Recycling method of CNC (Computer Numerical Control) glass waste residue

Abstract

The invention discloses a CNC (computer numerical control) glass waste residue recycling method which comprises the following steps: drying CNC glass waste residues to prepare a glass material; carrying out acid leaching and calcination on the glass material, and recovering glass; the molar concentration of the acid liquor for acid leaching is 1 mol / L to 10 mol / L; according to the recycling process of the CNC glass waste residues, substances such as metal, metal oxide and organic impurities in the CNC glass waste residues are removed through physical and chemical combination, glass components of the CNC glass waste residues are efficiently recycled, the recycled glass components are high in purity and good in transparency, and the recycling process of the CNC glass waste residues is simple, green, economical and suitable for industrial production. And the method is suitable for industrial batch recovery treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of recycling of glass waste residues, and particularly to a method for recycling CNC glass waste residues. Background Art

[0002] Glass is a commonly used material in modern human life. After fine processing, glass can be made into various utensils, vessels, flat glass, etc., generally common types of glass products such as soda-lime glass and borosilicate glass. A lot of glass waste and scraps will be generated during the processing of glass. If it can be recycled, the resource utilization rate can be effectively improved. Especially in the glass CNC precision carving process, according to the design size and shape of the product, and in order to achieve specific patterns, textures or shapes, it is necessary to cut and precisely carve the glass, removing a part of the material on the glass surface, generating CNC glass waste such as glass chips and small pieces of glass. With the development of technology and the improvement of the quality of human life, the glass CNC precision carving process is used more and more widely, generating a large amount of CNC glass waste. If it can be recycled, the recycling of resources can be realized. However, there is still a lack of effective mechanisms and processes for recycling CNC glass waste residues. Summary of the Invention

[0003] Based on this, it is necessary to provide a recycling method capable of recovering high-purity and high-transparency glass from CNC glass waste residues.

[0004] In a first aspect, the present invention provides a method for recycling CNC glass waste residues, comprising the following steps:

[0005] Dry the CNC glass waste residues to prepare glass materials;

[0006] Acid-leach and calcine the glass materials to recover the glass;

[0007] The molar concentration of the acid solution for acid leaching is 1 mol / L - 10 mol / L.

[0008] In some embodiments, the acid solution includes inorganic acid and / or organic acid;

[0009] Optionally, the inorganic acid includes one or more of nitric acid, hydrochloric acid and sulfuric acid;

[0010] Optionally, the organic acid includes one or more of oxalic acid, acetic acid and citric acid.

[0011] In some embodiments, the acid solution includes inorganic acid and organic acid;

[0012] Optionally, the molar concentration ratio of the inorganic acid to the organic acid is (9 - 1):(1 - 9).

[0013] In some embodiments, the acid solution further satisfies at least one of the following (1) to (2):

[0014] (1) The inorganic acid contains at least nitric acid;

[0015] Optionally, the molar concentration ratio of the nitric acid to the organic acid is (1 - 9):(9 - 1);

[0016] (2) The organic acid contains at least oxalic acid;

[0017] Optionally, the molar concentration ratio of the inorganic acid to the oxalic acid is (1 - 9):(9 - 1).

[0018] In some embodiments, an oxidant is further added to the acid solution.

[0019] In some embodiments, the oxidant includes one or more of hydrogen peroxide, potassium permanganate, and sodium hypochlorite; and / or

[0020] the mass content of the oxidant in the acid solution is 1% - 10%.

[0021] In some embodiments, the temperature of the acid leaching is 20°C - 80°C; and / or the time of the acid leaching is 1 h - 48 h.

[0022] In some embodiments, the temperature of the drying is 100°C - 300°C; and / or the time of the drying is 1 h - 24 h.

[0023] In some embodiments, the temperature of the calcination is 500°C - 900°C; and / or the time of the calcination is 0.5 h - 12 h.

[0024] In some embodiments, after the acid leaching, washing is further performed, and the washing solution includes an alkali solution and / or water;

[0025] Optionally, the molar concentration of the alkali solution is 0.1 mol / L - 10 mol / L.

[0026] In a second aspect, the present invention also provides glass, which is obtained by recycling the CNC glass waste residue provided in the first aspect.

[0027] Compared with the traditional glass waste residue recycling technology, the beneficial effects of the technical solution of the present invention are:

[0028] The present invention provides a method for recycling CNC glass waste residue, which prepares high-purity and high-transparency glass by drying, acid leaching, and calcining the CNC glass waste residue. The technical solution of the present invention adopts a combined chemical and physical impurity removal technology to recover high-purity and high-transparency glass components from CNC glass waste residue with complex impurity components containing a large amount of metals, metal oxides, organic impurities, etc. It has made significant progress compared with traditional glass recycling technologies, and has low cost and easy operation, suitable for industrial batch processing, realizing the recycling of CNC glass waste residue resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a TG thermogravimetric analysis diagram of the CNC glass waste residue of the present invention.

