CA2221013C - Process and system for recycling glass - Google Patents
Process and system for recycling glass Download PDFInfo
- Publication number
- CA2221013C CA2221013C CA 2221013 CA2221013A CA2221013C CA 2221013 C CA2221013 C CA 2221013C CA 2221013 CA2221013 CA 2221013 CA 2221013 A CA2221013 A CA 2221013A CA 2221013 C CA2221013 C CA 2221013C
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- Canada
- Prior art keywords
- cutlet
- drum
- glass
- cullet
- contaminants
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/06—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse
- B03B9/061—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse the refuse being industrial
- B03B9/062—General arrangement of separating plant, e.g. flow sheets specially adapted for refuse the refuse being industrial the refuse being glass
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
- B03B5/48—Washing granular, powdered or lumpy materials; Wet separating by mechanical classifiers
- B03B5/56—Drum classifiers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/52—Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/60—Glass recycling
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- Processing Of Solid Wastes (AREA)
Abstract
A system and method for recycling a waste glass cullet includes a first screening station for separating large glass shards of approximately one inch in diameter from smaller glass shards in the cullet, a crusher to reduce the large glass shards to smaller glass shards smaller than approximately one inch in diameter, a second screening station to separate remaining large contaminants having a diameter of approximately one inch or greater from the cullet, a series of vacuum inlets disposed along a conveyor to remove light contaminants, a presoaking apparatus comprising a holding tank partly filled with a presoaking solution, a rotary washing apparatus comprising a drum with vanes disposed along an inner wall of the drum to toss the cullet in the washing solution, the vanes being oriented so that the cullet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the cullet, a dewatering apparatus to remove excess water from the cullet, and a dryer for reducing the moisture content of the cullet. The system and method may further include a second rotary crusher for reducing the cullet size to 12 mesh or smaller and a vibratory multi-deck screen to separate the crushed glass cullet into specified particle sizes. In the preferred embodiment the rotary drum washer for includes a rotating drum having one or more vanes disposed along an inner wall of the drum to toss the cullet in the washing solution, the vanes being oriented so that the cullet is tossed progressively forwardly toward a discharge outlet of the drum.
Description
Field of Invention This invention relates to a system and process for recycling glass. In particular, this invention relates to a system and process for recycling glass Gullet to a purity suitable for re-use in industrial applications, requiring only preliminary separation of waste from the Gullet prior to recycling.
Background of the Invention The benefits of recycling materials are well known. Most common household materials, including paper, metals and glass, can be recycled for re-use by industry. However, the cost of recycling varies depending upon the material.
Recycling of glass in particular has been a costly process. The main reason is that industries which use recycled glass require that the glass be largely contaminant free. Household waste recycling programs generally do not discriminate between glass and ceramic recyclables, or between glasses of different colours. As such, glass recyclables collected by recycling authorities tend to be a mixture of different colours of glasses and ceramics, as well as contaminants such as foil or paper labels and any non-recyclable refuse that finds its way into a bottle or jar or other refuse in a recycling bin.
These contaminants present a problem in conventional recycling processes. Prior to the invention there has not been a satisfactory method available for eliminating contaminants such as small paper and foil particles and chemical adhesives from the recycled glass. These contaminants render the recycled glass unsuitable for use in many industrial processes.
Moreover, the ceramic content of the mixture presents a particular problem, because ceramic does not burn off at temperatures which will eliminate most other contaminants and it is often difficult to physically distinguish ceramic from glass so it is virtually impossible to eliminate the ceramic content of the mixture prior to processing. However, recycled glass with any significant content of large ceramic particles is useless to many industries, for example bottle production, because these particles weaken the structure of the recycled product.
As such, existing recycling programs cannot recover much of the glass which is collected for recycling and end up disposing of it in landfill sites with other non-recoverable refuse.
The present invention provides a system and method for recycling glass from a three-mix Gullet which includes whole and broken glass recyclables of any colour as well as ceramics and other contaminants. The system and method of the invention requires minimal preliminary separation of materials, saving time and labour costs. The recycled glass Gullet is over 99% contaminant free, which is acceptable for use in most industries, and can be produced in a powder form particularly suitable for producing glass fiber insulation, sand blasting slurries,water filtrates, glass beads for reflective paint and many other uses. The recycled glass is also environmentally safe and does not cause silicosis, even in powder form.
