Treatment method of hydrometallurgy extraction wastewater

Abstract

The invention provides a hydrometallurgy extraction wastewater treatment method, which comprises: (1) mixing extraction wastewater and a calcium source, carrying out primary stirring, and carrying out solid-liquid separation to obtain a first filtrate; (2) mixing the first filtrate and carbonate, carrying out secondary stirring, and filtering to remove calcium, so as to obtain a second filtrate; (3) mixing the second filtrate and a fluorine removal agent, and sequentially carrying out acid-base adjustment, third stirring and solid-liquid separation to obtain a third filtrate; and (4) mixing the third filtrate with a sodium hypochlorite solution, and stirring for four times to obtain treated clear water. By adopting the treatment method provided by the invention, fluorine ions and oil content in the wastewater can be effectively reduced, and the wastewater discharge standard is met; in addition, the treatment method is low in cost, low in energy consumption, free of pollution and easy to operate, and has important application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a method for treating hydrometallurgical extraction wastewater. Background Art

[0002] Cobalt, nickel and manganese mineral resources are important raw materials for the production of NCM ternary precursors. Generally, cobalt, nickel and manganese are purified through leaching-extraction process, and the organic phase is acid-washed-washed-saponified to achieve the recycling of the extractant. This process method produces extraction wastewater that cannot be discharged directly because it contains fluoride ions and oil. At present, the main methods for removing fluoride ions from wastewater are defluorination by defluoridation agent, resin adsorption or lime precipitation; the main methods for removing oil are activated carbon adsorption deoiling or using deoiling device.

[0003] However, when the fluorine concentration in the wastewater is high, the defluoridation agent, as a deep defluoridation agent, often fails to achieve the deep defluoridation level and has low economic benefits. Extraction wastewater has the characteristics of high oil, high salt and high hardness, which will affect the adsorption performance of the resin and cause the problem of hardening, and the resin regeneration also has the problem of low economic benefits. The chemical precipitation method is affected by the solubility of the precipitate and has a defluoridation limit, which is generally 20 mg / L.

[0004] CN 111646591A discloses a method for treating semiconductor fluoride-containing wastewater, the method comprising the following steps: adding calcium salt and conditioned sludge to the wastewater to be treated, stirring and reacting to obtain a reaction solution; adding a flocculant to the reaction solution, and then performing mud-water separation to obtain sludge containing calcium fluoride and treated clean water. CN117509936A discloses a method for removing fluoride from high-concentration fluoride-containing wastewater, the method comprising the following steps: (1) adding a water-soluble calcium-containing compound to the fluoride-containing wastewater, and then adding a composite flocculant and a coagulant aid, reacting, and removing the precipitate therein; (2) adjusting the pH value of the fluoride-containing wastewater treated in step (1) to 7-10, and then entering an electric flocculation unit for deep treatment; (3) removing the precipitate from the water produced by the electric flocculation unit to obtain the final water product.

[0005] The above patents all disclose how to remove fluorine from wastewater, but do not disclose how to remove oil from fluorine-containing wastewater.

[0006] Therefore, providing a process method that can simultaneously treat fluoride ions and oil in wastewater has important application prospects. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for treating hydrometallurgical extraction wastewater. The treatment method achieves the purpose of deep defluorination and deoiling of hydrometallurgical extraction wastewater at low cost through step-by-step treatment. The treatment method is simple to operate, requires simple equipment, has low energy consumption, and is pollution-free, and has important application prospects.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0010] (1) mixing the extraction wastewater and the calcium source, stirring once, and then performing solid-liquid separation to obtain a first filtrate;

[0011] (2) mixing the first filtrate and carbonate, stirring twice, filtering and removing calcium, and obtaining a second filtrate;

[0012] (3) mixing the second filtrate and the defluorinating agent, sequentially performing acid-base adjustment, three-time stirring, and solid-liquid separation to obtain a third filtrate;

[0013] (4) The third filtrate and the sodium hypochlorite solution are mixed and stirred four times to obtain treated clean water.

