Method for recovering valuable elements in copper-containing sludge

Abstract

The invention discloses a method for recycling valuable elements in copper-containing sludge, and relates to the technical field of resource utilization, the recycling method comprises the following steps: dewatering, drying and crushing the copper-containing sludge to obtain copper-containing powder; putting into a sulfuric acid solution for acid leaching and dissolving to obtain an acid leaching solution; carrying out pretreatment and oxidation to obtain a copper-containing solution; adjusting the pH value to a first pH value, filtering to obtain first filtrate and ferric hydroxide precipitate, adding sodium sulfide, and filtering to obtain cadmium sulfide precipitate; adding Ti-MOFs, and carrying out solid-liquid separation to obtain a second filtrate and filter residues; immersing the filter residue into a desorption solution, and carrying out centrifugal separation to obtain a copper-containing filtrate and Ti-MOFs; adding sodium hydroxide into the copper-containing filtrate, filtering and calcining to obtain copper oxide; and sequentially adding the extraction liquid and a PH regulator into the second filtrate, and respectively recovering zinc ions, nickel ions and chromium ions, so that the technical problems of competitive adsorption of multiple metal elements, poor adsorption and separation effects and cross contamination of the metal elements caused by adsorption of the metal elements by a traditional adsorbent in the prior art can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resource utilization, and particularly relates to a method for recovering valuable elements in copper-containing sludge. BACKGROUND

[0002] Copper-containing sludge is widely produced in the industries of electroplating, non-ferrous metal smelting, electronic manufacturing, circuit board processing, etc. In the treatment of electroplating wastewater sludge, copper elements, zinc elements, nickel elements, chromium elements, cadmium elements, etc. are enriched by chemical precipitation, and copper-containing sludge is also produced in processes such as smelting slag acid leaching and electronic component etching. This kind of sludge belongs to hazardous waste (HW22, copper-containing waste), and if it is exposed to the open air or simply landfilled, it will lead to the risk of heavy metal migration, the pollution of soil and groundwater by the dissolution of heavy metal elements with rainwater, the enrichment of the food chain, and harm to human health, and also cause resource waste.

[0003] At present, the recovery of valuable elements in copper-containing sludge generally uses traditional adsorbents (ion exchange resins, activated carbon) to adsorb metal elements, which will lead to the competition of multiple metal elements for adsorption, poor adsorption and separation effect, and cross contamination of metal elements. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a method for recovering valuable elements in copper-containing sludge, which aims to solve the technical problems of the prior art that traditional adsorbents adsorb metal elements, which will lead to the competition of multiple metal elements for adsorption, poor adsorption and separation effect, and cross contamination of metal elements.

[0005] The first aspect of the present application is to provide a method for recovering valuable elements in copper-containing sludge, which comprises:

[0006] The copper-containing sludge is dewatered, dried and crushed to obtain copper-containing powder;

[0007] The copper-containing powder is placed in a sulfuric acid solution with a preset concentration for acid leaching and dissolution to obtain an acid leaching solution;

[0008] The acid leaching solution is pretreated and oxidized to remove impurities to obtain a copper-containing solution;

[0009] The copper-containing solution is adjusted to a first PH value, stirred at a first preset temperature for a first preset time, filtered to obtain a first filtrate and an iron hydroxide precipitate, and sodium sulfide is added to the first filtrate, adjusted to a second PH value, and filtered to obtain a cadmium sulfide precipitate;

[0010] Ti-MOFs is added to the first filtrate, adjusted to a third PH value, constant temperature oscillation, and solid-liquid separation to obtain a second filtrate and a filter residue;

[0011] The filter residue is immersed in a desorption liquid, constant temperature stirring, centrifugal separation, washing, drying, to obtain a copper-containing filtrate and Ti-MOFs;

[0012] The copper-containing filtrate is added into sodium hydroxide to adjust to a fourth PH value, to generate copper hydroxide precipitate, filtering, calcining to obtain copper oxide;

[0013] The second filtrate is sequentially added into zinc extraction liquid, nickel extraction liquid, PH regulator, to recover zinc ion, nickel ion and chromium ion respectively.