The invention accomplishes this by crushing the three mix Gullet to a size at which the glass and ceramic can be separated from metal, plastic and other contaminants, washing the resulting mixture in a rotary drum apparatus to remove adhesives and other buoyant or "floatable" contaminants, heating the washed mixture to eliminate any remaining combustibles and reduce moisture content, and optionally further crushing the glass particles to a particle size of minus 12 mesh.
It has been found that ceramics when reduced to a particle size of less than 20 mesh do not adversely affect recycled glass. Ceramic particles of this size dissipate in industrial furnaces and do not form part of the recycled product.
Thus, it becomes unnecessary to eliminate ceramics from the recycling mixture, so long as they are crushed to the required size so that they no longer form contaminants in the recycled product. By virtually eliminating contaminants such as paper, foil, ferrous and non-ferrous metals and chemical adhesives, recycled glass produced by the invention is suitable for reuse in most industrial applications which would otherwise be unable to use recycled glass.
The invention further provides a novel glass washing apparatus, comprising a rotating drum having vanes disposed along its interior wall. The drum is composed of sections, each section being supported by rollers and being differentially rotated by a drive mechanism to reduce wear caused by misalignment of the drum on the rollers. As the drum rotates the glass slurry is tossed forwardly by the vanes, and progressively conveyed toward the discharge outlet. The abrasion of the glass particles against the vanes and against neighbouring particles in the presence of the wash solution removes any adhering buoyant contaminants.
The present invention thus provides a system for recycling a waste glass Gullet, comprising a first screening station for separating large glass shards of approximately one inch in diameter from smaller glass shards in the Gullet, a crusher to reduce the large glass shards to smaller glass shards smaller than approximately one inch in diameter, a second screening station to separate remaining large contaminants having a diameter of approximately one inch or greater from the Gullet, a presoak holding tank partially filled with a presoaking solution, a rotary washing apparatus comprising a drum having a vane disposed along an inner wall of the drum to toss the Gullet in a washing solution, the vane being oriented so that the Gullet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the Gullet, a dewatering apparatus to remove excess water from the Gullet, and a dryer for reducing the moisture content of the Gullet.
The present invention further provides method of recycling a waste glass Gullet, comprising the steps of separating large glass shards of approximately one inch in diameter from smaller glass shards in the Gullet, crushing the large glass shards to smaller glass shards smaller than approximately one inch in diameter, separating large contaminants having a diameter of approximately one inch or greater from the Gullet, presoaking the Gullet in a presoaking solution, washing the Gullet in a rotary washing apparatus comprising a drum with a vane disposed along an inner wall of the drum to toss the Gullet in a washing solution, the vane being oriented so that the Gullet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the Gullet, dewatering the Gullet to remove excess water, and reducing the moisture content of the Gullet.
The present invention further provides a rotary drum washer for removing buoyant contaminants from glass Gullet, comprising a rotating drum having a helical vane disposed along an inner wall of the drum and one or more radially oriented paddles disposed along an inner wall of the drum to toss the Gullet in a washing solution, the vane being oriented so that the Gullet is tossed progressively forwardly toward a discharge outlet of the drum.
Brief Description of the Drawing In drawings which illustrate by way of example only a preferred embodiment of the invention, Figure 1 is a schematic diagram showing the glass recycling system of the invention, Figure 2 is a side elevation of a preferred embodiment of the rotary drum washer, Figure 3 is a top plan view of the rotary drum washer of Figure 2, Figure 4 is a cross-section of the rotary drum washer of Figure 2, and Figure 5 is a side elevation of a preferred embodiment of a rotary screw conveyor for the system of the invention.
Detailed Description of the Invention A preferred embodiment of the glass recycling system of the invention is illustrated in Figure 1. Raw recyclables are collected by civic or other authorities and transported to the recycling plant where they are stored until ready for processing. The recycling system and process comprises the following stages:
a) Feeding of raw material to a manual or mechanical sorting station - The raw recyclables are loaded into a conventional vibratory feeder 3 which feeds the raw material at a selected rate to a manual or mechanical sorting station 4 for separation of large contaminants.
b) Sorting - At the manual or mechanical sorting station 4 large contaminants such as plastic bottles, metal, aluminum, ceramics stones and the like are manually or mechanically removed from the raw mixture and discarded into bins. The remaining three-mix Gullet (referring to the three colours of glass in the mixture) is placed onto a conveyor 5 and conveyed to the first screening station 6.