[0014] In the present invention, the preliminary treatment of fluoride ions and oil in the extraction wastewater is achieved by mixing a calcium source, and then the deep treatment of calcium ions in the filtrate is achieved by mixing a carbonate, and then the deep treatment of fluoride ions in the wastewater is achieved by mixing a defluoridating agent, and finally the deep treatment of oil in the wastewater is achieved by sodium hypochlorite;

[0015] The present invention can effectively reduce fluoride ions and oil in the extraction wastewater through step-by-step treatment to meet the discharge standard; the treatment method is simple to operate, uses simple equipment, has low energy consumption, is pollution-free, and has important application prospects.

[0016] In addition, the extraction wastewater of the present invention is a mixed wastewater of extract, washing acid and washing water generated after nickel sulfate and lithium carbonate are extracted, impurities are removed and enriched; the extraction wastewater contains high concentrations of fluoride ions and oil;

[0017] The discharge standard of the extraction wastewater of the present invention is: the oil content in the wastewater is ≤5mg / L, the calcium ion content is ≤5mg / L, and the fluoride ion content is ≤5mg / L.

[0018] As a preferred technical solution of the present invention, the fluoride ion content in the extraction wastewater in step (1) is ≥150 mg / L, for example, it can be 150 mg / L, 170 mg / L, 190 mg / L, 210 mg / L, 230 mg / L, 250 mg / L or 270 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, the oil content in the extraction wastewater in step (1) is ≥80 mg / L, for example, it can be 80 mg / L, 90 mg / L, 100 mg / L, 110 mg / L, 120 mg / L or 130 mg / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] As a preferred technical solution of the present invention, the calcium source in step (1) includes any one of calcium hydroxide, calcium oxide or calcium chloride, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of calcium hydroxide and calcium oxide, a combination of calcium hydroxide and calcium chloride, a combination of calcium oxide and calcium chloride, or a combination of calcium hydroxide, calcium oxide and calcium chloride.

[0021] Preferably, the molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source in step (1) is 1:8-12, for example, 1:8, 1:8.8, 1:9.6, 1:10.4, 1:11.2 or 1:12, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] In the present invention, the role of the calcium source is to combine with fluoride ions to produce calcium fluoride to achieve preliminary removal of fluoride ions by chemical precipitation method; if the amount of its addition is too high, it will lead to a high calcium content in the first filtrate, a high amount of subsequent carbonate addition, a high salt content in the final wastewater, and low economic benefits; conversely, if the amount of its addition is too low, it will lead to a high fluorine content in the first filtrate, a high amount of subsequent defluoridation agent addition, and low economic benefits.

[0023] As a preferred technical solution of the present invention, the stirring time in step (1) is 30 to 120 minutes, for example, it can be 30 minutes, 50 minutes, 70 minutes, 90 minutes, 110 minutes or 120 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] As a preferred technical solution of the present invention, the carbonate in step (2) includes sodium carbonate.

[0025] Preferably, the Ca in the third filtrate is 2+ and CO in carbonates 3 2-The molar ratio is 1:2 to 2.5, for example, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] As a preferred technical solution of the present invention, the calculation formula for the addition amount w of the defluorination agent in step (3) is as follows:

[0027] w=c(F - )×V×m×n

[0028] Among them, c(F - ) is the F in the second filtrate - concentration, V is the volume of the second filtrate, m is the magnification, and n is the theoretical excess coefficient of the defluorination agent.

[0029] Preferably, the value range of m is 3 to 5, for example, 3, 4 or 5, but is not limited to the listed values, and other values ​​not listed within the value range are also applicable.

[0030] In the present invention, the value of the magnification m is further determined according to the type of the defluorination agent selected.

[0031] As a preferred technical solution of the present invention, the reagent used for acid-base adjustment in step (3) includes any one of hydrochloric acid, sulfuric acid or nitric acid, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of hydrochloric acid and sulfuric acid, a combination of hydrochloric acid and nitric acid, a combination of sulfuric acid and nitric acid, or a combination of hydrochloric acid, sulfuric acid and nitric acid.

