Method for removing silicate iron minerals in iron ore through reverse flotation at low temperature

Abstract

The invention relates to a method for removing silicate iron minerals in iron ore through reverse flotation at low temperature, which is characterized by comprising the following process steps of: adding water into mixed magnetic concentrate containing silicate iron gangue minerals for size mixing, sequentially adding a pH regulator, an inhibitor, an activating agent and a low-temperature collecting agent for stirring, and then carrying out reverse flotation roughing to obtain roughing concentrate and roughing tailings; after an activating agent and a collecting agent are added into the roughing concentrate, primary concentration is conducted, and final concentrate is obtained; and an activating agent is added into the roughing tailings for two times of scavenging, and final tailings are obtained. The method has the advantages that 1, the low-temperature collecting agent is used for enabling the silicate gangue minerals to enter foam products in the rough separation section in a flotation mode, meanwhile, activating agents are added in the fine separation section and the scavenging section respectively, the surface activity of the silicate gangue minerals is improved, and therefore effective separation of the silicate gangue minerals and iron minerals in the low-temperature environment of 10-20 DEG C is achieved; 2, by shortening the scavenging operation times, discharge of the silicate gangue minerals from the scavenging tailing end is accelerated, and unstable process caused by middling accumulation is prevented;

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a method for removing iron silicate minerals from iron ore by reverse flotation at low temperature. Background Art

[0002] my country's iron ore resources are generally characterized by "poor, fine and mixed", with poor iron ore accounting for about 94.6% of the total reserves. Affected by the properties of the ore, iron concentrate generally has the problems of low concentrate grade and high silicon content. The anion reverse flotation process has the characteristics of strong adaptability and high selectivity for improving the quality and reducing silicon content of low-grade iron ore. It has been widely used in China, but its disadvantage is that it has high requirements for the temperature of the flotation slurry, generally above 35°C, and requires heated flotation, which wastes energy astonishingly. With the continuous improvement of national energy-saving and environmental protection requirements, the problems of high flotation temperature and reagent heating preparation in anion reverse flotation have become increasingly prominent, seriously restricting the further development of domestic iron mines, but at the same time it has also driven the research and development of low-temperature reverse flotation technology for iron ore.

[0003] A large number of studies have been conducted in China on the low-temperature reverse flotation technology of anions, including the development of low-temperature flotation agents and the improvement of separation processes, and certain progress has been made. For example, a certain concentrator of Anshan Iron and Steel Group used a new type of combined low-temperature agent to treat Anshan-type lean hematite, and achieved low-temperature reverse flotation of iron ore at 15°C, with stable industrial application indicators; Liaoning University of Science and Technology used a new type of fatty acid-resistant low-temperature collector to achieve effective low-temperature reverse flotation of iron ore in a concentrator in Anshan; Anhui Jinrisheng Mining used room-temperature collectors to achieve low-temperature reverse flotation of iron ore through process adjustments such as pulp concentration and feed particle size control; Anhui Liloujing Iron Mine used CY fatty acid collectors for reverse flotation at low temperatures to obtain separation indicators equivalent to those at high temperatures, etc. However, the above research results are generally concentrated on iron ores with quartz as the main gangue mineral, and there are no reports on the application of reverse flotation of iron ores with ferrosilicon as the main gangue mineral at low temperatures and obtaining high-grade iron concentrates. Due to the low surface activity of iron silicate minerals, their interaction with activators and collectors is weak in low temperature environments. Conventional reagents or separation processes are difficult to achieve efficient separation and it is difficult to obtain high-grade iron concentrates. They often need to be heated to above 45°C to obtain good mineral processing indicators, resulting in higher production costs and more serious energy consumption. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a low-temperature reverse flotation process for removing iron silicate minerals from iron ore, which is suitable for flotation in a low-temperature environment of 5 to 35°C.