c) First screening - At the first screening station 6 a conventional vibratory screen filter with a 1 inch filter mesh separates large glass shards having a diameter of approximately 1 inch or greater from the mixture. Glass shards and particles smaller than approximately 1 inch drop into a second screening station 8. A
magnetic head pulley 6a is preferably provided near the top of the infeed conveyor to the first roll crusher 7, to remove large ferrous contaminants such as bottle caps prior to primary crushing.
d) First crushing - The larger shards having a diameter of 1 inch or greater remaining in the first screening station 6 are fed into a first roll crusher 7 and reduced to shards and particles smaller than 1 inch, which are then deposited into the second screening station 8.
e) Second screening - At the second screening station 8 another conventional vibratory screen filter with a 1 inch filter mesh separates any large contaminants having a diameter of 1 inch or greater from the mixture, such as plastic caps, bottle labels etc. which are not significantly reduced in size by the roll crusher 7.
At this stage all particles larger than 1" are contaminants and are discarded into bins.
f) Air vacuuming - Glass shards and particles, and any remaining contaminants smaller than 1 inch, drop onto a second conveyor 8a. Air vacuum inlets 8b disposed at selected points along the conveyor 8a remove any light contaminants (paper, foil etc.) smaller than 1 inch prior to presoaking.
g) Presoaking - The presoak holding tank 30 is partially filled with recirculated filtered water from the washing stage, to which a small amount of fresh water is added to reduce stagnation. A commercially available surfactant cleansing agent is introduced to the holding tank 30 to dissolve glues and foreign compounds adhering to the glass shards prior to the washing stage. An infeed rotary screw conveyor 10, comprising an auger 20 axially disposed within Gullet trough 32 similar to the conveyor illustrated in Figure 5 but oriented horizontally at the base of the presoak holding tank 30, regulates the feed of the glass shards, water and surfactant mixture (washing solution) into the rotary drum washer 11 at a rate controlled by the drum rotation speed.
h) Washing - The washing solution is fed into the holding tank 30 through Gullet inlet 32, and drains into the drum 40 along with the glass Gullet. As the drum 40 rotates paddles 51 disposed along the inner wall of the drum 40 toss the Gullet in the washing solution. Abrasion of the glass particles against the paddles 51 and against neighbouring glass particles in the presence of the surfactant removes any remaining adhering contaminants such as label paper or foil, adhesives, dirt etc. A
helical vane 50 is provided along the inner wall of the drum 40 so that the glass mixture is tossed progressively forwardly toward the Gullet discharge outlet 44 of the drum 40.
All remaining buoyant or "floatable" contaminants are eliminated during the washing process and are discharged with the washing solution, preferably into a filter unit (not shown) which filters the washing solution for reuse.
The glass Gullet now consists of cleaned, three-colour glass shards 1 inch or less in _7_ diameter.
i) Dewatering - The cleaned glass Gullet is discharged from the drum 40 into a vibratory dewatering screen conveyor 12, which removes excess water from the mixture (the water is preferably filtered and recirculated through the rotary drum washer 11). Alternatively, another rotary screw conveyor 10 such as the conveyor 10 illustrated in Figure 5 can be used to convey the cleaned glass mixture to the dryer 13 for drying. In this embodiment the rotary screw conveyor 10 is preferably inclined upwardly from inlet 24 to outlet 26, as shown in Figure 5, allowing excess water to flow down the trough 22 toward a water discharge port 28 near the Gullet inlet 24.
j ) Drying - The dewatered glass Gullet is discharged into a hopper feeding a vibrating float dryer 13 which distributes the glass particles evenly on a dryer bed, preferably a "W" shaped dryer bed which allows the heated air blown through the bed to disperse to all surfaces of the glass particles. An example of a suitable dryer 13 is known as a "fluidized bed dryer" made by Carrier Vibrating Equipment Inc.
The mixture is dried, preferably to reduce the moisture content to 0.5% or less, and any remaining residue of combustible or flammable particles is burned off and suctioned off by a conventional air vacuum system (not shown) into a suitable commercially available dust collector (not shown).
k) Storage of the recycled glass powder - The cleaned glass Gullet is discharged from the vibrator screen 16 to a conveyor 17, which conveys the Gullet to a bucket elevator feed 19 for deposit into storage silos 20.