[0030] Figure 2 It is a TG thermogravimetric analysis diagram of the glass recovered in Example 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To facilitate the understanding of the present invention, the following provides a more comprehensive description of the technical solution of the present invention with reference to the preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0032] It should be noted that the experimental methods without specific conditions in the following embodiments of the present invention are usually carried out according to conventional conditions or according to the conditions recommended by the manufacturer. All common chemical reagents used in the embodiments are commercially available products.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] The main sources of glass waste residue include: (1) When cutting large glass raw materials into blanks that meet the processing dimensions, part of the materials on the glass surface fall off in the form of debris, forming waste residue; (2) Using a tool to engrave on the glass surface to achieve engraving effects such as patterns, textures, or marks on the glass surface, and the glass materials removed during the engraving process become waste residue; (3) In the fine grinding stage, further removing the tiny defects on the glass surface to obtain a smooth and transparent glass surface will generate finer glass waste residue; (4) Drilling holes, milling grooves, etc. on the glass will generate larger-sized glass waste residue.

[0035] The components of glass waste are complex, especially the impurities in the glass waste generated by the fine carving CNC process are even more complex. For example, in the fine carving (CNC) process commonly used for high-precision processing such as mobile phone glass panels and optical components, in order to ensure the processing effect and quality, auxiliary materials such as cutting fluid and lubricating oil are usually used. These substances will be mixed with the glass waste to form a complex organic-inorganic hybrid system. In addition, the glass waste from the fine carving CNC process may also contain impurities such as metal debris generated from equipment wear and dust introduced during the processing. Therefore, the glass waste generated by the fine carving CNC process contains more impurities and has complex components, increasing the difficulty of separating impurities from the glass. If traditional glass recycling processes are used, it is difficult to achieve complete separation, the glass recycling is difficult, and the purity of the components of the recycled glass is not high. Other properties of the recycled glass, such as transparency, are also not high, resulting in the recycled glass being restricted in related application fields. It is difficult to completely separate the glass from the impurities using traditional screening, filtering and other methods. Especially for fine impurity particles and organic substances attached to the glass surface, the conventional physical separation means have poor effects. Therefore, complex technologies and equipment may be required, with high costs. For example, recycling technologies such as magnetic separation, flotation, and optoelectronic sorting are used, but these technologies have large equipment investments, high operating costs, and strict operating conditions. For large-scale waste residue treatment, it is difficult to achieve economical and efficient separation, and it is difficult to realize the recycling of a large quantity of CNC glass waste in industry. Based on this, there is currently no effective treatment method for recycling high-purity and high-transparency glass from CNC glass waste.

[0036] The present invention provides a method for recycling CNC glass waste, which can recycle high-purity and high-transparency glass from the glass waste and realize resource recycling.

[0037] In the first aspect, the present invention provides a method for recycling CNC glass waste, comprising the following steps:

[0038] Dry the CNC glass waste to prepare glass materials.

[0039] Perform acid leaching and calcination on the glass materials to recycle the glass.

[0040] The molar concentration of the acid solution for acid leaching is 1 mol / L - 10 mol / L.

[0041] The present invention removes metal impurities and organic impurities from CNC glass waste residues by combining physical and chemical methods. Among them, the CNC glass waste residues are dried to effectively solve the problems of caking and agglomeration generated during the impurity removal process, and improve the full impurity removal effect of physical and chemical methods. At the same time, some organic impurities can be decomposed during the drying process, avoiding the decomposition of organic impurities during the subsequent calcination process from affecting the quality of the recycled glass, and also avoiding the residue of organic impurities on the glass surface during the subsequent calcination process, reducing the purity and transparency of the recycled glass. Acid leaching can effectively remove a large amount of metal impurities from the CNC glass waste residues during the recycling process, and the calcination process has a good decomposition effect on the carbon-containing organic matter in the CNC glass waste residues, especially lubricants and resins in the CNC glass waste residues, improving the purity and transparency of the recycled glass.

[0042] In the method for recycling CNC glass waste residues of the present invention, when the acid concentration is in the range of 1 mol / L - 10 mol / L, the reaction rate between the acid solution and metal impurities can be increased, the acid leaching time can be shortened, and thus the impurity removal efficiency can be improved. When the molar concentration of the acid solution is lower than 1 mol / L, the reaction with metal impurities during the acid leaching process is not sufficient, and the impurities cannot be completely removed; when the molar concentration of the acid solution exceeds 10 mol / L, it is easy to cause corrosion of the treatment equipment, resulting in equipment loss and making subsequent treatment difficult. Therefore, the acid solution within this concentration range has an excellent removal effect on the metal impurities, and ensures the feasibility, industrialization, safety and reliability of this process. As a non-limiting example, in some embodiments, the molar concentration of the acid solution includes, but is not limited to, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, or any concentration range formed by any two of the foregoing and any value within the range.

