Efficient magnetic carbon-based adsorbent as well as preparation method and application thereof

Abstract

The invention discloses an efficient magnetic carbon-based adsorbent as well as a preparation method and application thereof, and belongs to the technical field of solid waste recycling, the preparation method comprises the following steps: mixing sieved pyrogenic process gold extraction waste residues with hydrochloric acid, carrying out primary microwave reaction, carrying out solid-liquid separation, and washing to obtain iron-rich acid leaching liquid; the method comprises the following steps: carrying out ball milling on blast furnace blowing ash to obtain fine slag, mixing the fine slag with an iron-rich acid leaching solution, carrying out a secondary microwave reaction, adjusting the pH value to be alkaline to obtain a mixed solution of ferric hydroxide and carbon, carrying out suction filtration to obtain iron-carbon mixed filter residues, washing the iron-carbon mixed filter residues to be neutral, drying, and carrying out high-temperature pyrolysis in nitrogen to obtain the efficient magnetic carbon-based adsorbent. According to the method, the acidic copper chloride etching waste liquid can be efficiently adsorbed and desorbed while the recycling rate of the pyrogenic process gold extraction waste residues is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of solid waste resource utilization, and specifically relates to a high-efficiency magnetic carbon-based adsorbent and a preparation method and application thereof. Background Art

[0002] At present, my country has become a major producer of printed circuit boards (PCBs) in the world. Printed circuit board etching waste liquid is divided into alkaline etching liquid and acidic etching liquid. The PCB industry line produces more than 2.8 million tons of acidic copper chloride etching waste liquid each year, and this data is still increasing. Because the copper and hydrochloric acid content in acidic copper chloride etching waste liquid is high, the copper content is generally around 120g / L~180, and the hydrochloric acid content is around 65g / L~140g / L, so it has a very high recycling value, but because it contains other inorganic and organic substances, recycling and utilization have certain challenges. At present, the treatment methods of acidic copper chloride etching waste liquid are mainly divided into two categories: one is that most companies send the etching waste liquid to a specific recycling and treatment center, and use the neutralization method for centralized treatment to recover the copper, etc. This method focuses on the neutralization treatment of waste liquid, and the resource utilization rate is not high. The second is that a small number of companies use a large amount of oxidant treatment to regenerate the etching waste liquid, restore its original etching ability, and then realize recycling. This method requires a large amount of oxidant, which increases the treatment cost.

[0003] At the same time, my country's gold production ranks among the top in the world. With the continuous development of gold mines and the maturity of gold extraction technology, the output of pyrometallurgical gold extraction waste slag has continued to increase. As of 2021, the production of pyrometallurgical gold extraction waste slag has reached 130 million tons. Since pyrometallurgical gold extraction waste slag generally contains harmful components, it is difficult to recycle and reuse, the overall utilization rate is low, and the conversion and utilization rate of high value-added resources is less than 17%. Therefore, a large amount of waste slag accumulation causes land occupation and environmental pollution, and is prone to collapse, posing a huge safety hazard.

[0004] Therefore, it is urgent to make full use of the acid copper chloride etching waste liquid while improving the recycling rate of pyrometallurgical gold extraction waste slag. Summary of the invention

[0005] The purpose of the present invention is to provide a high-efficiency magnetic carbon-based adsorbent and a preparation method and application thereof, which can improve the recycling rate of pyrometallurgical gold extraction waste slag and efficiently adsorb and desorb acidic copper chloride etching waste liquid.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a method for preparing a high-efficiency magnetic carbon-based adsorbent comprises the following steps: The sieved pyrometallurgical gold extraction waste residue is mixed with hydrochloric acid, subjected to a microwave reaction, solid-liquid separation, and washed to obtain an iron-rich acid leaching solution; The blast furnace ash is ball-milled to obtain fine slag, which is mixed with an iron-rich acid leaching solution and subjected to a secondary microwave reaction. The pH is adjusted to alkaline to obtain a mixed solution of iron hydroxide and carbon. After suction filtration, an iron-carbon mixed filter residue is obtained, which is washed with water to neutrality, dried, and pyrolyzed at high temperature under nitrogen to obtain a high-efficiency magnetic carbon-based adsorbent.

