A method for selectively separating and recovering boron from a boron-containing aluminosilicate glass

Abstract

The application provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, which comprises the following steps: (1) ball milling the boron-containing aluminosilicate glass, slurryizing the material after roasting treatment by adding water, mixing the slurryized material with sulfuric acid, and obtaining a boron-containing leaching solution after pressure acid leaching treatment; (2) adjusting the pH of the boron-containing leaching solution, adding sodium carbonate to carry out magnesium removal treatment, and obtaining a sodium borate solution; (3) carrying out concentration and crystallization treatment on the sodium borate solution, and obtaining borax. The method adopts the processes of ball milling-transformation roasting-pressure acid leaching-carbonation magnesium removal-evaporation crystallization, recovers boron in the form of borax from the glass, synchronously recovers magnesium carbonate as a byproduct, and realizes selective separation and recovery of boron, magnesium and sodium elements in the glass powder.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of resource recycling, and relates to a method for selectively separating and recycling boron from boron-containing aluminosilicate glass. BACKGROUND

[0002] Glass products are generally prepared by sintering components such as silicon dioxide, sodium oxide, magnesium oxide, aluminum oxide, etc. In order to increase the transparency of the glass and improve the thermal expansion coefficient, different proportions of boron compounds are generally added for adjustment. In addition, in the manufacturing process of 3C electronic device glass screens, in order to reduce the temperature and viscosity of the melt during glass melting, improve the density and smoothness of the glass, and improve the strength, ductility, corrosion resistance and heat shock resistance of the product, etc., lithium concentrate or lithium compounds are also added to the glass batch.

[0003] In actual production, a large amount of scrap glass is generated due to operation and product quality problems, and the increasing stockpiling not only causes waste of resources, but also pollutes the environment to a certain extent.

[0004] At present, the main recycling method of glass recycling is low-value utilization: 1. Physical cleaning - remelting, the remelted glass directly has complex composition and poor stability, and has low value, and is applied to the ultra-low end field; 2. Stockpiling, landfill or building material field, mainly used in cement and concrete fields as low-value building materials, with low utilization rate. High-value utilization is to recover valuable elements by metallurgical method. The glass powder mainly contains silicon, aluminum, magnesium, boron and other elements, and 1% to 3% of lithium in special glass for 3C electronic devices. Due to the difference in glass composition produced by different manufacturers, the difficulty of recycling valuable elements in the glass is increased. SUMMARY

[0005] The purpose of the present application is to provide a method for selectively separating and recycling boron from boron-containing aluminosilicate glass. The present application adopts ball milling - transformation roasting - pressure acid leaching - carbonation magnesium removal - evaporation crystallization and other processes to recover boron in the form of borax from the glass, synchronously recover magnesium carbonate byproduct, and realize the selective separation and recovery of boron, magnesium and sodium elements in the glass powder.

[0006] In order to achieve the purpose of the present application, the following technical scheme is adopted:

[0007] In a first aspect, the present application provides a method for selectively separating and recycling boron from boron-containing aluminosilicate glass, which comprises the following steps:

[0008] (1) Ball milling of boron-containing aluminosilicate glass, slurry after roasting treatment, mixing the slurry with sulfuric acid, and obtaining boron-containing leaching solution after pressure acid leaching treatment;

[0009] (2) After adjusting the pH of the boron-containing leaching solution, sodium carbonate is added for magnesium precipitation treatment to obtain a sodium borate solution;

[0010] (3) The sodium borate solution is subjected to concentration and crystallization treatment to obtain borax.

[0011] The over-transformation roasting makes lithium, aluminum and silicon in the boron-containing aluminosilicate glass form crystal phases that are relatively more stable than boron, and the selective leaching of boron, magnesium and sodium is achieved by using a pressurized acid leaching method, so as to achieve the effect of separating and recovering boron and lithium elements. The magnesium in the leaching solution is removed by using carbonic acid, and a sodium borate solution is obtained. Subsequently, borax products can be prepared by evaporation and concentration-temperature reduction crystallization. The method for glass recovery or pre-removal of boron is less studied at present. Compared with the prior art, the method has the characteristics of strong raw material adaptability, good selective separation effect, high boron recovery rate and the like, and has certain production significance.

