High-efficiency flocculating dewatering agent and preparation method thereof

Abstract

The application discloses a preparation method of a flocculation dewatering agent, and comprises the following steps: fully mixing polyacrylamide, a modifier and a catalyst, and reacting under nitrogen protection and at 70-100 DEG C for 1-4 hours; dispersing polymeric ferric sulfate in chloroform, adding the above step, and continuing to react at 70-80 DEG C for 1-2 hours; and obtaining modified polymeric ferric sulfate after centrifugal washing and drying of the product. The flocculation dewatering agent provided by the application is used in phosphate ore flotation tailings, and the moisture content of the filter cake is about 10%, and meanwhile, the prepared flocculation dewatering agent is used in combination with other substances, and the effect is better.

Description

Technical Field

[0001] This invention belongs to the field of solid-liquid separation technology, specifically relating to a highly efficient flocculant and dehydrating agent and its preparation method. Background Technology

[0002] Dry stacking of phosphate rock flotation tailings is currently a major treatment method. However, due to the fine particle size of the tailings, dewatering is difficult, resulting in a moisture content of 15-20% after filtration. This brings significant construction difficulties and maintenance workload to the tailings storage, while water loss affects the mineral processing water balance and phosphorus loss. Conventional solutions involve adding conventional polyacrylamide flocculants during the concentration stage and using high-efficiency filter presses for filtration, but it is difficult to control the filter cake moisture content below 15%. This invention adds polyferric sulfate, ferric chloride, sodium polyacrylate, biochar, and chitosan-acrylamide graft copolymer to polyacrylamide, enhancing the flocculation of fine particles while also providing filtration assistance, effectively improving tailings dewatering and filtration efficiency. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a highly efficient flocculant and dewatering agent and its preparation method, which uses a combination of various flocculants to treat flotation tailings slurry, enabling it to be rapidly filtered through pressure.

[0004] (1) Mix polyacrylamide, modifier and catalyst thoroughly, and heat to react under inert gas protection;

[0005] (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.

[0006] The modifier is at least one of diethylene glycol or triethylene glycol.

[0007] The reaction temperature in step (1) is 70-100℃ and the reaction time is 1-4h; the reaction temperature in step (2) is 70-80℃ and the reaction time is 1-2h.

[0008] The catalyst in step (1) is an acidic catalyst, preferably sulfuric acid, with a mass fraction of 1-10% and a mass ratio of polyacrylamide to sulfuric acid solution of 1:0.02-0.2.

[0009] The inert gas in step (1) is at least one of nitrogen, argon or helium; the organic solvent in step (2) is chloroform.

[0010] 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.

[0011] 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.

[0012] The present invention also provides a flocculation and dehydration composition comprising the following components: 50-75 parts of modified polyferric 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, ferric chloride, sodium polyacrylate, and biochar are not simultaneously 0 parts.

[0013] Preferably, it 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.

[0014] Application of the above-mentioned flocculation and dewatering composition in phosphate rock flotation tailings.

[0015] In this invention, amide and hydroxyl groups are modified on the surface of polyferric sulfate to link the polyferric sulfate, making the surface more susceptible to adsorption of finer substances. During the concentration process of flotation tailings, the flocculant can adsorb finer tailings onto the surface, achieving the effect of flocculation, adsorption, and dehydration.

[0016] In this scheme, a composition including ferric chloride, sodium polyacrylate, biochar, and chitosan acrylamide graft copolymer is added to the flocculant. The chitosan acrylamide graft copolymer is a high molecular polymer that can rapidly coagulate suspended solids and colloidal particles in water to form larger flocs and accelerate their settling speed. It also has good stability and can effectively remove turbidity and particulate matter from water.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention provides a highly efficient flocculant dewatering agent with high stability and advantages such as high efficiency and cleanliness, effectively removing pollutants and turbidity from water. Specifically, compared to single flocculant dewatering agents, it offers the following advantages: better tailings dewatering effect, reducing tailings moisture content to approximately 10%; and it effectively addresses the problems encountered when using single flocculant dewatering agents, such as rapid flocculation and sedimentation leading to difficulty in tailings compression, and easy tailings compression resulting in high filter cake moisture content. Detailed Implementation

[0019] The embodiments of the present invention will be described in detail below with reference to the examples. The following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0020] In the following examples and comparative examples, the tailings slurry used was phosphate rock tailings slurry with a water content of 45%. Its main solid components and proportions are shown in Table 1.