[0032] Preferably, the endpoint of the acid-base adjustment in step (3) is a pH value of 7 to 8, for example, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9 or 8, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] In the present invention, the purpose of acid-base adjustment in step (3) is to maximize the sedimentation efficiency of the defluorinating agent; if the pH value is too low, the fluoride ion removal will be incomplete, and conversely, if the pH value is too high, the fluoride ion removal will be incomplete.

[0034] As a preferred technical solution of the present invention, the time for the three stirrings in step (3) is 8 to 12 minutes, for example, it can be 8 minutes, 9 minutes, 10 minutes, 11 minutes or 12 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] As a preferred technical solution of the present invention, the addition amount of the sodium hypochlorite solution in step (4) is 2 to 15 mL / L, for example, 2 mL / L, 5 mL / L, 8 mL / L, 10 mL / L, 12 mL / L or 15 mL / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] Preferably, the concentration of the sodium hypochlorite solution in step (4) is 10-15wt%, for example, 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%, but is not limited to the listed values, and other values ​​within the numerical range not listed are also applicable.

[0037] Preferably, the time for the four stirrings in step (4) is 2 to 4.5 h, for example, 2 h, 3.6 h, 3.7 h, 3.8 h, 3.9 h, 4 h, 4.1 h, 4.2 h, 4.3 h, 4.4 h or 4.5 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] As a preferred technical solution of the present invention, the method for treating hydrometallurgical extraction wastewater provided by the present invention comprises the following steps:

[0039] (1) mixing the extraction wastewater and the calcium source, stirring for 30 to 120 minutes at a time, and then performing solid-liquid separation to obtain a first filtrate;

[0040] Wherein, the fluoride ion content in the extraction wastewater is ≥150mg / L, and the oil content is ≥80mg / L;

[0041] The molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source is 1:8-12;

[0042] (2) mixing the first filtrate and sodium carbonate, stirring twice, filtering and removing calcium, and obtaining a second filtrate;

[0043] Wherein, the Ca in the third filtrate 2+ and CO in carbonates 3 2- The molar ratio is 1:2 to 2.5;

[0044] (3) mixing the second filtrate and the defluoridating agent, adjusting the pH value to 7 to 8, stirring for 8 to 12 minutes three times, and performing solid-liquid separation to obtain a third filtrate;

[0045] Wherein, the addition amount of the defluorination agent w=c(F - )×V×m×n,,c(F - ) is the F in the second filtrate -concentration, V is the volume of the second filtrate, m is the magnification, and n is the theoretical excess coefficient of the defluorination agent;

[0046] (4) mixing the third filtrate with a sodium hypochlorite solution having a concentration of 10 to 15 wt %, and stirring for four times for 2 to 4.5 hours to obtain treated clean water.

[0047] It is worth noting that the present invention does not limit the solid-liquid separation method, as long as the separation of solid and liquid in the reaction liquid can be achieved.

[0048] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The treatment method provided by the present invention achieves the purpose of deep defluorination and oil removal of extraction wastewater at low cost through a step-by-step treatment method of "primary deoiling and defluorination - decalcification - deep defluorination - deep deoiling", and has important application prospects;

[0051] (2) The treatment method provided by the present invention has the advantages of simple operation, simple equipment, low energy consumption and no pollution;

[0052] (3) The treatment method provided by the present invention achieves the discharge of extraction wastewater in compliance with the discharge standards, and solves the problem of high cost of oil and fluorine in the extraction wastewater and the use of high-cost equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a process flow chart of the method for treating hydrometallurgical extraction wastewater provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] The defluorinating agent used in the following examples and comparative examples is GMS-F3 defluorinating agent produced by Shandong Huanrui Ecological Technology Co., Ltd., and its theoretical excess coefficient is 50.

