Fluorine removal agent for mine water gas flotation integrated process and preparation method thereof

Abstract

The application relates to the technical field of water treatment, and discloses a defluorination agent for a mine water air flotation defluorination integrated process and a preparation method thereof, the preparation method comprising the following steps: proportionally mixing sodium aluminate, water-soluble sodium silicate, rare earth oxides, active kaolin, magnesium hydroxide or calcium hydroxide and disodium hydrogen phosphate, wet grinding, drying, high-temperature sintering, crushing, adding deionized water for stirring and dispersing, and then adding citric acid or sodium tripolyphosphate and PAC powder, and stirring and aging to obtain the defluorination agent. The prepared defluorination agent has high reaction activity, moderate pH and dense flocs, and is suitable for efficient removal of fluorine ions in high-flow mine water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a defluorination agent for mine water air flotation defluorination integrated process and a preparation method thereof. BACKGROUND

[0002] Coal mine water is essentially groundwater, which is the groundwater near the coal seam and the development roadway in the mining area. Fluoride in mine water is one of the main pollutants in water. The fluorine in mine water is mainly formed by weathering, leaching, migration and enrichment of the original fluorine in the commonly existing apatite and fluorite in the stratum. Long-term drinking of high-fluorine water can cause fluorine ions to combine with calcium ions in the blood to form insoluble calcium fluoride, which can cause hypocalcemia and even osteoporosis and osteosclerosis.

[0003] The fluoride concentration in mine water is usually required to be less than 1 mg / L. In actual operation, it is difficult to limit the fluoride to 1 mg / L in the face of large water inflow from coal mines.

[0004] Currently, the defluorination processes used in industry include chemical precipitation, resin exchange, adsorption, coagulation sedimentation, electrocoagulation and electrodialysis. Among them, the chemical precipitation method is generally used to treat high-fluorine wastewater. By adding calcium ions to the fluorine-containing water, the fluorine ions react to form insoluble substances, and then the fluorine ions are removed by solid-liquid separation. However, a large number of experimental studies have shown that when the concentration of fluorine ions in the solution is reduced to about 10 mg / L, its concentration will not change much with the increase of the concentration of calcium ions. The resin exchange method, also known as ion exchange method, commonly uses amino phosphoric acid resin which has a strong complexation effect on fluorine ions. The maximum adsorption capacity of the resin is 9.31 mg / L, and the removal rate is greater than 75%. Luo Ting et al. used ion exchange resin method to reduce the fluorine concentration to about 0.35 mg / L, but it was limited by the flow rate (15-18 m / s) and exchange capacity (7-10 mg / L), and was not suitable for large water inflow conditions. Zheng Lixiang et al. explored the effect of lanthanum-loaded activated alumina on defluorination and found that the surface hydroxyl groups provided by La2O3 could exchange with fluorine ions to achieve the purpose of removal. The fluorine ion concentration can be reduced to below 1 mg / L at a running cost of about 1.159 yuan / t. However, the defluorination capacity of general adsorbents is low, resulting in large equipment, and the adsorbent needs to be regenerated after saturation, and the regeneration effect will decrease, and the cost of replacing the filter material is high. Therefore, the use of adsorption method also has its limitations and disadvantages. The coagulation sedimentation method, electrocoagulation method and electrodialysis method cannot be used for defluorination process under large water inflow conditions due to various disadvantages.

[0005] Therefore, it is necessary to develop a defluorination agent with excellent defluorination performance under the condition of large water inflow. SUMMARY

[0006] In view of this, the present application provides a defluorination agent for mine water flotation defluorination integrated process and a preparation method thereof, aiming at solving the problems existing in the above content.