[0021] Table 1

[0022]

[0023] Example 1

[0024] The preparation of the flocculant dehydrating agent (modified polyferric sulfate) includes the following steps:

[0025] (1) Mix 10g of polyacrylamide (cationic polyacrylamide with a molecular weight of 12 million) and 5g of diethylene glycol thoroughly, and add 2g of sulfuric acid solution with a mass fraction of 1%. Under nitrogen protection, heat to 100℃ and react for 1h.

[0026] (2) Disperse 200g of polyferric sulfate in 3kg of chloroform, add it to step (1), and continue to react at 70℃ for 2h. The product is centrifuged, washed and dried to obtain modified polyferric sulfate.

[0027] Example 2

[0028] Preparation of flocculation and dehydration composition:

[0029] Raw material ratio: 65 parts of 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.

[0030] The specific preparation process is as follows: 65g of modified polyferric sulfate, 15g of ferric chloride, 5g of sodium polyacrylate, 5g of biochar, and 5g of chitosan-acrylamide graft copolymer are added under stirring. The mixture is stirred evenly at room temperature and pressure at a stirring speed of 100 rpm for 20 minutes. After stirring, it is allowed to air dry naturally to obtain the high-efficiency flocculant dehydrating agent (flocculation dehydration composition) of this invention.

[0031] Add 500g of tailings slurry to a beaker, start the stirrer, and pour 0.02g of high-efficiency flocculant / dewatering agent into the beaker. Stir at 300 rpm for 10 minutes. After stirring, transfer the solution to a filter press for dewatering. After dewatering, place the filter cake in an oven to dry at 110℃ for 8 hours. Calculate the moisture content of the filter cake using the following formula:

[0032]

[0033] Where m0 and m1 are the weights of the filter cake before flocculation, dehydration and drying and the weights of the filter cake after dehydration and drying, respectively.

[0034] The measured moisture content of the filter cake after pressure filtration was 9.07%, the filtration time was 53 min, the turbidity was 25.09 NTU, and the tailings specific resistance (SRF) was 0.21 × 10⁻⁶. 7 s2 / g.

[0035] Example 3

[0036] The method and steps are the same as in Example 2, except that the modified polyferric sulfate 70g, ferric chloride 20g, sodium polyacrylate 2g, biochar 2g, and chitosan acrylamide graft copolymer 3g were prepared in Example 1.

[0037] The moisture content of the filter cake after pressure filtration was measured to be 9.62%, the filtration time was 60 min, and the turbidity was 31.21 NTU. The specific resistance of the tailings, SRF, was 0.22 × 10⁻⁶ NTU. 7 s 2 / g.

[0038] Example 4

[0039] The method and steps are the same as in Example 2, except that the modified polyferric sulfate 70g, ferric chloride 5g, sodium polyacrylate 3g, biochar 4g, and chitosan acrylamide graft copolymer 3g were prepared in Example 1.

[0040] The moisture content of the filter cake after pressure filtration was measured to be 9.28%, the filtration time was 54 min, and the turbidity was 29.16 NTU. The specific resistance of the tailings, SRF, was 0.22 × 10⁻⁶ NTU. 7 s 2 / g.

[0041] Example 5

[0042] The method and steps are the same as in Example 2, except that the modified polyferric sulfate 50g, ferric chloride 20g, sodium polyacrylate 5g, biochar 5g, and chitosan acrylamide graft copolymer 5g were prepared in Example 1.

[0043] The moisture content of the filter cake after pressure filtration was measured to be 10.01%, the filtration time was 55 min, and the turbidity was 33.16 NTU. The specific resistance of the tailings, SRF, was 0.23 × 10⁻⁶ NTU. 7 s 2 / g.

[0044] Example 6

[0045] The preparation of the flocculant dehydrating agent (modified polyferric sulfate) includes the following steps:

[0046] (1) Mix 10g of polyacrylamide (cationic polyacrylamide with a molecular weight of 12 million) and 5g of triethylene glycol thoroughly, and add 2g of sulfuric acid solution with a mass fraction of 1%. Under nitrogen protection, heat to 100℃ and react for 1h.

[0047] (2) Disperse 200g of polyferric sulfate in 3kg of chloroform, add it to step (1), and continue to react at 70℃ for 2h. The product is centrifuged, washed and dried to obtain modified polyferric sulfate.

