Efficient flocculation dehydrating agent and preparation method thereof

Abstract

The invention discloses a preparation method of a flocculation dehydrating agent, which comprises the following steps: fully mixing polyacrylamide, a modifier and a catalyst, heating to 70-100 DEG C under the protection of nitrogen, and reacting for 1-4 hours; dispersing polyferric sulfate in chloroform, adding into the previous step, continuously reacting at 70-80 DEG C for 1-2 hours, and centrifugally washing and drying the product to obtain the modified polyferric sulfate. The flocculation dehydrating agent provided by the invention is used for phosphorite flotation tailings, the water content of a filter cake is about 10%, and meanwhile, the prepared flocculation dehydrating agent is compounded with other substances, so that the use effect is better.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-liquid separation, and particularly relates to a high-efficiency flocculating dehydrating agent and a preparation method thereof. Background Art

[0002] Dry discharge and dry stacking of phosphate ore flotation tailings is a major current treatment method. However, due to the fine particle size of the tailings and the difficulty of dehydration, the water content of the tailings after filtration is 15 - 20%, which brings great construction difficulties and tailings pond maintenance workload for the stacking of tailings. At the same time, the loss of water affects the beneficiation water balance and the loss of phosphorus. The conventional solution is to add conventional polyacrylamide flocculants in the concentration stage, and high-efficiency filter presses are used for filtration, but it is difficult to control the filter cake moisture content within 15%. The present invention adds polyferric sulfate, ferric chloride, sodium polyacrylate, biochar, and chitosan acrylamide graft copolymer to polyacrylamide, which not only improves the flocculation of fine particles but also has a filter aid function, effectively improving the tailings dehydration and filtration efficiency. Summary of the Invention

[0003] In view of the above technical problems, the present invention provides a high-efficiency flocculating dehydrating agent and a preparation method thereof, which can quickly pass through a filter press after treating flotation tailings slurry by compounding multiple flocculants.

[0004] (1) Fully mix polyacrylamide, a modifier, and a catalyst, and under the protection of an inert gas, raise the temperature for reaction; (2) Disperse polyferric sulfate in an organic solvent, add it to step (1), continue the reaction, and the product is centrifuged, washed, and dried to obtain modified polyferric sulfate.

[0005] The modifier is at least one of diethylene glycol or triethylene glycol.

[0006] The reaction temperature in step (1) is 70 - 100°C, and the reaction time is 1 - 4 h; the reaction temperature in step (2) is 70 - 80°C, and the reaction time is 1 - 2 h.

[0007] The catalyst in step (1) is an acidic catalyst, preferably sulfuric acid. The mass fraction of the sulfuric acid solution is 1 - 10%, and the mass ratio of polyacrylamide to the sulfuric acid solution is 1:0.02 - 0.2.

[0008] The inert gas in step (1) is at least one of nitrogen, argon, or helium; the organic solvent in step (2) is chloroform. >

[0009] The mass ratio of polyacrylamide to the modifier is 1:0.1 - 0.5; the mass ratio of polyacrylamide to polyferric sulfate is 1:10 - 20.

[0010] The polyacrylamide described above is one of cationic polyacrylamide, anionic polyacrylamide or non-ionic polyacrylamide; preferably, the polyacrylamide is cationic polyacrylamide with a molecular weight of 12 million.

[0011] The present invention also provides a flocculation and dehydration composition, comprising the following components: 50 - 75 parts of modified polymeric ferric sulfate, 0 - 20 parts of ferric chloride, 0 - 5 parts of sodium polyacrylate, 0 - 5 parts of biochar, 0 - 5 parts of chitosan acrylamide graft copolymer; wherein, ferric chloride, sodium polyacrylate and biochar are not all 0 at the same time; Preferably, it comprises the following components: 60 - 75 parts of modified polymeric ferric sulfate, 5 - 15 parts of ferric chloride, 2 - 5 parts of sodium polyacrylate, 2 - 5 parts of biochar, 3 - 5 parts of chitosan acrylamide graft copolymer.

[0012] Application of the above flocculation and dehydration composition in phosphate ore flotation tailings.

[0013] In the technical solution of the present invention, amide groups and hydroxyl groups are modified on the surface of polymeric ferric sulfate to link polymeric ferric sulfate, making it easier to adsorb high-fineness substances on the surface. During the concentration process of flotation tailings, the flocculation and dehydration agent can adsorb on the surface of high-fineness tailings to achieve the effect of flocculation adsorption and dehydration.

[0014] In this solution, by adding a composition including one or more of ferric chloride, sodium polyacrylate, biochar, chitosan acrylamide graft copolymer to the flocculant, wherein chitosan acrylamide graft copolymer is a high molecular polymer, which can rapidly coagulate suspended substances and colloidal particles in water to form larger flocs and accelerate their sedimentation speed, and also has good stability, and can effectively remove turbidity and particulate matters in water.