[0007] In one aspect, the preparation method of the defluorination agent for mine water flotation defluorination integrated process provided by the present application comprises the following steps:

[0008] (1) Mix sodium aluminate 20-30 parts, water-soluble sodium silicate 10-20 parts, rare earth oxide 1-5 parts, active kaolin 15-25 parts, disodium hydrogen phosphate 1-3 parts, and magnesium hydroxide or calcium hydroxide 10-15 parts by mass fraction to obtain a mixed raw material;

[0009] (2) Wet mill the mixed raw material in a planetary ball mill for 2h to form a uniform precursor mixture;

[0010] (3) Dry the precursor mixture and then sinter it at a high temperature, the sintering temperature is 950-1050℃, the holding time is 2-4h, to obtain a sintered solid;

[0011] (4) Grind and sieve the sintered solid after cooling to room temperature, the sieve size is 50-150μm, to obtain an active powder;

[0012] (5) Add the active powder to deionized water, the mass ratio of the active powder to deionized water is 18:1, stir for 30min and ultrasonic disperse for 10min to obtain a dispersion slurry;

[0013] (6) Add 0.1-0.3 parts of citric acid or sodium tripolyphosphate by mass fraction to the dispersion slurry, and add 0.5-2.0 parts of PAC powder by mass fraction, continue to stir for 20min, and stand for aging for 24h to obtain the defluorination agent.

[0014] Preferably, the rare earth oxide is lanthanum oxide and cerium oxide, and the mass ratio of lanthanum oxide to cerium oxide is 2-1:1.

[0015] Preferably, deionized water is used as the dispersion medium in the wet ball milling process, and the liquid-solid mass ratio is controlled to be 1.5-2.5:1.

[0016] Preferably, the sintering process is carried out in nitrogen or argon, and the flow rate is controlled at 50-150mL / min.

[0017] Preferably, after adding the disodium hydrogen phosphate, the pH value of the 1% volume fraction of the defluorination agent aqueous solution is 3.5-6.5.

[0018] Preferably, the standing time during the aging process is not less than 24h, and the temperature is controlled within the range of 20-30℃.

[0019] Preferably, the active powder has a nanoscale porous structure of 5-50 nm and a specific surface area greater than 150 m². 2 / g.

[0020] Preferably, anionic polyacrylamide powder with a mass fraction of 0.1 to 0.3 parts is added to the dispersion obtained in step (6).

[0021] On the other hand, the present invention also protects the defluorinating agent used in the integrated defluorination process of mine water flotation obtained by the above preparation method.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1) This invention overcomes the problems of excessive acidity and corrosiveness of existing defluorinating agents on the market. It has many active sites and reacts quickly. Under the same conditions, when the dosage is 40 mg / L, the concentration of F ions in the raw water can be reduced from 1.62 mg / L to 0.73 mg / L, and the defluorination effect is obvious. If the dosage is increased to 100 mg / L, the defluorination rate can reach more than 70%.

[0024] 2) The defluoridating agent of the present invention exhibits excellent defluoridation effect on the effluent of pre-sedimentation tank with high solids content.

[0025] 3) The defluoridator of the present invention has a wide range of applications, and the defluoridation effect is best in the raw water pH range of 7-9.

[0026] 4) The optimal dosage of the defluorinating agent of this invention is 30 mg / L for PAC and 1.0 mg / L for PAM.

[0027] 5) Using complexation-induced defluoridating agents to remove fluoride from mine water has the advantages of simple process, stable treatment effect, easy operation and management and low treatment cost.

[0028] 6) The air flotation defluorination integrated process is also applicable to the deep defluorination process of high-fluoride wastewater in the photovoltaic industry and the deep defluorination process of high-fluoride wastewater in the chip processing industry. Attached Figure Description

[0029] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0030] Figure 1 The SS=80-150mg / L defluorinating agent dosage provided in this embodiment of the invention affects the removal of fluoride after fluoride removal. - Concentration effect diagram.

[0031] Figure 2The SS = 80-150 mg / L provided by the embodiment of the present application, the defluorination agent dosage has influence on F - The F removal rate influence graph.

[0032] Figure 3 The SS = 3-5 mg / L provided by the embodiment of the present application, the defluorination agent dosage has influence on F - The F concentration influence graph.

[0033] Figure 4 The SS = 3-5 mg / L provided by the embodiment of the present application, the defluorination agent dosage has influence on F - The F removal rate influence graph.