[0005] The objective of the present invention is achieved through the following technical solutions: The present invention discloses a method for removing iron silicate minerals from iron ore by reverse flotation at low temperature, comprising the steps of treating the ore containing iron silicate ore by crushing and grinding-weak magnetic and strong magnetic operation, discarding the strong magnetic tailings, and obtaining a mixed magnetic concentrate, characterized in that the mixed magnetic concentrate is fed as a flotation feed into a subsequent reverse flotation process for separation treatment, and the reverse flotation process adopts a separation process of "one coarse, one fine, and two sweeps", and the specific reverse flotation separation process steps are as follows: Step 1: Prepare the feed slurry Add water to the mixed magnetic concentrate to adjust the slurry, and obtain reverse flotation feed slurry with a concentration of 42% to 48%; Step 2: Rough selection After adding pH adjuster, inhibitor, activator and low-temperature collector to the feed slurry in sequence and stirring evenly, the slurry is fed into the roughing operation for reverse flotation of the feed slurry to obtain roughing concentrate and roughing tailings, wherein the roughing concentrate is the underflow product and the roughing tailings is the foam product; The pH adjuster is NaOH, the inhibitor is corn starch or its modified product, the activator is CaO or CaCl2; the low-temperature collector is a composite collector, the main components of which include C 13 ~C 18 One or more combinations of saturated or unsaturated straight-chain or branched fatty acids, C2-C 10 One or more combinations of straight-chain or branched fatty alcohols and one or more combinations of methyl benzoate, dimethyl phthalate, methyl acetate, ethyl acetate, butyl acetate, etc.

[0006] In step 2, the pH adjuster is added in an amount of 600-1200 g per ton of mixed magnetic concentrate, i.e., 600-1200 g / t, the inhibitor is added in an amount of 500-800 g / t, the activator is added in an amount of 200-500 g / t, and the low-temperature collector is added in an amount of 600-1000 g / t.

[0007] Step 3: Select assignments After adding activator and low-temperature collector to the rougher concentrate, the rougher concentrate is selected to obtain the selected concentrate and the selected tailings. The selected concentrate, i.e. the underflow product, is the final concentrate, and the selected tailings are the foam product returned to the rougher operation; In step 3, the amount of the activator is 50-250 g / t, and the amount of the low-temperature collector is 200-300 g / t.

[0008] Step 4: One-scan operation and two-scan operation The roughing tailings are added with 100-200g / t of activating agent and fed into the first sweeping operation for first sweeping separation of the roughing tailings to obtain first sweep concentrate and first sweep tailings; the first sweep concentrate is returned to the roughing operation, and the first sweep tailings are added with 50-100g / t of activating agent and fed into the second sweeping operation for second sweep separation of the first sweep tailings to obtain second sweep concentrate and second sweep tailings; the second sweep concentrate is returned to the first sweep operation, and the second sweep tailings, i.e., the second sweep foam, is the final tailings.

[0009] Preferably, the useful iron minerals in the mixed magnetic concentrate are a mixture of one or more of hematite, magnetite and limonite, and the TFe grade of the mixed magnetic concentrate is 45%-50%; the gangue minerals in the mixed magnetic concentrate are mainly iron silicate minerals, wherein the iron silicate minerals are one or more combinations of olivine, garnet, pyroxene, amphibole, biotite, chlorite, actinolite, epidote, etc., and the content of iron silicate minerals is ≥10%; the -200 mesh content of the mixed magnetic concentrate is 85%-95%.

[0010] Preferably, the pH adjuster is NaOH, the inhibitor is corn starch or a modified product thereof, and the activator is CaO or CaCl2; the low-temperature collector is a composite collector, which is obtained by reacting fatty acids, alcohols, esters, inorganic bases and water as raw materials, and the above raw materials are composed of the following mass percentages: the total mass percentage is 100%, the fatty acid content is 30%-80%, the alcohol mass content is 10%~30%, the ester mass content is 3%~10%, the inorganic base mass content is 3%-10%, and the balance is water, and the molar ratio of the inorganic base to the fatty acid is 0.5~1:1.