[0014] Compared with the prior art, the beneficial effects of the present application are that the valuable element recovery method in the copper-containing sludge provided by the present application can effectively improve the recovery of each metal element, specifically, the iron ion and cadmium ion are recovered by the precipitation method to prevent affecting the subsequent recovery of copper ion, indirectly improve the adsorption selectivity of Ti-MOFs, and further improve the selective adsorption of copper ion by Ti-MOFs selection and modification, improve the recovery rate and purity of copper ion, and then realize multi-metal "cascade purification" through precise separation of fractional extraction, realize the recovery of each element, thereby solving the technical problems of the prior art that the traditional adsorbent for metal elements will cause competitive adsorption of multiple metal elements, poor adsorption and separation effect, and cross contamination of metal elements.

[0015] According to one aspect of the above technical solution, the preparation method of Ti-MOFs comprises:

[0016] TiCl4 is dissolved in ethanol to obtain a first solution, and 4-tert-butyl pyridine-2, 6-dicarboxylic acid is dissolved in DMF to obtain a second solution;

[0017] The first solution and the second solution are mixed, benzoic acid is added, and the mixture is placed in a reaction kettle and reacted at a third preset temperature for a third preset time, and then filtered, washed and dried to obtain a Ti-MOFs crude product;

[0018] The Ti-MOFs crude product is dispersed in a dilute hydrochloric acid solution, stirred at room temperature, filtered, washed and dried to obtain Ti-MOFs.

[0019] According to one aspect of the above technical solution, the solid-liquid ratio of TiCl4 to ethanol is (100mg-300mg):5ml, and the solid-liquid ratio of 4-tert-butyl pyridine-2, 6-dicarboxylic acid to DMF is (100mg-280mg):20ml;

[0020] The volume ratio of the first solution to the second solution is 1:(2-7), and the addition amount of benzoic acid is 120℃-180℃, and the third preset time is 12h-48h;

[0021] The concentration of the dilute hydrochloric acid is 0.05M-0.2M, and the solid-liquid ratio of the Ti-MOFs crude product and the dilute hydrochloric acid is (0.5g-2g):1L.

[0022] According to an aspect of the above technical solution, the preset concentration is 10wt%-30wt%, the solid-liquid ratio of the copper-containing powder and the sulfuric acid solution is 1g:(5L-10L), the acid leaching temperature is 50°C-100°C, and the acid leaching time is 1h-4h.

[0023] According to an aspect of the above technical solution, the pretreatment and oxidation steps include:

[0024] Na2SO3 is added to reduce hexavalent chromium ions in the acid leaching solution to trivalent chromium ions;

[0025] Hydrogen peroxide is added to oxidize divalent iron ions in the acid leaching solution to trivalent iron ions;

[0026] Calcium sulfate precipitate is filtered, and calcium ions in the acid leaching solution are recovered.

[0027] According to an aspect of the above technical solution, the reagent for adjusting the first PH value of the copper-containing solution is copper oxide, the first PH value is 3-3.5, the first preset temperature is 20°C-40°C, and the first preset time is 0.5h-2h.

[0028] According to an aspect of the above technical solution, the second PH value is 3-4.

[0029] According to an aspect of the above technical solution, the liquid-solid ratio of the first filtrate and Ti-MOFs is (15ml-25ml):1g, the temperature of constant-temperature oscillation is 20°C-40°C, the time is 5h-12h, and the third PH value is 2.5-3.

[0030] According to an aspect of the above technical solution, the desorption agent is a 0.3M-1M sulfuric acid solution, the solid-liquid ratio of the filter residue and the desorption agent is 1g:(3L-7L), the temperature of constant-temperature stirring is 30°C-50°C, and the time is 0.5h-2h.

[0031] According to an aspect of the above technical solution, the fourth PH value is 10-12. BRIEF DESCRIPTION OF DRAWINGS

[0032] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings, of embodiments of the present application, wherein:

[0033] Figure 1 A flowchart of the method for recovering valuable elements from copper-containing sludge according to the present application. DETAILED DESCRIPTION

[0034] In order to make the objects, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the drawings. Several embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0035] Please refer to Figure 1 , which shows a method for recovering valuable elements in copper-containing sludge provided by the present application, and the recovery method comprises steps S10-S17,

[0036] Step S10, the copper-containing sludge is dewatered, dried and crushed to obtain copper-containing powder;

[0037] Among them, the copper-containing sludge comes from electroplating sludge, containing Cu element, Zn element, Ni element, Cr element, Fe element, Cd element, Ca element.

