Method for cooper recovery from metallurgical sludge by bio-adsorption and dissociation

Abstract

The application provides a method for cooperatively recovering copper in metallurgical sludge by bio-adsorption and complex breaking, comprising the following steps: 1) in a circulating system, pumping organic acid solution into a metallurgical sludge packed column and an ethylenediaminetetraacetic acid dianhydride modified bio-adsorbent packed column in sequence, and carrying out cyclic leaching; 2) after the cyclic leaching, adopting a calcination method to recover copper-based recovery materials adsorbed on the modified bio-adsorbent. The recovery process combining organic acid leaching and bio-adsorption complex breaking can realize efficient and selective leaching and recovery of copper ions under low acidity conditions; the recovery process is simple and convenient to operate, the organic acid complexing agent can be reused, the cost is low, and the method is suitable for popularization and application.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization technology, specifically relating to a method for the synergistic recovery of copper from metallurgical sludge through bio-adsorption and complex breaking. Background Technology

[0002] my country is a major copper smelting country, and the smelting process generates a large amount of sludge containing heavy metals such as copper. Metallurgical sludge is both a source of heavy metal pollution and a renewable resource; improper treatment can cause water pollution. How to harmlessly treat metallurgical solid waste and achieve low-cost, low-material-consumption, and efficient recovery of valuable metals has always been a concern for researchers and environmentalists.

[0003] Currently, wet processing technologies for heavy metals in solid waste mainly include traditional techniques such as chemical leaching, solvent extraction, ion exchange, precipitation, and reduction, as well as several new processes. Among these, chemical leaching is one of the effective means of resource utilization of solid waste. In the chemical leaching method, inorganic acids, organic acids, and complexing agents are commonly used as leaching agents. Inorganic acids, when used as leaching agents, require high acid concentrations, easily corrode equipment, and as broad-spectrum leaching agents, they have poor selectivity, resulting in numerous interfering ions and complex compositions in the leachate, which is not conducive to the selective separation and recovery of copper ions. In conventional organic acid leaching, copper ions mainly dissolve in aqueous solution as organic acid / copper complexes. Subsequent copper ion recovery is primarily achieved through strong acid complex breaking or precipitation-based complex breaking, which consumes large amounts of acid and precipitants, easily leading to secondary pollution. Furthermore, the concentration of the organic acid leaching agent decreases significantly during leaching as the organic acid / copper complex forms. Achieving a high leaching rate often requires a large amount of leaching agent, resulting in high operating costs. Moreover, high dosages or high concentrations of leaching agent can easily lead to an increase in the content of coexisting metal ions. In addition, the organic acid and metal complexes generated during leaching are difficult to recover and reuse, greatly limiting their application. Summary of the Invention

[0004] The main objective of this invention is to address the problems and shortcomings of existing technologies by providing a method for the synergistic recovery of copper from metallurgical sludge through bio-adsorption and complex breaking. This method utilizes a modified biosorbent with a high affinity for copper ions to dissociate organic acid / copper complexes. While adsorbing and fixing copper ions, it releases organic carboxylic acids, reducing the amount of organic acid used. Simultaneously, it maintains a low concentration of copper in the leachate, effectively improving the leaching efficiency of copper from the sludge. This method enables highly efficient and selective leaching of copper ions under low acidity conditions, effectively reducing the equipment requirements for copper leaching processes in metallurgical sludge and lowering the concentration of interfering ions during leaching. The organic acid used can be recycled after complex breaking with copper ions, significantly reducing the amount of leaching agent used and operating costs, making it suitable for widespread application.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for the synergistic recovery of copper from metallurgical sludge through biosorption and complex breaking includes the following steps:

[0007] 1) In the circulating system, organic acid solution (complexing agent) is pumped into the metallurgical sludge packing column and the ethylenediaminetetraacetic acid dianhydride modified biosorbent packing column at a certain flow rate for circulating leaching, so as to realize the leaching of copper in metallurgical sludge and bio-adsorption to break the complex.

[0008] 2) After cyclic leaching, the copper-based recoverable material (mainly copper oxide) adsorbed on the modified biosorbent is recovered by calcination.