[0056] Example 1

[0057] This embodiment provides a method for treating hydrometallurgical extraction wastewater, such as Figure 1 As shown, the processing method comprises the following steps:

[0058] (1) mixing the extracted wastewater and a calcium hydroxide slurry having a concentration of 25 wt %, stirring for 60 min, and then performing solid-liquid separation to obtain a first filtrate;

[0059] Among them, the fluoride ion content in the extraction wastewater is 183.22 mg / L, and the oil content is 89.57 mg / L;

[0060] The molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source is 1:8;

[0061] After testing and analyzing the first filtrate, it was found that the precipitation rate of F was 91.77%, the F content was 15.07 mg / L, the Ca content was 273.5 mg / L, and the oil content was 66.79 mg / L;

[0062] (2) mixing the first filtrate and sodium carbonate, stirring for a second time for 1 hour, filtering and removing calcium to obtain a second filtrate;

[0063] Wherein, the Ca in the third filtrate 2+ and CO in carbonates 3 2- The molar ratio is 1:2;

[0064] After testing and analyzing the second filtrate, it was found that the precipitation rate of Ca was 99.41%, the F ion content was 15.07 mg / L, the Ca ion content was 3.4 mg / L, and the oil content was 66.79 mg / L;

[0065] (3) After mixing the second filtrate and the defluorinating agent, the mixture is adjusted with hydrochloric acid to a pH value of 7.5, and then stirred for 10 minutes three times and solid-liquid separation is performed to obtain a third filtrate;

[0066] Wherein, the addition amount of the defluorination agent w=c(F - )×V×150,c(F - ) is the F in the second filtrate - concentration, V is the volume of the second filtrate;

[0067] After testing and analyzing the third filtrate, it was found that the precipitation rate of F was 81.5%, the F ion content was 2.78 mg / L, the Ca ion content was 3.4 mg / L, and the oil content was 66.79 mg / L;

[0068] (4) mixing the third filtrate and a 10 wt % sodium hypochlorite solution, stirring for 4 hours four times, and obtaining treated clean water;

[0069] Wherein, the addition amount of the sodium hypochlorite solution is 10mL / L.

[0070] Example 2

[0071] This embodiment provides a method for treating hydrometallurgical extraction wastewater, such as Figure 1 As shown, the processing method comprises the following steps:

[0072] (1) mixing the extracted wastewater and a calcium oxide slurry having a concentration of 25 wt %, stirring for 50 min, and then performing solid-liquid separation to obtain a first filtrate;

[0073] Among them, the fluoride ion content in the extraction wastewater is 154.92 mg / L, and the oil content is 94.23 mg / L;

[0074] The molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source is 1:12;

[0075] After testing and analyzing the first filtrate, it was found that the precipitation rate of F was 92.3%, the F ion content was 12.45 mg / L; the Ca ion content was 892.5 mg / L; and the oil content was 41.96 mg / L;

[0076] (2) mixing the first filtrate and sodium carbonate, stirring twice, filtering and removing calcium, and obtaining a second filtrate;

[0077] Wherein, the Ca in the third filtrate 2+ and CO in carbonates 3 2- The molar ratio is 1:2.5;

[0078] After testing and analyzing the second filtrate, it was found that the precipitation rate of Ca was 99.41%; the F ion content was 12.45 mg / L; the Ca ion content was 2.21 mg / L; and the oil content was 41.96 mg / L;

[0079] (3) mixing the second filtrate and the defluorinating agent, adjusting the pH value to 7.5, stirring for 8 minutes three times, and performing solid-liquid separation to obtain a third filtrate;

[0080] Wherein, the addition amount of the defluorination agent w=c(F - )×V×150,c(F - ) is the F in the second filtrate - concentration, V is the volume of the second filtrate;

[0081] After testing and analyzing the third filtrate, it was found that the precipitation rate of F was 81.5%; the F ion content was 2.79 mg / L; the Ca ion content was 2.21 mg / L; and the oil content was 41.96 mg / L.