[0038] Step S11, the copper-containing powder is put into a sulfuric acid solution with a preset concentration for acid leaching and dissolution to obtain an acid leaching solution;

[0039] Among them, the metals in the copper-containing sludge exist in the form of oxides, hydroxides and carbonates, and the addition of sulfuric acid solution for acid leaching converts them into soluble sulfates into the solution.

[0040] In addition, the sludge (such as chromate CrO4 2- ) in the sludge is converted into strong oxidizing Cr2O7 2- under acidic environment through condensation reaction.

[0041] Among them, the preset concentration is 10wt%-30wt%, the solid-liquid ratio of the copper-containing powder to the sulfuric acid solution is 1g:(5L-10L), the acid leaching temperature is 50°C-100°C, and the acid leaching time is 1h-4h.

[0042] It should be noted that the setting of the acid leaching temperature will improve the dissolution rate of the metal elements, for example, the solubility of calcium sulfate is low at room temperature, but when the acid leaching temperature rises, the solubility can be improved, so that the calcium element is dissolved out.

[0043] Step S12, the acid leaching solution is pretreated and oxidized to remove impurities to obtain a copper-containing solution;

[0044] The pretreatment and oxidation step includes:

[0045] Na2SO3 is added to reduce hexavalent chromium ions in the acid leaching solution to trivalent chromium ions;

[0046] Hydrogen peroxide is added to oxidize divalent iron ions in the acid leaching solution to trivalent iron ions;

[0047] Continuously adding sulfuric acid, filtering the calcium sulfate precipitate, and recovering the calcium ions in the acid leaching solution.

[0048] Part of the calcium sulfate is dissolved by high-temperature acid leaching, and the subsequent excess sulfuric acid provides driving force to promote the crystallization of calcium sulfate, thereby recovering the calcium ions in the acid leaching solution.

[0049] Step S13: The copper-containing solution is adjusted to a first PH value, stirred at a first preset temperature for a first preset time, and filtered to obtain a first filtrate and a ferric hydroxide precipitate. Sodium sulfide is added to the first filtrate, adjusted to a second PH value, and filtered to obtain a cadmium sulfide precipitate.

[0050] Further, in order to reduce the competition of iron and cadmium elements with copper elements for adsorption on Ti-MOFs, the iron element is first recovered.

[0051] The reagent for adjusting the first PH value of the copper-containing solution is copper oxide, the first PH value is 3-3.5, the first preset temperature is 30-50℃, and the first preset time is 0.5-2h.

[0052] The first PH value is adjusted by selecting copper oxide, which does not introduce new impurities and ensures the stability of the first PH value. In addition, copper oxide can effectively reduce the co-precipitation of Cr(OH)3 caused by adjusting the first PH value with hydroxide, thereby improving the purity of metal recovery.

[0053] Further, in order to improve the recovery purity of cadmium elements and avoid zinc element co-precipitation, the precipitation PH of zinc sulfide is higher, and therefore the second PH value is 3-4.

[0054] Step S14: Ti-MOFs are added to the first filtrate, adjusted to a third PH value, and constant-temperature oscillated, and then solid-liquid separation is performed to obtain a second filtrate and a filter residue.

[0055] The preparation method of Ti-MOFs comprises:

[0056] TiCl4 is dissolved in ethanol to obtain a first solution, and 4-tert-butylpyridine-2,6-dicarboxylic acid is dissolved in DMF to obtain a second solution.

[0057] It should be noted that TiCl4 is partially hydrolyzed and condensed in alcohol solvents to form titanium oxygen clusters (such as Ti8O8(OH)4). The titanium oxygen clusters are coordinated and connected with polydentate organic ligands (4-tert-butylpyridine-2,6-dicarboxylic acid) under solvothermal conditions to form a three-dimensional network structure of metal organic framework.