[0012] Preferably, the median particle size D50 of the boron-containing aluminosilicate glass powder obtained by ball milling in step (1) is ≤ 150 μm.

[0013] Preferably, the temperature of the roasting treatment in step (1) is 800-1200℃, for example, 800℃, 900℃, 1000℃, 1100℃ or 1200℃, etc., and is not limited to the listed values, and other values not listed in this value range are also applicable.

[0014] Preferably, the time of the roasting treatment in step (1) is 1-4h, for example, 1h, 1.5h, 2h, 3h or 4h, etc., and is not limited to the listed values, and other values not listed in this value range are also applicable.

[0015] Preferably, the slurry liquid-solid ratio of the water slurry in step (1) is (2-5):1, for example, 2:1, 2.5:1, 3:1, 4:1 or 5:1, etc., and is not limited to the listed values, and other values not listed in this value range are also applicable.

[0016] Preferably, the acid-ore ratio of the addition of sulfuric acid in step (1) is (0.3-0.5):1, for example, 0.3:1, 0.35:1, 0.4:1, 0.45:1 or 0.5:1, etc., and is not limited to the listed values, and other values not listed in this value range are also applicable.

[0017] Preferably, the temperature of the pressurized acid leaching in step (1) is 120-160℃, for example, 120℃, 130℃, 140℃, 150℃ or 160℃, etc., and is not limited to the listed values, and other values not listed in this value range are also applicable.

[0018] Preferably, the pressure of the pressure acid leaching in step (1) is 1.2-1.8 MPa, for example 1.2 MPa, 1.3 MPa, 1.5 MPa, 1.6 MPa or 1.8 MPa, and the like, and the range of values is not limited to the listed values, and other values not listed within the range of values are also applicable.

[0019] Preferably, the time of the pressure acid leaching in step (1) is 1-4 h, for example 1 h, 1.5 h, 2 h, 3 h or 4 h, and the like, and the range of values is not limited to the listed values, and other values not listed within the range of values are also applicable.

[0020] Preferably, the pH adjusting agent for adjusting the pH of the boron-containing leaching solution in step (2) comprises sodium hydroxide.

[0021] Preferably, the pH in step (2) is 9-13, for example 9, 10, 11, 12 or 13, and the like, and the range of values is not limited to the listed values, and other values not listed within the range of values are also applicable.

[0022] Preferably, the molar ratio of carbonate ions to magnesium ions in the system after the addition of sodium carbonate in step (2) is (1.0-1.1):1, for example 1.0:1, 1.02:1, 1.05:1, 1.08:1 or 1.1:1, and the like, and the range of values is not limited to the listed values, and other values not listed within the range of values are also applicable.

[0023] Preferably, the temperature of the magnesium precipitation treatment in step (2) is 40-70℃, for example 40℃, 45℃, 50℃, 60℃ or 70℃, and the like, and the range of values is not limited to the listed values, and other values not listed within the range of values are also applicable.

[0024] As a preferred scheme of the present application, the method comprises the following steps:

[0025] (1) a boron-containing aluminosilicate glass powder with a median particle size D50≤150 μm is obtained after ball milling of a boron-containing aluminosilicate glass, the boron-containing aluminosilicate glass powder is calcined at 800-1200℃ for 1-4 h, then water is added for slurry formation according to a slurry liquid-to-solid ratio of (2-5):1, sulfuric acid is added according to an acid-to-ore ratio of (0.3-0.5):1, and pressure acid leaching is carried out at 120-160℃ and 1.2-1.8 MPa for 1-4 h to obtain a boron-containing leaching solution;

[0026] (2) sodium hydroxide is added to adjust the pH of the boron-containing leaching solution to 9-13, sodium carbonate is added to control the molar ratio of carbonate ions to magnesium ions in the system to (1.0-1.1):1, and magnesium precipitation treatment is carried out at 40-70℃ to obtain a sodium borate solution;

[0027] (3) the sodium borate solution is subjected to concentration and crystallization treatment to obtain borax.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] (1) The present application makes lithium, aluminum and silicon generate crystal phases that are more stable than boron by means of transformation roasting, and makes boron, magnesium and sodium selectively leach by means of pressure acid leaching, so as to achieve the effect of separating and recovering boron and lithium, etc. The magnesium in the leaching solution is removed by using sodium carbonate, and the sodium borate solution obtained can be used to prepare borax products through evaporation concentration-temperature reduction crystallization. The method has the characteristics of strong adaptability to raw materials, good selective separation effect, high boron recovery rate, etc.