[0048] Preparation of flocculation and dehydration composition:

[0049] Raw material ratio: 65 parts modified polyferric sulfate, 15 parts ferric chloride, 5 parts sodium polyacrylate, 5 parts biochar, and 5 parts chitosan acrylamide graft copolymer.

[0050] The specific preparation process is as follows: Under stirring, add 65g of modified polyferric sulfate, 15g of ferric chloride, 5g of sodium polyacrylate, 5g of biochar, and 5g of chitosan-acrylamide graft copolymer prepared in this embodiment. Stir evenly at room temperature and pressure, with a stirring speed of 100 rpm and a stirring time of 20 minutes. After stirring, allow to air dry naturally to obtain the high-efficiency flocculant dehydrating agent (flocculation dehydrating composition) of this invention.

[0051] The measured moisture content of the filter cake after pressure filtration was 8.40%, the filtration time was 53 min, the turbidity was 23.87 NTU, and the tailings specific resistance (SRF) was 0.19 × 10⁻⁶. 7 s 2 / g.

[0052] Comparative Example 1

[0053] The method and steps are the same as in Example 2, except that the modified polyferric sulfate is replaced with unmodified polyferric sulfate.

[0054] The moisture content of the filter cake after pressure filtration was measured to be 20.12%, the filtration time was 60 min, and the turbidity was 39.98 NTU. The specific resistance of the tailings, SRF, was 0.35 × 10⁻⁶. 7 s 2 / g.

[0055] Comparative Example 2

[0056] The difference from Example 6 is that the sulfuric acid concentration is 15%, while the rest is the same as in Example 6.

[0057] The moisture content of the filter cake after pressure filtration was measured to be 17.54%, the filtration time was 56 min, and the turbidity was 38.06 NTU. The specific resistance of the tailings, SRF, was 0.26 × 10⁻⁶ NTU. 7 s 2 / g.

[0058] Comparative Example 3

[0059] The difference from Example 6 is that triethylene glycol is replaced with ethylene glycol, otherwise the same as in Example 6.

[0060] The moisture content of the filter cake after pressure filtration was measured to be 14.83%, the filtration time was 54 min, and the turbidity was 35.22 NTU. The specific resistance of the tailings, SRF, was 0.25 × 10⁻⁶. 7 s 2 / g.

Claims

1. A method for preparing a flocculating dewatering agent, characterized by, It comprises the following steps: (1) mixing polyacrylamide, modifier and catalyst, and reacting under the protection of inert gas; (2) dispersing polymeric ferric sulfate in organic solvent, adding it into step (1), and continuing the reaction, and then centrifuging, washing and drying the product to obtain modified polymeric ferric sulfate; The modifier is at least one of diethylene glycol or triethylene glycol; The reaction temperature in step (1) is 70-100℃, and the reaction time is 1-4h; the reaction temperature in step (2) is 70-80℃, and the reaction time is 1-2h; The catalyst in step (1) is sulfuric acid, and the mass fraction of the sulfuric acid solution is 1-10%.

2. The method of claim 1, wherein the flocculating dehydrating agent is prepared by the steps of: The mass ratio of polyacrylamide to sulfuric acid solution is 1:0.02-0.

2.

3. The method of claim 1, wherein the flocculating dehydrating agent is prepared by the steps of: The inert gas in step (1) is at least one of nitrogen, argon or helium; the organic solvent in step (2) is chloroform.

4. The method of claim 1, wherein the flocculating dehydrating agent is prepared by the steps of: The mass ratio of polyacrylamide to modifier is 1:0.1-0.5; and the mass ratio of polyacrylamide to polymeric ferric sulfate is 1:10-20.

5. The method for preparing the flocculant and dehydrating agent according to claim 1, characterized in that, The polyacrylamide is one of cationic polyacrylamide, anionic polyacrylamide or non-ionic polyacrylamide.

6. The method of claim 1, wherein the flocculating dehydrating agent is prepared by the steps of: The polyacrylamide is cationic polyacrylamide with a molecular weight of 12 million.

7. A flocculating dewatering composition characterized in that, The composition comprises the following components: 50-75 parts of modified polymeric ferric sulfate, 5-20 parts of ferric chloride, 2-5 parts of sodium polyacrylate, 2-5 parts of biochar and 3-5 parts of chitosan acrylamide graft copolymer.

8. A flocculating dewatering composition according to claim 7, wherein, The composition 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 and 3-5 parts of chitosan acrylamide graft copolymer.

9. The use of the flocculation dewatering composition of claim 7 in phosphate ore flotation tailings.

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