[0082] (4) mixing the third filtrate and a sodium hypochlorite solution having a concentration of 12 wt %, stirring for 4.5 h four times to obtain treated clean water;

[0083] The amount of sodium hypochlorite solution added is 10 mL / L.

[0084] Example 3

[0085] This embodiment provides a method for treating hydrometallurgical extraction wastewater, such as Figure 1 As shown, the processing method comprises the following steps:

[0086] (1) mixing the extracted wastewater and a calcium chloride slurry having a concentration of 25 wt %, stirring for 70 min, and then performing solid-liquid separation to obtain a first filtrate;

[0087] Among them, the fluoride ion content in the extraction wastewater is 297.98 mg / L, and the oil content is 93.67 mg / L;

[0088] The molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source is 1:10;

[0089] (2) mixing the first filtrate and sodium carbonate, stirring twice, filtering and removing calcium, and obtaining a second filtrate;

[0090] Wherein, the Ca in the third filtrate 2+ and CO in carbonates 3 2- The molar ratio is 1:2.25;

[0091] (3) mixing the second filtrate and the defluorinating agent, adjusting the pH to 8, stirring for 12 minutes three times, and performing solid-liquid separation to obtain a third filtrate;

[0092] Wherein, the addition amount of the defluorination agent w=c(F - )×V×150,c(F - ) is the F in the second filtrate - concentration, V is the volume of the second filtrate;

[0093] (4) mixing the third filtrate and a 15 wt % sodium hypochlorite solution, stirring for 2.5 h four times, and obtaining treated clean water;

[0094] The amount of sodium hypochlorite solution added is 8 mL / L.

[0095] Example 4

[0096] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0097] In this embodiment, the molar ratio of fluoride ions in the extraction wastewater and calcium ions in the calcium source in step (1) is adjusted to 1:5.

[0098] Example 5

[0099] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0100] In this embodiment, the molar ratio of fluoride ions in the extraction wastewater and calcium ions in the calcium source in step (1) is adjusted to 1:15.

[0101] Example 6

[0102] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0103] In this embodiment, the Ca in the third filtrate of step (2) is 2+ and CO in carbonates 3 2- The molar ratio was adjusted to 1.8:1.

[0104] Example 7

[0105] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0106] In this embodiment, the Ca in the third filtrate of step (2) is 2+ and CO in carbonates 3 2- The molar ratio was adjusted to 3.0:1.

[0107] Example 8

[0108] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0109] In this embodiment, the endpoint of the acid-base adjustment in step (3) is adjusted to a pH value of 6.5.

[0110] Example 9

[0111] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0112] In this embodiment, the endpoint of the acid-base adjustment in step (3) is adjusted to a pH value of 8.5.

[0113] Example 10

[0114] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0115] In this embodiment, the amount of sodium hypochlorite solution added in step (3) is adjusted to 1 mL / L.

[0116] Embodiment 11

[0117] This embodiment provides a method for treating hydrometallurgical extraction wastewater, the method comprising the following steps:

[0118] In this embodiment, the amount of sodium hypochlorite solution added in step (3) is adjusted to 18 mL / L.

[0119] Comparative Example 1

[0120] This comparative example provides a method for treating hydrometallurgical extraction wastewater, which comprises the following steps:

[0121] In this comparative example, step (1) and step (2) were omitted.

[0122] Comparative Example 2

[0123] This comparative example provides a method for treating hydrometallurgical extraction wastewater, which comprises the following steps:

[0124] In this comparative example, the sodium hypochlorite solution in step (4) is adjusted to a potassium permanganate solution of equal concentration.

[0125] Comparative Example 3

[0126] This comparative example provides a method for treating hydrometallurgical extraction wastewater, which comprises the following steps:

[0127] In this comparative example, the mixing order of the defluoridating agent and sodium hypochlorite is adjusted, that is, step (3) and step (4) of the treatment method are adjusted to:

[0128] (3) mixing the second filtrate and a sodium hypochlorite solution having a concentration of 10 wt %, stirring for 4 h, and then performing solid-liquid separation to obtain a third filtrate; the amount of the sodium hypochlorite solution added is 10 mL / L;

[0129] (4) The third filtrate and the defluoridating agent are mixed, and then hydrochloric acid is mixed to adjust the pH value to 7.5, and then stirred three times for 10 minutes and solid-liquid separation is performed to obtain treated clean water.

