Glass bead production process

Abstract

The invention discloses a glass bead production process. The process comprises the following steps: mixing raw materials; treating a batch in an electric melting furnace which adopts a composite heating main molten pool and an electrode heating clarification tank for partitioned melting and tempering; carrying out water quenching, drying, crushing and screening on discharged molten glass to obtain qualified particles, coarse slag and fine powder; spheroidizing the qualified particles; the production process effectively solves the problems of low glass melting efficiency, difficulty in melt quality control, low material utilization rate, unsmooth circulation and the like in the prior art through an optimized partitioned composite electric melting technology, accurate granularity control and an unqualified material full-closed circulation system, and remarkably improves the melt quality, the raw material utilization rate and the production efficiency; the quality of glass bead products is ensured; and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of glass melting, and particularly to a production process of glass beads. Background Art

[0002] As an important functional inorganic non-metallic material, glass beads are widely used in many fields due to their unique physical and chemical properties, such as high strength, wear resistance, chemical stability, good fluidity, and especially their optical reflection performance. Typical applications include reflective materials for road traffic markings to improve night visibility, industrial sandblasting and shot peening for cleaning or strengthening metal surfaces, as reinforcing or functional fillers in composite materials (such as plastics, rubbers), and for decorative purposes, etc.

[0003] The traditional production method of glass beads generally includes the following key steps: First, raw materials containing glass-forming oxides (such as silica) and other auxiliary components (such as fluxes, stabilizers, etc.) are accurately weighed according to a specific formula and uniformly mixed; Then, the mixed batch materials are fed into a high-temperature melting furnace for melting to form a homogeneous glass melt; Subsequently, the glass melt is transformed into small spheres through a specific forming process. Common forming methods include flame spraying method, direct dropping forming method, or quenching the melt with water to form glass particles (glass slag) first, and then feeding these particles into a spheroidizing furnace for secondary heating and softening and spheroidization under the action of surface tension; Finally, the formed glass beads usually need to go through subsequent processes such as cooling, screening (to obtain products within a specific particle size range), drying, and possibly surface treatment.

[0004] In the whole production process, the glass melting link is the core that determines the quality of the final glass bead product (such as chemical composition uniformity, bubble content, roundness, transparency) and production cost (mainly energy consumption). Existing glass melting technologies, especially when applied to the production of large-scale and cost-sensitive products like glass beads, face some challenges. For example, some traditional melting methods (such as flame kilns) may have problems such as low thermal efficiency, uneven temperature distribution, or difficulty in precisely controlling the melt atmosphere, which may lead to incomplete melting, volatilization of glass components, more residual bubbles in the melt, or the generation of defects such as stones and streaks, affecting the optical properties and physical strength of the final glass beads. At the same time, in the context of pursuing high production and low cost, how to efficiently transform solid raw materials into a homogeneous and appropriately temperature glass melt that meets the requirements of subsequent forming and minimize energy consumption is a technical issue that the industry has been continuously concerned about.

[0005] In addition, when adopting the water quenching - crushing - spheroidizing process route, how to effectively and rapidly cool the glass melt into glass slag that is easy to handle, crush and screen it to a specific particle size range suitable for spheroidizing treatment, while minimizing the generation of overly fine powder or overly coarse particles, and realizing the effective recycling of unqualified materials back to the furnace is also a key factor affecting the efficiency, yield and economy of the entire process flow. In the existing process, there may be problems such as low crushing efficiency, inaccurate control of particle size distribution, and unsmooth recycling of unqualified materials, resulting in waste of raw materials, increased energy consumption or an increase in the cost of the final product. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: to solve the above - mentioned existing technical problems, an improved glass bead production process that can achieve efficient melting, precise temperature control, good homogenization, and can be efficiently connected with subsequent processes such as crushing, screening, and spheroidizing, thereby improving the quality of glass bead products, enhancing production efficiency and reducing energy consumption.

