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Melting Temperature Dependent Separations Of Metallic Electronic Wastes And Wires Using Centrifugal Forces

Gopi Krishna Mandadi

Department of Mechanical Engineering

04/25/2016

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Acknowledgements

I would like to thank my advisor and committee chair, Dr. Ramazan Asmatulu,

for his continuous guidance and support throughout this project. I would like to thank Mr.

Ricky Shipman for allowing me to use the Cessna Manufacturing laboratory and also for

his guidance towards this project success. I would also like to thank the Mr. Bryan and Mr.

Matt from the electrical shop, physical plant for their assistance and help in fixing the

Induction heater furnace. I thank Dr. Rajeev Nair and Dr. Abu Asaduzzaman for readily

agreeing to be a committee member. I also I would like to thank Mr. Vamsidhar Patlolla, a

Ph.D. student in mechanical engineering for his guidance and help towards my thesis. Last

but not the least, I am indebted to my friends who have helped me in this research work.

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Table Of Contents

• Introduction• Acknowledgement• Literature review• Experimental setup• Results • Conclusion• References

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Introduction

• E-waste is a popular, informal name for electronic products nearing the end of their useful life.

• An emotional increment in the generation and utilization of electrical and electronic equipment’s (EEEs) with a sharp abatement in their lifespan has prompted the era of expansive amounts of E-waste.

• This is the quickest developing waste stream in the world with a 3-5% expanding rate for each year than era of municipal wastes.

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Classification: Types of E-waste

• Mobile phones

• Computers

• Servers

• Telecom

• TV

• Calculators

• Audio

• Scanners

• Printers

• Air conditioner

• Micro wave

• Washing machine

• Cartridges

• Military electronic

• Mother board

• Alarm

• Sirens

• Automobile catalytic convertor

• Sensor

• CD

• Security device

• Electrical wires

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Why E - Waste must be Recycled ?

• The developing amount of e-waste from electronic industry is starting to achieve tragic extents. It is

evaluated that the world creates 20-50 million tons every year (Herat 2013). Consumer Electronics

Association (CEA) estimated that an average person owns 24 electronic products.

https://www.youtube.com/watch?v=dd_ZttK3PuM




https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwie_cK3kKjMAhXjrYMKHXxrCz4QjRwIBw&url=https://ericsantosblognet.wordpress.com/2014/07/25/no-end-in-sight-the-e-waste-menace-in-ghana/&bvm=bv.119745492,d.amc&psig=AFQjCNHlzR6AK0vPJ1nvjtCy0RobJJkc7A&ust=1461616547391732

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Contd..

Usage of PC’s for 100 persons [4]

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Reasons for Recycling Waste • The driving forces behind recycling e-waste are economic, environmental, public health and data

security.

• Electronic devices contain up to 60 different elements, many of which are valuable, such as precious

and special metals, and some of which are hazardous. Precious metals are rare, naturally occurring

metallic elements which traditionally have a higher melting point, and are more ductile than other metals.

• They have a high economic value. Special metals include nickel, nickel base alloys, cobalt base alloys,

titanium and titanium base alloys. Electronic equipment is a primary consumer of precious and special

metals and therefore it is imperative that a circular flow is established in order to recover these metals

and valuable elements. Investments are being made to treat e-scrap and reclaim the valuable metals,

especially as raw materials become more scarce and expensive.

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjaxZaGj6jMAhXrnYMKHZS8BQ8QjRwIBw&url=http://www.semachinery.com/e_waste_recycling_531/&psig=AFQjCNFSPkRCcAz12cdfxgvJxJ6iEzg1lw&ust=1461616211196343

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwie_cK3kKjMAhXjrYMKHXxrCz4QjRwIBw&url=http://www.earthwatchmedia.org/ecology/e-waste/&bvm=bv.119745492,d.amc&psig=AFQjCNHlzR6AK0vPJ1nvjtCy0RobJJkc7A&ust=1461616547391732

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Concentration Of Metals In Electronics

Electronic Copper (% by weight) Silver (ppm) Gold(ppm) Palladium(ppm)

Television TV Board 10% 280 20 10

Personal Computer

board (PCB)

20% 1000 250 110

Mobile phone 13% 3500 340 130

DVD Player Scrap 5% 115 15 4

Portable audio Scrap 21% 150 10 4

Concentration of metals in electronics (2007)

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E-Waste

• Circuit boards contain the highest value of precious metals in a

computer, as well as most of the heavy metals (United States

Geological Survey (USGS), 2001). The components of a personal

computer have the highest economic value, due to gold plated

connectors, components, pins and transistors:

• Motherboard (main circuit board)

• Peripheral Component Interconnect (PCI) boards

• Random Access Memory (RAM)

• Processor

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Hazardous Metals in E-Waste

• It is estimated that 50-80% of e-waste collected in developed nations is exported to developing countries such as china, India due to cheap labor and lenient environmental regulations.