[0007] In some embodiments, the pyrometallurgical gold extraction waste slag is sieved through a 200-mesh sieve, the solid-liquid ratio of the pyrometallurgical gold extraction waste slag to hydrochloric acid is 1 g: (3-10) mL, and the mass fraction of the hydrochloric acid is 5%-35%.

[0008] In some embodiments, the power of the primary microwave reaction is 240W-800W, the time is 10min-60min, and the temperature is 70°C-110°C.

[0009] In some embodiments, the ball milling speed is 500 rpm and the time is 20 min to 60 min.

[0010] In some embodiments, the mass ratio of iron to carbon in the fine slag is 1:(1~5), the solid-liquid ratio of the fine slag to the iron-rich acid leaching solution is (0.504~2.760) g:20 mL, and the power of the secondary microwave reaction is 180W~420W, and the time is 1min~30min.

[0011] In some embodiments, the pH is adjusted to 10 using sodium hydroxide.

[0012] In some embodiments, the high temperature pyrolysis is performed at a temperature of 300° C. to 600° C. and for a time of 5 min to 30 min.

[0013] In a second aspect, a high-efficiency magnetic carbon-based adsorbent is obtained by using the method for preparing a high-efficiency magnetic adsorbent, wherein the magnetic carbon specific surface area of ​​the high-efficiency magnetic carbon-based adsorbent is 578.2 m 2 / g ~639.5m 2 / g, and the magnetization intensity is 15.48 emu / g ~18.58emu / g.

[0014] In a third aspect, a high-efficiency magnetic carbon-based adsorbent is used for adsorbing printed circuit board etching waste liquid, wherein the fifth adsorption rate of the high-efficiency magnetic carbon-based adsorbent in a cyclic adsorption experiment is 37.1% to 87.4%, the adsorption rate of the high-efficiency magnetic carbon-based adsorbent to the acidic etching liquid is 72.5% to 99.1%, and the desorption rate of the acidic etching liquid is 83.1% to 98.4%; The applicable pH range of the magnetic carbon-based adsorbent is 1-7, and the adsorption rate of the magnetic carbon-based adsorbent to the acidic etching solution within the applicable pH range is greater than 85%.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses two kinds of industrial solid wastes, namely, pyrometallurgical gold extraction waste slag and blast furnace ash, as raw materials, which solves the environmental problems caused by solid waste accumulation. In addition, the pyrometallurgical gold extraction waste slag itself has a high iron content, which can ensure sufficient iron source while avoiding activation and crushing of waste slag, thereby reducing raw material costs. The present invention mixes the pyrometallurgical gold extraction waste slag with hydrochloric acid and adopts microwave reaction for auxiliary treatment, which can significantly shorten the treatment cycle compared with traditional direct acid leaching treatment. The present invention mixes fine slag with an iron-rich acid leaching solution, and then undergoes a secondary microwave reaction to adjust the pH to alkaline to obtain a mixed solution of iron hydroxide and carbon. Compared with the traditional magnetic carbon material using biochar and iron salt solution to compound, the process of compounding the iron-rich acid leaching solution with blast furnace spray ash not only digests the solid waste, but also acid-modifies the blast furnace spray ash, introduces more oxygen-containing functional groups, and increases the number of negative charges on its surface, thereby enhancing the adsorption capacity for metal ions. In addition, the iron-rich acid leaching solution can wash away impurities in the pores between the blast furnace spray ash, and through microwave-assisted compounding, the acid and alkali resistance and stability of the magnetic carbon are improved, so that the high-efficiency magnetic carbon-based adsorbent finally obtained can achieve high-efficiency adsorption and high-efficiency desorption in a wider pH range. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the XRD diagram of the blast furnace spray ash of Example 1; Figure 2 This is the XRD pattern of the high-efficiency magnetic carbon-based adsorbent prepared in Example 1; Figure 3 The scanning electron microscope images of the high-efficiency magnetic carbon-based adsorbent prepared in Example 1, wherein (a) is a scanning electron microscope image of magnetic carbon, (b) is a C distribution energy spectrum image, (c) is an O distribution energy spectrum image, and (d) is an Fe distribution energy spectrum image; Figure 4 This is the XPS graph of the high-efficiency magnetic carbon-based adsorbent prepared in Example 1; Figure 5 The effect diagram of water magnetic recovery of the high-efficiency magnetic carbon-based adsorbent prepared in Example 1, wherein (a) is a diagram of the high-efficiency magnetic carbon-based adsorbent before water magnetic recovery, and (b) is a diagram of the high-efficiency magnetic carbon-based adsorbent after water magnetic recovery; Figure 6 This is a result diagram of the copper ion concentration of the high-efficiency magnetic carbon-based adsorbent prepared in Example 1 tested by ICP-OES; Figure 7 This is a graph showing the results of a cyclic adsorption test of the high-efficiency magnetic carbon-based adsorbent prepared in Example 1. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below: The waste slag from pyrometallurgical gold extraction usually has a finer particle size. Due to the different types of ores, the composition of the waste slag is also different. According to the type of metal elements, it can be divided into: gold-quartz type, gold-pyrite type, gold-polymetallic type, gold-copper type, gold-antimony type, gold-antimony-tungsten type, gold-arsenopyrite type, gold-bismuth type, gold-uranium type, gold-tellurium type, etc. The raw material type used in the present invention is gold-pyrite type, the mineral of the ore is mainly pyrite, and the gangue mineral is mainly quartz.

