Application of dye waste acid as inhibitor in reverse flotation of phosphorite

Abstract

The invention discloses application of dye waste acid as an inhibitor in phosphorite reverse flotation, which is characterized in that the dye waste acid and sulfuric acid are combined to serve as an inhibitor of apatite to be used in phosphorite reverse flotation, and phosphate concentrate and phosphate tailings are obtained after one-roughing, one-refining and one-scavenging operation. The acid dye wastewater is used as the apatite inhibitor, the utilization rate of the acid dye wastewater can be greatly increased, the wastewater treatment cost is reduced, the environmental harm is reduced, meanwhile, the dosage of a sulfuric acid reagent in the reverse flotation process is reduced, the mineral separation cost is reduced, and the method has the advantages of being wide in application range and high in product index.

Description

Technical Field

[0001] The present invention relates to the application of dye waste acid as an inhibitor in the reverse flotation of phosphate rock, and specifically relates to the technical field of beneficiation reagents. Background Art

[0002] Phosphate rock is a non-renewable strategic resource, which is mainly divided into three major types: magmatic rock type, metamorphic rock type and sedimentary rock type. The reserves of phosphate rock resources in China rank second in the world, mainly concentrated in Yunnan, Guizhou, Sichuan and other places. The phosphate rock resources in Yunnan Province belong to sedimentary rock type phosphate rock. The phosphate-containing minerals of this type are often associated with carbonate minerals such as dolomite. In industry, the reverse flotation process is mainly used to treat this type of phosphate rock, that is, sulfuric acid, phosphoric acid or a combination thereof is used as an inhibitor for apatite, and fatty acid is used as a collector for dolomite to achieve separation. However, there are problems such as a large amount of sulfuric acid consumption and high cost of phosphoric acid. The invention patent "A Reverse Flotation Process for Phosphate Rock" with the application number CN2013109134970.6 discloses a reverse flotation process for phosphate rock that adds small molecule organic acids in combination with sulfuric acid or phosphoric acid to inhibit phosphate minerals. Although the inhibition effect is improved, the reagent cost is high.

[0003] China is a major country in the dye production and printing and dyeing industries. During the production and application of dyes, a large amount of dye waste acid is easily generated, which has characteristics such as high chemical oxygen demand and high organic matter content. Its common treatment methods are chemical oxidation methods, which mainly use the strong oxidizing property of oxidants to oxidize and destroy the organic matter in the waste acid. In addition, there are biochemical treatment methods, neutralization methods, membrane separation methods and biological methods. The invention patent "A Production Process for Recycling Ammonium Sulfate from Dye Wastewater" with the application number CN202411409346.7 discloses a method for recycling ammonium sulfate from acidic dye wastewater by using calcium carbonate for neutralization treatment, which can achieve efficient recovery of the sulfuric acid component in the wastewater. However, its treatment process is complex and the treatment cost is high. Summary of the Invention

[0004] To solve the above problems, the present invention provides the application of dye waste acid as an inhibitor in the reverse flotation of phosphate rock. The present invention combines dye waste acid with sulfuric acid and uses it as an inhibitor for apatite in the reverse flotation of phosphate rock. The present invention improves the utilization rate of dye waste acid, reduces the cost of treating waste acid, reduces the risk of environmental harm, and at the same time takes into account the grade and recovery rate of apatite under low beneficiation cost.

[0005] The technical solution of the present invention is: the application of dye waste acid as an inhibitor in the reverse flotation of phosphate rock, where the dye waste acid and sulfuric acid are combined and used as an inhibitor for apatite. The specific steps are as follows:

[0006] (1) First, the mixed phosphate rock is crushed and then ground to obtain a pulp in which apatite and dolomite are monomer-dissociated. The grinding fineness of the phosphate ore is -200 mesh accounting for 84-85%, so that apatite and dolomite are monomer-dissociated;