[0034] Figure 5 The initial F concentration provided by the embodiment of the present application has influence on F - The F concentration influence graph.

[0035] Figure 6 The initial F concentration provided by the embodiment of the present application has influence on F - The F removal rate influence graph.

[0036] Figure 7 The initial PH provided by the embodiment of the present application has influence on F - The F concentration influence graph.

[0037] Figure 8 The PAC dosage provided by the embodiment of the present application has influence on F - The F concentration influence graph.

[0038] Figure 9 The PAC dosage provided by the embodiment of the present application has influence on the removal rate.

[0039] Figure 10 The PAM dosage provided by the embodiment of the present application has influence on F - The F concentration influence graph.

[0040] Figure 11 The PAM dosage provided by the embodiment of the present application has influence on F - The F removal rate influence graph.

[0041] Figure 12 The defluorination effect detection graph of the defluorination agent provided by the embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0043] Embodiment

[0044] (1) Raw material ratio: 25 parts of sodium aluminate, 15 parts of water-soluble sodium silicate, 4 parts of rare earth oxides (the mass ratio of lanthanum oxide to cerium oxide is 2:1), 20 parts of active kaolin, 12 parts of magnesium hydroxide and 2 parts of disodium hydrogen phosphate are weighed according to the mass fraction, and are uniformly mixed to obtain a mixed raw material;

[0045] (2) Wet grinding treatment: the mixed raw material is added into deionized water for wet grinding, the liquid-solid mass ratio is 2:1, wet grinding is performed in a planetary ball mill for 2 hours to form a uniform precursor mixture;

[0046] (3) Sintering activation: after the precursor mixture is dried, sintering is performed at 1000°C for 3 hours under a nitrogen atmosphere (flow rate 100 mL / min) to obtain a sintered solid;

[0047] (4) Crushing and sieving: after the sintered solid is cooled to room temperature, it is crushed and sieved to control the particle size at 80-150 μm to obtain an active powder, and the specific surface area of which is greater than 150 m 2 / g, and the pore size is mainly distributed in the range of 5-50 nm;

[0048] (5) Dispersion treatment: the obtained active powder is added into deionized water at a mass ratio of 18:1, stirred for 30 minutes and ultrasonically dispersed for 10 minutes to prepare a dispersion slurry;

[0049] (6) Component compounding: 0.2 parts of citric acid and 1.5 parts of PAC powder are added into the dispersion slurry, 0.2 parts of anionic polyacrylamide powder is added at the same time, and stirring is continued for 20 minutes, and aging is performed at 25°C for 24 hours to obtain a final fluorine removal agent.

[0050] The fluorine removal performance of the fluorine removal agent in this embodiment is tested in a small-scale industrial test as follows:

[0051] Test instrument

[0052] Shanghai Sixin Fluoride Ion Concentration Meter: WS100 type

[0053] Lei magnet portable ion meter: PXBJ-216F

[0054] Miko pH detector: MIK-PH160S

[0055] Test scheme design

[0056] The industrial site water treatment plant has about 28000m 3 / d, there are two sets of water purification system in parallel, each set of operation when the water treatment capacity of 600m 3 / h, the fluoride content of raw water is about 2mg / L, fluoride source is mainly produced when coal mining, the required emission standard is <1.0mg / L).

[0057] Using a PAC liquid preparation tank, according to 20-30% concentration (mass percent) of fluoride removal agent solution, through two PAC dosing pump, fluoride removal agent is added to the pipe inlet position of the regulating pool lifting pump, after the coagulation reaction tank, inclined tube sedimentation tank, discharge into the transfer pool. According to the fluoride ion concentration in the water, the dosage is adjusted, the fluoride ion content in the water is detected once every hour.