[0058] In addition, copper ions are cross-linked acids, which have a high binding force with cross-linked bases (pyridine nitrogen). 4-tert-butylpyridine-2,6-dicarboxylic acid contains pyridine nitrogen sites, and through the steric hindrance of the tert-butyl group, the large-volume tert-butyl group constructs a spatial barrier, allowing only copper ions of suitable size to approach the coordination site, which can effectively selectively adsorb copper ions and repel other metal ions.

[0059] Furthermore, TiCl4 needs to be slowly added dropwise to ethanol under ice bath conditions to avoid local overheating, and the mixture should be stirred for 30 minutes.

[0060] Preferably, the solid-liquid ratio of TiCl4 to ethanol is (100mg~300mg): 5ml, and the solid-liquid ratio of 4-tert-butylpyridine-2,6-dicarboxylic acid to DMF is (100mg~280mg): 20ml.

[0061] The first and second solutions were mixed, benzoic acid was added, and the mixture was placed in a reaction vessel. The reaction was carried out at a third preset temperature for a third preset time. After filtration, washing, and drying, crude Ti-MOFs were obtained.

[0062] It should be noted that benzoic acid is used to control the crystal size of Ti-MOFs, so that Ti-MOFs have suitable pore size for selective adsorption of copper ions, repulsion of other metal ions, and prevention of Ti... 4+ Excessive hydrolysis results in amorphous TiO2.

[0063] Preferably, the volume ratio of the first solution to the second solution is 1:(2-7), the amount of benzoic acid added is 1.5 to 4 times the mass of TiCl4, the third preset temperature is 120℃ to 180℃, and the third preset time is 12h to 48h.

[0064] The crude Ti-MOFs were dispersed in a dilute hydrochloric acid solution, stirred at room temperature, filtered, washed, and dried to obtain Ti-MOFs.

[0065] Furthermore, in order to improve the selective adsorption of copper ions, positive charges were modified on the surface of crude Ti-MOFs. The modification enhanced the selectivity for copper ions, and the copper ions achieved binding by virtue of the energy advantage of the coordination bond (coordination releases energy to overcome repulsion), thereby enhancing the repulsion of other metal cations.

[0066] Preferably, the concentration of dilute hydrochloric acid is 0.05M to 0.2M, and the solid-liquid ratio of crude Ti-MOFs to dilute hydrochloric acid is (0.5g to 2g): 1L.

[0067] Furthermore, the liquid-to-solid ratio of the first filtrate to Ti-MOFs is (15ml~25ml):1g, the constant temperature oscillation is 20℃~40℃, the time is 5h~12h, and the third pH value is 2.5~3.

[0068] Step S15, immerse the filter residue in the desorption liquid, constant temperature stirring, centrifugal separation, washing, drying, to obtain the copper-containing filtrate and Ti-MOFs;

[0069] Preferably, the desorption agent is 0.3M-1M sulfuric acid solution, the solid-liquid ratio of the filter residue and the desorption agent is 1g:(3L-7L), the temperature of constant temperature stirring is 30℃-50℃, and the time is 0.5h-2h.

[0070] Step S16, add the copper-containing filtrate to sodium hydroxide to adjust to a fourth PH value, generate copper hydroxide precipitate, filter, and calcine to obtain copper oxide;

[0071] Step S17, add the second filtrate to zinc extraction liquid, nickel extraction liquid, and PH adjuster in sequence, respectively recover zinc ions, nickel ions, and chromium ions;

[0072] The PH of the second filtrate is adjusted to 1-2, the zinc extraction liquid includes P204 and kerosene, kerosene is a diluent, the volume ratio of P204 (diisooctyl phosphate) to kerosene is 1:3, the volume ratio of the zinc extraction liquid to the second filtrate is 1:1, mixing is performed for 10 min, the upper organic phase is separated, and then back extraction is performed on the upper organic phase by using 0.5M sulfuric acid solution at a volume ratio of 1:1, mixing is performed for 10 min, and after standing and layering, the lower zinc sulfate solution is separated, and the upper zinc extraction liquid can be continuously used for zinc ion extraction.