If a fine glass powder is desired, the system and method of the invention may optionally include the following stages:
1) Second crushing - The dried Gullet is discharged from the dryer 13 to a conveyor 13a which conveys the cleaned mixture to a vibratory surger hopper 14 that discharges the Gullet in metered amounts into a second crusher 15, preferably a rotary rock on rock crusher, which crushes the Gullet to a particle size of between _8_ plus 12 mesh and minus 12 mesh.
m) Second separation - The crushed cutlet may be conveyed to a multi-deck vibrator screen 16 having a plurality of spaced apart minus 12 mesh and smaller filters. Particles of the selected sizes (plus 12 mesh and smaller) are discharged from the vibrator screens 16 to separate conveyors 17, which convey the glass powders to bucket elevator feeds 19 for deposit into storage silos 20 according to particle size.
n) Re-crushing - All particles larger than the desired particle size are discharged from the vibrator screen 16 to a recirculatory conveyor 18 which conveys the cutlet back to the rotary rock on rock crusher 15 for further crushing along with the continual discharge of glass cutlet from the Burger hopper 14.
The rotary drum washer 11, illustrated in Figures 2 to 4, comprises a holding tank 30 in communication with a steel drum 40 through a cutlet trough 32.
The drum 40 is preferably composed of three sections 42 welded together or otherwise suitably joined along seams 42a and welded to ends 46. The sections are each independently supported by sets of free-rolling support rollers 60 and drive rollers 62 disposed near each seam 42a. The rollers 60, 62 are mounted on posts 61 embedded in the concrete slab floor 4. Preferably a separate hydraulic drive unit 66 drives each set of drive rollers 62 independently, as shown in Figures 2 and 3, reducing wear on the rollers 60, 62 caused by normal misalignment of the drum sections 42 and undulation during use.
The washing solution is pumped into the holding tank 30 through fluid inlet 34, and drains into the drum 40 through the cutlet inlet 32. A
helical stainless steel vane 50 is disposed along the inner wall 40a of the drum 40, as shown in phantom in Figure 2, so that as the drum 40 rotates the Gullet migrates progressively forwardly toward the outlet 44. The rotary speed of the drum 40 thus determines the duration of the washing cycle, which can be adjusted depending upon the desired recycling capacity, surfactant concentration and water temperature to ensure that the cutlet is substantially cleaned of contaminants before egressing from the drum 40.
T'he interior of the drum 40 further includes a series of generally rectangular paddles 51 oriented radially, preferably every 120° along the vane 50, as shown in Figure 4, so that as the drum 40 rotates the Gullet is tossed in the washing solution and drops back to the level of the washing solution as each paddle 51 approaches the top of the rotational cycle of the drum 40.
The "floatable" contaminants, including paper and foil label particles and adhesive residues, float to the top of the solution and are discharged with the solution through annular water discharge outlet 54 surrounding the Gullet outlet 44, preferably into a filter apparatus (not shown) which cleans the solution for reuse in the washing and presoaking stages.
The washed cutlet retains its ceramic content. To render the cutlet suitable for use in industries which require that the ceramics be eliminated, the second crushing stage described above is employed to produce a fine glass powder.
The fine ceramic particles dispersed throughout the glass powder will dissipate in further processing.
A preferred embodiment of the invention having been thus described by way of example only, it will be apparent to those skilled in the art that certain modifications and adaptations may be made without departing from the scope of the invention, as set out in the appended claims.
Background of the Invention The benefits of recycling materials are well known. Most common household materials, including paper, metals and glass, can be recycled for re-use by industry. However, the cost of recycling varies depending upon the material.
Recycling of glass in particular has been a costly process. The main reason is that industries which use recycled glass require that the glass be largely contaminant free. Household waste recycling programs generally do not discriminate between glass and ceramic recyclables, or between glasses of different colours. As such, glass recyclables collected by recycling authorities tend to be a mixture of different colours of glasses and ceramics, as well as contaminants such as foil or paper labels and any non-recyclable refuse that finds its way into a bottle or jar or other refuse in a recycling bin.
These contaminants present a problem in conventional recycling processes. Prior to the invention there has not been a satisfactory method available for eliminating contaminants such as small paper and foil particles and chemical adhesives from the recycled glass. These contaminants render the recycled glass unsuitable for use in many industrial processes.
