A method for recycling fluorine- and indium-containing waste liquids

Abstract

This invention discloses a method for recycling fluorine- and indium-containing wastewater, belonging to the field of resource recycling technology. The method involves adjusting the pH of the fluorine- and indium-containing wastewater to 3-5, effectively precipitating indium while reducing the precipitation of other ions. The precipitate is then calcined to promote the decomposition of indium oxide, followed by reduction calcination to obtain high-purity crude indium. The supernatant is then adjusted to pH 1-2 to effectively remove impurity metal elements, while simultaneously increasing the activity of additives and reducing side reactions. Finally, stepwise flocculation yields a filtrate and chromium- and fluorine-containing waste residue. The filtrate effectively removes metal and fluorine elements, while the chromium- and fluorine-containing waste residue can be sold directly as a byproduct, effectively improving economic benefits.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, specifically to a method for recycling fluorine- and indium-containing waste liquids. Background Technology

[0002] Indium is a rare dispersed metal with atomic number 49, relative atomic weight 114.82, melting point 429.76 K, and boiling point 2353.15 K. It is a silvery-white metal located in Group III A of the periodic table, characterized by high ductility, extremely soft texture, low melting point, and high boiling point. The directly mineable primary indium resources in the Earth's crust are less than 30,000 tons, and it is often found as an associated mineral in veins containing zinc, copper, and other metals.

[0003] In industry, metallic indium is often extracted, separated, and purified from recycled indium resources. Common recycled indium resources include indium-containing smelting waste (lead-zinc smelting waste, steel dust, flue ash, etc.) and wastewater (indium-containing etching waste liquid, indium electrolysis waste liquid, raffinate, etc.).

[0004] Therefore, this application is submitted. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for recycling fluorine- and indium-containing waste liquids. The method described in this invention not only removes harmful elements such as chromium and fluorine from the waste liquids, but also effectively recovers indium metal, which has extremely high economic benefits and application prospects.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0008] (1) Add sodium hydroxide solution to fluorine-containing and indium-containing waste liquid, adjust pH to 3-5, stir evenly, filter, and obtain supernatant and precipitate. Calcine the precipitate to obtain crude indium oxide.

[0009] (2) Mix crude indium oxide with anthracite and calcine to obtain crude indium;

[0010] (3) Add sulfuric acid solution to the supernatant of step (1), adjust pH to 1-2, add additives, adjust solution temperature to 45-55℃, adjust pH to 7-8 with sodium hydroxide solution, add polyaluminum chloride solution, stir evenly, add polyacrylamide solution, stir evenly, filter, and take supernatant.

[0011] (4) Add calcium oxide to the supernatant of step (3), then add polyaluminum chloride solution, stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0012] This invention adjusts the pH of fluorine- and indium-containing wastewater to 3-5, effectively precipitating indium while reducing the precipitation of other ions. The precipitate is then calcined to promote the decomposition of indium oxide, followed by reduction calcination to obtain high-purity crude indium. The supernatant is then adjusted to pH 1-2 to effectively remove impurity metal elements, while simultaneously increasing the activity of additives and reducing side reactions. Finally, stepwise flocculation yields a filtrate and chromium- and fluorine-containing waste residue. The filtrate effectively removes metal and fluorine elements, while the chromium- and fluorine-containing waste residue can be sold directly as a byproduct. The method described in this invention not only removes harmful elements such as chromium and fluorine from wastewater but also effectively recovers indium metal, demonstrating significant economic benefits and promising application prospects.

[0013] The method for recycling fluorine- and indium-containing wastewater described in this invention aims to achieve "green, efficient, and deep purification" in recycling and purification, thereby improving the utilization efficiency of indium metal from recycled indium resources, reducing the pollution and damage to the environment and equipment caused by other ions in the wastewater, and increasing the company's profits.

[0014] As a preferred embodiment of the present invention, the fluorine- and indium-containing waste liquid mainly includes the following components: indium 600-1200 mg / L, Zn 100-200 mg / L, Cr 200-300 mg / L, F 100-300 mg / L, As 50-200 mg / L, Sn 1000-1500 mg / L, and Fe 500-700 mg / L. In particular, when the content of each component is within this range, the purity of indium and the removal effect of fluorine and chromium can be more effectively improved.

[0015] As a preferred embodiment of the present invention, the calcination temperature in step (1) is 500-600°C and the time is 6-8 hours. The calcination is carried out in an oxygen atmosphere. Controlling the calcination temperature within this range can promote the decomposition of indium oxide. If the temperature is too high, indium monoxide will be generated, which will lead to a decrease in product purity. If the temperature is too low, the indium oxide will not decompose completely.

[0016] In a preferred embodiment of the present invention, the mass ratio of crude indium oxide to anthracite is 1:(3-5).

[0017] As a preferred embodiment of the present invention, the calcination temperature in step (1) is 1000-1100℃ and the time is 4-6h. By using anthracite as a reducing agent and controlling the amount of the reducing agent, the calcination temperature and time, the reduction can be thorough, the adhesion of anthracite and indium metal can be avoided, and the yield can be improved.