[0073] Further, the lower aqueous phase separated from the second filtrate is used for nickel ion extraction, ammonia water is used to adjust the PH to 4.5 to prevent co-extraction of chromium ions, the nickel extraction liquid includes P507 and kerosene, kerosene is a diluent, the volume ratio of P507 (2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester) to kerosene is 1:5.7, mixing is performed for 10 min, the upper organic phase is separated, and then back extraction is performed on the upper organic phase by using 1M sulfuric acid solution at a volume ratio of 1:1, mixing is performed for 10 min, and after standing and layering, the lower nickel sulfate solution is separated, and the upper nickel extraction liquid can be continuously used for nickel ion extraction.

[0074] Then, the lower aqueous phase left after nickel extraction is added with a PH adjuster, for example, sodium hydroxide, to adjust the PH to 5.5-6.5, to generate chromium hydroxide precipitate, which is filtered and separated.

[0075] The application is further described below by means of specific examples:

[0076] Example 1

[0077] The recovery method of valuable elements in the copper-containing sludge provided by the first embodiment of the application comprises steps S10-S17.

[0078] Step S10, dehydrate, dry, and crush the copper-containing sludge to obtain copper-containing powder;

[0079] Step S11, the copper-containing powder is put into a solution of sulfuric acid with a preset concentration for acid leaching and dissolution, to obtain an acid leaching solution;

[0080] The preset concentration is 20wt%, the solid-liquid ratio of the copper-containing powder to the sulfuric acid solution is 1g:8L, the acid leaching temperature is 80℃, and the acid leaching time is 2h.

[0081] Step S12, the acid leaching solution is pretreated and oxidized to remove impurities, to obtain a copper-containing solution;

[0082] The pretreatment and oxidation step includes:

[0083] Na2SO3 is added to reduce hexavalent chromium ions in the acid leaching solution to trivalent chromium ions;

[0084] Hydrogen peroxide is added to oxidize divalent iron ions in the acid leaching solution to trivalent iron ions;

[0085] Sulfuric acid is further added, and calcium sulfate precipitate is filtered to recover calcium ions in the acid leaching solution.

[0086] Excess Na2SO3, hydrogen peroxide, and sulfuric acid are added for sufficient reaction.

[0087] Step S13, the copper-containing solution is adjusted to a first PH value, stirred at a first preset temperature for a first preset time, filtered to obtain a first filtrate and iron hydroxide precipitate, and sodium sulfide is added to the first filtrate to adjust to a second PH value, and filtered to obtain cadmium sulfide precipitate;

[0088] The reagent for adjusting the copper-containing solution to the first PH value is copper oxide, the first PH value is 3.2, the first preset temperature is 40℃, and the first preset time is 1h.

[0089] Further, the second PH value is 3.5.

[0090] Step S14, Ti-MOFs is added to the first filtrate, adjusted to a third PH value, constant temperature oscillation, solid-liquid separation, to obtain a second filtrate and filter residue;

[0091] The preparation method of Ti-MOFs includes:

[0092] TiCl4 is dissolved in ethanol to obtain a first solution, and 4-tert-butyl pyridine-2,6-dicarboxylic acid is dissolved in DMF to obtain a second solution;

[0093] Further, TiCl4 is slowly added to ethanol under ice bath conditions to avoid local overheating, and the mixture is stirred for 30min.

[0094] Preferably, the solid-liquid ratio of TiCl4 and ethanol is 190 mg:5 ml, and the solid-liquid ratio of 4-tert-butyl pyridine-2,6-dicarboxylic acid and DMF is 260 mg:20 ml.

[0095] The first solution and the second solution are mixed, benzoic acid is added, and the mixture is placed in a reaction kettle and reacted at a third preset temperature for a third preset time. After filtration, washing, and drying, a Ti-MOFs crude product is obtained.

[0096] Preferably, the volume ratio of the first solution and the second solution is 1:4, the amount of benzoic acid added is 2 times the mass of TiCl4, the third preset temperature is 150°C, and the third preset time is 24 h.

[0097] The washing conditions are: first washing with DMF for 3 times, and then washing with ethanol for 3 times.

[0098] Further, the drying conditions are: drying at 60°C for 12 hours.

[0099] The Ti-MOFs crude product is dispersed in a dilute hydrochloric acid solution, stirred at room temperature, filtered, washed, and dried to obtain Ti-MOFs.

