention.

[0033] The ultra - fine hematite mud is taken from a foreign iron ore. The chemical multi - element analysis results of the sample are shown in Table 1 respectively, and the iron phase analysis results of the sample are shown in Table 2.

[0034] Table 1 Chemical multi - element analysis results (%)

[0035] Element Name TFe <![CDATA[SiO2]]> <![CDATA[Al2O3]]> CaO MgO S Content (%) 46.48 25.81 3.27 0.044 0.081 0.018 Element Name P <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[V2O5]]> CuO ZnO Content (%) 0.102 0.082 0.015 0.005 <0.005 <0.005 Element Name <![CDATA[Cr2O3]]> NiO MnO <![CDATA[TiO2]]> Content (%) <0.005 <0.005 0.136 0.103

[0036] Table 2 Results of iron phase analysis

[0037] Iron Phase Iron Content in Iron Phase Occupancy Rate Iron in Magnetite 0.38 0.82 Iron in Pyrite 0.05 0.11 Iron in Hematite (Limonite) 44.99 96.79 Iron in Iron Carbonate 0.05 0.11 Iron in Iron Silicate 1.01 2.17 Total 46.48 100.00

[0038] Table 3 Results of particle size analysis (%)

[0039]

[0040]

[0041] It can be seen from Table 1 and Table 2 that the ultrafine hematite mud has a high iron grade and fine particle size. The main recoverable useful iron minerals in the ore are hematite (limonite). The gangue minerals are mainly SiO2, accounting for more than 80% of the total gangue mineral components. Followed by Al2O3, and the contents of other elements are less.

[0042] From Figure 1 the principle process flow chart of a beneficiation method for recovering iron concentrate from ultrafine hematite mud shown in the present invention and combined with Figure 2 it can be seen that a beneficiation method for recovering iron concentrate from ultrafine hematite mud in the present invention includes the following processes and steps:

[0043] S1 Strong magnetic roughing of ultrafine hematite mud

[0044] Perform strong magnetic roughing on the ultrafine hematite mud. The strong magnetic roughing uses a Slon-750 vertical ring pulsating high-gradient magnetic separator with a magnetic field intensity of 1.4T to obtain a strong magnetic roughing iron concentrate with a yield of 47.31% and a TFe grade of 58.98%, and discharge the strong magnetic roughing tailings.

[0045] S2 Strong magnetic scavenging of strong magnetic roughing tailings

[0046] Perform strong magnetic scavenging on the strong magnetic roughing tailings discharged in step S1. The strong magnetic scavenging is two open-circuit scavengings, namely strong magnetic scavenging 1 and strong magnetic scavenging 2. Strong magnetic scavenging 1 and strong magnetic scavenging 2 also use a Slon-750 vertical ring pulsating high-gradient magnetic separator with a magnetic field intensity of 1.4T, and obtain a strong magnetic scavenging 1 concentrate with a yield of 12.35% and a TFe grade of 58.82%, a strong magnetic scavenging 2 concentrate with a yield of 6.06% and a TFe grade of 56.04%, and discard the strong magnetic scavenging 2 tailings with a yield of 34.28% and a TFe grade of 23.11%.

[0047] S3 Reverse flotation roughing

[0048] The strongly magnetic rough concentrate, strongly magnetic scavenging 1 concentrate, and strongly magnetic scavenging 2 concentrate obtained in steps S1 and S2 are merged and fed into the reverse flotation roughing operation. In the reverse flotation roughing operation, sodium hydroxide is used as the pH adjuster, corn starch is used as the iron mineral inhibitor, and dodecylamine is used as the collector. The dosage of sodium hydroxide is 400 g / t, the dosage of corn starch is 400 g / t, and the dosage of dodecylamine is 150 g / t. The reverse flotation rough concentrate with a yield of 40.66% and a TFe grade of 64.04% is obtained, and the reverse flotation rough tailings are discharged.

[0049] S4 Reverse Flotation Scavenging of Reverse Flotation Rough Tailings

[0050] The reverse flotation rough tailings discharged in step S3 are fed into the reverse flotation scavenging operation, and no medicine is added in the reverse flotation scavenging operation. The reverse flotation scavenging operation is three open-circuit scavengings, namely reverse flotation scavenging 1, reverse flotation scavenging 2, and reverse flotation scavenging 3. The reverse flotation scavenging 1 concentrate with a yield of 7.63% and a TFe grade of 61.45%, the reverse flotation scavenging 2 concentrate with a yield of 2.93% and a TFe grade of 61.05%, and the reverse flotation scavenging 3 concentrate with a yield of 2.30% and a TFe grade of 57.95% are obtained respectively, and the reverse flotation scavenging 3 tailings with a yield of 12.20% and a TFe grade of 38.58% are discarded. The reverse flotation rough concentrate obtained in step S3, the reverse flotation scavenging 1 concentrate, the reverse flotation scavenging 2 concentrate, and the reverse flotation scavenging 3 concentrate are merged into the final iron concentrate. The total yield of the final iron concentrate is 53.52%, the TFe grade is 63.25%, and the total recovery rate of iron is as high as 72.83%. The strongly magnetic scavenging 2 tailings and the reverse flotation scavenging 3 tailings discarded in step S2 are merged into the total tailings. The yield of the final total tailings is 46.48%, and the TFe grade is 27.17%.

[0051] The specific values of the above parameters such as magnetic field intensity and reagent dosage can all be determined according to the ore properties through the laboratory test results.