[0043] To better understand the technical solution of the present invention, the composition of the CNC glass waste residues is described as follows, which does not limit the technical solution of the present invention.

[0044] As a non-limiting example, in some embodiments, the composition of the CNC glass waste residues includes: glass, metal impurities, and organic impurities.

[0045] In some embodiments, the metal impurities in the CNC glass waste residues include metal and metal oxide impurities; the metal and metal oxides include iron and iron oxide, and may also include metal and metal oxides such as aluminum and aluminum oxide.

[0046] In some embodiments, the organic impurities in the glass waste residues include carbon-containing organic matter, especially organic impurities such as lubricants and resins.

[0047] As a non-limiting example, in some embodiments, by mass percentage, the composition of the CNC glass waste residue includes: 30-60% glass, 10-30% metal impurities, and 10-30% organic impurities.

[0048] As a non-limiting example, in some embodiments, by mass percentage, the composition of the glass waste residue includes: 50-60% glass, 10-20% metal oxides, and 10-20% carbon-containing organic substances.

[0049] As a non-limiting example, in some embodiments, by mass percentage, the composition of the glass waste residue includes: 30-50% glass, 20-30% Fe2O3, and 20-30%.

[0050] As a non-limiting example, in some embodiments, the glass components in the glass waste residue include but are not limited to SiO2, Al2O3, Na2O, MgO, CaO, ZrO2, SnO2, K2O, ZnO, BaO, and TiO2. By mass percentage, the content of the glass components in the glass waste residue is: 10-30% SiO2, 5-15% Al2O3, Na2O 5-15%, MgO 0.1-1%, CaO 0.01-1%, ZrO2 0.01-1%, SnO2 <0.01%%, K2O <0.01%%, ZnO <0.01%%, BaO <0.01%% and TiO2 <0.01%.

[0051] As a non-limiting example, in some embodiments, by mass percentage, the composition of the glass waste residue includes: 10-30% SiO2, 5-15% Al2O3, Na2O 5-15%, MgO 0.1-1%, CaO 0.01-1%, ZrO2 0.01-1%, SnO2 <0.01%%, K2O <0.01%%, ZnO <0.01%%, BaO <0.01%% and TiO2 <0.01%, 10-30% Fe2O3, and 10-30% C.

[0052] In some embodiments, the composition of the CNC glass waste residue further contains organic-inorganic impurities. As a non-limiting example, the organic-inorganic impurities include difficult-to-remove impurities such as chelates.

[0053] During the drying process of the present invention, it can decompose the complex organic-inorganic mixed impurity system in part of the CNC glass waste residue, realizing the disintegration of difficult-to-remove organic impurities such as organic-inorganic mixed impurities. It avoids the decomposition of difficult-to-remove organic impurities during the subsequent calcination process from affecting the quality of the recycled glass, and also avoids the residue of organic-inorganic mixed impurities on the glass surface during the subsequent calcination process, reducing the purity and transparency of the recycled glass.

[0054] In the method for recycling CNC glass waste residue provided by the present invention, the sequential steps of acid leaching and calcination treatment of the glass material are not limited. Exemplarily, in some embodiments, the glass material can be first subjected to acid leaching treatment and then to calcination treatment. In some embodiments, the glass material can be first subjected to calcination treatment and then to acid leaching treatment.

[0055] In some embodiments, the acid solution includes inorganic acid and / or organic acid.

[0056] Optionally, the inorganic acid includes one or more of nitric acid, hydrochloric acid, and sulfuric acid.

[0057] Optionally, the organic acid includes one or more of oxalic acid, acetic acid, and citric acid.

[0058] The present invention uses organic acid and / or inorganic acid, which will not introduce new impurities during the treatment of glass waste residue and can also be removed by burning during the calcination process. Therefore, the technical solution of the present invention can effectively remove metal impurities and organic impurities in the glass waste residue, realizing high-purity glass recycling.

[0059] In some embodiments, the acid solution includes inorganic acid and organic acid. By using inorganic acid and organic acid in combination, it can better remove metals and metal oxides in the CNC glass waste residue. Among them, the inorganic acid has strong acidity and oxidizing property, which can chemically react with metal oxide impurities in the glass waste residue, dissolve them and convert them into water-soluble metal salts, so as to achieve the purpose of removing impurities. The organic acid has certain complexing ability and can form stable complexes with some metal ions. These complexes have good solubility in aqueous solution, making it possible to dissolve and remove metal impurities that are originally difficult to remove more effectively. Therefore, the present invention preferably uses a compound of inorganic acid and organic acid. The two can play their respective advantages and produce a synergistic effect. The inorganic acid quickly dissolves some easily reactive impurities, exposing the glass part originally wrapped by impurities. The organic acid then uses its complexing ability to further remove impurities that are difficult to completely dissolve or remove by the inorganic acid, especially some transition metal ions, etc., thereby improving the overall impurity removal effect. At the same time, the compound of inorganic acid and organic acid can also reduce the corrosion effect of the inorganic acid on the glass component in the waste residue, protecting the integrity of the glass component and structure.