[0100] Preferably, the concentration of the dilute hydrochloric acid is 0.1 M, and the solid-liquid ratio of the Ti-MOFs crude product and the dilute hydrochloric acid is 1 g:1 L.

[0101] The washing conditions are: washing with deionized water until the pH of the washing liquid is neutral.

[0102] In addition, the drying conditions are: drying at 80°C for 8 hours.

[0103] Further, the liquid-solid ratio of the first filtrate and Ti-MOFs is 20 ml:1 g, the temperature of constant-temperature oscillation is 30°C, the time is 10 h, and the third pH value is 2.8.

[0104] Step S15, the filter residue is immersed in a desorption liquid, constant-temperature stirring, centrifugal separation, washing, and drying to obtain a copper-containing filtrate and Ti-MOFs;

[0105] Preferably, the desorption agent is a 0.5 M sulfuric acid solution, the solid-liquid ratio of the filter residue and the desorption agent is 1 g:5 L, the temperature of constant-temperature stirring is 40°C, and the time is 1 h.

[0106] Step S16, the copper-containing filtrate is added to sodium hydroxide to adjust to a fourth pH value, to generate a copper hydroxide precipitate, which is filtered and calcined to obtain copper oxide.

[0107] The fourth pH value is 11.

[0108] Further, the copper hydroxide precipitate needs to be washed with deionized water before calcination, until the conductivity of the filtrate is less than or equal to 50 muS / cm. The washed precipitate is placed in a vacuum drying oven at 60 DEG C for 2 hours to remove the surface adsorbed water.

[0109] Further, the calcination conditions are: calcination at 350 DEG C for 3 hours.

[0110] Step S17, the second filtrate is sequentially added into zinc extraction liquid, nickel extraction liquid and PH regulator to recover zinc ions, nickel ions and chromium ions respectively.

[0111] The PH of the second filtrate is adjusted to 1-2, the zinc extraction liquid includes P204 and kerosene, kerosene is a diluent, the volume ratio of P204 (diisooctyl phosphate) to kerosene is 1:3, the volume ratio of the zinc extraction liquid to the second filtrate is 1:1, mixed for 10 minutes, the upper organic phase is separated, then 0.5M sulfuric acid solution is used for back extraction according to the volume ratio of 1:1, mixed for 10 minutes, and then the mixture is left to separate into two layers, the lower zinc sulfate solution is separated, and the upper zinc extraction liquid can be recycled to extract zinc ions.

[0112] Further, the lower aqueous phase separated from the second filtrate is used to extract nickel ions, ammonia is used to adjust the PH to 4.5 to prevent co-extraction of chromium ions, the nickel extraction liquid includes P507 and kerosene, kerosene is a diluent, the volume ratio of P507 (2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester) to kerosene is 1:5.7, mixed for 10 minutes, the upper organic phase is separated, then 1M sulfuric acid solution is used for back extraction according to the volume ratio of 1:1, mixed for 10 minutes, and then the mixture is left to separate into two layers, the lower nickel sulfate solution is separated, and the upper nickel extraction liquid can be recycled to extract nickel ions.

[0113] Then, the lower aqueous phase left after the nickel extraction is added with a PH regulator, for example, sodium hydroxide, to adjust the PH to 5.5-6.5 to generate chromium hydroxide precipitate, which is filtered and separated.

[0114] Example 2

[0115] The second embodiment of the present application provides a valuable element recovery method in copper-containing sludge, which is different from the valuable element recovery method in copper-containing sludge in the first embodiment in that:

[0116] The liquid-solid ratio of the first filtrate to Ti-MOFs is 15 ml:1 g.

[0117] Example 3

[0118] The third embodiment of the present application provides a valuable element recovery method in copper-containing sludge, which is different from the valuable element recovery method in copper-containing sludge in the first embodiment in that:

[0119] The liquid-solid ratio of the first filtrate to the Ti-MOFs is 25ml:1g.

[0120] Embodiment 4

[0121] The fourth embodiment of the present application provides a method for recovering valuable elements in copper-containing sludge, and the method for recovering valuable elements in copper-containing sludge in the fourth embodiment is different from the method for recovering valuable elements in copper-containing sludge in the first embodiment in that:

[0122] The third PH value is 2.5.