[0058] Experimental study

[0059] (1) the influence of fluoride removal agent dosage on the effect of fluoride removal

[0060] 1) in the raw water turbidity SS = 80-150mg / L, the influence of fluoride removal agent dosage on the effect of fluoride removal small industrial test

[0061] Table 1 the influence of fluoride removal agent dosage on the effect of fluoride removal (SS = 80-150(mg / L))

[0062]

[0063] From Figure 1 it can be seen that when the raw water turbidity SS is about 150mg / L, the PAM dosage is 1.0mg / L, the PAC dosage is 30-50mg / L, with the increase of fluoride removal agent dosage from 40 to 120mg / L, the effluent F ion concentration gradually decreases; fluoride removal agent dosage 40mg / L can reduce the fluoride ion from 1.62mg / L to 0.73mg / L.

[0064] From Figure 2 it can be seen that when the raw water turbidity SS is about 150mg / L, the PAM dosage is 1.0mg / L, the PAC dosage is 30-50mg / L, with the increase of fluoride removal agent dosage from 40 to 120mg / L, the defluorination rate gradually increases; the defluorination rate is 61.11% when the fluoride removal agent dosage is 40mg / L; the defluorination rate is 84.57% when the fluoride removal agent dosage is 120mg / L.

[0065] 2) in the raw water turbidity SS = 3-5mg / L, the influence of fluoride removal agent dosage on the effect of fluoride removal small industrial test

[0066] Table 2 Effect of defluorination agent dosage on defluorination effect (SS = 3-5 (mg / L)

[0067]

[0068] 3) Effect of defluorination agent dosage on defluorination effect when SS = 3-5 mg / L

[0069] From Figure 3 it can be seen that when the raw water turbidity SS is about 3-5 mg / L, i.e. the pretreatment process effluent, the PAM dosage is 0.5, 1.0, 2.0 mg / L, and as the defluorination agent dosage increases from 40 to 60 mg / L, the effluent F ion concentration slightly increases; from 60 to 120 mg / L, the effluent F ion concentration gradually decreases; the defluorination agent dosage of 120 mg / L can reduce the raw water F ion from 1.62 mg / L to 0.63 mg / L.

[0070] From Figure 4 it can be seen that when the raw water turbidity SS is about 3-5 mg / L, i.e. the pretreatment process effluent, the PAM dosage is 0.5, 1.0, 2.0 mg / L, and as the defluorination agent dosage increases from 40 to 60 mg / L, the defluorination rate slightly decreases; from 60 to 120 mg / L, the defluorination rate gradually increases; the defluorination rate is the highest 68.18% when the defluorination agent dosage is 120 mg / L.

[0071] (2) Effect of initial fluorine ion concentration on defluorination effect

[0072] 1) Effect of initial fluorine ion concentration on defluorination effect

[0073] Table 3 Effect of initial fluorine ion concentration on defluorination effect

[0074]

[0075] From Figure 5 , 6 it can be seen that when the PAM dosage is 1.0 mg / L, the PAC dosage is 30 mg / L, and the defluorination agent dosage is 60 mg / L, as the raw water F ion concentration increases, the defluorination rate slightly increases; the defluorination rate basically maintains at 50-55%.

[0076] (3) Effect of initial pH on defluorination effect

[0077] Table 4 Effect of initial pH on defluorination effect

[0078]

[0079] From Figure 7 , Figure 8It can be seen that when the PAM dosage is 1.0 mg / L, the PAC dosage is 30 mg / L, and the defluorination agent dosage is 60 mg / L, the defluorination rate gradually increases with the increase of the pH of raw water; when the pH of raw water reaches 9, the defluorination rate gradually decreases with the increase of the pH of raw water. Because too much OH- in water consumes the positive potential of the defluorination agent, the defluorination rate decreases. The optimal pH range of the defluorination agent for raw water is 7-9.