[0009] In the above scheme, the concentration of the organic acid solution is 0.001-5 mol / L, and the solid-liquid ratio of the metallurgical sludge to the organic acid solution is 1 g:(1-1000) mL.

[0010] Preferably, the concentration of the organic acid solution is 0.005–0.5 mol / L.

[0011] More preferably, the concentration of the organic acid solution is 0.005 to 0.15 mol / L.

[0012] In the above scheme, the organic acid is one or more of citric acid, acetic acid, formic acid, oxalic acid, malic acid, tartaric acid, succinic acid, etc.

[0013] In the above scheme, the pumping rate of the organic acid solution in the metallurgical sludge and modified biosorbent packed column is 1-20 mL / min.

[0014] In the above scheme, the cyclic leaching time is 0.1 to 5 hours.

[0015] In the above scheme, the calcination temperature is 300-800℃.

[0016] In the above scheme, the mass ratio of the metallurgical sludge to the ethylenediaminetetraacetic acid dianhydride modified biosorbent is 1:(1-10).

[0017] In the above scheme, the ethylenediaminetetraacetic dianhydride modified biosorbent is obtained by adding biological material to an ethylenediaminetetraacetic dianhydride (EDTAD) solution and carrying out a heat-preserving reaction; the specific preparation method includes: adding the biosorbent to an ethylenediaminetetraacetic dianhydride solution, heating and carrying out a heat-preserving reaction, and then filtering, washing and drying.

[0018] In the above scheme, the biosorbent includes one or more of the following: waste rapeseed stalks, peanut shells, cotton stalks, rice stalks, wheat stalks, loofah sponges, water hyacinth, etc.

[0019] In the above scheme, the solvent used in the ethylenediaminetetraacetic dianhydride solution is one or more of N, N-dicarboxamide, dimethyl sulfoxide, pyridine, etc.

[0020] In the above scheme, the mass ratio of the biosorbent to ethylenediaminetetraacetic anhydride is 1:(0.1-5).

[0021] In the above scheme, the mass ratio of ethylenediaminetetraacetic dianhydride to solvent in the ethylenediaminetetraacetic dianhydride solution is (0.1-5):(10-50).

[0022] In the above scheme, the heat preservation reaction temperature is 10-90℃ and the time is 10-300min.

[0023] In the above scheme, the drying method is blower drying, vacuum drying, freeze drying, or spray drying, etc.

[0024] In the above scheme, the main metal elements and their contents in the metallurgical sludge include: copper 10-100 mg / g, lead 1-30 mg / g, iron 20-60 mg / g, zinc 10-100 mg / g, calcium 50-200 mg / g, magnesium 1-30 mg / g, and chromium 20-80 mg / g.

[0025] Using the above-mentioned recycling method, the copper recovery rate in metallurgical sludge reaches over 91%.

[0026] This invention employs a solid-phase bioadsorption complex-breaking method. During the leaching of copper from metallurgical sludge, the modified bioadsorbent utilizes the strong coordination ability of chelating functional groups such as carboxyl and amine groups on its surface with copper ions to dissociate the organic acid / copper complex. This adsorbs and fixes copper ions on the surface of the solid-phase bioadsorbent, effectively reducing the concentration of copper ions in the leachate. Simultaneously, the dissociation of the organic acid / copper complex releases the organic acid complexing agent into the leaching system for recycling. Throughout the cyclic leaching process, the complexing agent concentration remains at a high level while the copper ion concentration remains at a low level, effectively improving the selective leaching efficiency of copper in the sludge and achieving efficient separation and recovery of copper ions.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1) This invention can effectively overcome the problem of difficult recovery of metal ions during organic acid leaching, effectively reduce the amount of organic acid leaching agent, and achieve efficient and selective separation and recovery of copper ions under low acidity conditions using simple and easy methods; avoid equipment corrosion and other problems caused by high acidity during conventional inorganic acid leaching, and improve the recovery efficiency of heavy metals in metallurgical sludge.

[0029] 2) The recycling process involved in this invention is simple and easy to operate. The organic acid complexing agent can be reused repeatedly and has a low cost. It has high selective recovery efficiency for copper ions and is suitable for widespread application. Detailed Implementation

[0030] This invention is not limited to the embodiments described above. Those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention. Contents not described in detail in this specification are prior art known to those skilled in the art.