[0007] The technical solution adopted by the present invention to solve its technical problems is: A glass bead production process, comprising the following steps: S1. Mix glass raw materials to obtain a glass batch; S2. Transport and feed the glass batch into an electric melting furnace; S3. Conduct melting and conditioning in the electric melting furnace. This step includes: in the main melting pool area of the electric melting furnace, melting the glass batch by a combined heating method including upper radiation heating and internal direct electrode heating to form a glass melt, and transporting the glass melt to the clarification pool area of the electric melting furnace; and in the clarification pool area, heating and conditioning the glass melt by direct electrode heating to obtain glass liquid meeting a predetermined state; S4. Discharge the glass liquid and conduct water quenching treatment to form glass slag; S5. Dry and crush the glass slag; S6. Screen the crushed glass slag to separate qualified glass particles with particle sizes within a predetermined target range, coarse slag with particle sizes greater than the upper limit of the target range, and fine powder with particle sizes less than the lower limit of the target range; S7. Heat - spheroidize the qualified glass particles to obtain glass bead products; S8. Return the coarse slag and fine powder separated in step S6 to the electric melting furnace in step S3 for remelting.

[0008] Preferably, in step S3, the upper radiation heating in the main melting pool area is provided by a resistance heating element arranged above the main melting pool; the internal direct electrode heating in the main melting pool area is provided by electrodes inserted into the side wall of the main melting pool.

[0009] Preferably, in step S3, the direct electrode heating in the clarifier area is provided by electrodes inserted from the top of the clarifier.

[0010] Preferably, the process further includes: monitoring the temperature by temperature sensing devices arranged in the main melting pool area and the clarifier area, and adjusting the power of the resistance heating elements and each electrode based on the monitored temperature and preset process parameters through a control system to perform the heating in step S3.

[0011] Preferably, the water quenching treatment in step S4 is carried out in a water quenching system including a water quenching tank, a water quenching pool, a water quenching circulation pump, and a slag skimmer. The glass melt contacts the circulating cooling water in the water quenching tank to form glass slag. The glass slag settles in the water quenching pool and is taken out by the slag skimmer. The water quenching circulation pump is used to transport water from the water quenching pool back to the water quenching tank.

[0012] Preferably, in step S6, the particle size of the qualified glass particles is 1 mm to 3 mm; the particle size of the coarse slag is greater than 3 mm; the particle size of the fine powder is less than 1 mm.

[0013] Preferably, in step S8, the coarse slag and the fine powder are fed into the electric melting furnace in step S3 and mixed with the newly prepared glass batch in step S1 for remelting together.

[0014] The technical effects that the present invention can achieve include the following points: By adopting a partitioned electric melting furnace and implementing a combined heating method of upper radiation heating and internal direct electrode heating in the main melting pool, and at the same time performing direct electrode heating in the clarifier, combined with precise temperature sensing and a closed-loop control system, efficient, uniform heating and precise temperature control of the glass melting process are achieved, solving the technical challenges of low efficiency in the glass melting link and difficult control of the melt quality, significantly improving the homogeneity and clarity of the glass melt, reducing the generation of defects, providing a high-quality melt basis for the production of high-quality glass beads, and helping to reduce the energy consumption per unit product.

[0015] By carrying out crushing treatment on the water-quenched glass slag with a specific target particle size in the water quenching - crushing - spheroidizing process route, and then precisely separating the glass particles within the qualified particle size range for spheroidizing by multi-stage screening. At the same time, all unqualified materials generated by screening, namely the coarse slag with too large particle size and the fine powder with too small particle size, are all collected and returned to the electric melting furnace to be remelted together with the new materials, constructing a subsequent treatment system for precise particle size control and full closed-loop circulation of materials, effectively solving the problems of precise particle size control and efficient and complete recycling of unqualified materials in the post-treatment of water-quenched materials, minimizing material loss to the greatest extent, improving the comprehensive utilization rate of raw materials, and optimizing the process flow efficiency. Description of the Drawings

[0016] Figure 1Schematic structural diagram of a glass bead production process for Embodiment 1; Figure 2 Schematic structural diagram of the electric melting furnace in Step 3 of Embodiment 1.