[0007] (2) In the apatite and dolomite monomer dissociation pulp obtained in step (1), an inhibitor and a collector are added in sequence for roughing operation to obtain a roughing underflow product and a roughing froth product. The dosage of the inhibitor (dyestuff waste acid: sulfuric acid = 2 - 3:1) is 10 - 11 kg / t, and the dosage of the collector LS-901 is 800 - 900 g / t;

[0008] (3) An inhibitor and a collector are added in sequence to the roughing underflow product for cleaning operation to obtain a cleaning froth product and a cleaning underflow product (i.e., apatite concentrate). The dosage of the inhibitor (waste acid: sulfuric acid = 2 - 3:1) is 3 - 4 kg / t, and the dosage of the collector LS-901 is 300 - 400 g / t; The collector LS-901 is developed by the Key Laboratory of Green Separation and Enrichment of Strategic Metal Mineral Resources in Yunnan Province and is a fatty acid collector composed of oleic acid, palmitic acid and oxidized paraffin soap = 3:2:5;

[0009] (4) Sulfuric acid is added to the roughing froth product for scavenging operation to obtain a scavenging underflow product and a scavenging froth product (i.e., apatite tailings). The dosage of sulfuric acid is 1 - 1.2 kg / t;

[0010] (5) The scavenging underflow product and the cleaning froth product are combined and returned to the previous stage to form a closed circuit.

[0011] Preferably, the duration of the roughing operation in step (2) is 5 - 6 minutes.

[0012] Preferably, the duration of the cleaning operation in step (3) is 3 - 4 minutes.

[0013] Preferably, the duration of the scavenging operation in step (4) is 4 - 5 minutes.

[0014] The principle of the present invention is:

[0015] The dyestuff waste acid used is taken from a dyeing factory in Yunnan, and its basic water quality is shown in Table 1. The pH value of the dyestuff waste acid is 2.46, which has strong acidity. The acidic components are mainly sulfuric acid, and SO4 in sulfuric acid 2- acts on the Ca sites on the apatite surface to form calcium sulfate covering the apatite surface, hindering the adsorption of fatty acid collectors. In addition, CO3 on the dolomite surface 2- will dissolve into carbon dioxide and water under acidic conditions, exposing the Ca and Mg sites on the dolomite surface, which is beneficial to the adsorption of fatty acid collectors. Under acidic conditions, it is easier to form a fatty acid ion adsorption layer on the dolomite surface, promoting the increase of the hydrophobicity and floatability of the dolomite surface. At the same time, the dyestuff waste acid also contains a large amount of organic substances such as benzene, phenol and anthraquinone. Among them, phenol and anthraquinone organic substances have foaming properties and can replace the use of foaming agents in the flotation process.

[0016] Table 1 Quality of Dye Waste Acid

[0017] pH Total Organic Carbon (mg / L) Chemical Oxygen Demand (mg / L) 2.46 736 4410

[0018] Advantages of the present invention:

[0019] (1) The present invention can broaden the utilization path of dye waste acid, improve the recycling rate, reduce the treatment cost, and thus reduce the risk of environmental pollution.

[0020] (2) The present invention uses waste acid combined with a small amount of sulfuric acid as an inhibitor for apatite, and the inhibition effect is close to that of using sulfuric acid alone. While ensuring the production indexes of phosphorite concentrate, the beneficiation cost is reduced.

[0021] (3) The organic components contained in the dye waste acid of the present invention can act as foaming agents in the reverse flotation process of phosphate rock, reducing the reagent cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the process flow chart of the present invention;

[0023] Figure 2 is the comparative process flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention will be further described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the content described.

[0025] The phosphate rock used in the following examples is taken from the original ore of a phosphate mine in Yunnan Province, with a phosphorus grade of 19 - 21% and a magnesium grade of 3 - 4%; the phosphorus-containing minerals are mainly fluorapatite, accounting for 25 - 30%; the rest is hydroxyapatite, accounting for 5 - 10%; the carbonate minerals are mainly dolomite, accounting for 5 - 10%; the siliceous minerals are mainly quartz, accounting for 45 - 50%.