[0031] In the following examples, the metallurgical sludge used was taken from the sludge produced during the strong calcium oxide treatment of copper smelting wastewater. The main metal elements and their contents in the sludge were tested and found to be: copper 47.6 mg / g, lead 1.2 mg / g, iron 35.1 mg / g, zinc 44.2 mg / g, calcium 113.0 mg / g, magnesium 7.9 mg / g, and chromium 32.1 mg / g.

[0032] Example 1

[0033] A method for the synergistic recovery of copper from metallurgical sludge through biosorption and complex breaking includes the following steps:

[0034] 1) Add 1.0g of dried rapeseed stalk powder to 50mL of N,N dicarboxamide containing 2.0g EDTAD, heat at 70℃ for 4h, filter and wash the material after the reaction, wash twice with DMF, sodium hydroxide at pH=10 and anhydrous ethanol, and vacuum dry at 60℃ for 12h to obtain modified rapeseed stalk (modified biosorbent);

[0035] 2) 0.2g of metallurgical sludge and 0.4g of modified rapeseed stalk were respectively loaded into two glass packed columns. 100mL of malic acid solution (0.08mol / L) was pumped into the two packed columns connected in series at a flow rate of 5mL / min using a peristaltic pump (first the metallurgical sludge column and then the modified rapeseed stalk column) for cyclic leaching. The leaching and adsorption were completed after 4 hours.

[0036] 3) Collect the modified rapeseed stalks obtained by cyclic leaching in step 2) and calcine them at 600℃ for 5 hours to obtain copper oxide-based recoveries.

[0037] Tests showed that the copper content in the copper oxide-based recycled material obtained in this embodiment reached 9.1 mg, and the recovery amounts of coexisting metal ions zinc, calcium, iron, chromium and magnesium ions were 1.9, 2.6, 1.7, 0.5 and 0.2 mg, respectively. Using the recovery method described in this invention, the copper recovery rate reached 95.6%, while the recovery rates of coexisting metal ions were all less than 25%.

[0038] Example 2

[0039] A method for the synergistic recovery of copper from metallurgical sludge through biosorption and complex breaking includes the following steps:

[0040] 1) Add 1.0g of dried rice straw powder to 50mL of N,N dicarboxamide containing 2.0g EDTAD, heat at 70℃ for 4h, filter and wash the material after the reaction, wash twice with DMF, sodium hydroxide at pH=10 and anhydrous ethanol, and vacuum dry at 60℃ for 12h to obtain modified rice straw (modified biosorbent);

[0041] 2) 0.2g of metallurgical sludge and 0.4g of modified rice straw were respectively loaded into two glass packed columns. 100mL of 0.1mol / L citric acid solution was pumped into the two packed columns in series at a flow rate of 5mL / min using a peristaltic pump for cyclic leaching. The leaching and adsorption were completed after 4 hours.

[0042] 3) Collect the modified rice straw obtained by cyclic leaching in step 2) and calcine it at 600℃ for 5 hours to obtain copper oxide-based recycled material.

[0043] Tests showed that the copper content in the copper oxide-based recycled material obtained in this embodiment reached 9.0 mg, and the recovery amounts of coexisting metal ions zinc, calcium, iron, chromium and magnesium ions were 1.7, 2.5, 1.6, 0.6 and 0.3 mg, respectively; the copper recovery rate reached 94.5%, while the recovery rates of coexisting metal ions were all less than 25%.

[0044] Example 3

[0045] A method for the synergistic recovery of copper from metallurgical sludge through biosorption and complex breaking includes the following steps:

[0046] 1) Add 1.0g of dried peanut shell powder to 50mL of N,N dicarboxamide containing 2.0g EDTAD, heat at 70℃ for 4h, filter and wash the material after the reaction, wash twice with DMF, sodium hydroxide at pH=10 and anhydrous ethanol, and vacuum dry at 60℃ for 12h to obtain modified peanut shell (modified biosorbent);

[0047] 2) 0.2g of metallurgical sludge and 0.4g of modified peanut shell were respectively loaded into two glass packed columns. 100mL of 0.1mol / L succinic acid solution was pumped into the two series packed columns at a rate of 5mL / min using a peristaltic pump for cyclic leaching. Leaching and adsorption were completed after 4 hours.