[0017] Reference numerals: 1, main melting pool; 2, clarification pool; 3, silicon carbide rod; 4, electrode; 5, thermocouple; 6, discharge port. Detailed implementation manners

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but these specific implementation manners do not limit the protection scope of the present invention in any way.

[0019] Embodiment 1 Refer to Figure 1 , this embodiment discloses a glass bead production process, which is realized through a specially designed production system. The production system at least includes: a mixer for mixing powdered or granular glass raw materials metered according to the formula; an elevator for vertically transporting the mixed batch materials to a high position; a mixed material bin for temporarily storing the batch materials; a feeder connected below the mixed material bin for sending out the batch materials at a controllable rate; an electric melting furnace as the core equipment for glass melting; a water quenching system following the electric melting furnace immediately for quickly cooling and crushing the high-temperature glass liquid into glass slag; a dryer for removing the moisture of the water quenched slag; a crusher for further crushing the dried glass slag to the target particle size range; a vibrating screen for grading the particle size of the crushed materials; and a glass spheroidizing furnace for converting the selected qualified glass particles into spherical finished products. The main equipment units in the system are orderly connected through corresponding material conveying devices (such as belt conveyors, chutes, pipelines, etc., not shown one by one), ensuring that the materials can flow smoothly according to the technological process.

[0020] Based on the above production system, the glass bead production process described in this embodiment is specifically implemented according to the following steps: Step 1: Raw material mixing This step is carried out in the mixer. First, according to the chemical composition requirements of the target glass bead product, accurately weigh the required batches of various glass raw material components, such as silica sand, soda ash, limestone, feldspar, etc. Put the weighed raw materials into the inner cavity of the mixer, start the mixer, and use the internal stirring mechanism (such as paddle blades, plow blades, etc.) to forcibly mix the materials for a preset time (such as 10 - 20 minutes) until each component reaches a highly uniform distribution state, forming a glass batch.

[0021] Step 2: Batch material conveying and feeding The mixed batch is discharged from the mixer and enters the feed inlet of the elevator. The elevator vertically lifts the batch above the production line and discharges it into the batch bin. The batch bin serves as a buffer storage unit and continuously feeds the electric melting furnace. The bottom outlet of the batch bin is connected to a feeder (such as an electromagnetic vibrating feeder with precisely adjustable amplitude). The operator sets the feeding rate of the feeder according to the melting capacity and process requirements of the electric melting furnace. After starting the feeder, the batch enters the main melting pool 1 area of the electric melting furnace through the feeding channel under the action of gravity and the driving force of the feeder at a stable, continuous and uniformly controlled flow rate. In this step, the automatic transportation of the batch from the low-level mixing point to the high-level melting furnace is realized, and the feeding rate to the electric melting furnace is ensured to be constant through the precise control of the feeder.

[0022] Step 3: Melting and conditioning in the electric melting furnace Reference Figure 2 After the batch enters the electric melting furnace, the transformation from solid state to high-temperature, homogeneous glass liquid that meets the requirements of subsequent processes is completed here.

[0023] In the electric melting furnace of this embodiment, its furnace body is built with high-temperature refractory materials to form an inner cavity for containing high-temperature glass liquid, and a steel structure frame is provided outside for support. The inner cavity of the furnace body is functionally divided into at least two areas: the main melting pool 1 at the front end and the clarification pool 2 at the rear end. The main melting pool 1 and the clarification pool 2 are connected through a liquid flow channel designed at the furnace bottom or side wall, allowing the molten glass liquid to flow into the clarification pool 2 in an orderly manner for subsequent treatment after preliminary melting.

[0024] Melting process (main melting pool 1): The batch first enters the main melting pool 1 and is heated by a composite heating method: In the upper part of the furnace space of the main melting pool 1, several silicon carbide rods 3 (or other high-temperature resistance heating elements) are vertically suspended and installed. After being powered on, the silicon carbide rods 3 generate heat and high temperature, and heat the surface layer of the batch below and the furnace space through radiation heat transfer.