[0018] The present invention provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Mix the screened pyrometallurgical gold extraction waste slag and hydrochloric acid, perform a microwave reaction, perform solid-liquid separation, and wash to obtain an iron-rich acid leaching solution, and use the GB / T 3049-2006 method to test the iron ion content in the iron-rich acid leaching solution; Preferably, in step 1, the pyrometallurgical gold extraction waste residue is sieved through a 200-mesh sieve, the solid-liquid ratio of the pyrometallurgical gold extraction waste residue to hydrochloric acid is 1 g: (3-10) mL, the mass fraction of the hydrochloric acid is 5%-35%, the power of a microwave reaction is 240 W-800 W, the time is 10 min-60 min, and the temperature is 70° C.-110° C. During the microwave reaction, a sealed environment is ensured and a condensation reflux device is added.

[0019] Step 2: using a planetary ball mill to ball-mill the blast furnace injection ash to obtain fine slag, mixing the fine slag with the iron-rich acid leaching solution obtained in step 1, and then putting the mixture into a microwave chemical reactor for secondary microwave reaction to obtain a post-reaction solution; Preferably, in step 2, the ball milling speed is 500 rpm, the time is 20 min to 60 min, agate beads are used for ball milling, the mass ratio of agate beads to blast furnace ash is 20:1, the mass ratio of iron to carbon in the fine slag is 1:(1~5), the solid-liquid ratio of the fine slag to the iron-rich acid leaching solution is (0.504~2.760) g:20 mL, the power of the secondary microwave reaction is 180 W~420 W, and the time is 1 min to 30 min.

[0020] Step 3: The pH of the reaction solution obtained in step 2 is adjusted to alkaline to obtain a mixed solution of iron hydroxide and carbon.

[0021] Preferably, in step 3, sodium hydroxide is used to adjust the pH value to 10.

[0022] Step 4: The mixed solution of iron hydroxide and carbon obtained in step 3 is filtered to obtain an iron-carbon mixed residue, which is washed with water until neutral and then dried to obtain a dried residue.