[0015] The beneficial effects of the present invention are as follows: An efficient flocculation and dehydration agent obtained by the present invention has high stability, and has the advantages of high efficiency and cleanness, and can effectively remove pollutants and turbidity in water. Specific advantages compared with a single flocculation and dehydration agent: good tailings dehydration effect, which can reduce the water content of tailings to about 10%; it can effectively change the problems such as fast flocculation sedimentation but difficult pressing of tailings and high water content of filter cake when using a single flocculation and dehydration agent. Specific Embodiments

[0016] The following will describe the implementation schemes of the present invention in detail in combination with embodiments. The following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0017] In the following examples and comparative examples, the selected tailings slurry is phosphate ore tailings slurry with a water content of 45%, and the main solid components and their proportions are shown in Table 1.

[0018] Table 1

[0019] Example 1 Preparation of the flocculating dehydrating agent (modified polyferric sulfate) comprises the following steps: (1) Thoroughly mix 10 g of polyacrylamide (cationic polyacrylamide, molecular weight 12 million) and 5 g of diethylene glycol, add 2 g of a 1% sulfuric acid solution, and under nitrogen protection, raise the temperature to 100 °C and react for 1 h; (2) Disperse 200 g of polyferric sulfate in 3 kg of chloroform, add the product of step (1), and continue to react at 70 °C for 2 h. The product is centrifuged, washed, and dried to obtain modified polyferric sulfate.

[0020] Example 2 Preparation of the flocculating dehydrating composition: Raw material ratio: 65 parts of the modified polyferric sulfate prepared in Example 1, 15 parts of ferric chloride, 5 parts of sodium polyacrylate, 5 parts of biochar, and 5 parts of chitosan acrylamide graft copolymer.

[0021] The specific preparation process is as follows: Under stirring, add 65 g of the modified polyferric sulfate, 15 g of ferric chloride, 5 g of sodium polyacrylate, 5 g of biochar, and 5 g of chitosan acrylamide graft copolymer. Under normal temperature and pressure, stir evenly at a stirring speed of 100 revolutions per minute for 20 minutes. After stirring, air dry naturally to obtain the high-efficiency flocculating dehydrating agent (flocculating dehydrating composition) of the present invention.

[0022] Add 500 g of tailings slurry to a beaker, start the stirrer and pour 0.02 g of the high-efficiency flocculating dehydrating agent into the beaker. The stirrer speed is 300 revolutions per minute and the stirring time is 10 minutes. After stirring, transfer the solution to a pressure filtration device for dehydration. After dehydration, place the filter cake in an oven to dry, and dry at an oven temperature of 110 °C for 8 h. Calculate the filter cake moisture content according to the following formula:

[0023] where m0 and m1 are the weights of the filter cake before and after flocculation dehydration and drying, respectively.

[0024] The measured moisture content of the filter cake after pressure filtration is 9.07%, the pressure filtration time is 53 min, the turbidity is 25.09 NTU, and the tailings specific resistance SRF = 0.21×10 7 s 2 / g.

[0025] Example 3 The method and steps are the same as those in Example 2. The differences from Example 2 are as follows: 70 g of the modified polyferric sulfate prepared in Example 1, 20 g of ferric chloride, 2 g of sodium polyacrylate, 2 g of biochar, and 3 g of chitosan acrylamide graft copolymer.

[0026] The water content of the filter cake after pressure filtration was measured to be 9.62%, the pressure filtration time was 60 min, and the turbidity was 31.21 NTU. The specific resistance of the tailings SRF = 0.22×10 7 s 2 / g.

[0027] Example 4 The method and steps are the same as those in Example 2. The differences from Example 2 are as follows: 70 g of the modified polyferric sulfate prepared in Example 1, 5 g of ferric chloride, 3 g of sodium polyacrylate, 4 g of biochar, and 3 g of chitosan acrylamide graft copolymer.

[0028] The water content of the filter cake after pressure filtration was measured to be 9.28%, the pressure filtration time was 54 min, and the turbidity was 29.16 NTU. The specific resistance of the tailings SRF = 0.22×10 7 s 2 / g.

[0029] Example 5 The method and steps are the same as those in Example 2. The differences from Example 2 are as follows: 50 g of the modified polyferric sulfate prepared in Example 1, 20 g of ferric chloride, 5 g of sodium polyacrylate, 5 g of biochar, and 5 g of chitosan acrylamide graft copolymer.

[0030] The water content of the filter cake after pressure filtration was measured to be 10.01%, the pressure filtration time was 55 min, and the turbidity was 33.16 NTU. The specific resistance of the tailings SRF = 0.23×10 7 s 2 / g.

[0031] Example 6 Preparation of the flocculation dewatering agent (modified polyferric sulfate), including the following steps: (1) Thoroughly mix 10 g of polyacrylamide (cationic polyacrylamide, molecular weight 12 million) and 5 g of triethylene glycol, add 2 g of a 1% sulfuric acid solution, and under nitrogen protection, heat to 100 °C and react for 1 h; (2) Disperse 200 g of polyferric sulfate in 3 kg of chloroform, add it to step (1), and continue to react at 70 °C for 2 h. The product is centrifuged, washed, and dried to obtain the modified polyferric sulfate.