[0018] The sodium hydroxide solution contains 35-50% by mass.

[0019] The sulfuric acid solution has a mass fraction of 10-20%.

[0020] As a preferred embodiment of the present invention, the additive includes at least one of iron powder, sodium sulfite, sodium thiosulfate, ferrous sulfate, and sodium bisulfite, and the amount of the additive added is 5-10 g / L.

[0021] In a preferred embodiment of the present invention, the mass fraction of the polyaluminum chloride solution is 5-15%; the mass fraction of the polyaluminum chloride solution is 2-8%.

[0022] In a preferred embodiment of the present invention, the amount of polyaluminum chloride solution added in step (4) is 100-300 mg / L, and the amount of polyacrylamide solution added is 10-30 mg / L.

[0023] In a preferred embodiment of the present invention, the amount of calcium oxide added is 200-300 mg / L.

[0024] As a preferred embodiment of the present invention, in step (4), the amount of polyaluminum chloride solution added is 100-300 mg / L, and the amount of polyacrylamide solution added is 20-50 mg / L.

[0025] The reaction equation in step (4) is: Ca 2+ +F - =CaF2.

[0026]

[0027] The beneficial effects of the present invention are as follows: (1) The present invention adjusts the pH of fluorine-containing and indium-containing waste liquid to 3-5, which can effectively precipitate indium and reduce the precipitation of other ions. Then, the precipitate is calcined to promote the decomposition of indium oxide, and then reduced and calcined to obtain high-purity crude indium. The pH of the supernatant is adjusted to 1-2 to effectively remove impurity metal elements, while improving the activity of additives and reducing the occurrence of side reactions. Finally, after stepwise flocculation, filtrate and chromium- and fluorine-containing waste residue are obtained. The metal elements and fluorine elements in the filtrate are effectively removed, while the chromium- and fluorine-containing waste residue can be sold directly as by-products. The method described in the present invention not only removes harmful elements such as chromium and fluorine in the waste liquid, but also effectively recovers indium metal, which has extremely high economic benefits and application prospects. (2) The recycling method of fluorine-containing and indium-containing waste liquid described in the present invention takes "green, efficient and deep purification" as the recycling and purification purpose, improves the utilization efficiency of indium metal from recycled indium resources, reduces the pollution and damage of other ions in wastewater to the environment and equipment, and increases the profits of enterprises. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0030] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0031] In this application, there are no particular restrictions on the specific dispersion and mixing methods.

[0032] Unless otherwise specified, all components, raw materials, or instruments used in the embodiments and comparative examples of this invention are commercially available, and the components and raw materials used in each parallel experiment are the same.

[0033] The following embodiments are provided to facilitate understanding of the invention. These embodiments are not intended to limit the scope of the claims.

[0034] Example 1

[0035] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0036] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0037] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0038] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0039] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0040] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite at an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution at an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution at an addition amount of 20-50 mg / L, stir evenly, filter, and take the supernatant.

[0041] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0042] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0043] Example 2

[0044] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0045] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0046] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0047] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 3, stir evenly at 30°C, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter under pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500°C for 8 hours under an oxygen atmosphere to obtain crude indium oxide.

[0048] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0049] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0050] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0051] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0052] Example 3

[0053] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0054] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0055] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0056] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 600℃ for 4 hours in an oxygen atmosphere to obtain crude indium oxide.

[0057] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0058] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0059] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0060] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0061] Example 4

[0062] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0063] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0064] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0065] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0066] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0067] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 2, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0068] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0069] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0070] Example 5

[0071] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0072] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0073] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0074] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0075] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0076] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 7 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0077] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0078] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0079] Comparative Example 1

[0080] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0081] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0082] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0083] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0084] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0085] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, adjust the solution temperature to 50°C, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add a polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add a polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0086] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0087] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0088] Comparative Example 2

[0089] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0090] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0091] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0092] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0093] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0094] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0095] (5) Add polyaluminum chloride solution at a dosage of 200 mg / L, stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0096] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0097] Comparative Example 3

[0098] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0099] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0100] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0101] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0102] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0103] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0104] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0105] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0106] Comparative Example 4

[0107] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0108] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0109] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0110] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 2, stir evenly at 30℃, wait for the supernatant and precipitate in the reaction vessel to separate into distinct layers, filter under pressure to obtain the supernatant and precipitate, calcine the precipitate at 500℃ for 8 hours under an oxygen atmosphere to obtain crude indium oxide.

[0111] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0112] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0113] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0114] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0115] Comparative Example 5

[0116] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0117] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0118] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0119] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 7, stir evenly at 30°C, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500°C for 8 hours under an oxygen atmosphere to obtain crude indium oxide.

[0120] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0121] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0122] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0123] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0124] Comparative Example 6

[0125] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0126] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0127] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0128] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0129] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0130] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 0.5, add sodium sulfite at a concentration of 8 g / L, adjust the solution temperature to 50°C, stir evenly, adjust the pH to 8 with a concentration of 46 wt% sodium hydroxide solution, add polyaluminum chloride solution at a concentration of 200 mg / L, stir evenly, add polyacrylamide solution at a concentration of 200 mg / L, stir evenly, filter, and take the supernatant.