[0023] Step 5: The dried filter residue obtained in step 4 is subjected to high-temperature pyrolysis under the condition of passing nitrogen to obtain a high-efficiency magnetic carbon-based adsorbent.

[0024] Preferably, in step 5, the temperature of high temperature pyrolysis is 300° C. to 600° C., and the time is 5 min to 30 min.

[0025] The present invention will be described in detail below in conjunction with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0026] The following detailed description is the description of the embodiments, and is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0027] Embodiment 1 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 35 mL of 25% hydrochloric acid, control the microwave reaction temperature at 80°C under a microwave reaction condition of 560 W, stir and react for 30 min, further separate the solid and liquid, wash, and obtain 67 mL of iron-rich acid leaching solution, the iron ion concentration of which is measured to be 33.2 mg / L, and the iron leaching rate is 91.2%.

[0028] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 45min to obtain fine slag. Take 1.992g of fine slag with an iron-carbon ratio of 1:3 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 180W for 10min to obtain a post-reaction solution.

[0029] Step 3: The reaction solution obtained in step 2 is slowly added with sodium hydroxide solution to adjust the pH to 10 to obtain a mixed solution of iron hydroxide and carbon.

[0030] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0031] Step 5: The dried filter residue obtained in step 4 was pyrolyzed at 600°C for 10 min under the condition of nitrogen passing to obtain 2.7968 g of a high-efficiency magnetic carbon-based adsorbent.

[0032] The magnetic carbon specific surface area of ​​the magnetic carbon-based adsorbent is 615.4 m 2 / g, the magnetization intensity is 18.02emu / g, and the material structure of blast furnace ash is detected by X-ray diffractometer, such as Figure 1 As shown, the round peak appearing at 20° is the characteristic peak of carbon; The structure of the high-efficiency magnetic carbon-based adsorbent prepared in Example 4 below was detected by X-ray diffractometer. Figure 2 As shown in the figure, the diffraction peak at 20° is significantly weakened after magnetization. Figure 1 The newly added diffraction peaks at 30.29°, 35.55°, 43.08°, 57.36°, and 62.74° are consistent with the data of Fe3O4 cubic crystal system, proving that magnetic carbon was successfully prepared.

[0033] Figure 3 This indicates that iron is uniformly loaded on the carbon surface. Figure 4 The peaks at 711.68 and 714.18 are Fe 3+ and Fe 2+ , which is related to Fe3O4, and the composite is a chemical composite, indicating that the magnetic carbon-based adsorbent has been successfully prepared.

[0034] Take 10 mL of an acidic etching solution from a place in Henan and dilute it to 100 mL, wherein the main components are: copper content of 11.28%, HCl content of 12.71%, weigh 5 g of the magnetic carbon-based adsorbent prepared in this example, add it to the acidic etching solution, adjust the magnetic stirring speed to 300 r / min, take a sample every 10 minutes, and measure the copper ion concentration by ICP-OES (Inductively Coupled PlasmaOptical Emission Spectrometer), as shown Figure 6 As shown, the adsorption rate can reach 99.1% in 75 min, and then solid-liquid separation is carried out by suction filtration. After drying, the residue is placed in a desorption solution prepared by methanol and hydrochloric acid, and solid-liquid separation is carried out after ultrasonic treatment for 30 minutes. The desorption rate can reach 98.4%. Weak alkali is further used to adjust the pH of the desorption solution to 6.4 for solid-liquid separation. The solid phase is washed and dried, and then low-temperature roasted for 20 minutes to obtain copper oxide.