[0025] Multiple electrodes 4 are inserted horizontally into the side wall of the main melting pool 1 to a certain depth. These electrodes 4 are in direct contact with the batch / glass melt. By applying a voltage to the electrodes 4, the current directly flows through the batch with a certain conductivity and the molten glass liquid, and Joule heat is generated using its resistance to achieve direct heating of the inside of the melt. Utilize the Joule heat effect generated by the current passing through the glass batch and the gradually formed glass melt to heat from the inside.

[0026] Upper radiation heating helps to quickly melt the surface batch material and compensate for surface heat dissipation. The internal electrode 4 heating can directly and efficiently transfer energy to the deep melt, overcoming the problem of low heat transfer efficiency to the interior during pure surface heating, accelerating the overall melting rate, and helping to form a temperature gradient conducive to melt circulation. A thermocouple 5 is provided in the main melting pool 1 area to monitor the key temperature points of the melt in this area in real time.

[0027] The preliminarily melted glass liquid flows into the clarification tank 2 through the flowing liquid channel. The glass melt entering the clarification tank 2 is continuously heated and temperature-controlled by the electrode 4 vertically inserted from the top of this area. This area is a key refining stage in the glass melting process. The main purposes include promoting the floating and escaping of the remaining tiny bubbles in the glass melt by maintaining a relatively high and stable temperature and sufficient residence time, improving the transparency and quality of the glass; using the thermal convection or possible electromagnetic stirring effect generated by the electrode 4 to further promote the uniformity of the glass melt composition and eliminate defects such as streaks and nodules; precisely adjusting and stabilizing the glass melt at the specific viscosity and temperature suitable for the downstream glass bead forming process. The thermocouple 5 in this area is used to accurately monitor and control the temperature in this stage.

[0028] The entire electric furnace system is managed by a set of central control systems (not shown in the figure). This system receives the real-time temperature signals from each thermocouple 5 in the main melting pool 1 and the clarification tank 2, compares them with the preset process temperature curve (including the set values for the heating-up, heat-preserving, and cooling-down stages), and automatically adjusts the power output supplied to the silicon carbide rods 3 and each group of electrodes 4 through control logics such as the PID algorithm. The operator monitors the furnace condition through the control system interface and makes parameter adjustments when necessary.

[0029] When the refined glass melt in the clarification tank 2 meets the quality and temperature requirements to form glass liquid, it can be stably, continuously, or intermittently taken out through the discharge port 6 at its bottom and directly supplied to the subsequent glass bead forming equipment. The discharge port 6 at the bottom of the main melting pool 1 is usually used to discharge the sediment generated during the melting process, empty the furnace when changing the glass variety, or discharge the material under special circumstances.

[0030] Step 4: Water quenching to make slag After being fully conditioned in the clarifying tank 2 of the electric melting furnace, the homogeneous glass liquid reaching the predetermined temperature and viscosity steadily flows out from the discharging port 6 at the bottom of the clarifying tank 2. The glass liquid flow directly falls into the water quenching tank of the water quenching system arranged below. The outside of the water quenching tank is connected with a water quenching circulating pump and a water quenching pool, and continuous flowing cooling water is enabled in the water quenching tank through the water quenching pool and the water quenching circulating pump. When the high-temperature glass liquid contacts the cold water instantaneously, intense heat exchange occurs, the glass liquid rapidly loses heat and solidifies, and automatically breaks into irregular granular solids of different sizes due to huge internal stress, namely wet glass slag. The impact and carrying effect of the water flow transport the generated glass slag to the water quenching pool communicated with the water quenching tank. In the water quenching pool, the glass slag sinks to the bottom of the pool due to its larger density. The water quenching circulating pump extracts the relatively clarified cooling water with a somewhat increased temperature from the upper part of the water quenching pool, and after cooling, it is sent back to the water quenching tank, forming a closed-loop cycle of water to save water resources and continuously take away the heat released by the glass liquid. The wet glass slag deposited at the bottom of the water quenching pool is continuously or intermittently fished out by a slag scraper (such as a chain bucket type or a scraper conveyor type) and transported to the next process.