[0030] (2) The lithium leaching rate of the method for selectively separating and recovering boron from boron-containing aluminosilicate glass can reach 1.1% or less, the aluminum leaching rate can reach 0.1% or less, the boron leaching rate can reach 99.1% or more, the magnesium leaching rate can reach 98.1% or more, the sodium leaching rate can reach 98.5% or more, and the magnesium removal rate can reach 99.0% or more, so that the main content of borax can reach 98.5% or more. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0032] Embodiment 1

[0033] The present embodiment provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, which comprises the following steps:

[0034] (1) The boron-containing aluminosilicate glass powder with a median particle size D50 of 50 μm is obtained by ball milling the boron-containing aluminosilicate glass, and the boron-containing aluminosilicate glass powder is calcined at 1000℃ for 2h, then water is added for slurry according to the slurry liquid-solid ratio of 5:1, and sulfuric acid is added according to the acid ore ratio of 0.4:1, and pressure acid leaching is carried out at 160℃ and 1.6MPa for 2h to obtain a boron-containing leaching solution;

[0035] (2) The pH of the boron-containing leaching solution is adjusted to 9 by adding sodium hydroxide, and the molar ratio of carbonate ions to magnesium ions in the system is controlled to 1.05:1 by adding sodium carbonate, and magnesium removal treatment is carried out at 50℃ to obtain a sodium borate solution;

[0036] (3) The sodium borate solution is subjected to concentration crystallization treatment to obtain borax.

[0037] Embodiment 2

[0038] The present embodiment provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, which comprises the following steps:

[0039] (1) The boron-containing aluminosilicate glass powder with a median particle size D50 = 100 μm obtained after ball milling of the boron-containing aluminosilicate glass is calcined at 1000°C for 2 h, then water is added for slurry according to a slurry liquid-solid ratio of 4:1, sulfuric acid is added according to an acid-ore ratio of 0.5:1, and pressure acid leaching is carried out at 150°C and 1.8 MPa for 1 h to obtain a boron-containing leaching solution;

[0040] (2) The pH of the boron-containing leaching solution is adjusted to 11 by adding sodium hydroxide, the molar ratio of carbonate ions to magnesium ions in the system is controlled to 1.08:1 by adding sodium carbonate, and magnesium precipitation treatment is carried out at 60°C to obtain a sodium borate solution;

[0041] (3) The sodium borate solution is subjected to concentration and crystallization treatment to obtain borax.

[0042] Example 3

[0043] The embodiment provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, which comprises the following steps:

[0044] (1) The boron-containing aluminosilicate glass powder with a median particle size D50 = 50 μm obtained after ball milling of the boron-containing aluminosilicate glass is calcined at 1000°C for 4 h, then water is added for slurry according to a slurry liquid-solid ratio of 4:1, sulfuric acid is added according to an acid-ore ratio of 0.5:1, and pressure acid leaching is carried out at 140°C and 1.8 MPa for 4 h to obtain a boron-containing leaching solution;

[0045] (2) The pH of the boron-containing leaching solution is adjusted to 10 by adding sodium hydroxide, the molar ratio of carbonate ions to magnesium ions in the system is controlled to 1.02:1 by adding sodium carbonate, and magnesium precipitation treatment is carried out at 70°C to obtain a sodium borate solution;

[0046] (3) The sodium borate solution is subjected to concentration and crystallization treatment to obtain borax.

[0047] Example 4

[0048] The embodiment provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, which comprises the following steps:

[0049] (1) The boron-containing aluminosilicate glass powder with a median particle size D50 = 50 μm obtained after ball milling of the boron-containing aluminosilicate glass is calcined at 1000°C for 2 h, then water is added for slurry according to a slurry liquid-solid ratio of 5:1, sulfuric acid is added according to an acid-ore ratio of 0.4:1, and pressure acid leaching is carried out at 140°C and 1.6 MPa for 2 h to obtain a boron-containing leaching solution;

[0050] (2) adding sodium hydroxide to adjust the pH of the boron-containing leaching solution to 9, adding sodium carbonate to control the molar ratio of carbonate ions to magnesium ions in the system to 1.05:1, and performing magnesium precipitation treatment at 50°C to obtain a sodium borate solution;

[0051] (3) performing concentration and crystallization treatment on the sodium borate solution to obtain borax.