[0035] Take 100 mg of the magnetic carbon-based adsorbent prepared in this example and add it to 50 mL of printed circuit board acid etching solution. The copper ion concentration of the etching solution is 200 mg / L. Adjust the magnetic stirring speed to 200 r / min. Measure Cu by ico-max. 2+ Concentration, under the condition of pH ranging from 1 to 7, the 15min adsorption rate is above 85%, especially at pH=6, the adsorption effect is the best, and the 15min adsorption rate can reach 92.46%, which shows that the magnetic carbon-based adsorbent prepared in this embodiment is universal for a wide range of pH.

[0036] A printed circuit board etching solution with a concentration of 200 mg / L was prepared, 1 g of the magnetic carbon-based adsorbent prepared in this example was taken and a cyclic adsorption experiment was carried out under the condition of pH=1. After adsorption saturation, ultrasonic desorption was performed using a methanol solution with a volume fraction of 60% for 30 min, and further drying was performed before the adsorption experiment was repeated 5 times. The results are shown in the attached figure. Figure 7 As shown, the fifth adsorption rate can still reach 87.4%, indicating that the magnetic carbon-based adsorbent prepared in this example has good recycling ability.

[0037] Embodiment 2 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 45 mL of 15% hydrochloric acid, control the microwave reaction temperature at 100 ° C under the condition of 800 W, stir and react for 20 minutes, further separate the solid and liquid, wash, and obtain 75 mL of iron-rich acid leaching solution, the iron ion concentration of which is measured to be 28.2 mg / L, and the iron leaching rate is 86.5%.

[0038] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 45min to obtain fine slag. Take 2.256g of fine slag with an iron-carbon ratio of 1:4 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 300W for 12min to obtain a post-reaction solution.

[0039] Step 3: The reaction solution obtained in step 2 is slowly added with sodium hydroxide solution to adjust the pH to 10 to obtain a mixed solution of iron hydroxide and carbon.

[0040] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0041] Step 5: The dried filter residue obtained in step 4 was pyrolyzed at 500°C for 30 min under nitrogen flow to obtain 3.1256 g of a high-efficiency magnetic carbon-based adsorbent.

[0042] The magnetic carbon specific surface area of ​​the magnetic carbon-based adsorbent is 628.2 m 2 / g, the magnetization intensity is 16.02emu / g, the adsorption rate of acidic etching solution can reach 95.1%, and the desorption rate can reach 94.3%; in the cyclic adsorption experiment, the fifth adsorption rate can reach 71.2%.

[0043] Embodiment 3 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 25 mL of 30% hydrochloric acid, control the microwave reaction temperature at 70°C under a microwave reaction condition of 600 W, stir and react for 20 min, further separate the solid and liquid, wash, and obtain 58 mL of iron-rich acid leaching solution, the iron ion concentration of which is measured to be 37.8 mg / L, and the iron leaching rate is 89.5%.

[0044] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 45min to obtain fine slag. Take 1.512g of fine slag with an iron-carbon ratio of 1:2 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 240W for 8min to obtain a post-reaction solution.

[0045] Step 3: The reaction solution obtained in step 2 is slowly added with sodium hydroxide solution to adjust the pH to 10 to obtain a mixed solution of iron hydroxide and carbon.

[0046] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0047] Step 5: The dried filter residue obtained in step 4 was pyrolyzed at 500°C for 30 min under nitrogen flow to obtain 2.2462 g of a high-efficiency magnetic carbon-based adsorbent.

[0048] The magnetic carbon specific surface area of ​​the magnetic carbon-based adsorbent is 578.2 m 2 / g, the magnetization intensity is 18.45emu / g, the adsorption rate of acidic etching solution can reach 92.2%, and the desorption rate can reach 93.5%; in the cyclic adsorption experiment, the fifth adsorption rate can reach 51.2%.

[0049] Embodiment 4 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 40 mL of 15% hydrochloric acid, control the microwave reaction temperature at 90°C under a microwave reaction condition of 720 W, stir and react for 20 min, further separate the solid and liquid, wash, and obtain 76 mL of iron-rich acid leaching solution, in which the iron ion concentration is measured to be 27.6 mg / L, and the iron leaching rate is 85.5%.