[0060] In some embodiments, the molar concentration ratio of the inorganic acid to the organic acid is (9 - 1):(1 - 9), including but not limited to 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, or the concentration ranges formed by any two of the foregoing and any value within the range. Within this molar concentration ratio range, the removal of metal impurities can be better achieved, resulting in better technical effects.

[0061] In some embodiments, the inorganic acid contains at least nitric acid. Compared with acid solutions containing only other inorganic acids such as sulfuric acid and hydrochloric acid, the acid solution containing nitric acid used in the present invention has stronger acidity and oxidizing properties, a higher reaction rate with metal oxide impurities in the CNC glass waste residue, high efficiency in dissolving and converting them into water-soluble metal salts, and sufficient conversion, thus better achieving the purpose of removing impurities.

[0062] In some embodiments, the molar concentration ratio of the nitric acid to the organic acid is (1 - 9):(9 - 1), including but not limited to 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, or the concentration ranges formed by any two of the foregoing and any value within the range.

[0063] In some embodiments, the organic acid contains at least oxalic acid. Compared with acid solutions containing only other organic acids such as acetic acid and citric acid, the acid solution containing oxalic acid used in the present invention exhibits a better complexing effect during the treatment of CNC glass waste residue, which may be related to the impurity components and contents of the CNC glass waste residue, especially the relatively high content of some transition metal ions. The acid solution containing oxalic acid forms stable complexes with certain metal ions in the CNC glass waste residue, and these complexes have good solubility in aqueous solutions, enabling the originally difficult-to-remove metal impurities to be more effectively dissolved and removed.

[0064] In some embodiments, the acid solution contains nitric acid and oxalic acid. The combination of the two can play their respective advantages and produce a synergistic effect, thereby improving the overall impurity removal effect. At the same time, the combination of inorganic acid and organic acid can also reduce the corrosion of the inorganic acid dosage on the glass components in the waste residue and related treatment equipment, protecting the integrity of the glass components, equipment, and structures.

[0065] In some embodiments, the molar concentration ratio of the nitric acid to the oxalic acid in the acid solution is (1 - 9):(9 - 1), including but not limited to 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, or the concentration ranges formed by any two of the foregoing and any value within the range.

[0066] In some embodiments, the acid solution source for acid leaching in the present invention can be a prepared acid solution or acidic waste liquid. Using acidic waste liquid for acid leaching treatment can make full use of waste and reduce the discharge of waste acid at the same time.

[0067] In some embodiments, an oxidant is further added to the acid solution. On the one hand, the added oxidant has oxidizing properties and can oxidize some metal impurities in the CNC glass waste residue into ions with higher valence states, thereby increasing the solubility of the impurities in the acid solution and making it easier to separate from the glass, thus improving the impurity removal effect. On the other hand, there may be organic impurities such as cutting fluid and lubricating oil attached to the surface of the CNC glass waste residue. Adding an oxide can decompose these organic substances and convert them into harmless substances such as carbon dioxide and water, further improving the purity and transparency of the glass, and also contributing to subsequent processing. In addition, adding an oxide can accelerate the reaction rate between the acid solution and metal impurities, and can generate some strongly oxidizing free radicals in the acid solution. These free radicals can attack the metal surface and make the metal more easily dissolved by the acid, thereby improving the efficiency of the entire impurity removal process and shortening the processing time.

[0068] As a non-limiting example, in some embodiments, the oxidant includes one or more of hydrogen peroxide, potassium permanganate, and sodium hypochlorite. In particular, adding hydrogen peroxide can better achieve the technical effects of the present invention.

[0069] In some embodiments, the mass content of the oxidant in the acid solution is 1% - 10%, including but not limited to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or the concentration range formed by any two of the foregoing and any value within that range.

[0070] In some embodiments, the temperature of acid leaching is 20°C - 80°C, including but not limited to 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, or the temperature range formed by any two of the foregoing and any value within that range. There is a good reaction rate within the acid leaching temperature range. When the temperature is lower than 20°C, the reaction rate is low, and when the temperature exceeds 80°C, it is easy to cause acid solution volatilization and reduce the impurity removal efficiency.

[0071] In some embodiments, the time of acid leaching is 1h - 48h, including but not limited to 1h, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 24h, 30h, 36h, 40h, 45h, 48h, or the time range formed by any two of the foregoing and any value within that range.