[0123] Embodiment 5

[0124] The fifth embodiment of the present application provides a method for recovering valuable elements in copper-containing sludge, and the method for recovering valuable elements in copper-containing sludge in the fifth embodiment is different from the method for recovering valuable elements in copper-containing sludge in the first embodiment in that:

[0125] The third PH value is 3.

[0126] Embodiment 6

[0127] The sixth embodiment of the present application provides a method for recovering valuable elements in copper-containing sludge, and the method for recovering valuable elements in copper-containing sludge in the sixth embodiment is different from the method for recovering valuable elements in copper-containing sludge in the first embodiment in that:

[0128] The volume ratio of the first solution to the second solution is 1:2.

[0129] Embodiment 7

[0130] The seventh embodiment of the present application provides a method for recovering valuable elements in copper-containing sludge, and the method for recovering valuable elements in copper-containing sludge in the seventh embodiment is different from the method for recovering valuable elements in copper-containing sludge in the first embodiment in that:

[0131] The volume ratio of the first solution to the second solution is 1:6.

[0132] Embodiment 8

[0133] The eighth embodiment of the present application provides a method for recovering valuable elements in copper-containing sludge, and the method for recovering valuable elements in copper-containing sludge in the eighth embodiment is different from the method for recovering valuable elements in copper-containing sludge in the first embodiment in that:

[0134] The addition amount of benzoic acid is 1.5 times the mass of TiCl4.

[0135] Embodiment 9

[0136] The ninth embodiment of the present application provides a method for recovering valuable elements from copper-containing sludge, which is different from the method for recovering valuable elements from copper-containing sludge in the first embodiment in that:

[0137] The amount of benzoic acid added is 3 times the mass of TiCl4.

[0138] Example 10

[0139] The tenth embodiment of the present application provides a method for recovering valuable elements from copper-containing sludge, which is different from the method for recovering valuable elements from copper-containing sludge in the first embodiment in that:

[0140] The concentration of the dilute hydrochloric acid solution is 0.15M.

[0141] Example 11

[0142] The eleventh embodiment of the present application provides a method for recovering valuable elements from copper-containing sludge, which is different from the method for recovering valuable elements from copper-containing sludge in the first embodiment in that:

[0143] The concentration of the dilute hydrochloric acid solution is 0.05M.

[0144] Comparative Example 1

[0145] The first comparative example of the present application provides a method for recovering valuable elements from copper-containing sludge, which is different from the method for recovering valuable elements from copper-containing sludge in the first embodiment in that:

[0146] The Ti-MOFs crude product is not surface-modified with a dilute hydrochloric acid solution.

[0147] Comparative Example 2

[0148] The second comparative example of the present application provides a method for recovering valuable elements from copper-containing sludge, which is different from the method for recovering valuable elements from copper-containing sludge in the first embodiment in that:

[0149] No benzoic acid is added.

[0150] Comparative Example 3

[0151] The third comparative example of the present application provides a method for recovering valuable elements from copper-containing sludge, which is different from the method for recovering valuable elements from copper-containing sludge in the first embodiment in that:

[0152] The 4-tert-butyl pyridine-2,6-dicarboxylic acid is replaced by 2,6-pyridine dicarboxylic acid.

[0153] Referring to Table 1 below, parameters corresponding to the above-mentioned examples and comparative examples of the present application are shown.

[0154] Table 1

[0155]

[0156]

[0157] According to the data of the examples and comparative examples, the recovery rate and purity of each metal element can be effectively improved by using the method for recovering valuable elements from copper-containing sludge according to the present application.