[0031] In this step, the high-temperature molten glass liquid is rapidly transformed into a solid particle form that is easy to handle, store, and mechanically process later, and the glass is preliminarily broken by the thermal stress generated by quenching, reducing the difficulty for subsequent fine crushing. At the same time, the water circulation system realizes the effective utilization of the cooling medium, and the particle size can be preliminarily controlled below 20 mm in this step.

[0032] Step Five: Drying and Crushing The wet glass slag sent out by the slag scraper contains a large amount of attached water and some internal water, and needs to be dried. The material is fed into a dryer. In this embodiment, a fluidized bed dryer with hot air circulation can be used, and a rotary drum dryer can also be selected as other preferred embodiments. In the dryer, the wet glass slag is in full contact with the heat medium (such as hot air), and the water is evaporated and removed to obtain dry glass slag with a moisture content meeting the requirements. The dried glass slag is immediately fed into a crusher. The crusher uses high-speed rotating hammer heads, rollers moving towards each other, or the mutual impact between materials, etc. to strongly crush the input glass slag, further finely crushing the dry glass slag with a wide size distribution so that most of its particle size reaches below 3 mm to meet the requirements of the subsequent screening and spheroidizing processes for the raw material particle size.

[0033] Step Six: Screening and Classification The glass slag mixture after being processed by the crusher contains particles and powders of different particle sizes and needs to be precisely classified through a vibrating screen. The material is evenly fed onto the top screen surface of a multi-layer screen vibrating screen. Under the action of the exciting force, the material jumps and advances on the inclined screen surface and is separated by different layers of screens according to the particle size: Coarse slag: Particles with a particle size larger than the aperture of the top sieve (>3 mm) cannot pass through the sieve and move along the sieve surface to the discharge port 6 of this layer and are discharged.

[0034] Qualified glass particles: Particles with a particle size between the aperture of the top sieve and the aperture of the next lower sieve (1 - 3 mm) can pass through the top sieve but are intercepted by the next lower sieve, move along the sieve surface of this layer to the corresponding discharge port 6 and are discharged. This part is the target material for subsequent spheroidization.

[0035] Fine powder: Fine particles and powders with a particle size smaller than the aperture of the bottommost sieve (e.g., <1 mm) can pass through all sieve layers and are discharged from the discharge port 6 at the bottom of the vibrating sieve.

[0036] In this step, the crushed material is precisely separated into three or more parts with preset particle size ranges, obtaining qualified glass particles (1 - 3 mm) with a narrow particle size distribution and meeting the spheroidization requirements. At the same time, the unqualified materials that are too coarse (>3 mm) and too fine (<1 mm) are effectively separated, providing a basis for subsequent spheroidization and material recycling.

[0037] Step Seven: Spheroidization of Qualified Particles The qualified glass particles with a particle size in the range of 1 - 3 mm screened out are used as the direct raw materials for preparing glass beads and are transported to a glass spheroidization furnace (the spheroidization furnace can be a vertical flame furnace, a horizontal rotary furnace, etc.). In the high-temperature zone of the spheroidization furnace (the temperature needs to reach above the softening point of the glass but below the complete liquefaction temperature), the glass particles are heated quickly and evenly. Under the action of high temperature, the surface tension of the particles becomes the dominant force, causing the softened irregular particles to spontaneously contract and deform, tending to be spherical with the lowest surface energy. The particles stay in the high-temperature zone for an appropriate time to complete the spheroidization process, and then leave the high-temperature zone and enter the cooling zone for rapid cooling and shaping to form qualified glass bead products with good roundness and a smooth surface. The final products can be packaged after collection, possible post-treatment (such as cleaning, grading, surface coating, etc.) and inspection.