Moreover, the ceramic content of the mixture presents a particular problem, because ceramic does not burn off at temperatures which will eliminate most other contaminants and it is often difficult to physically distinguish ceramic from glass so it is virtually impossible to eliminate the ceramic content of the mixture prior to processing. However, recycled glass with any significant content of large ceramic particles is useless to many industries, for example bottle production, because these particles weaken the structure of the recycled product.
As such, existing recycling programs cannot recover much of the glass which is collected for recycling and end up disposing of it in landfill sites with other non-recoverable refuse.
The present invention provides a system and method for recycling glass from a three-mix Gullet which includes whole and broken glass recyclables of any colour as well as ceramics and other contaminants. The system and method of the invention requires minimal preliminary separation of materials, saving time and labour costs. The recycled glass Gullet is over 99% contaminant free, which is acceptable for use in most industries, and can be produced in a powder form particularly suitable for producing glass fiber insulation, sand blasting slurries,water filtrates, glass beads for reflective paint and many other uses. The recycled glass is also environmentally safe and does not cause silicosis, even in powder form.
The invention accomplishes this by crushing the three mix Gullet to a size at which the glass and ceramic can be separated from metal, plastic and other contaminants, washing the resulting mixture in a rotary drum apparatus to remove adhesives and other buoyant or "floatable" contaminants, heating the washed mixture to eliminate any remaining combustibles and reduce moisture content, and optionally further crushing the glass particles to a particle size of minus 12 mesh.
It has been found that ceramics when reduced to a particle size of less than 20 mesh do not adversely affect recycled glass. Ceramic particles of this size dissipate in industrial furnaces and do not form part of the recycled product.
Thus, it becomes unnecessary to eliminate ceramics from the recycling mixture, so long as they are crushed to the required size so that they no longer form contaminants in the recycled product. By virtually eliminating contaminants such as paper, foil, ferrous and non-ferrous metals and chemical adhesives, recycled glass produced by the invention is suitable for reuse in most industrial applications which would otherwise be unable to use recycled glass.
The invention further provides a novel glass washing apparatus, comprising a rotating drum having vanes disposed along its interior wall. The drum is composed of sections, each section being supported by rollers and being differentially rotated by a drive mechanism to reduce wear caused by misalignment of the drum on the rollers. As the drum rotates the glass slurry is tossed forwardly by the vanes, and progressively conveyed toward the discharge outlet. The abrasion of the glass particles against the vanes and against neighbouring particles in the presence of the wash solution removes any adhering buoyant contaminants.
The present invention thus provides a system for recycling a waste glass Gullet, comprising a first screening station for separating large glass shards of approximately one inch in diameter from smaller glass shards in the Gullet, a crusher to reduce the large glass shards to smaller glass shards smaller than approximately one inch in diameter, a second screening station to separate remaining large contaminants having a diameter of approximately one inch or greater from the Gullet, a presoak holding tank partially filled with a presoaking solution, a rotary washing apparatus comprising a drum having a vane disposed along an inner wall of the drum to toss the Gullet in a washing solution, the vane being oriented so that the Gullet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the Gullet, a dewatering apparatus to remove excess water from the Gullet, and a dryer for reducing the moisture content of the Gullet.
The present invention further provides method of recycling a waste glass Gullet, comprising the steps of separating large glass shards of approximately one inch in diameter from smaller glass shards in the Gullet, crushing the large glass shards to smaller glass shards smaller than approximately one inch in diameter, separating large contaminants having a diameter of approximately one inch or greater from the Gullet, presoaking the Gullet in a presoaking solution, washing the Gullet in a rotary washing apparatus comprising a drum with a vane disposed along an inner wall of the drum to toss the Gullet in a washing solution, the vane being oriented so that the Gullet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the Gullet, dewatering the Gullet to remove excess water, and reducing the moisture content of the Gullet.
The present invention further provides a rotary drum washer for removing buoyant contaminants from glass Gullet, comprising a rotating drum having a helical vane disposed along an inner wall of the drum and one or more radially oriented paddles disposed along an inner wall of the drum to toss the Gullet in a washing solution, the vane being oriented so that the Gullet is tossed progressively forwardly toward a discharge outlet of the drum.