[0080] (4) Effect of PAC dosage on defluorination effect

[0081] 1) Effect of PAC dosage on defluorination effect (I)

[0082] Table 5 Effect of dosage on defluorination effect (I)

[0083]

[0084] 2) Effect of PAC dosage on defluorination effect (II)

[0085] Table 6 Effect of PAC dosage on defluorination effect (II)

[0086]

[0087] From Figure 9 It can be seen that when the PAM dosage is 0.5 mg / L and the defluorination agent dosage is 60 mg / L, the fluoride ion concentration gradually decreases as the PAC dosage increases from 15 mg / L to 60 mg / L; when the PAC dosage is 60 mg / L, the fluoride ion concentration is the lowest, 0.58 mg / L. When the PAM dosage is 1.0 mg / L and the defluorination agent dosage is 60 mg / L, the F ion concentration gradually decreases as the PAC dosage increases from 15 mg / L to 45 mg / L; when the PAC dosage increases from 45 mg / L to 60 mg / L, the F ion concentration remains basically unchanged.

[0088] From Figure 10 It can be seen that when the PAM dosage is 0.5 mg / L and the defluorination agent dosage is 60 mg / L, the defluorination rate gradually increases as the PAC dosage increases from 15 mg / L to 60 mg / L; when the PAC dosage is 60 mg / L, the defluorination rate is the maximum, 64.2%. When the PAM dosage is 1.0 mg / L and the defluorination agent dosage is 60 mg / L, the defluorination rate gradually increases as the PAC dosage increases from 15 mg / L to 60 mg / L; when the PAC dosage reaches 45 mg / L, the maximum defluorination rate tends to be stable as the PAC dosage increases.

[0089] (5) Effect of PAM dosage on defluorination effect

[0090] 1) Effect of PAM dosage on defluorination effect (I)

[0091] Table 7 PAM dosage on the effect of fluoride removal agent fluoride removal (one)

[0092]

[0093] 2) PAM dosage on the effect of fluoride removal agent fluoride removal (two)

[0094] Table 8 PAM dosage on the effect of fluoride removal (two)

[0095]

[0096] 3) PAM dosage on the effect of fluoride removal agent fluoride removal (three)

[0097] Table 9 PAM dosage on the effect of fluoride removal (three)

[0098]

[0099] From Figure 11 , 12 it can be seen that when the PAC dosage is 30 mg / L and the fluoride removal agent dosage is 60 mg / L, the F ion concentration gradually decreases as the PAM dosage increases from 0.5 mg / L to 2.0 mg / L; when the PAC dosage is 45 mg / L and the fluoride removal agent dosage is 60 mg / L, the F ion concentration slightly decreases as the PAM dosage increases from 0.5 mg / L to 1.5 mg / L, and if the PAM is further increased, the F ion concentration slightly increases; when the PAC dosage is 60 mg / L and the fluoride removal agent dosage is 60 mg / L, the F ion concentration slightly increases as the PAM dosage increases from 0.5 mg / L to 1.0 mg / L, and slightly decreases as the PAM dosage increases from 1.0 mg / L to 2.0 mg / L.

[0100] (6) Fluoride removal effect detection of fluoride removal agent

[0101] Select the products of three representative domestic manufacturers of fluoride removal agents, the form and origin are shown in Table 10.

[0102] Table 10 Fluoride removal agent form and origin table

[0103]

[0104] The above three fluoride removal agents (F1-F3) and the fluoride removal agent of the present embodiment were monitored for fluoride removal time and anion concentration in water under the same environment and the same parameters, and the results are shown in Table 11, and the corresponding line graph of Table 11 is shown in Figure 12 .

[0105] Table 11 Reaction time comparison table

[0106]

[0107] From the table, it can be seen that: the existing fluorine removal reaction time of coagulation and sedimentation fluorine removal agent on the market is generally 30-60min (reducing the negative ion concentration to less than 1mg / L), and the reaction time is difficult to meet the actual requirements; the components formed by the reaction of the existing coagulation and sedimentation fluorine removal agent on the market with F ions in wastewater are complex, the floc is small, and it is not easy to be captured by PAC and PAM, resulting in that the SS of the effluent exceeds the standard and the index requirement of SS less than 10mg / L cannot be met; the existing coagulation and sedimentation fluorine removal agent on the market will cause new pollutants to enter the water body, although it plays a certain role in fluorine removal, but it increases new ions such as Cl-, SO42-, Al3+, Mg2+, SiO3, etc., which brings trouble and pressure to subsequent treatment, and if it is used as an end treatment process, it will cause other indicators that have already met the standard to exceed the standard. The fluorine removal agent of the embodiment fundamentally solves the above problems.