[0072] The present invention uses the above-mentioned specific acid leaching concentration, temperature or time to treat glass waste residue, which can shorten the acid soaking time, reduce the loss of acid, and improve the impurity removal efficiency, especially the removal effect of metals / metal oxides is better; while too low or too high acid concentration will lead to a decrease in the reaction rate, increasing the temperature can increase the reaction rate, but too high temperature will cause the volatilization of acid and water. Therefore, the acid leaching treatment conditions adopted by the present invention have the best treatment and recovery effect on glass waste residue.

[0073] In some embodiments, after the acid leaching treatment, centrifugation is further included to further separate the impurities from the glass.

[0074] In some embodiments, the centrifugation speed of the centrifugation treatment is 2000 rpm - 10000 rpm, including but not limited to 2000 rpm, 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm or any rotation speed within the rotation speed range formed by any two of the foregoing. The recovery treatment process of the present invention can achieve good solid-liquid separation effect with a centrifugation speed of 2000 rpm - 10000 rpm. Within this range, not only can impurities be removed, but also the operation can be simplified and the centrifugation efficiency can be improved. When the rotation speed of the centrifuge is lower than 2000 rpm, the centrifugation time is longer, and there is partial solid-liquid non-separation, resulting in difficulty in removing impurities. A large amount of metal and metal oxide impurities are contained in some solid precipitates, making subsequent treatment difficult, and due to incomplete solid-liquid separation, the glass resources in the glass waste residue are wasted. When the rotation speed of the centrifuge exceeds 10000 rpm, the solid-liquid separation is complete, but due to the too high centrifugation speed, the solid matter is too tightly combined with the container wall and cannot be separated, making subsequent treatment difficult and it is also difficult to achieve industrial treatment.

[0075] In some embodiments, after the acid leaching is completed, washing is also carried out, and the washing solution includes alkali solution and / or water to quickly neutralize the acid in the solid matter.

[0076] In some embodiments, the alkali solution includes weak alkali and / or strong alkali, and the strong alkali includes one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide.

[0077] In some embodiments, the weak alkali includes one or more of sodium carbonate, potassium carbonate, ammonia water and aluminum hydroxide.

[0078] In some embodiments, the molar concentration of the alkali solution is 0.1 mol / L - 10 mol / L, including but not limited to 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, or the concentration ranges formed by any two of the foregoing and any value within the ranges. When the concentration of the alkali solution is lower than 0.1 mol / L, the washing process is insufficient, resulting in a large amount of alkali solution wastewater, difficult post-treatment, and an environmental burden. When the concentration of the alkali solution exceeds 10 mol / L, it is easy to cause corrosion of the treatment equipment, resulting in equipment loss and difficult subsequent treatment.

[0079] In some embodiments, the drying temperature is 100°C - 300°C, including but not limited to 100°C, 105°C, 120°C, 150°C, 180°C, 200°C, 220°C, 250°C, 280°C, 300°C, or the temperature ranges formed by any two of the foregoing and any value within the ranges. When the drying temperature of the glass waste residue is lower than 100°C, the drying time is longer, the energy consumption is too large, and it is not suitable for industrial treatment. When the temperature exceeds 300°C, due to the too high temperature, the waste residue in the drying process agglomerates, the subsequent treatment process is insufficient, and the impurities are not completely removed.

[0080] In some embodiments, the drying time is 1 h - 24 h, including but not limited to 1 h, 3 h, 5 h, 6 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 24 h, or the time ranges formed by any two of the foregoing and any value within the ranges.

[0081] In some embodiments, the calcination temperature is 500°C - 900°C, including but not limited to 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, or the temperature ranges formed by any two of the foregoing and any value within the ranges.

[0082] In some embodiments, the calcination time is 0.5 h - 12 h, including but not limited to 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, or the time ranges formed by any two of the foregoing and any value within the ranges.

[0083] The calcination temperature adopted in the present invention has a good decomposition effect on the carbon-containing organic matter in the glass waste residue. The carbon-containing organic matter in the glass waste residue of the present invention mainly includes lubricants and resins, etc. Calcining at a temperature of 500°C - 900°C for 0.5 h - 12 h can better decompose the carbon-containing organic matter impurities. When the calcination temperature exceeds 900°C, the solid sinters into blocks and performance testing cannot be carried out.

[0084] The present invention recovers high-purity glass from glass waste residue, and the treatment method is green and economical, suitable for batch treatment in industry, realizing the recycling of waste resources.

[0085] In a second aspect, the present invention also provides glass, which is obtained by recycling the CNC glass waste residue provided in the first aspect.

[0086] For the experimental parameters not specified in the following specific examples, preferably refer to the guidance given in this application document, and it is also possible to refer to the experimental manuals in this field or other experimental methods known in this field, or refer to the experimental conditions recommended by the manufacturer.