[0052] Example 5

[0053] The embodiment provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, and the method comprises the following steps:

[0054] (1) ball milling the boron-containing aluminosilicate glass to obtain boron-containing aluminosilicate glass powder with a median particle size D50 of 50 μm, roasting the boron-containing aluminosilicate glass powder at 1000°C for 2 h, adding water to slurry the boron-containing aluminosilicate glass powder according to a slurry liquid-solid ratio of 5:1, adding sulfuric acid according to an acid-ore ratio of 0.4:1, and performing pressure acid leaching at 160°C and 1.6 MPa for 2 h to obtain a boron-containing leaching solution;

[0055] (2) adding sodium hydroxide to adjust the pH of the boron-containing leaching solution to 9, adding sodium carbonate to control the molar ratio of carbonate ions to magnesium ions in the system to 1.0:1, and performing magnesium precipitation treatment at 50°C to obtain a sodium borate solution;

[0056] (3) performing concentration and crystallization treatment on the sodium borate solution to obtain borax.

[0057] Example 6

[0058] The embodiment provides a method for selectively separating and recovering boron from boron-containing aluminosilicate glass, and the method comprises the following steps:

[0059] (1) ball milling the boron-containing aluminosilicate glass to obtain boron-containing aluminosilicate glass powder with a median particle size D50 of 50 μm, roasting the boron-containing aluminosilicate glass powder at 1000°C for 2 h, adding water to slurry the boron-containing aluminosilicate glass powder according to a slurry liquid-solid ratio of 5:1, adding sulfuric acid according to an acid-ore ratio of 0.4:1, and performing pressure acid leaching at 160°C and 1.6 MPa for 2 h to obtain a boron-containing leaching solution;

[0060] (2) adding sodium hydroxide to adjust the pH of the boron-containing leaching solution to 9, adding sodium carbonate to control the molar ratio of carbonate ions to magnesium ions in the system to 1.05:1, and performing magnesium precipitation treatment at 50°C to obtain a sodium borate solution;

[0061] (3) performing concentration and crystallization treatment on the sodium borate solution to obtain borax.

[0062] Example 7

[0063] The embodiment differs from example 1 only in that the calcination temperature is 700℃, and other conditions and parameters are completely the same as example 1.

[0064] Example 8

[0065] The embodiment differs from example 1 only in that the calcination temperature is 1300℃, and other conditions and parameters are completely the same as example 1.

[0066] Example 9

[0067] The embodiment differs from example 1 only in that the slurry liquid-solid ratio is 2:1, and other conditions and parameters are completely the same as example 1.

[0068] Example 10

[0069] The embodiment differs from example 1 only in that the slurry liquid-solid ratio is 6:1, and other conditions and parameters are completely the same as example 1.

[0070] Comparative example 1

[0071] The comparative example differs from example 1 only in that no ball milling treatment is performed, and other conditions and parameters are completely the same as example 1.

[0072] Comparative example 2

[0073] The comparative example differs from example 1 only in that no calcination treatment is performed, and other conditions and parameters are completely the same as example 1.

[0074] Performance test:

[0075] The leaching test results of different elements in the example and comparative example are shown in table 1:

[0076] Table 1

[0077]

[0078]

[0079] As can be seen from table 1, according to examples 1-6, the method for selectively separating and recovering boron from the boron-containing aluminosilicate glass, the lithium leaching rate can reach 1.1% or less, the aluminum leaching rate can reach 0.1% or less, the boron leaching rate can reach 99.1% or more, the magnesium leaching rate can reach 98.1% or more, the sodium leaching rate can reach 98.5% or more, the magnesium removal rate can reach 99.0% or more, and the main content of borax can reach 98.5% or more.

[0080] From the comparison of Example 1 and Examples 7-8, it can be seen that in the method for selectively separating and recovering boron from the boron-containing aluminosilicate glass according to the present application, the temperature of the calcination affects the recovery effect. If the temperature of the calcination is controlled to be 800-1200℃, the recovery effect is better. If the temperature of the calcination is too low, the crystal is not transformed, and the full elements are synchronously leached. If the temperature of the calcination is too high, the glass is melted, the crystal is transformed into a more dense crystal form, and the boron compound is encapsulated, which leads to difficult leaching.