[0026] Example 1: This example corresponds to the original ore with relatively low phosphorus and magnesium grades, with a total phosphorus grade of 19.53% and a total magnesium grade of 3.07%.

[0027] Use the dye waste acid (combined with a small amount of sulfuric acid) from a dyeing factory in Yunnan as an inhibitor for apatite, and use a fatty acid collector with the code LS - 901 to collect dolomite. The flotation flow chart is as Figure 1 shown, and the specific steps are as follows:

[0028] (1) The phosphate rock is crushed and then ground to a fineness of -200 mesh accounting for 84% to obtain a pulp in which apatite and dolomite are monomer-dissociated;

[0029] (2) In the apatite and dolomite monomer dissociation pulp obtained in step (1), successively add 10 kg / t of inhibitor (waste acid: sulfuric acid = 2.5:1), with an action time of 3 min, 1800 g / t of collector LS-901, with an action time of 3 min, conduct rough selection operation, scrape foam for 5 min, and obtain rough selection underflow product and rough selection foam product;

[0030] (3) To the rough selection underflow intermediate product, successively add 3 kg / t of inhibitor (waste acid: sulfuric acid = 2:1), with an action time of 3 min, 1300 g / t of collector LS-901, with an action time of 3 min, conduct cleaning operation, scrape foam for 3 min, and obtain cleaning foam product and cleaning underflow product (i.e., phosphate concentrate);

[0031] (4) Add 1 kg / t of inhibitor sulfuric acid to the rough selection foam product, with an action time of 3 min, conduct scavenging operation, scrape foam for 4 min, and obtain scavenging underflow product and scavenging foam product (i.e., phosphate tailings);

[0032] (5) Combine the scavenging underflow product and the cleaning foam product and return them to the previous level to form a closed circuit.

[0033] The flotation product indexes of Example 1 are shown in Table 2, and the water quality of the ore dressing wastewater after dehydration of the flotation pulp is shown in Table 3.

[0034] Table 2 Flotation Product Indexes of Example 1

[0035]

[0036]

[0037] As can be seen from Table 2, when the method of the present invention is used to treat relatively low-grade raw ore, phosphate concentrate with a P2O5 grade of 25.70%, a P2O5 recovery rate of 82.67%, an MgO grade of 0.57%, and an MgO recovery rate of 11.36% is obtained, achieving considerable separation effect and concentrate indexes.

[0038] Table 3 Water Quality of Ore Dressing Wastewater in Example 1

[0039] pH Total Organic Carbon (mg / L) Chemical Oxygen Demand (mg / L) 5.06 134.1 805

[0040] Comparing with the water quality of the dye waste acid in Table 1, the pH value in the ore dressing wastewater can be adjusted in the actual production closed circuit, and both the total organic carbon and the chemical oxygen demand meet the third-level sewage discharge standard of GB8978-1996.

[0041] Example 2: This example corresponds to raw ore with relatively high phosphorus and magnesium grades, with a total phosphorus grade of 20.65% and a total magnesium grade of 3.75%.

[0042] The waste acid from a dye factory in Yunnan (mixed with a small amount of sulfuric acid) was used as the inhibitor for apatite, and a fatty acid collector code-named LS-901 was used to collect dolomite. The flotation flow chart is as shown in Figure 1 shown below. The specific steps are as follows:

[0043] (1) The phosphate ore was crushed and then ground to a fineness where -200 mesh accounted for 85%, obtaining a pulp in which apatite and dolomite were monomerically dissociated;

[0044] (2) In the pulp in which apatite and dolomite were monomerically dissociated obtained in step (1), 11 kg / t of inhibitor (waste acid: sulfuric acid = 2.5:1) was added successively, with an action time of 3 min, and 900 g / t of collector LS-901 was added, with an action time of 3 min. Then roughing operation was carried out, and froth was scraped for 5 min, obtaining a roughing underflow intermediate product and a roughing foam intermediate product;