[0048] 3) Collect the modified peanut shells obtained by cyclic leaching in step 2) and calcine them at 600℃ for 5 hours to obtain copper oxide-based recoveries.

[0049] Tests showed that the copper content in the copper oxide-based recycled material obtained in this embodiment reached 8.7g, and the recovery amounts of coexisting metal ions zinc, calcium, iron, chromium and magnesium ions were 1.5, 2.1, 1.3, 0.5 and 0.3g, respectively; the copper recovery rate reached 91.4%, while the recovery rates of coexisting metal ions were all less than 25%.

[0050] Comparative Example 1

[0051] A method for recovering copper from metallurgical sludge includes the following steps:

[0052] 100 mL of 0.1 mol / L malic acid solution was pumped into a packed column containing 0.2 g of metallurgical sludge at a flow rate of 5 mL / min for cyclic leaching.

[0053] After 4 hours of cyclic leaching, the copper leaching rate was measured to be 78%, while the recovery rates of coexisting metal ions zinc, calcium, iron, chromium, and magnesium ions were less than 30%. The copper ion leaching rate was low, and the ions were mainly present in the solution, making them difficult to separate and recover. Further increasing the concentration of malic acid solution to 0.5 mol / L and leaching for 4 hours increased the copper leaching rate to 85%, but the leaching rates of zinc, calcium, iron, chromium, and magnesium ions were 21%, 39%, 24%, 22%, and 41%, respectively.

[0054] Comparative Example 2

[0055] A method for recovering copper from metallurgical sludge includes the following steps:

[0056] 100 mL of 0.1 mol / L citric acid solution was pumped into a packed column containing 0.2 g of metallurgical sludge at a flow rate of 5 mL / min for cyclic leaching.

[0057] After 4 hours of cyclic leaching, the copper leaching rate was measured to be 74%, while the recovery rates of coexisting metal ions such as zinc, calcium, iron, chromium, and magnesium ions were less than 40%. The copper ion leaching rate was low, and the copper ions were mainly present in the solution, making them difficult to separate and recover. Further increasing the concentration of citric acid solution to 0.5 mol / L and leaching for 4 hours, the copper leaching rate increased to 85%, while the leaching rates of zinc, calcium, iron, chromium, and magnesium ions were 22%, 33%, 20%, 21%, and 36%, respectively.

[0058] Comparative Example 3

[0059] A method for recovering copper from metallurgical sludge includes the following steps:

[0060] 100 mL of 0.1 mol / L tartaric acid solution was pumped into a packed column containing 0.2 g of metallurgical sludge at a flow rate of 5 mL / min for cyclic leaching.

[0061] After 4 hours of cyclic leaching, the copper leaching rate was measured to be 75%, while the recovery rates of coexisting metal ions zinc, calcium, iron, chromium, and magnesium ions were less than 40%. The copper ion leaching rate was low, and the copper ions were mainly present in the solution, making them difficult to separate and recover. Further increasing the concentration of tartaric acid solution to 0.5 mol / L and leaching for 4 hours, the copper leaching rate increased to 85%, while the leaching rates of zinc, calcium, iron, chromium, and magnesium ions were 25%, 39%, 29%, 20%, and 39%, respectively.

[0062] Comparative Example 4

[0063] A method for recovering copper from metallurgical sludge includes the following steps:

[0064] 100 mL of 0.1 mol / L succinic acid solution was pumped into a packed column containing 0.2 g of metallurgical sludge at a flow rate of 5 mL / min for cyclic leaching.

[0065] After 4 hours of cyclic leaching, the copper leaching rate was measured to be 60%, while the recovery rates of coexisting metal ions such as zinc, calcium, iron, chromium, and magnesium ions were less than 40%. The copper ion leaching rate was low, and the copper ions were mainly present in the solution, making them difficult to separate and recover. Further increasing the concentration of succinic acid solution to 0.5 mol / L and leaching for 4 hours, the copper leaching rate increased to 85%, while the leaching rates of zinc, calcium, iron, chromium, and magnesium ions were 23%, 40%, 31%, 19%, and 39%, respectively.