[0158] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0159] The above-mentioned examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A method for recovery of valuable elements from copper-containing sludge, characterized in that, The recovery method comprises: The copper-containing sludge is dewatered, dried and crushed to obtain copper-containing powder; The copper-containing powder is put into a solution of sulfuric acid with a preset concentration for acid leaching and dissolution to obtain an acid leaching solution; The acid leaching solution is pretreated and oxidized to remove impurities to obtain a copper-containing solution; The copper-containing solution is adjusted to a first PH value, stirred at a first preset temperature for a first preset time, filtered to obtain a first filtrate and iron hydroxide precipitate, sodium sulfide is added to the first filtrate, adjusted to a second PH value, and filtered to obtain cadmium sulfide precipitate; Ti-MOFs is added to the first filtrate, adjusted to a third PH value, constant temperature oscillation, solid-liquid separation, to obtain a second filtrate and filter residue; The filter residue is immersed in a desorption solution, constant temperature stirring, centrifugal separation, washing, drying, to obtain a copper-containing filtrate and Ti-MOFs; The copper-containing filtrate is added to sodium hydroxide to adjust to a fourth PH value to generate copper hydroxide precipitate, which is filtered and calcined to obtain copper oxide; The second filtrate is sequentially added to zinc extraction liquid, nickel extraction liquid and PH adjuster to recover zinc ions, nickel ions and chromium ions respectively.

2. The process for recovery of valuable elements from copper-containing sludge according to claim 1, characterized in that, The preparation method of Ti-MOFs comprises: TiCl4 is dissolved in ethanol to obtain a first solution, and 4-tert-butyl pyridine-2,6-dicarboxylic acid is dissolved in DMF to obtain a second solution; The first solution and the second solution are mixed, benzoic acid is added, and the mixture is placed in a reaction kettle and reacted at a third preset temperature for a third preset time, and then filtered, washed and dried to obtain Ti-MOFs crude product; The Ti-MOFs crude product is dispersed in a dilute hydrochloric acid solution, stirred at room temperature, filtered, washed and dried to obtain Ti-MOFs.

3. The process for recovery of valuable elements from copper-containing sludge according to claim 2, characterized in that, The solid-liquid ratio of TiCl4 to ethanol is (100mg-300mg):5ml, and the solid-liquid ratio of 4-tert-butyl pyridine-2,6-dicarboxylic acid to DMF is (100mg-280mg):20ml; The volume ratio of the first solution to the second solution is 1:(2-7), the amount of benzoic acid added is 1.5-4 times the mass of TiCl4, the third preset temperature is 120-180℃, and the third preset time is 12-48h; The concentration of dilute hydrochloric acid is 0.05-0.2M, and the solid-liquid ratio of Ti-MOFs crude product to dilute hydrochloric acid is (0.5g-2g):1L.

4. The process for recovery of valuable elements from copper containing sludge as claimed in claim 1 wherein, The preset concentration is 10-30wt%, the solid-liquid ratio of the copper-containing powder to the sulfuric acid solution is 1g:(5-10L), the acid leaching temperature is 50-100℃, and the acid leaching time is 1-4h.

5. The process for recovery of valuable elements from copper containing sludge as claimed in claim 1 wherein, The pretreatment and oxidation steps comprise: Na2SO3 is added to reduce hexavalent chromium ions in the acid leaching solution to trivalent chromium ions; Hydrogen peroxide is added to oxidize divalent iron ions in the acid leaching solution to trivalent iron ions; Sulfuric acid is further added, calcium sulfate precipitate is filtered, and calcium ions in the acid leaching solution are recovered.

6. The process for recovery of valuable elements from copper containing sludge as claimed in claim 1 wherein, The reagent for adjusting the first PH value of the copper-containing solution is copper oxide, the first PH value is 3-3.5, the first preset temperature is 30-50℃, and the first preset time is 0.5-2h.

7. The process for recovery of valuable elements from copper containing sludge as claimed in claim 1 wherein, The second PH value is 3-4.

8. The process for recovery of valuable elements from copper containing sludge as claimed in claim 1 wherein, The liquid-solid ratio of the first filtrate to Ti-MOFs is (15ml-25ml):1g, the temperature of constant temperature oscillation is 20-40℃, the time is 5-12h, and the third PH value is 2.5-3.

9. The process for recovery of valuable elements from copper containing sludge as claimed in claim 1 wherein, The desorption agent is a 0.3M-1M sulfuric acid solution, the solid-liquid ratio of the filter residue to the desorption agent is 1g:(3L-7L), the temperature of constant temperature stirring is 30-50℃, and the time is 0.5-2h.

10. The silicone slurry treatment system of claim 1, wherein, The fourth PH value is 10-12.

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