[0050] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 45min to obtain fine slag. Take 2.760g of fine slag with an iron-carbon ratio of 1:5 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 200W for 15min to obtain a post-reaction solution.

[0051] Step 3: The reaction solution obtained in step 2 is slowly added with sodium hydroxide solution to adjust the pH to 10 to obtain a mixed solution of iron hydroxide and carbon.

[0052] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0053] Step 5: The dried filter residue obtained in step 4 was pyrolyzed at 500°C for 30 min under the condition of nitrogen passing through to obtain 3.102 g of a high-efficiency magnetic carbon-based adsorbent.

[0054] The magnetic carbon specific surface area of ​​the magnetic carbon-based adsorbent is 629.5 m 2 / g, the magnetization intensity is 15.48emu / g, the adsorption rate of acidic etching solution can reach 95.5%, and the desorption rate can reach 92.5%; in the cyclic adsorption experiment, the fifth adsorption rate can reach 48.8%.

[0055] Embodiment 5 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 50 mL of 35% hydrochloric acid, control the microwave reaction temperature at 60°C under a microwave reaction condition of 480 W, stir and react for 20 min, further separate the solid and liquid, wash, and obtain 81 mL of iron-rich acid leaching solution, in which the iron ion concentration is measured to be 25.2 mg / L, and the iron leaching rate is 83.5%.

[0056] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 45min to obtain fine slag. Take 0.504g of fine slag with an iron-carbon ratio of 1:1 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 420W for 6min to obtain a post-reaction solution.

[0057] Step 3: The reaction solution obtained in step 2 is slowly added with sodium hydroxide solution to adjust the pH to 10 to obtain a mixed solution of iron hydroxide and carbon.

[0058] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0059] Step 5: The dried filter residue obtained in step 4 was pyrolyzed at 500°C for 30 min under nitrogen flow to obtain 1.245 g of a high-efficiency magnetic carbon-based adsorbent.

[0060] The magnetic carbon specific surface area of ​​the magnetic carbon-based adsorbent is 639.5 m 2 / g, the magnetization intensity is 18.58emu / g, the adsorption rate of acidic etching solution can reach 72.5%, and the desorption rate can reach 83.1%; in the cyclic adsorption experiment, the fifth adsorption rate can reach 37.1%.

[0061] Embodiment 6 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 15 mL of 5% hydrochloric acid, control the microwave reaction temperature at 110°C under a microwave reaction condition of 240 W, stir the reaction for 10 min, further separate the solid and liquid, and wash to obtain an iron-rich acid leaching solution.

[0062] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 20min to obtain fine slag. Take 1.992g of fine slag with an iron-carbon ratio of 1:3 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 180W for 1min to obtain a post-reaction solution.

[0063] Step 3: The reaction solution obtained in step 2 is slowly added with sodium hydroxide solution to adjust the pH to 10 to obtain a mixed solution of iron hydroxide and carbon.

[0064] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0065] Step 5: The dried filter residue obtained in step 4 is pyrolyzed at 300° C. for 5 min under the condition of nitrogen passing to obtain a high-efficiency magnetic carbon-based adsorbent.

[0066] Embodiment 7 This embodiment provides a method for preparing a high-efficiency magnetic carbon-based adsorbent, comprising the following steps: Step 1: Add 5 g of sieved pyrometallurgical gold extraction waste slag into 45 mL of 15% hydrochloric acid, control the microwave reaction temperature to 70°C under a microwave reaction condition of 800 W, stir the reaction for 60 min, further separate the solid and liquid, wash, and obtain an iron-rich acid leaching solution.

[0067] Step 2: Take 10g of blast furnace ash and 200g of agate beads, mix them evenly and place them in an agate ball jar. Use a planetary ball mill to mill at 500rpm for 60min to obtain fine slag. Take 2.256g of fine slag with an iron-carbon ratio of 1:4 and mix it with 20mL of the iron-rich acid leaching solution obtained in step 1, then put it into a microwave chemical reactor, microwave it at a power of 300W for 30min to obtain a post-reaction solution.