[0087] The raw materials and reagents involved in the following specific examples can be obtained commercially, or those skilled in the art can prepare them according to known means.

[0088] Example 1

[0089] The collected glass waste residue was dried in an oven at 150 °C for 12 h to obtain dry glass waste residue.

[0090] Then the dry glass waste residue was put into an acid solution of nitric acid and oxalic acid (the volume ratio of nitric acid with a concentration of 1 mol / L and oxalic acid with a concentration of 1 mol / L is 5:5) for soaking. The soaking temperature was 20 °C and the soaking time was 36 h. After the soaking, the mixture was centrifuged at a centrifuge speed of 6000 rpm for 10 min, and the supernatant was discarded, that is, the metal or metal oxide impurities in the glass waste residue were removed, and the solid matter was collected.

[0091] The collected solid matter was soaked and washed with a mixed alkali solution with a concentration of 4 mol / L (the mass ratio of sodium hydroxide and sodium carbonate is 5:5). The soaking temperature was 20 °C and the soaking time was 4 h. The soaking and washing can be repeated multiple times until the solid matter is washed to neutral, and then the neutral solid matter was centrifuged and recovered.

[0092] The neutral solid matter was placed in an oven at 150 °C for drying for 10 h to obtain dry neutral solid matter.

[0093] The dry neutral solid matter was subjected to high-temperature calcination to remove the lubricant and resin in the neutral solid matter. The calcination temperature was 650 °C and the calcination time was 1.5 h, and finally the glass was recovered.

[0094] Example 2

[0095] The collected glass waste residue was dried in an oven at 150 °C for 12 h to obtain dry glass waste residue.

[0096] Then, the dried glass waste residue is put into an acid solution of nitric acid and oxalic acid (the volume ratio of nitric acid with a concentration of 1 mol / L and oxalic acid with a concentration of 1 mol / L is 5:5) for soaking. Hydrogen peroxide (with a concentration of 30%) is also added to the soaking solution, and the addition amount is 7% of the soaking solution. The soaking temperature is 60 °C, and the soaking time is 2 h. After the soaking is completed, the mixture is centrifuged at a centrifuge speed of 6000 rpm for 10 min, and the supernatant is discarded, that is, the metal or metal oxide impurities in the glass waste residue are removed, and the solid matter is collected.

[0097] The collected solid matter is soaked and washed with an aqueous potassium carbonate solution with a concentration of 10 mol / L. The soaking temperature is 80 °C, and the soaking time is 0.5 h. The soaking and washing can be repeated multiple times until the solid matter is washed to neutral, and then the neutral solid matter is recovered by centrifugation.

[0098] The neutral solid matter is placed in an oven at 300 °C for drying, and the drying time is 1 h to obtain the dried neutral solid matter.

[0099] The dried neutral solid matter is subjected to high-temperature calcination to remove the lubricant and resin in the neutral solid matter. The calcination temperature is 900 °C, and the calcination time is 0.5 h. Finally, the glass is recovered.

[0100] Example 3

[0101] The collected glass waste residue is dried in an oven at 150 °C for 12 h to obtain the dried glass waste residue.

[0102] Then, the dried glass waste residue is put into a mixed solution of sulfuric acid, nitric acid and oxalic acid (the volume ratio of sulfuric acid with a concentration of 10 mol / L, nitric acid with a concentration of 10 mol / L and oxalic acid with a concentration of 10 mol / L is 4:3:3) for soaking. Hydrogen peroxide (with a concentration of 50%) is also added to the soaking solution, and the addition amount is 10% of the soaking solution. The soaking temperature is 80 °C, and the soaking time is 1 h. After the soaking is completed, the mixture is centrifuged at a centrifuge speed of 6000 rpm for 10 min, and the supernatant is discarded, that is, the metal or metal oxide impurities in the glass waste residue are removed, and the solid matter is collected.

[0103] The collected solid matter is soaked and washed with an aqueous sodium carbonate solution with a concentration of 10 mol / L. The soaking temperature is 60 °C, and the soaking time is 1 h. The soaking and washing can be repeated multiple times until the solid matter is washed to neutral, and then the neutral solid matter is recovered by centrifugation.

[0104] The neutral solid matter is placed in an oven at 300 °C for drying, and the drying time is 1 h to obtain the dried neutral solid matter.

[0105] The dry neutral solid is calcined at a high temperature to remove the lubricant and resin in the neutral solid. The calcination temperature is 900 °C and the calcination time is 0.5 h. Finally, glass is recovered.

[0106] Example 4

[0107] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, a hydrochloric acid solution with a concentration of 10 mol / L is used.

[0108] The remaining steps are the same as those in Example 1.

[0109] Example 5

[0110] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, a nitric acid solution with a concentration of 10 mol / L is used.

[0111] The remaining steps are the same as those in Example 1.