[0032] Preparation of the flocculation dewatering composition: Raw material ratio: 65 parts of modified polyferric sulfate, 15 parts of ferric chloride, 5 parts of sodium polyacrylate, 5 parts of biochar, and 5 parts of chitosan acrylamide graft copolymer.

[0033] The specific preparation process is as follows: Under stirring, 65 g of the modified polyferric sulfate prepared in this example, 15 g of ferric chloride, 5 g of sodium polyacrylate, 5 g of biochar, and 5 g of chitosan acrylamide graft copolymer are added. Under normal temperature and pressure, it is stirred evenly. The stirring speed is 100 revolutions per minute, and the stirring time is 20 minutes. After stirring, it is naturally air-dried to obtain the high-efficiency flocculant and dehydrating agent (flocculation and dehydration composition) of the present invention.

[0034] The measured moisture content of the filter cake after pressure filtration is 8.40%, the pressure filtration time is 53 min, the turbidity is 23.87 NTU, and the specific resistance of tailings SRF = 0.19×10 7 s 2 / g.

[0035] Comparative Example 1 The method and steps are the same as those in Example 2. The difference from Example 2 is that the modified polyferric sulfate is replaced by unmodified polyferric sulfate.

[0036] The measured moisture content of the filter cake after pressure filtration is 20.12%, the pressure filtration time is 60 min, the turbidity is 39.98 NTU. The specific resistance of tailings SRF = 0.35×10 7 s 2 / g.

[0037] Comparative Example 2 The difference from Example 6 is that the sulfuric acid concentration is 15%, and the rest is the same as Example 6.

[0038] The measured moisture content of the filter cake after pressure filtration is 17.54%, the pressure filtration time is 56 min, the turbidity is 38.06 NTU. The specific resistance of tailings SRF = 0.26×10 7 s 2 / g.

[0039] Comparative Example 3 The difference from Example 6 is that triethylene glycol is replaced by ethylene glycol, and the rest is the same as Example 6.

[0040] The measured moisture content of the filter cake after pressure filtration is 14.83%, the pressure filtration time is 54 min, the turbidity is 35.22 NTU. The specific resistance of tailings SRF = 0.25×10 7 s 2 / g.

Claims

1. A preparation method of a flocculating dehydrating agent, characterized in that, The following steps are involved: (1) Fully mix polyacrylamide, modifier and catalyst, and heat to react under the protection of inert gas; (2) Dispersing the polyferric sulfate in an organic solvent, adding the solution to step (1), and continuing the reaction, the product is washed by centrifugation and dried to obtain modified polyferric sulfate.

2. The preparation method of the flocculating dehydrating agent according to claim 1, characterized in that, The modifier is at least one of diethylene glycol or triethylene glycol.

3. The preparation method of the flocculating dehydrating agent according to claim 1, wherein, The reaction temperature in step (1) is 70-100°C, and the reaction time is 1-4 hours; the reaction temperature in step (2) is 70-80°C, and the reaction time is 1-2 hours.

4. The preparation method of the flocculating dehydrating agent according to claim 1, characterized in that, The catalyst in step (1) is an acidic catalyst, preferably sulfuric acid, the mass fraction of the sulfuric acid solution is 1-10%, and the mass ratio of polyacrylamide to sulfuric acid solution is 1:0.02-0.

2.

5. The preparation method of the flocculating dehydrating agent according to claim 1, wherein, The inert gas in step (1) is at least one of nitrogen, argon or helium; and the organic solvent in step (2) is chloroform.

6. The preparation method of the flocculation dehydrating agent according to claim 1, wherein, The mass ratio of polyacrylamide to modifier is 1:0.1-0.5; the mass ratio of polyacrylamide to polyferric sulfate is 1:10-20.

7. The preparation method of the flocculation dehydrating agent according to claim 1, characterized in that, The polyacrylamide is one of cationic polyacrylamide, anionic polyacrylamide or nonionic polyacrylamide; preferably, the polyacrylamide is cationic polyacrylamide with a molecular weight of 12 million.

8. A flocculating dehydration composition, characterized in that, The invention relates to a modified polymeric ferric sulfate prepared by the preparation method according to any one of claims 2 to 8; the composition comprises the following components: 50-75 parts of modified polymeric ferric sulfate, 0-20 parts of ferric chloride, 0-5 parts of sodium polyacrylate, 0-5 parts of biochar, and 0-5 parts of chitosan acrylamide graft copolymer; wherein the ferric chloride, sodium polyacrylate, and biochar are not all 0 at the same time.

9. The flocculation dehydration composition according to claim 8, characterized in that, The invention comprises the following components: 60-75 parts of modified polyferric sulfate, 5-15 parts of ferric chloride, 2-5 parts of sodium polyacrylate, 2-5 parts of biochar and 3-5 parts of chitosan acrylamide graft copolymer.

10. Use of the flocculation and dehydration composition according to claim 8 in phosphate rock flotation tailings.

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