Brief Description of the Drawing In drawings which illustrate by way of example only a preferred embodiment of the invention, Figure 1 is a schematic diagram showing the glass recycling system of the invention, Figure 2 is a side elevation of a preferred embodiment of the rotary drum washer, Figure 3 is a top plan view of the rotary drum washer of Figure 2, Figure 4 is a cross-section of the rotary drum washer of Figure 2, and Figure 5 is a side elevation of a preferred embodiment of a rotary screw conveyor for the system of the invention.
Detailed Description of the Invention A preferred embodiment of the glass recycling system of the invention is illustrated in Figure 1. Raw recyclables are collected by civic or other authorities and transported to the recycling plant where they are stored until ready for processing. The recycling system and process comprises the following stages:
a) Feeding of raw material to a manual or mechanical sorting station - The raw recyclables are loaded into a conventional vibratory feeder 3 which feeds the raw material at a selected rate to a manual or mechanical sorting station 4 for separation of large contaminants.
b) Sorting - At the manual or mechanical sorting station 4 large contaminants such as plastic bottles, metal, aluminum, ceramics stones and the like are manually or mechanically removed from the raw mixture and discarded into bins. The remaining three-mix Gullet (referring to the three colours of glass in the mixture) is placed onto a conveyor 5 and conveyed to the first screening station 6.
c) First screening - At the first screening station 6 a conventional vibratory screen filter with a 1 inch filter mesh separates large glass shards having a diameter of approximately 1 inch or greater from the mixture. Glass shards and particles smaller than approximately 1 inch drop into a second screening station 8. A
magnetic head pulley 6a is preferably provided near the top of the infeed conveyor to the first roll crusher 7, to remove large ferrous contaminants such as bottle caps prior to primary crushing.
d) First crushing - The larger shards having a diameter of 1 inch or greater remaining in the first screening station 6 are fed into a first roll crusher 7 and reduced to shards and particles smaller than 1 inch, which are then deposited into the second screening station 8.
e) Second screening - At the second screening station 8 another conventional vibratory screen filter with a 1 inch filter mesh separates any large contaminants having a diameter of 1 inch or greater from the mixture, such as plastic caps, bottle labels etc. which are not significantly reduced in size by the roll crusher 7.
At this stage all particles larger than 1" are contaminants and are discarded into bins.
f) Air vacuuming - Glass shards and particles, and any remaining contaminants smaller than 1 inch, drop onto a second conveyor 8a. Air vacuum inlets 8b disposed at selected points along the conveyor 8a remove any light contaminants (paper, foil etc.) smaller than 1 inch prior to presoaking.
g) Presoaking - The presoak holding tank 30 is partially filled with recirculated filtered water from the washing stage, to which a small amount of fresh water is added to reduce stagnation. A commercially available surfactant cleansing agent is introduced to the holding tank 30 to dissolve glues and foreign compounds adhering to the glass shards prior to the washing stage. An infeed rotary screw conveyor 10, comprising an auger 20 axially disposed within Gullet trough 32 similar to the conveyor illustrated in Figure 5 but oriented horizontally at the base of the presoak holding tank 30, regulates the feed of the glass shards, water and surfactant mixture (washing solution) into the rotary drum washer 11 at a rate controlled by the drum rotation speed.
h) Washing - The washing solution is fed into the holding tank 30 through Gullet inlet 32, and drains into the drum 40 along with the glass Gullet. As the drum 40 rotates paddles 51 disposed along the inner wall of the drum 40 toss the Gullet in the washing solution. Abrasion of the glass particles against the paddles 51 and against neighbouring glass particles in the presence of the surfactant removes any remaining adhering contaminants such as label paper or foil, adhesives, dirt etc. A
helical vane 50 is provided along the inner wall of the drum 40 so that the glass mixture is tossed progressively forwardly toward the Gullet discharge outlet 44 of the drum 40.
All remaining buoyant or "floatable" contaminants are eliminated during the washing process and are discharged with the washing solution, preferably into a filter unit (not shown) which filters the washing solution for reuse.