[0130] The treated clean water provided in the above embodiments and comparative examples was tested and analyzed, and the F ion concentration, calcium ion concentration and oil content in the clean water were detected. The results are shown in Table 1.

[0131] Table 1

[0132]

[0133]

[0134] According to Table 1, we can know the following points:

[0135] (1) Comprehensive analysis of Examples 1-3 shows that the treatment method provided by the present invention can effectively reduce the fluoride ions and oil content in wastewater and meet the wastewater discharge standards;

[0136] In addition, the treatment method is low in cost, low in energy consumption, pollution-free and simple to operate, and has important application prospects;

[0137] (2) Comprehensive analysis of Example 1 and Examples 4-5 shows that the amount of calcium source added will affect the effect of the preliminary defluorination and deoiling of the extraction wastewater; when the amount of calcium source added is too low, a large amount of defluorination agent will be added, and the fluoride ion concentration will be too high; on the contrary, when the amount of calcium source added is too high, if the treated water is to meet the discharge standard, a large amount of sodium carbonate needs to be added, which will increase the treatment cost;

[0138] It is worth noting that in Example 5, when the amount of calcium source added in step (1) is too high, in order to make the calcium ion content in the treated water meet the standard, it is necessary to add excessive sodium carbonate, thereby increasing the treatment cost;

[0139] (3) Comprehensive analysis of Example 1 and Examples 6-7 shows that the amount of sodium carbonate added in step (2) will affect the removal effect of calcium ions in wastewater; when the amount of sodium carbonate added is too low, the calcium ion removal will be incomplete; conversely, when the amount of sodium carbonate added is too high, it will lead to higher costs;

[0140] (4) Comprehensive analysis of Example 1 and Examples 8-9 shows that the environmental pH during the deep defluorination process (step (3)) will affect the defluorination effect; when the environmental pH value is low or high, the fluoride ion concentration will be high and the emission standard cannot be met;

[0141] (5) Comprehensive analysis of Example 1 and Examples 10-11 shows that the amount of sodium hypochlorite added will affect the deep oil removal effect; when the amount of sodium hypochlorite added is too low, the oil removal rate will be low; on the contrary, when the amount of sodium hypochlorite added is too high, the cost will be high, and the excess sodium hypochlorite in the treated clean water will cause secondary pollution;

[0142] (6) Comprehensive analysis of Example 1 and Comparative Example 1 shows that if the preliminary defluorination and oil removal process is omitted and the defluorination agent and oxidant are directly used for deep defluorination and oil removal, the impurity ions in the treated clean water will not meet the discharge standard. If the impurity concentration is to be reduced, a large amount of defluorination agent and sodium hypochlorite need to be added, which will increase the treatment cost.

[0143] (7) Comprehensive analysis of Example 1 and Comparative Example 2 shows that, compared with the use of sodium hypochlorite as an oxidant, the use of potassium permanganate, hydrogen peroxide and other oxidants for oil removal cannot efficiently remove the oil in the wastewater, making it impossible to meet the discharge standards;

[0144] (8) Comprehensive analysis of Example 1 and Comparative Example 3 shows that changing the treatment sequence of deep oil removal and deep fluorine removal will lead to a higher pH value in the treatment system, a decrease in the oxidation performance of sodium hypochlorite, and further lead to a higher oil content.

[0145] In summary, the treatment method provided by the present invention can effectively reduce the fluoride ions and oil in wastewater and meet the wastewater discharge standards; in addition, the treatment method has low cost, low energy consumption, no pollution and simple operation, and has important application prospects.