• These developing nations lack the health and safety infrastructure to process and dispose of materials safely, and consequently workers handle toxic metals without proper equipment.

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End of Life Options for E-Waste

• Reuse of functional electronics.

• Refurbishment and repair of electronics

• Reuse and recovery of electronic components.

• End processing for recovering metals.

• Disposal.

Reuse, refurbishment is the better option out of the above, however it should be working and must be functional.

If it is not functional then the best option we have is the recycling. It allows to collect the precious metals and reduces the effect on environment.

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Global Scenario

• If you are throwing your electronics away in regular garbage you are violating a number of state and federal laws, contributing to global warming, polluting the environment significantly and contributing to the illness and death of thousands throughout the world who live and work in landfills, pulling apart electronics and selling the recyclable parts.

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Contd.

• In 2001, the Basel Action Network (BAN) led several groups in an investigation of e-waste processing in China, India, and Pakistan. The investigation uncovered an entire area known as Guiyu in Guangdong Province, surrounding the Lianjiang River where about 100,000 poor migrant workers are employed breaking apart and processing obsolete computers imported primarily from North America. The workers were found to be using 19th century technologies to clean up the wastes from the 21st century.

Lianjian River [20]

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Cont.…

• The United Nations estimated that 41.8 million tons of e-waste, a broad term that encompasses anything with an electrical cord or a battery, were dumped globally in 2014. Of that only 6.5 million tons was recycled and properly disposed of.

• The U.S. contributed the most to this global problem, dumping 7.1 million tons and recycling less than a million tons.

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E-waste Policy in the U.S.

• Currently there is no U.S. Federal mandate to recycle electronic waste; however twenty five states have enacted legislation requiring statewide e-waste recycling. Despite state-wide recycling efforts, it is estimated that 13.6%9 to 26.6%10 to e-waste is recycled in the U.S.

• According to the U.S. Environmental Protection Agency (EPA) Office of Resource Conservation and Recovery report “Electronics Waste Management in the United States through 2009,” 2.44 million short tons were ready for end-of-life management in 2010 Based on this estimated generation and the aforementioned U.S. e-waste recycling rates, approximately 332,000 to 649,000 short tons of e-waste was recycled in the U.S. in 2010.

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• There is a lack of information regarding how much e-waste is generated, from where and to where it is moving.

• E-waste recycling hotspots have been identified in Asia-Pacific countries such as China, India, Pakistan and in some African countries such as Senegal, Ghana and Nigeria.

• Other countries including Mexico, Morocco, Colombia, Peru, Kenya, South Africa, Senegal, Uganda, Brazil, Cambodia, Indonesia and Thailand are additional growing destinations for e-waste.

The e-waste trade

Dumping Yards in China [10]

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Cont.

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Literature Review

• Yang et al. used leaching process to initially recover gold fingers from PCB’s and then implemented hydrometallurgical processing for gold recovery. It has been reported that hydrometallurgical process along with thiourea leaching and iodide leaching make more possible to replace cyanide leaching.

• Jiran cui et al. used pyrometallurgical, hydrometallurgical, and biometallurgical process and compared the results and concluded that pyrometallurgical process have greater recovery rates.

• Waldir A. Bizzo et al. used the existing leaching process to analyse and determine their metal content and characterized them as solid waste and fuel. It has been reported that concentration of precious metals (gold and silver) has declined over time

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Current Techniques

• Pretreatment Low Temperature Freezing Method

The United States patent -No. 3990641 came up with low temperature freezing method to separate the copper and insulating layer of the waste wires. Low temperature freezing method is suitable for processing all kinds of wires and cables. Freezing makes insulation brittle first and shocking separates the insulation layer and the copper wire.

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Cont.

Chemical Stripping Method

The method adopts a kind of organic solvent to dissolve insulating layer of the waste wire to separate the copper wire and insulation layer. Sodium hydroxide (NaOH) is used as a solvent. The advantage of this method is to get high quality copper wire, but the disadvantage is that the solvent is difficult to deal with , and the price of solvent is higher. the development direction of the technology is to study a cheap practical effective solvent.

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Cont.

• Shredding & Melting– copper items stripped by the wire stripping machine needs

to be shredded before packing. Because the entire copper wire is not so convenient to be transported to the melting device. When the copper reach the smelting facilities, the bales are fed into a furnace where they are heated until they become molten copper. The molten metal is then poured into casters or molds to form items needed.

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Cont.

• Two other process that are currently in existence are – Melting at a copper smelter along with copper ore

• At a copper smelter, the scrap copper and alloy components are loaded into the furnace which is then fired up. The copper ore is fed into the furnace along with the required amount of limestone and sand. Oxygen and air are supplied and when the mix has become molten, it is then tapped into rectangular molds.