[0011] Preferably, the fatty acid is at least one of C13-C18 unsaturated straight-chain or branched-chain fatty acids, with an iodine value of 130-140 and a freezing point of -15-8°C; The alcohol is at least one of C2-C10 straight-chain or branched fatty alcohols; The ester is at least one of methyl benzoate, dimethyl phthalate, methyl acetate, ethyl acetate and butyl acetate.

[0012] Preferably, in step 2, the pH adjuster is used in an amount of 600-1200 g per ton of mixed magnetic concentrate, i.e., 600-1200 g / t, the inhibitor is used in an amount of 500-800 g / t, the activator is used in an amount of 200-500 g / t, and the low-temperature collector is used in an amount of 600-1000 g / t.

[0013] Preferably, in step 3, the amount of the activator is 50-250 g / t, and the amount of the low-temperature collector is 200-300 g / t.

[0014] The present invention adopts a "one coarse, one fine and two scavenging" separation process, uses a low-temperature collector in the coarse selection section to float most of the gangue minerals into the foam product, and at the same time adds an activator at multiple points in the fine and scavenging sections to strengthen the interaction between the iron-containing silicate gangue minerals and the collector in the fine and scavenging sections under a low-temperature environment, thereby achieving effective separation of iron minerals and iron-containing silicate gangue minerals under a low-temperature environment of 5 to 35°C; in addition, by shortening the number of scavenging operations, the discharge of iron-containing silicate gangue minerals from the scavenging tailings outlet is accelerated, the accumulation of intermediate ore circulation causing process instability is prevented, and a high-grade iron concentrate product can be obtained, with the iron concentrate TFe grade being above 67%. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The process flow chart of the present invention is implemented. DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with the embodiments, but the protection scope of the present invention is not limited to the following embodiments. Example

[0017] The mixed magnetic concentrate containing iron silicate iron ore in Liaoning area was taken as flotation raw material. The particle size analysis results showed that the content of -0.075mm was 92.70%, the TFe grade was 49.49%, and the content of iron silicate minerals was 17.30%.

[0018] like Figure 1 As shown, a method for removing iron silicate minerals from iron ore by reverse flotation at low temperature of the present invention comprises subjecting the ore containing iron silicate ore to crushing and grinding-weak magnetic and strong magnetic processing, discarding the strong magnetic tailings, and obtaining a mixed magnetic concentrate, characterized in that the mixed magnetic concentrate is fed as a flotation feed to a subsequent reverse flotation process for separation treatment, and the reverse flotation process adopts a "one coarse, one fine and two sweep" separation process, and the specific reverse flotation separation process steps are as follows: Step 1, mixing the mixed magnetic concentrate with water to obtain a reverse flotation feed slurry with a concentration of 42%; Step 2: feed the feed slurry into anion reverse flotation roughing at a slurry temperature of 20°C, add 900 g / t of pH adjuster NaOH, 800 g / t of inhibitor corn starch, 200 g / t of activator, and 600 g / t of low-temperature collector; Step 3, the rougher concentrate obtained in step 2 is concentrated at a pulp temperature of 20°C, 100 g / t of activator and 200 g / t of low-temperature collector are added to obtain a final concentrate product; The low-temperature collectors in step 2 and step 3 are both composite collectors, which are obtained by reacting fatty acids, alcohols, esters, inorganic bases and water as raw materials, and the above raw materials are composed of the following mass percentages: the total mass percentage is 100%, the fatty acid is 30%-80%, the alcohol mass content is 10%~30%, the ester mass content is 3%~10%, the inorganic base mass content is 3%-10%, and the balance is water, and the molar ratio of the inorganic base to the fatty acid is 0.5~1:1; The fatty acid is at least one of C13-C18 unsaturated straight-chain or branched-chain fatty acids, with an iodine value of 130-140 and a freezing point of -15-8°C; The alcohol is at least one of C2-C10 straight-chain or branched fatty alcohols; The ester is at least one of methyl benzoate, dimethyl phthalate, methyl acetate, ethyl acetate and butyl acetate; The introduction of hydroxyl groups through alcohols increases the interaction between the collector and water molecules, improves the solubility and dispersibility of the agent, and can also enhance the stability of the foam and improve the flotation efficiency. The introduction of ester groups through esters can improve the surface activity of the collector, which not only improves the product quality of the final concentrate obtained in the selection operation, but also avoids the desorption of silicate iron gangue minerals and collectors in the scavenging section, which causes the silicate iron gangue minerals to enter the concentrate product and make the concentrate product quality fail to meet the standards.