[0146] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for treating hydrometallurgical extraction wastewater, characterized in that: The processing method comprises the following steps: (1) mixing the extraction wastewater and the calcium source, stirring once, and then performing solid-liquid separation to obtain a first filtrate; (2) mixing the first filtrate and carbonate, stirring twice, filtering and removing calcium, and obtaining a second filtrate; (3) mixing the second filtrate and the defluorinating agent, sequentially performing acid-base adjustment, three-time stirring, and solid-liquid separation to obtain a third filtrate; (4) The third filtrate and the sodium hypochlorite solution are mixed and stirred four times to obtain treated clean water.

2. The processing method according to claim 1, characterized in that: The fluoride ion content in the extraction wastewater in step (1) is ≥150 mg / L; Preferably, the oil content in the extraction wastewater in step (1) is ≥80 mg / L.

3. The processing method according to claim 1 or 2, characterized in that: The calcium source in step (1) includes any one of calcium hydroxide, calcium oxide or calcium chloride, or a combination of at least two thereof; Preferably, the molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source in step (1) is 1:8-12.

4. The processing method according to any one of claims 1 to 3, characterized in that: The stirring time in step (1) is 30 to 120 minutes.

5. The processing method according to any one of claims 1 to 4, characterized in that: The carbonate in step (2) comprises sodium carbonate; Preferably, the Ca in the third filtrate is 2+ and CO3 in carbonates 2- The molar ratio is 1:2~2.

5.

6. The processing method according to any one of claims 1 to 5, characterized in that: The calculation formula of the addition amount w of the defluorination agent in step (3) is as follows: w=c(F - )×V×m×n Among them, c(F - ) is the F in the second filtrate - concentration, V is the volume of the second filtrate, m is the magnification, and n is the theoretical excess coefficient of the defluorination agent; Preferably, the value range of m is 3-5.

7. The processing method according to any one of claims 1 to 6, characterized in that: The reagent used for acid-base adjustment in step (3) includes any one of hydrochloric acid, sulfuric acid or nitric acid, or a combination of at least two thereof; Preferably, the end point of the acid-base adjustment in step (3) is a pH value of 7 to 8.

8. The processing method according to any one of claims 1 to 7, characterized in that: The time of the three stirrings in step (3) is 8 to 12 minutes.

9. The processing method according to any one of claims 1 to 8, characterized in that: The amount of sodium hypochlorite solution added in step (4) is 2 to 15 mL / L, preferably 8 to 10 mL / L; Preferably, the concentration of the sodium hypochlorite solution in step (4) is 10-15 wt %; Preferably, the time for the four stirrings in step (4) is 2 to 4.5 hours.

10. The processing method according to any one of claims 1 to 9, characterized in that: The processing method comprises the following steps: (1) mixing the extraction wastewater and the calcium source, stirring for 30 to 120 minutes at a time, and then performing solid-liquid separation to obtain a first filtrate; Wherein, the fluoride ion content in the extraction wastewater is ≥150mg / L, and the oil content is ≥80mg / L; The molar ratio of fluoride ions in the extraction wastewater to calcium ions in the calcium source is 1:8-12; (2) mixing the first filtrate and sodium carbonate, stirring twice, filtering and removing calcium, and obtaining a second filtrate; Wherein, the Ca in the third filtrate 2+ and CO3 in carbonates 2- The molar ratio is 1:2 to 2.5; (3) mixing the second filtrate and the defluoridating agent, adjusting the pH value to 7 to 8, stirring for 8 to 12 minutes three times, and performing solid-liquid separation to obtain a third filtrate; Wherein, the addition amount of the defluorination agent w=c(F - )×V×m×n,c(F - ) is the F in the second filtrate - concentration, V is the volume of the second filtrate, m is the magnification, and n is the theoretical excess coefficient of the defluorination agent; (4) mixing the third filtrate with a sodium hypochlorite solution having a concentration of 10 to 15 wt %, and stirring for four times for 2 to 4.5 hours to obtain treated clean water.

Images