[0038] Step Eight: Recycling of Unqualified Materials The coarse slag (particle size >3 mm) and fine powder (particle size <1 mm) generated during the screening process in Step Six are regarded as unqualified products because their particle sizes do not meet the spheroidization requirements. In the production process design of this embodiment, these two parts of materials are not discarded, but are uniformly sent back to the electric melting furnace in Step Three as recycled materials through a special collection and transportation system (such as pneumatic transportation or mechanical transportation), and enter the electric melting furnace again for melting together with the newly prepared glass batch. This step realizes the closed-loop recycling of the by-products (unqualified particle size materials) generated during the production process, maximizes the conversion rate of raw materials, reduces the generation of solid waste, significantly reduces production costs, and helps to maintain the material balance and stable operation of the entire production system.

[0039] In summary, a glass bead production process provided by this embodiment realizes continuous, efficient, low-consumption, and environmentally friendly production from raw materials to high-quality glass bead products through the integrated and optimized electric furnace melting technology (composite heating, zone control), efficient water quenching and slag making, precise drying, crushing, and multi-stage screening technology, as well as a perfect closed-loop recycling system for unqualified materials.

[0040] The above are only the preferred embodiments of the present invention and do not limit the protection scope of the present invention. Any innovative improvement or replacement based on the present invention should fall within the scope of the claims of the present invention. At the same time, the various parameters, materials, and processes mentioned in the above embodiments are not unique. Without departing from the technical essence of the present invention, those of ordinary skill in the art can make various alternative selections, and these alternative solutions should also be regarded as falling within the protection scope of the present invention.

Claims

1. A glass bead production process, characterized in that, It includes the following steps: S1. Mix the glass raw materials to obtain a glass batch; S2. Transport and feed the glass batch into an electric melting furnace; S3. Carry out melting and conditioning in the electric melting furnace. This step includes: in the main melting pool area of the electric melting furnace, melting the glass batch by a combined heating method including upper radiation heating and internal direct electrode heating to form a glass melt, and transporting the glass melt to the clarification tank area of the electric melting furnace; and in the clarification tank area, heating and conditioning the glass melt by the direct electrode heating method to obtain glass liquid meeting the predetermined state; S4. Discharge the glass liquid and carry out water quenching treatment to form glass slag; S5. Carry out drying and crushing treatment on the glass slag; S6. Screen the crushed glass slag to separately obtain qualified glass particles with particle sizes within the predetermined target range, coarse slag with particle sizes larger than the upper limit of the target range, and fine powder with particle sizes smaller than the lower limit of the target range; S7. Carry out heating and spheroidizing treatment on the qualified glass particles to obtain glass bead products; S8. Return the coarse slag and fine powder separated in step S6 to the electric melting furnace in step S3 for remelting.

2. The glass bead production process according to claim 1, wherein, In step S3, the upper radiation heating in the main melting pool area is provided by a resistance heating element arranged above the main melting pool; the internal direct electrode heating in the main melting pool area is provided by an electrode inserted into the side wall of the main melting pool.

3. The glass bead production process according to claim 2, characterized in that, In step S3, the direct electrode heating in the clarification tank area is provided by an electrode inserted from the top of the clarification tank.

4. The glass bead production process according to claim 3, characterized in that, This process further includes: monitoring the temperature by temperature sensing devices arranged in the main melting pool area and the clarification tank area, and adjusting the power of the resistance heating element and each electrode based on the monitored temperature and preset process parameters through a control system to perform the heating in step S3.

5. The glass bead production process according to claim 1, characterized in that, The water quenching treatment in step S4 is carried out in a water quenching system including a water quenching tank, a water quenching pool, a water quenching circulation pump and a slag skimmer. The glass liquid contacts the circulating cooling water in the water quenching tank to form glass slag. The glass slag settles in the water quenching pool and is taken out by the slag skimmer. The water quenching circulation pump is used to transport water from the water quenching pool back to the water quenching tank.

6. The glass bead production process according to claim 1, wherein, In step S6, the particle size of the qualified glass particles is 1 mm to 3 mm; the particle size of the coarse slag is larger than 3 mm; the particle size of the fine powder is smaller than 1 mm.

7. The glass bead production process according to any one of claims 1-6, characterized in that, In step S8, the coarse slag and the fine powder are fed into the electric melting furnace in step S3 and mixed with the newly prepared glass batch in step S1 for remelting together.

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