[0066] Comparative Example 5

[0067] A method for recovering copper from metallurgical sludge includes the following steps:

[0068] 1) Add 1.0g of dried peanut shell powder to 50mL of N,N dicarboxamide containing 2.0g of pyromellitic dianhydride, heat at 80℃ for 4h, filter and wash the material after the reaction, wash twice with DMF, sodium hydroxide at pH=10 and anhydrous ethanol, and vacuum dry at 60℃ for 12h to obtain modified peanut shell (pyromellitic dianhydride modified biosorbent);

[0069] 2) 0.2g of metallurgical sludge and 0.4g of modified peanut shell were respectively loaded into two glass packed columns. 100mL of 0.1mol / L succinic acid solution was pumped into the two series packed columns at a rate of 5mL / min using a peristaltic pump for cyclic leaching. Leaching and adsorption were completed after 4 hours.

[0070] 3) Collect the modified peanut shells obtained by cyclic leaching in step 2) and calcine them at 600℃ for 5 hours to obtain copper oxide-based recoveries.

[0071] Tests showed that the copper content in the copper oxide-based recycled material obtained in this embodiment reached 4.0g; the copper recovery rate reached 42.0%, while the recovery rate of other metals was less than 40%.

[0072] Comparative Example 6

[0073] A method for recovering copper from metallurgical sludge includes the following steps:

[0074] 1) Add 1.0g of dried peanut shell powder to 50mL of N,N dicarboxamide containing 10g of thiourea, heat at 130℃ for 1h, then add 10mL of concentrated phosphoric acid, continue the reaction for 4h, wash twice with DMF, sodium hydroxide at pH=10 and anhydrous ethanol, and vacuum dry at 60℃ for 12h to obtain modified peanut shell (modified biosorbent);

[0075] 2) 0.2g of metallurgical sludge and 0.4g of modified peanut shell were respectively loaded into two glass packed columns. 100mL of 0.1mol / L succinic acid solution was pumped into the two series packed columns at a rate of 5mL / min using a peristaltic pump for cyclic leaching. Leaching and adsorption were completed after 4 hours.

[0076] 3) Collect the modified peanut shells obtained by cyclic leaching in step 2) and calcine them at 600℃ for 5 hours to obtain copper oxide-based recoveries.

[0077] Tests showed that the copper content in the copper oxide-based recycled material obtained in this embodiment reached 4.3g; the copper recovery rate reached 45.1%, while the recovery rate of other metals was less than 40%.

[0078] Obviously, the above preferred embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for bio-sorption and decomplexation synergistic recovery of copper from metallurgical sludge, characterized in that, It comprises the following steps: 1) Pumping the organic acid solution into the metallurgical sludge packed column and ethylenediamine tetraacetic acid dianhydride modified biosorbent packed column in sequence in a circulating system, and carrying out circulating leaching; 2) After the circulating leaching, the copper-based recovery material adsorbed on the modified biosorbent is recovered by calcination method; The concentration of the organic acid solution is 0.001-5 mol / L, and the solid-liquid ratio of the metallurgical sludge and the organic acid solution is 1g:1-1000 mL; The ethylenediamine tetraacetic acid dianhydride modified biosorbent is obtained by adding biological material into ethylenediamine tetraacetic acid dianhydride solution and carrying out heat preservation reaction; The mass ratio of the biosorbent and ethylenediamine tetraacetic acid dianhydride is 1:0.1-5; The heat preservation reaction temperature is 10-90℃, and the time is 10-300 min.

2. The method of claim 1, wherein, The organic acid is one or several of citric acid, acetic acid, formic acid, oxalic acid, malic acid, tartaric acid and succinic acid.

3. The method of claim 1, wherein, The biological material comprises one or several of rape straw, peanut shell, cotton stalk, rice straw, wheat straw, loofah pulp and water hyacinth.

4. The method of claim 1, wherein, The pumping speed of the organic acid solution in the metallurgical sludge and modified biosorbent packed column is 1-20 mL / min.

5. The method according to claim 1, wherein the circulating leaching time is 0.1-5 h.

6. The method according to claim 1, wherein the calcination temperature is 300-800℃.