[0052] Since the TFe grade of the final total tailings is 27.17%, and the particle size is very fine, and the mineral components are mainly SiO2, Fe2O3, and Al2O3, it is a high-quality raw material for Portland cement (iron corrective agent). After concentration, filtration, and dehydration, it can be sold to a Portland cement factory for use as an iron corrective agent, and finally, the full utilization of ultrafine hematite mud is realized.

[0053] The beneficiation method for recovering iron concentrate from ultrafine hematite mud in the present invention maximizes the recovery rate of iron concentrate under the condition of ensuring that the iron grade of the iron concentrate is greater than 63.0%. The overall recovery rate is more than 70%. It largely solves the contradiction between improving the iron grade of iron concentrate and the significant reduction of the recovery rate of iron concentrate, realizes "turning waste into treasure", and is expected to have significant economic, social, and environmental benefits, achieving unexpected technical effects.

Claims

1. A beneficiation method for recovering iron concentrate from ultra-fine hematite mud, which is used to treat ultra-fine hematite mud with a TFe grade of 45% to 50%, a particle size of -0.030 mm particle size fraction content of 80% to 90%, and more than 80% of SiO2 in gangue minerals, It is implemented by the following steps: S1 Strong magnetic rough separation of ultrafine hematite mud Perform strong magnetic rough separation on the ultrafine hematite mud to obtain strong magnetic rough separation iron concentrate and discharge the strong magnetic rough separation tailings; S2 Strong magnetic scavenging of strong magnetic rough separation tailings Perform strong magnetic scavenging on the strong magnetic rough separation tailings discharged in step S1. The strong magnetic scavenging is two open-circuit scavengings, namely strong magnetic scavenging 1 and strong magnetic scavenging 2, to obtain strong magnetic scavenging 1 concentrate and strong magnetic scavenging 2 concentrate respectively, and discard the strong magnetic scavenging 2 tailings; S3 Reverse flotation rough separation The strong magnetic rough separation iron concentrate, strong magnetic scavenging 1 concentrate, and strong magnetic scavenging 2 concentrate obtained in step S1 and step S2 are merged and fed into the reverse flotation rough separation operation. The reverse flotation rough separation operation uses sodium hydroxide as the pH regulator, corn starch as the iron mineral inhibitor, and dodecylamine as the collector to obtain reverse flotation rough separation iron concentrate and discharge the reverse flotation rough separation tailings; S4 Reverse flotation scavenging of reverse flotation rough separation tailings The reverse flotation rough separation tailings discharged in step S3 are fed into the reverse flotation scavenging operation without adding drugs. The reverse flotation scavenging operation is three open-circuit scavengings, namely reverse flotation scavenging 1, reverse flotation scavenging 2, and reverse flotation scavenging 3, to obtain reverse flotation scavenging 1 concentrate, reverse flotation scavenging 2 concentrate, and reverse flotation scavenging 3 concentrate respectively, and discard the reverse flotation scavenging 3 tailings. The reverse flotation rough separation iron concentrate obtained in step S3 and the reverse flotation scavenging 1 concentrate, reverse flotation scavenging 2 concentrate, and reverse flotation scavenging 3 concentrate are merged into the final iron concentrate. The final iron concentrate has a TFe grade > 63.0% and an Fe recovery rate > 72.0%. The strong magnetic scavenging 2 tailings discarded in step S2 and the reverse flotation scavenging 3 tailings are merged into the total tailings.

2. The ore dressing method for recovering iron concentrate from ultrafine hematite mud as described in claim 1, characterized in that: The magnetic separation equipment used in the strong magnetic rough separation in step S1 and the strong magnetic scavenging in step S2 is the Slon type vertical ring pulsating high-gradient magnetic separator. The magnetic field intensities of the strong magnetic rough separation and the strong magnetic scavenging are both between 1.35T and 1.50T, and the magnetic field intensities of the strong magnetic rough separation and the strong magnetic scavenging are the same.

3. The ore dressing method for recovering iron concentrate from ultrafine hematite mud as claimed in claim 1 or 2, characterized in that: In step S3, the dosage of the pH regulator sodium hydroxide is 300 - 500g / t, the dosage of the inhibitor corn starch is 300 - 500g / t, and the dosage of the collector dodecylamine is 100 - 200g / t. The addition amounts of all the above-mentioned drugs are converted into the dry ore amount of the flotation feed.

4. A beneficiation method for recovering iron concentrate from ultrafine hematite mud as described in claim 3, characterized in that: In step S3, by adjusting the drug addition amount and the reverse flotation rough separation operation time of the reverse flotation rough separation operation, control the TFe grade in the reverse flotation rough separation iron concentrate to be between 63.5% and 64.5%; In step S4, by adjusting the operation time of the reverse flotation scavenging 1, control the TFe grade of the reverse flotation scavenging 1 concentrate to be between 61.0% and 62.0%; by adjusting the operation time of the reverse flotation scavenging 2, control the TFe grade of the reverse flotation scavenging 2 concentrate to be between 60.7% and 61.3%; by adjusting the operation time of the reverse flotation scavenging 3, control the TFe grade of the reverse flotation scavenging 3 concentrate to be between 57.5% and 58.5%.

5. The ore dressing method for recovering iron concentrate from superfine hematite mud as described in claim 4, characterized in that: The magnetic field intensities of the strong magnetic rough separation in step S1 and the strong magnetic scavenging in step S2 are both 1.4T.

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