[0068] Step 3: The pH of the reaction solution obtained in step 2 is adjusted to 10 by slowly adding sodium hydroxide solution to obtain a mixed solution of iron hydroxide and carbon.

[0069] Step 4: After the mixed solution of iron hydroxide and carbon obtained in step 3 is filtered, it is repeatedly washed with water until the washing liquid is neutral, and then dried to obtain a dried filter residue.

[0070] Step 5: The dried filter residue obtained in step 4 is pyrolyzed at 500° C. for 30 min under the condition of nitrogen passing through to obtain a high-efficiency magnetic carbon-based adsorbent.

[0071] The embodiments described above are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for preparing a high-efficiency magnetic carbon-based adsorbent, characterized in that: The following steps are involved: The sieved pyrometallurgical gold extraction waste residue is mixed with hydrochloric acid, subjected to a microwave reaction, solid-liquid separation, and washed to obtain an iron-rich acid leaching solution; The blast furnace ash is ball-milled to obtain fine slag, which is mixed with an iron-rich acid leaching solution and subjected to a secondary microwave reaction. The pH is adjusted to alkaline to obtain a mixed solution of iron hydroxide and carbon. After suction filtration, an iron-carbon mixed filter residue is obtained, which is washed with water to neutrality, dried, and pyrolyzed at high temperature under nitrogen to obtain a high-efficiency magnetic carbon-based adsorbent.

2. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: The pyrometallurgical gold extraction waste slag is sieved through a 200-mesh sieve, the solid-liquid ratio of the pyrometallurgical gold extraction waste slag to hydrochloric acid is 1 g: (3-10) mL, and the mass fraction of the hydrochloric acid is 5%-35%.

3. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: The power of the primary microwave reaction is 240W-800W, the time is 10min-60min, and the temperature is 70°C-110°C.

4. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: The ball milling speed is 500 rpm, and the time is 20 min to 60 min.

5. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: In the fine slag, the mass ratio of iron to carbon is 1:(1-5); the solid-liquid ratio of the fine slag to the iron-rich acid leaching solution is (0.504-2.760) g:20 mL.

6. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: The power of the secondary microwave reaction is 180W-420W, and the time is 1min-30min.

7. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: The process of adjusting the pH to alkalinity is to use sodium hydroxide to adjust the pH value to 10.

8. The method for preparing a high-efficiency magnetic carbon-based adsorbent according to claim 1, characterized in that: The high temperature pyrolysis temperature is 300°C to 600°C, and the time is 5min to 30min.

9. A high-efficiency magnetic carbon-based adsorbent, characterized in that: The method for preparing a high-efficiency magnetic adsorbent according to any one of claims 1 to 8 is used to obtain the high-efficiency magnetic carbon-based adsorbent, wherein the magnetic carbon specific surface area of ​​the high-efficiency magnetic carbon-based adsorbent is 578.2 m 2 / g ~639.5m 2 / g, and the magnetization intensity is 15.48 emu / g ~18.58emu / g.

10. The high-efficiency magnetic carbon-based adsorbent according to claim 9 is used to adsorb printed circuit board etching liquid, characterized in that: The fifth adsorption rate of the high-efficiency magnetic carbon-based adsorbent in the cyclic adsorption experiment is 37.1% to 87.4%, the adsorption rate of the high-efficiency magnetic carbon-based adsorbent to the acidic etching solution is 72.5% to 99.1%, and the desorption rate of the acidic etching solution is 83.1% to 98.4%; The applicable pH range of the magnetic carbon-based adsorbent is 1-7, and the adsorption rate of the magnetic carbon-based adsorbent to the acidic etching solution within the applicable pH range is greater than 85%.

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