[0019] Step 4: The rougher tailings obtained in step 2 are scavenged twice at a pulp temperature of 20°C, with 100 g / t of activator added in the first scavenging and 50 g / t of activator added in the second scavenging to obtain the final flotation tailings.

[0020] Other drugs are known in the art and will not be described in detail here.

[0021] The closed-loop test of this process flow achieved the separation indicators of 61.43% concentrate yield, 68.15% TFe grade and 85.97% recovery rate. Example

[0022] The mixed magnetic concentrate containing iron silicate iron ore in Liaoning area was taken as flotation raw material. The particle size analysis results showed that the content of -0.075mm was 90.52%, the TFe grade was 48.91%, and the content of iron silicate minerals was 16.15%.

[0023] Step 1, mixing the mixed magnetic concentrate with water to obtain a reverse flotation feed slurry with a concentration of 45%; Step 2: feed the feed slurry into anion reverse flotation roughing at a slurry temperature of 13°C, add 700 g / t of pH adjuster NaOH, 800 g / t of inhibitor corn starch, 200 g / t of activator, and 750 g / t of low-temperature collector; Step 3, the rougher concentrate obtained in step 2 is concentrated at a pulp temperature of 20°C, 100 g / t of activator and 250 g / t of low-temperature collector are added to obtain a final concentrate product; Step 4: The roughing tailings obtained in step 2 are scavenged twice at a pulp temperature of 20°C, with 100 g / t of activator added in the first scavenging and 50 g / t of activator added in the second scavenging to obtain the final flotation tailings.

[0024] The closed-loop test of this process flow achieved the separation indicators of 63.68% concentrate yield, 67.51% TFe grade and 87.88% recovery rate. Example

[0025] The mixed magnetic concentrate containing iron silicate iron ore in Liaoning area was taken as flotation raw material. The particle size analysis results showed that the content of -0.075mm was 91.12%, the TFe grade was 48.41%, and the content of iron silicate minerals was 14.36%.

[0026] Step 1, mixing the mixed magnetic concentrate with water to obtain a reverse flotation feed slurry with a concentration of 46%; Step 2: feed the feed slurry into anion reverse flotation roughing at a slurry temperature of 18°C, add 1000 g / t of pH adjuster NaOH, 800 g / t of inhibitor corn starch, 500 g / t of activator, and 900 g / t of low-temperature collector; Step 3, the rougher concentrate obtained in step 2 is concentrated at a pulp temperature of 20°C, 200 g / t of activator and 250 g / t of low-temperature collector are added to obtain a final concentrate product; Step 4: The roughing tailings obtained in step 2 are scavenged twice at a pulp temperature of 20°C, with 150 g / t of activator added in the first scavenging and 100 g / t of activator added in the second scavenging to obtain the final flotation tailings.

[0027] The closed-loop test of this process flow achieved the separation indicators of 62.03% concentrate yield, 67.97% TFe grade and 87.10% recovery rate.