[0112] Example 6

[0113] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, a sulfuric acid solution with a concentration of 10 mol / L is used.

[0114] The remaining steps are the same as those in Example 1.

[0115] Example 7

[0116] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, an oxalic acid solution with a concentration of 10 mol / L is used.

[0117] The remaining steps are the same as those in Example 1.

[0118] Example 8

[0119] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, a mixed acid solution of hydrochloric acid and nitric acid (the volume ratio of hydrochloric acid with a concentration of 1 mol / L and nitric acid with a concentration of 1 mol / L is 5:5) is used.

[0120] The remaining steps are the same as those in Example 1.

[0121] Example 9

[0122] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, a mixed acid solution of hydrochloric acid and oxalic acid (the volume ratio of hydrochloric acid with a concentration of 6 mol / L and oxalic acid with a concentration of 6 mol / L is 5:5) is used.

[0123] The remaining steps are the same as those in Example 1.

[0124] Example 10

[0125] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, a hydrochloric acid solution with a concentration of 10 mol / L is used, and hydrogen peroxide (hydrogen peroxide concentration is 30%) is added, and the addition amount is 5% of the acid solution.

[0126] The remaining steps are the same as those in Example 1.

[0127] Example 11

[0128] The difference from Example 1 lies in the calcination temperature and time. In this example, the calcination temperature used is 300 °C, and the calcination time is 3 h.

[0129] The remaining steps are the same as those in Example 1.

[0130] Comparative Example 1

[0131] The difference from Example 1 lies in the composition and concentration of the acid solution. In this example, an acid solution of nitric acid and oxalic acid (the volume ratio of nitric acid with a concentration of 0.1 mol / L and oxalic acid with a concentration of 0.1 mol / L is 5:5) is used.

[0132] The remaining steps are the same as those in Example 1.

[0133] Comparative Example 2

[0134] The difference from Example 1 is that no acid leaching treatment is carried out, and the remaining steps are the same as those in Example 1.

[0135] Comparative Example 3

[0136] The difference from Example 1 is that no calcination treatment is carried out, and the remaining steps are the same as those in Example 1.

[0137] Comparative Example 4

[0138] The CNC waste is not calcined and acid-treated. Water is added to the waste for centrifugation treatment, and the substance in the bottom layer is taken for drying after centrifugation is completed.

[0139] Test Example 1. Composition identification of the recycled glass from CNC glass waste

[0140] For Examples 1 to 11 and Comparative Examples 1 to 4, the recycled glass from CNC glass waste and the glass waste are subjected to X-ray fluorescence test for composition. The detection instrument used is XRF, model Thermo Fisher PFX-221, and the detection results are shown in Table 1;

[0141] Table 1: Detection results of the composition of the recycled glass (content, wt%)

[0142]

[0143] As can be seen from the results in Table 1, compared with the glass content of 56.61% in the CNC glass waste residue before treatment, the glass content in the glass recovered after treating the glass waste residue under different treatment process conditions in Examples 1 to 11 of the present invention is ≥70%. It can be seen that the treatment process of the present invention can treat the glass waste residue and effectively improve the recovery rate and purity of the glass in the glass waste residue. In particular, the glass recovered in Examples 1 to 3 is pure glass, indicating that the technical solutions in Examples 1 to 3 have better effects than those in Examples 4 to 11, and can better remove metal / metal oxide impurities and carbon-containing organic impurities such as lubricants and resins. From Comparative Examples 1 to 4, it can be known that too low acid concentration, omission of the acid leaching or calcination step cannot achieve the technical effects of the present invention, and the traditional glass recycling process in Comparative Example 4 cannot achieve the recycling of CNC glass waste residue.

[0144] Test Example 2: Color Test of Recycled Glass from CNC Glass Waste Residue

[0145] Color tests were carried out on the glass recovered from the CNC glass waste residue and the glass waste residue in Examples 1 to 11 and Comparative Examples 1 to 4. A X-Rite Ci64 color difference meter was used for color testing, and the test results are shown in Table 2;

[0146] Table 2: Color Test Results

[0147]

[0148] As can be seen from the color test results in Table 2, the color L value of the glass recovered from the CNC glass waste residue by the recovery treatment process in Examples 1 to 11 of the present invention is >85, which is significantly higher than the color L value of the glass recovered in the comparative examples. It can be seen that the technical solution of the present invention can effectively remove impurities such as metal / metal oxides and carbon-containing organic matters, and significantly improve the transparency of the glass. Among them, the color L value of the glass recovered in Examples 1 to 3 is as high as 99 - 100, and the color L value of the glass recovered from the glass waste residue in Examples 4 to 11 is 4 - 11 lower. The glass recovered in Examples 1 to 3 has higher transparency, indicating that the treatment process in Examples 1 to 3 can better remove organic impurities in the glass waste residue. It is difficult for Comparative Examples 1 to 4 to achieve the technical effects of this application. In particular, the traditional glass recycling method in Comparative Example 4 cannot recover glass with high transparency from the CNC glass waste residue.