[0081] From the comparison of Example 1 and Examples 9-10, it can be seen that in the method for selectively separating and recovering boron from the boron-containing aluminosilicate glass according to the present application, the slurry liquid-solid ratio of the water addition and slurry affects the recovery effect. If the slurry liquid-solid ratio is controlled to be 3-5:1, the recovery effect is better. If the slurry liquid-solid ratio is too low, the slurry is too viscous, and the stirring is difficult. If the slurry liquid-solid ratio is too high, the leaching effect is poor.

[0082] From the comparison of Example 1 and Comparative Example 1, it can be seen that in the present application, the boron-containing aluminosilicate glass is ground into a fine powder with a median particle size D50≤150μm, and the leaching rates of boron, magnesium, sodium and other elements are increased. It is shown that the lower the particle size of the powder, the better the leaching effect. If the particle size is continuously reduced, the leaching effect does not change significantly.

[0083] From the comparison of Example 1 and Comparative Example 2, it can be seen that in the present application, the lithium, aluminum and silicon are transformed by calcination to form a crystal phase which is relatively stable to boron, which is beneficial to the separation and recovery of boron and lithium.

[0084] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for selectively separating and recovering boron from boron-containing aluminosilicate glass, characterized in that, The method includes the following steps: (1) The boron-containing aluminum silicate glass is ball-milled, calcined, and then slurried with water. The slurried material is mixed with sulfuric acid and subjected to pressure acid leaching to obtain a boron-containing leachate. (2) After adjusting the pH of the boron-containing leachate, sodium carbonate is added to perform magnesium precipitation treatment to obtain a sodium borate solution; (3) The sodium borate solution is concentrated and crystallized to obtain borax.

2. The method as described in claim 1, characterized in that, The median particle size D50 of the boron-aluminosilicate glass powder obtained by ball milling in step (1) is ≤150μm.

3. The method as described in claim 1, characterized in that, The roasting temperature in step (1) is 800~1200℃.

4. The method as described in claim 1, characterized in that, The roasting process in step (1) takes 1 to 4 hours.

5. The method as described in claim 1, characterized in that, The liquid-to-solid ratio of the slurry in step (1) is (2~5):

1.

6. The method as described in claim 1, characterized in that, The acid-to-mineral ratio of sulfuric acid added in step (1) is (0.3~0.5):

1.

7. The method as described in claim 1, characterized in that, The temperature of the pressurized acid leaching in step (1) is 120~160℃.

8. The method as described in claim 1, characterized in that, The pressure of the acid leaching in step (1) is 1.2~1.8MPa.

9. The method as described in claim 1, characterized in that, The time for the pressurized acid leaching in step (1) is 1 to 4 hours.

10. The method as described in claim 1, characterized in that, The pH adjuster for adjusting the boron-containing leachate in step (2) includes sodium hydroxide.

11. The method as described in claim 1, characterized in that, The pH value in step (2) is 9-13.

12. The method as described in claim 1, characterized in that, In step (2), the molar ratio of carbonate ions to magnesium ions in the system after adding sodium carbonate is (1.0~1.1):

1.

13. The method as described in claim 1, characterized in that, The temperature for magnesium precipitation in step (2) is 40~70℃.

14. The method as described in claim 1, characterized in that, The method includes the following steps: (1) After ball milling boron-aluminosilicate glass, boron-aluminosilicate glass powder with a median particle size D50≤150μm is obtained. The boron-aluminosilicate glass powder is calcined at 800~1200℃ for 1~4h, and water is added to slurry at a liquid-to-solid ratio of (2~5):

1. Sulfuric acid is added at an acid-to-mineral ratio of (0.3~0.5):

1. The mixture is then subjected to pressure acid leaching at 120~160℃ and 1.2~1.8MPa for 1~4h to obtain boron-containing leachate. (2) Add sodium hydroxide to adjust the pH of the boron-containing leachate to 9~13, add sodium carbonate to control the molar ratio of carbonate and magnesium ions in the system to (1.0~1.1):1, and then perform magnesium precipitation treatment at 40~70℃ to obtain sodium borate solution; (3) The sodium borate solution is concentrated and crystallized to obtain borax.

Images