The glass Gullet now consists of cleaned, three-colour glass shards 1 inch or less in _7_ diameter.
i) Dewatering - The cleaned glass Gullet is discharged from the drum 40 into a vibratory dewatering screen conveyor 12, which removes excess water from the mixture (the water is preferably filtered and recirculated through the rotary drum washer 11). Alternatively, another rotary screw conveyor 10 such as the conveyor 10 illustrated in Figure 5 can be used to convey the cleaned glass mixture to the dryer 13 for drying. In this embodiment the rotary screw conveyor 10 is preferably inclined upwardly from inlet 24 to outlet 26, as shown in Figure 5, allowing excess water to flow down the trough 22 toward a water discharge port 28 near the Gullet inlet 24.
j ) Drying - The dewatered glass Gullet is discharged into a hopper feeding a vibrating float dryer 13 which distributes the glass particles evenly on a dryer bed, preferably a "W" shaped dryer bed which allows the heated air blown through the bed to disperse to all surfaces of the glass particles. An example of a suitable dryer 13 is known as a "fluidized bed dryer" made by Carrier Vibrating Equipment Inc.
The mixture is dried, preferably to reduce the moisture content to 0.5% or less, and any remaining residue of combustible or flammable particles is burned off and suctioned off by a conventional air vacuum system (not shown) into a suitable commercially available dust collector (not shown).
k) Storage of the recycled glass powder - The cleaned glass Gullet is discharged from the vibrator screen 16 to a conveyor 17, which conveys the Gullet to a bucket elevator feed 19 for deposit into storage silos 20.
If a fine glass powder is desired, the system and method of the invention may optionally include the following stages:
1) Second crushing - The dried Gullet is discharged from the dryer 13 to a conveyor 13a which conveys the cleaned mixture to a vibratory surger hopper 14 that discharges the Gullet in metered amounts into a second crusher 15, preferably a rotary rock on rock crusher, which crushes the Gullet to a particle size of between _8_ plus 12 mesh and minus 12 mesh.
m) Second separation - The crushed cutlet may be conveyed to a multi-deck vibrator screen 16 having a plurality of spaced apart minus 12 mesh and smaller filters. Particles of the selected sizes (plus 12 mesh and smaller) are discharged from the vibrator screens 16 to separate conveyors 17, which convey the glass powders to bucket elevator feeds 19 for deposit into storage silos 20 according to particle size.
n) Re-crushing - All particles larger than the desired particle size are discharged from the vibrator screen 16 to a recirculatory conveyor 18 which conveys the cutlet back to the rotary rock on rock crusher 15 for further crushing along with the continual discharge of glass cutlet from the Burger hopper 14.
The rotary drum washer 11, illustrated in Figures 2 to 4, comprises a holding tank 30 in communication with a steel drum 40 through a cutlet trough 32.
The drum 40 is preferably composed of three sections 42 welded together or otherwise suitably joined along seams 42a and welded to ends 46. The sections are each independently supported by sets of free-rolling support rollers 60 and drive rollers 62 disposed near each seam 42a. The rollers 60, 62 are mounted on posts 61 embedded in the concrete slab floor 4. Preferably a separate hydraulic drive unit 66 drives each set of drive rollers 62 independently, as shown in Figures 2 and 3, reducing wear on the rollers 60, 62 caused by normal misalignment of the drum sections 42 and undulation during use.
The washing solution is pumped into the holding tank 30 through fluid inlet 34, and drains into the drum 40 through the cutlet inlet 32. A
helical stainless steel vane 50 is disposed along the inner wall 40a of the drum 40, as shown in phantom in Figure 2, so that as the drum 40 rotates the Gullet migrates progressively forwardly toward the outlet 44. The rotary speed of the drum 40 thus determines the duration of the washing cycle, which can be adjusted depending upon the desired recycling capacity, surfactant concentration and water temperature to ensure that the cutlet is substantially cleaned of contaminants before egressing from the drum 40.
T'he interior of the drum 40 further includes a series of generally rectangular paddles 51 oriented radially, preferably every 120° along the vane 50, as shown in Figure 4, so that as the drum 40 rotates the Gullet is tossed in the washing solution and drops back to the level of the washing solution as each paddle 51 approaches the top of the rotational cycle of the drum 40.
The "floatable" contaminants, including paper and foil label particles and adhesive residues, float to the top of the solution and are discharged with the solution through annular water discharge outlet 54 surrounding the Gullet outlet 44, preferably into a filter apparatus (not shown) which cleans the solution for reuse in the washing and presoaking stages.
The washed cutlet retains its ceramic content. To render the cutlet suitable for use in industries which require that the ceramics be eliminated, the second crushing stage described above is employed to produce a fine glass powder.