[0149] Test Example 3: TG Test of Recycled Glass from CNC Glass Waste Residue

[0150] Thermogravimetric tests were carried out on the glass recovered from the CNC glass waste residue and the glass waste residue in Examples 1 to 11 and Comparative Examples 1 to 4. A DSC NETZSCH STA 449F5 differential scanning calorimeter was used for thermal analysis of the samples. The analysis conditions were: air atmosphere, heating from room temperature to 1000 °C, and the heating rate was 10 °C·min -1, and the results are shown in the appendix Figure 1 , appendix Figure 2 and Table 3 as shown below;

[0151] Table 3: TG Results

[0152]

[0153] From the TG test results in the appendix Figure 1 it can be seen that the weight loss ratio of the CNC glass waste residue sample from room temperature to 1000 °C is 57%, indicating that the content of organic component impurities in the CNC glass waste residue sample is relatively high.

[0154] From the TG test results in the appendix Figure 2 it can be seen that the weight loss ratio of the glass sample recovered in Example 1 from room temperature to 1000 °C is <1%, indicating that the organic component impurities in the sample have been basically removed.

[0155] As can be seen from the results in Table 3, the weight loss ratio of the glass recovered in Examples 1 to 11 is <25%, while the weight loss ratio of the glass recovered in Comparative Example 1 is >35%, indicating that the content of organic component impurities in the glass samples recovered in Examples 1 to 11 is relatively low. Further, as can be seen from Table 1, the weight loss ratio of the glass recovered in Examples 1 to 3 is lower than that in Examples 4 to 11. It can be seen that the recovery process in Examples 1 to 3 can more effectively remove the organic impurities in the CNC glass waste residue.

[0156] The results of Comparative Examples 1 to 4 show that omitting the calcination step will result in too high a TG loss of the recovered glass powder sample, indicating that the calcination process has a good effect on removing the organic impurities in the CNC glass waste. The TG losses of the glass powder samples recovered in Comparative Examples 1 to 2 are also relatively high. The possible reason is that the metal impurities are not removed, forming organic-inorganic impurities that are difficult to remove with the organic impurities. Comparative Example 4 uses the traditional glass recycling method and cannot effectively remove the organic impurities in the CNC glass waste residue.

[0157] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0158] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A method for recycling CNC glass waste residues, characterized in that It includes the following steps: Dry the CNC glass waste residue to prepare glass material; Perform acid leaching and calcination on the glass material to recover glass; The molar concentration of the acid solution for acid leaching is 1 mol / L - 10 mol / L.

2. The recycling method of CNC glass waste residue according to claim 1, characterized in that, The acid solution includes inorganic acid and / or organic acid; Optionally, the inorganic acid includes one or more of nitric acid, hydrochloric acid, and sulfuric acid; Optionally, the organic acid includes one or more of oxalic acid, acetic acid, and citric acid.

3. The recycling method of CNC glass waste residue according to claim 2, characterized in that, The acid solution includes inorganic acid and organic acid; Optionally, the molar concentration ratio of the inorganic acid to the organic acid is (9 - 1):(1 - 9).

4. The recycling method of CNC glass waste residue according to claim 3, characterized in that, The acid solution also satisfies at least one of the following (1) to (2): (1) The inorganic acid contains at least nitric acid; Optionally, the molar concentration ratio of the nitric acid to the organic acid is (1 - 9):(9 - 1); (2) The organic acid contains at least oxalic acid; Optionally, the molar concentration ratio of the inorganic acid to the oxalic acid is (1 - 9):(9 - 1).

5. The recycling method of CNC glass waste residue according to claim 1, characterized in that An oxidant is also added to the acid solution.

6. The recycling method of CNC glass waste residue according to claim 5, wherein, The oxidant includes one or more of hydrogen peroxide, potassium permanganate, and sodium hypochlorite; and / or, The mass content of the oxidant in the acid solution is 1% - 10%.

7. The recycling method of CNC glass waste residue according to claim 1, characterized in that, The temperature for acid leaching is 20°C - 80°C; and / or, The time for acid leaching is 1 h - 48 h.

8. The recycling method of CNC glass waste residue according to claim 1, characterized in that, The temperature for calcination is 500°C - 900°C; and / or, The time for calcination is 0.5 h - 12 h.

9. The recycling method of CNC glass waste residue according to claim 1, characterized in that, After acid leaching, washing is also performed, and the washing solution includes alkali solution and / or water; Optionally, the molar concentration of the alkali solution is 0.1 mol / L - 10 mol / L.

10. Glass, characterized in that, The glass is recovered by the method for recycling CNC glass waste residue according to any one of claims 1 to 9.

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