[0108] Specifically, the fluorine removal agent powder of the embodiment has a particle size of 50-150um, can be quickly dissolved in water to form a spatial network flocculation framework.

[0109] Through the calcination process, a spatial framework of silicate (MSiO3) is formed, and a certain proportion of aluminum atoms replaces silicon atoms to form aluminum-silicon-oxygen tetrahedron, which is stable in structure and will not release metal ions in water.

[0110] The fluorine removal agent powder after activation forms a nano-porous structure with a pore size distribution of 5-50nm, and since Si-F bond, Al-F bond, Ca-F bond, Mg-F bond, etc. have strong bonding effect, they can lock fluorine ions firmly in the framework structure, and then assist the capture effect of PAC and PAM, so that the fluorine removal rate is high, the effect is good, and the SS index of the effluent is less than 10mg / L, which can be used as an end treatment process.

[0111] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A method for preparing a fluorine removal agent for a mine water gas flotation fluorine removal integrated process, characterized in that, The method comprises the following steps: (1) mixing sodium aluminate 20-30 parts by mass, water-soluble sodium silicate 10-20 parts by mass, rare earth oxide 1-5 parts by mass, active kaolin 15-25 parts by mass, sodium hydrogen phosphate 1-3 parts by mass, and magnesium hydroxide or calcium hydroxide 10-15 parts by mass by mass fraction to obtain mixed raw materials; (2) wet-milling the mixed raw materials in a planetary ball mill for 2 hours to form a uniform precursor mixture; (3) drying the precursor mixture and then high-temperature sintering, with a sintering temperature of 950-1050°C and a holding time of 2-4 hours, to obtain a sintered solid; (4) crushing and sieving the sintered solid after cooling to room temperature, with a sieving particle size of 50-150 μm, to obtain an active powder; (5) adding the active powder to deionized water, with a mass ratio of the active powder to deionized water of 18:1, stirring for 30 minutes and ultrasonic dispersion for 10 minutes to obtain a dispersion slurry; (6) adding 0.1-0.3 parts by mass of citric acid or sodium tripolyphosphate and 0.5-2.0 parts by mass of PAC powder to the dispersion slurry, continuing to stir for 20 minutes, and standing for aging for 24 hours to obtain a defluorination agent; The active powder is a nano-sized porous structure of 5-50 nm, with a specific surface area of greater than 150 m 2 / g.

2. The method for preparing a fluorine removal agent for a mine water gas floatation fluorine integrated process according to claim 1, characterized in that, The rare earth oxide is lanthanum oxide and cerium oxide, with a mass ratio of lanthanum oxide:cerium oxide = 2-1:

1.

3. The method for preparing the defluorinating agent for the integrated mine water flotation defluorination process according to claim 1, characterized in that, Deionized water is used as a dispersion medium in the wet-milling process, with a liquid-solid mass ratio controlled at 1.5-2.5:

1.

4. The method for preparing the defluorinating agent for the integrated mine water flotation defluorination process according to claim 1, characterized in that, The sintering process is carried out in nitrogen or argon, with a flow rate controlled at 50-150 mL / min.

5. The method for preparing the defluorinating agent for the integrated mine water flotation defluorination process according to claim 1, characterized in that, After adding the sodium hydrogen phosphate, the pH value of a 1% volume fraction defluorination agent aqueous solution is 3.5-6.

5.

6. The method for preparing the defluorinating agent for the integrated mine water flotation defluorination process according to claim 1, characterized in that, The standing time in the aging process is not less than 24 hours, and the temperature is controlled within a range of 20-30°C.

7. The method for preparing the defluorinating agent for the integrated mine water flotation defluorination process according to claim 1, characterized in that, Anionic polyacrylamide powder is added to the dispersion liquid obtained in step (6).

8. A defluorination agent for mine water gas floatation and defluorination integrated process, which is obtained by the preparation method of any one of claims 1-7.

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