[0045] (3) To the roughing underflow intermediate product, 4 kg / t of inhibitor (waste acid: sulfuric acid = 2:1) was added successively, with an action time of 3 min, and 400 g / t of collector LS-901 was added, with an action time of 3 min. Then cleaning operation was carried out, and froth was scraped for 3 min, obtaining a cleaning foam product and a cleaning underflow product (i.e., phosphate concentrate);

[0046] (4) To the roughing foam product, 1.2 kg / t of inhibitor sulfuric acid was added, with an action time of 3 min. Then scavenging operation was carried out, and froth was scraped for 4 min, obtaining a scavenging underflow product and a scavenging foam product (i.e., phosphate tailings);

[0047] (5) The scavenging underflow product and the cleaning foam product were combined and returned to the previous stage to form a closed circuit.

[0048] The indexes of the flotation products in Example 2 are shown in Table 4, and the water quality of the ore dressing wastewater after dehydration of the flotation pulp is shown in Table 5.

[0049] Table 4 Indexes of Flotation Products in Example 2

[0050]

[0051]

[0052] It can be seen from Table 4 that when the method of the present invention was used to treat relatively high-grade raw ore, phosphate concentrate with a P2O5 grade of 27.11%, a P2O5 recovery rate of 82.72%, an MgO grade of 0.68%, and an MgO recovery rate of 11.43% was obtained. The flotation indexes of Example 2 were similar to those of Example 1, indicating that this method has strong adaptability to treat this type of phosphate ore and can well realize the separation of apatite and dolomite.

[0053] Table 5 Water Quality of Ore Dressing Wastewater in Example 2

[0054] pH Total Organic Carbon (mg / L) Chemical Oxygen Demand (mg / L) 5.13 129.8 798

[0055] Comparing with the water quality of the dye waste acid in Table 1, the pH value in the ore dressing wastewater can be adjusted during the closed-loop circulation of actual production, and both the total organic carbon and the chemical oxygen demand meet the third-level sewage discharge standard of GB8978-1996.

[0056] Example 3: This Example 3 is a comparative example of Example 1. The ore type processed in this Example 3 is the same as that in Example 1, and the process variables are described in the specific implementation manner. The conditions not described are the same as those in Example 1.

[0057] The specific operation steps are as follows:

[0058] (1) The flotation flow chart is as Figure 2 shown;

[0059] (2) The inhibitor selected in this Example 3 is single sulfuric acid. The dosage of sulfuric acid as the roughing inhibitor is 10 kg, and the dosage of sulfuric acid as the cleaning inhibitor is 3 kg;

[0060] (3) In this Example 3, the collector is added in the roughing operation and the cleaning operation, and 20 g / t and 10 g / t of the foaming agent No. 2 oil are added respectively after the action, and the action time is 1 min;

[0061] (4) No medicine is added in the scavenging operation of this Example 3.

[0062] The flotation indexes of this Example 3 are as shown in Table 6 below:

[0063] Table 6 Flotation product indexes of Comparative Example 3

[0064]

[0065] It can be seen from Table 6 that this Example 3 obtained phosphate concentrate with a P2O5 grade of 24.12%, a P2O5 recovery rate of 85.54%, an MgO grade of 0.52%, and an MgO recovery rate of 11.73%. Although the recovery rate of the P2O5 concentrate by this method is high, the P2O5 grade is about 1.58 percentage points lower than that in Example 1.

[0066] Example 4: This Example 4 is a comparative example of Example 2. The ore type processed in this Example 4 is the same as that in Example 2, and the process variables are described in the specific implementation manner. The conditions not described are the same as those in Example 2.

[0067] The specific operation steps are as follows:

[0068] (1) The flotation flow chart is as Figure 2 shown;

[0069] (2) The inhibitor selected in this Example 4 is sulfuric acid. The dosage of sulfuric acid as the roughing inhibitor is 11 kg, and the dosage of sulfuric acid as the cleaning inhibitor is 4 kg;

[0070] (3) In this Example 4, a collector was added in the rough selection operation and the cleaning operation, and after the action, 30 g / t and 20 g / t of the foaming agent No. 2 oil were added respectively and acted for 1 min.