Claims

1. A method for removing iron silicate minerals from iron ore by reverse flotation at low temperature, comprising treating the ore containing iron silicate ore by crushing and grinding-weak magnetic and strong magnetic operation, discarding the strong magnetic tailings, and obtaining a mixed magnetic concentrate, characterized in that: The mixed magnetic concentrate is used as flotation feed to be fed into the subsequent reverse flotation process for separation. The reverse flotation process adopts the separation process of "one coarse, one fine and two sweeps". The specific reverse flotation process steps are as follows: Step 1: Prepare the feed slurry Add water to the mixed magnetic concentrate to adjust the slurry, and obtain reverse flotation feed slurry with a concentration of 42% to 48%; Step 2: Rough selection After adding pH adjuster, inhibitor, activator and low-temperature collector to the feed slurry in sequence and stirring evenly, the slurry is fed into the roughing operation for reverse flotation of the feed slurry to obtain roughing concentrate and roughing tailings, wherein the roughing concentrate is the underflow product and the roughing tailings is the foam product; Step 3: Select assignments After adding activator and low-temperature collector to the rougher concentrate, the rougher concentrate is selected to obtain the selected concentrate and the selected tailings. The selected concentrate, i.e. the underflow product, is the final concentrate, and the selected tailings are the foam product returned to the rougher operation; Step 4: One-scan operation and two-scan operation The roughing tailings are added with 100-200g / t of activating agent and fed into the first sweeping operation for first sweeping separation of the roughing tailings to obtain first sweep concentrate and first sweep tailings; the first sweep concentrate is returned to the roughing operation, and the first sweep tailings are added with 50-100g / t of activating agent and fed into the second sweeping operation for second sweep separation of the first sweep tailings to obtain second sweep concentrate and second sweep tailings; the second sweep concentrate is returned to the first sweep operation, and the second sweep tailings, i.e., the second sweep foam, is the final tailings.

2. The useful iron minerals in the mixed magnetic concentrate are one or a mixture of hematite, magnetite and limonite, and the TFe grade of the mixed magnetic concentrate is 45%-50%; the gangue minerals in the mixed magnetic concentrate are mainly iron silicate minerals, wherein the iron silicate minerals are one or more combinations of olivine, garnet, pyroxene, amphibole, biotite, chlorite, actinolite, epidote, etc., and the content of iron silicate minerals is ≥10%; the content of -200 mesh size in the mixed magnetic concentrate is 85%-95%.

3. The method for removing iron silicate minerals from iron ore by reverse flotation at low temperature according to claim 1, characterized in that: The pH adjuster is NaOH, the inhibitor is corn starch or its modified product, and the activator is CaO or CaCl2; the low-temperature collector is a composite collector, which is obtained by reacting fatty acids, alcohols, esters, inorganic bases and water as raw materials, and the above raw materials are composed of the following mass percentages: the total mass percentage is 100%, the fatty acid content is 30%-80%, the alcohol mass content is 10%~30%, the ester mass content is 3%~10%, the inorganic base mass content is 3%-10%, and the balance is water, and the molar ratio of the inorganic base to the fatty acid is 0.5~1:

1.

4. A low-temperature reverse flotation method for iron silicate-rich iron ore according to claim 3, characterized in that: The fatty acid is at least one of C13-C18 unsaturated straight-chain or branched-chain fatty acids, with an iodine value of 130-140 and a freezing point of -15-8°C; The alcohol is at least one of C2-C10 straight-chain or branched fatty alcohols; The ester is at least one of methyl benzoate, dimethyl phthalate, methyl acetate, ethyl acetate and butyl acetate.

5. A method for removing iron silicate minerals from iron ore by reverse flotation at low temperature according to claim 1 or 4, characterized in that: In step 2, the pH adjuster is added in an amount of 600-1200 g per ton of mixed magnetic concentrate, i.e., 600-1200 g / t, the inhibitor is added in an amount of 500-800 g / t, the activator is added in an amount of 200-500 g / t, and the low-temperature collector is added in an amount of 600-1000 g / t.

6. A method for removing iron silicate minerals from iron ore by reverse flotation at low temperature according to claim 1 or 4, characterized in that: In step 3, the amount of the activator is 50-250 g / t, and the amount of the low-temperature collector is 200-300 g / t.

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