[0131] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0132] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0133] Comparative Example 7

[0134] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0135] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0136] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0137] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 500℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0138] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0139] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 3, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0140] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0141] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0142] Comparative Example 8

[0143] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0144] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0145] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0146] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 400℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0147] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0148] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0149] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0150] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0151] Comparative Example 9

[0152] A method for recycling fluorine- and indium-containing waste liquid includes the following steps:

[0153] (1) Fluorine- and indium-containing waste liquid is added to the enamel-lined reactor #1 equipped with an electromagnetic stirrer at a rate of 10 L / min. The liquid level in the container does not exceed 2 / 3 of the container volume.

[0154] The fluorine- and indium-containing waste liquid mainly includes the following components: indium 912 mg / L, Zn 160 mg / L, Cr 257 mg / L, F 200 mg / L, As 100 mg / L, Sn 1289 mg / L, and Fe 630 mg / L.

[0155] (2) Add a 46wt% sodium hydroxide solution to the fluorine-containing and indium-containing waste liquid, adjust the pH to 5, stir evenly at 30℃, and when the supernatant and precipitate in the reaction vessel are clearly separated into layers, filter by pressure to obtain the supernatant and precipitate. Calcine the precipitate at 700℃ for 8 hours in an oxygen atmosphere to obtain crude indium oxide.

[0156] (3) Crude indium oxide and anthracite are mixed evenly at a mass ratio of 1:4 and calcined at 1100℃ for 4 hours to obtain crude indium;

[0157] (4) Add a sulfuric acid solution with a concentration of 160 g / L to the supernatant of step (2), adjust the pH to 1, add sodium sulfite with an addition amount of 8 g / L, adjust the solution temperature to 50℃, stir evenly, adjust the pH to 8 with a sodium hydroxide solution with a concentration of 46 wt%, add polyaluminum chloride solution with an addition amount of 200 mg / L, stir evenly, add polyacrylamide solution with an addition amount of 200 mg / L, stir evenly, filter, and take the supernatant.

[0158] (5) Add calcium oxide to the supernatant of step (4) at a dosage of 300 mg / L, and then add polyaluminum chloride solution at a dosage of 200 mg / L. Stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

[0159] The concentration of the polyaluminum chloride solution is 10 wt%; the concentration of the polyaluminum chloride solution is 5 wt%.

[0160] Test case

[0161] The purity, chromium removal rate, and fluorine removal rate of the crude indium obtained in Example 1 and the comparative example are shown in Table 1.

[0162] Table 1

[0163]

[0164]

[0165] As can be seen from Table 1, the method described in this invention not only removes harmful elements such as chromium and fluorine from the waste liquid, but also effectively recovers indium metal, which has extremely high economic benefits and application prospects.

[0166] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for recycling fluorine- and indium-containing wastewater, characterized in that, Includes the following steps: (1) Add sodium hydroxide solution to fluorine-containing and indium-containing waste liquid, adjust pH to 3-5, stir evenly, filter, and obtain supernatant and precipitate. Calcine the precipitate to obtain crude indium oxide. (2) Mix crude indium oxide with anthracite and calcine to obtain crude indium; (3) Add sulfuric acid solution to the supernatant of step (1), adjust the pH to 1-2, add additives, adjust the solution temperature to 45-55℃, adjust the pH to 7-8 with sodium hydroxide solution, add polyaluminum chloride solution, stir evenly, add polyacrylamide solution, stir evenly, filter, and take the supernatant; the additives include at least one of iron powder, sodium sulfite, sodium thiosulfate, ferrous sulfate, and sodium bisulfite; (4) Add calcium oxide to the supernatant of step (3), then add polyaluminum chloride solution, stir evenly, filter, and obtain filtrate and chromium- and fluorine-containing waste residue.

2. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, The fluorine- and indium-containing waste liquid mainly includes the following components: indium 600~1200 mg / L, Zn 100~200 mg / L, Cr 200~300 mg / L, F 100~300 mg / L, As 50~200 mg / L, Sn 1000~1500 mg / L, and Fe 500~700 mg / L.

3. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, In step (1), the calcination temperature is 500~600℃ and the time is 6~8h.

4. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, The mass ratio of crude indium oxide to anthracite is 1:(3~5).

5. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, In step (2), the calcination temperature is 1000~1100℃ and the time is 4~6h.

6. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, The amount of the additive added is 5~10g / L.

7. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, The mass fraction of the polyaluminum chloride solution is 5-15%.

8. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, The amount of polyacrylamide solution added is 10~30 mg / L.

9. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, The amount of calcium oxide added is 200~300 mg / L.

10. The method for recycling fluorine- and indium-containing wastewater according to claim 1, characterized in that, In step (4), the amount of polyaluminum chloride solution added is 100~300 mg / L.

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