[0071] (4) No medicine was added in the scavenging operation of this Example 4.

[0072] The flotation indexes of this Example 4 are as shown in Table 7 below:

[0073] Table 7 Flotation product indexes of Comparative Example 4

[0074]

[0075] It can be seen from Table 7 that in this Example 4, a phosphate concentrate with a P2O5 grade of 25.37%, a P2O5 recovery rate of 85.41%, an MgO grade of 0.62%, and an MgO recovery rate of 11.49% was obtained. Compared with Example 2 in terms of product indexes, the recovery rate of P2O5 in the concentrate is high, but the P2O5 grade is reduced by 1.74 percentage points.

[0076] The results of Example 3 and Example 4 show that when single sulfuric acid is used as an inhibitor, the separation of apatite and dolomite can be achieved. However, due to the large amount of sulfuric acid used and the need to additionally add a foaming agent, not only the reagent cost is relatively high, but also the corrosion of equipment is serious and the manual maintenance cost is high. Compared with the results of Example 1 and Example 2, when dye waste acid is used to replace part of sulfuric acid as an apatite inhibitor, the treatment cost of dye waste acid in the printing and dyeing factory can be reduced, the environmental hazard can be reduced, at the same time, the amount of sulfuric acid used in the reverse flotation process of phosphate rock is reduced and no foaming agent needs to be used, the reagent cost is reduced, and the ore dressing wastewater reaches the third-level sewage discharge standard of GB8978-1996. The use of dye waste acid as an apatite inhibitor and its application in a reverse flotation process of phosphate rock described in this patent have double significance of economy and environmental protection.

[0077] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can still be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. Application of dye waste acid as an inhibitor in reverse flotation of phosphate rock, characterized in that: The dye waste acid is combined with sulfuric acid as an inhibitor of apatite. The specific steps are as follows: (1) firstly grinding the mixed phosphate ore to obtain a slurry of apatite and dolomite monomer dissociation; (2) adding an inhibitor and a collector in sequence to the monomer dissociated slurry obtained in step (1) to perform a roughing operation to obtain a roughing underflow product and a roughing foam product; (3) adding an inhibitor and a collector to the roughing underflow product obtained in step (2) in sequence to perform a concentrating operation to obtain a concentrating foam product and a concentrating underflow product, wherein the concentrating underflow product is phosphate concentrate; (4) adding sulfuric acid to the roughing foam product obtained in step (2) to perform a scavenging operation to obtain a scavenging underflow product and a scavenging foam product, wherein the scavenging foam product is the phosphate tailings; (5) The scavenged underflow product and the selected foam product are combined and returned to the previous level to form a closed loop.

2. The use of the dye waste acid as an inhibitor in reverse flotation of phosphate rock according to claim 1, characterized in that: The mass ratio of dye waste acid to sulfuric acid in the apatite inhibitor is 2-3:

1.

3. The use of the dye waste acid as an inhibitor in reverse flotation of phosphate rock according to claim 1, characterized in that: In step (1), the grinding fineness of -200 mesh accounts for 84-85%, achieving the monomer dissociation of apatite and dolomite.

4. The use of the dye waste acid as an inhibitor in reverse flotation of phosphate rock according to claim 1, characterized in that: In step (2), the inhibitor is a combination of dye waste acid and sulfuric acid, and the collector is LS-901, wherein the total amount of the inhibitor is 10-11 kg / t, and the amount of the collector LS-901 is 800-900 g / t.

5. The use of the spent dye acid as an inhibitor in reverse flotation of phosphate rock according to claim 1, characterized in that: In step (3), the dosage of the inhibitor is 3-4 kg / t, and the dosage of the collector LS-901 is 300-400 g / t.

6. The method of claim 1 for using waste dye acid as an apatite inhibitor in a phosphate rock reverse flotation process and its application, characterized in that: The amount of sulfuric acid used in step (4) is 1-1.2 kg / t.

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