The fine ceramic particles dispersed throughout the glass powder will dissipate in further processing.
A preferred embodiment of the invention having been thus described by way of example only, it will be apparent to those skilled in the art that certain modifications and adaptations may be made without departing from the scope of the invention, as set out in the appended claims.
Claims (8)
- I CLAIM:
A system for recycling a waste glass cutlet, comprising a) a first screening station for separating large glass shards of approximately one inch in diameter from smaller glass shards in the cutlet, b) a crusher to reduce the large glass shards to smaller glass shards smaller than approximately one inch in diameter, c) a second screening station to separate remaining large contaminants having a diameter of approximately one inch or greater from the cutlet, d) a conveyor for conveying the cutlet to a presoaking station having a series of vacuum inlets disposed above the conveyor for removing light contaminants prior to presoaking, e) a presoak holding tank partially filled with a presoaking solution, f) a rotary washing apparatus comprising a drum having a vane disposed along an inner wall of the drum to toss the cutlet in a washing solution, the vane being oriented so that the cutlet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the cutlet, g) a dewatering apparatus to remove excess water from the cutlet, and h) a dryer for reducing the moisture content of the cutlet. - 2. The system of claim 1 further including a second crusher for crushing the washed cutlet to a particle size of between plus 12 mesh and minus 12 mesh.
- 3. The system of claim 1 further including a magnetic head for removing large ferrous contaminants prior to infeeding a mixture to the first roll crusher.
- 4. The system of claim 1 in which the glass mixture is conveyed from the presoak holding tank to the rotary drum washer by a rotary screw conveyor.
- 5. A method of recycling a waste glass cutlet, comprising a) separating large glass shards of approximately one inch in diameter from smaller glass shards in the cutlet, b) crushing the large glass shards to smaller glass shards smaller than approximately one inch in diameter, c) separating large contaminants having a diameter of approximately one inch or greater from the cutlet, d) presoaking the cutlet in a presoaking solution, e) washing the cutlet in a rotary washing apparatus comprising a drum with a vane disposed along an inner wall of the drum to toss the cutlet in a washing solution, the vane being oriented so that the cutlet is tossed progressively forwardly toward a discharge outlet of the drum, to remove buoyant contaminants from the cutlet, f) dewatering the cutlet to remove excess water, and g) reducing the moisture content of the cutlet.
- 6. The method of claim 5 further including the step of crushing the washed cutlet to a particle size of between plus 12 mesh and minus 12 mesh.
- 7. The method of claim 5 further including the step of removing large ferrous contaminants prior to infeeding a mixture to the first roll crusher.
- 8. A rotary drum washer for removing buoyant contaminants from glass cutlet, comprising a rotating drum having a helical vane disposed along an inner wall of the drum and one or more radially oriented paddles disposed along an inner wall of the drum to toss the cutlet in a washing solution, the vane being oriented so that the cutlet is tossed progressively forwardly toward a discharge outlet of the drum.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2221013 CA2221013C (en) | 1997-11-13 | 1997-11-13 | Process and system for recycling glass |
| US09/324,509 US6168102B1 (en) | 1997-11-13 | 1999-06-03 | Rotary drum washer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2221013 CA2221013C (en) | 1997-11-13 | 1997-11-13 | Process and system for recycling glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2221013A1 CA2221013A1 (en) | 1999-05-13 |
| CA2221013C true CA2221013C (en) | 2004-09-07 |
Family
ID=29275206
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2221013 Expired - Lifetime CA2221013C (en) | 1997-11-13 | 1997-11-13 | Process and system for recycling glass |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2221013C (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110668674B (en) * | 2019-11-07 | 2022-03-04 | 湖南华兴玻璃有限公司 | Waste bottle remelting and waste cleaning system for glass production line |
| CN112916558A (en) * | 2021-01-18 | 2021-06-08 | 杭州艾古电子商务有限公司 | Automobile glass screening equipment with cleaning function |
| CN113816722B (en) * | 2021-09-26 | 2022-12-16 | 江西和美陶瓷有限公司 | Heat-resistant ceramic rock plate, manufacturing method and waste glass cleaning and recycling treatment method |
-
1997
- 1997-11-13 CA CA 2221013 patent/CA2221013C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CA2221013A1 (en) | 1999-05-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20171114 |