– Melting along with a proportion of copper ingots at a dedicated copper recycling plant

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Experimental Setup

• A workpiece that can hold various weight samples and which can bear the higher temperatures have to be manufactured.

• Complete experimental setup is as shown fig.

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Pro-E Design

Solid Base Perforated Basket Closing cap Bearing

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Cont.…

• Boring

Boring is the process of enlarging a hole that has already been drilled (or cast), by means of a single-point cutting tool (or of a boring head containing several such tools)

0.7cm1.8cm

FinalInitial

1.4cm 3.6cm

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Drilling

Drilling is a cutting process that uses a drill bit to cut a hole of circular cross-section in solid materials. The drill bit is a rotary cutting tool, often multipoint.

• A drill bit size of 1.1 cm has been used.

• Holes are drilled through half way of the workpiece.

• Holes are drilled throughout the circumference of the workpiece at an interval of 22.50.

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Closing caps

Welding is a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone, and with or without the use of filler material.

• After drilling the holes on the surface, on one of the closing caps of the workpiece, an external solid surface is inserted which is going to be on the top hand side of the workpiece. And that surface holds the workpiece when a centrifugal force is applied with the help of a drill machine.

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Machining

• A solid base is created at the bottom in which the workpiece is placed so that the workpiece will be in a static when centrifugal force is being applied. And also a large diameter hole that fits the bearing is bored in the solid surface.

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Cond…

• A gear is installed in to the grooved hole on the solid surface for an easy rotation when centrifugal is being applied.

• An external shield for the collection of molten metal is

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Experimental setup

Drill Machine

Shield

Solid Base

Workpiece

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Cont..

• After manufacturing the workpiece induction heater is need to setup with an electrical supply and water supply.

• There are 2 water inlets and 3 water outlets that needs to be plugged with water pipes.

• A ¾ manifold for water outlet is used and 2-1 manifold is used for water inlet.

• A 8 gauge wire is used for electrical supply.

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Water Fittings

¾ manifold 2-1 manifold

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Electrical Setup

Electric cables Insulation box

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Induction Heater Furnace

Induction Heater furnace.

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Experiment

• Electrical wires of different types such as copper wires, aluminum wires, solder, steel, high strength alloys, nickel plated conductors, tinned conductors etc. can be chosen for the recycling. Copper wires, electrical wires and solder are chosen for this experiment. Solder wires do not have a PVC material insulated on the metal whereas the copper wire and aluminum wire has a PVC material insulated on the meatal.

Aluminum wire Copper wires Solder metal

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Samples

• 5 g samples including solder, aluminum and copper wires without PVC at low speed.

• 10g samples including solder, aluminum and copper wires without PVC at low speed.



• 5 g samples including solder, aluminum and copper wires with PVC at low speed.




• 5 g samples including solder, aluminum and copper wires without PVC at high speed.

• 10g samples including solder, aluminum and copper wires without PVC at high speed.



• 5 g samples including solder, aluminum and copper wires with PVC at high speed.




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Weighing Scale

• Experimental part begins with the weighing of required samples and shearing the PVC (cap material) on the wires for aluminum and copper wires. Starting with Samples of 5g each i.e. copper wire 5g without PVC material, 5g of aluminum without PVC material and 5g of solder is weighed.

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E-Scrap

• All the materials that are weighed are fed into the workpiece.

• Later the feeding, the workpiece is closed with a cap.

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Workpiece Heating

• Now, The work piece is heated and allowed to reach melting points of certain metals such as for the solder the melting point is 183 0 C, so the workpiece is allowed to reach the temperature of 200 0 C.

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Workpiece Heating

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Extracting the Metal

• After it reaches to the melting point of the solder the heating is stopped and shield is placed around the work piece and drill machine is used as an external force for the application of centrifugal force.

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Recovered Metal

• By the action of centrifugal force the metal that is melted hits the wall surfaces of the workpieces and as there are holes drilled throughout the circumference of the workpiece, the molten metals is forced out of the workpiece and collected in the shield at bottom.

Recovered Solder

Solder

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Recovered Metal

• Similarly the experiment is further continued and allowed the workpiece to reach the melting point of aluminum which is 660.30 C and then again the drill machine is attached to the workpiece and centrifugal force is applied and the aluminum metal is recovered.

Aluminum recovered

Aluminum

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Recovered Metal

• Experiment is further continued, but as we fed 3 types of metals into the workpiece and out of which we have taken out the two metals which are aluminum and solder, all the left over material in the workpiece is copper and their residues. So further heating is to just make sure the copper metal is completely burnt and keeping no traces of other metals.

Copper Residues

Copper Metal

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Measure of Recovered Metal

• Recovered metals are weighed and the percentage of recovery is calculated.

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E- Scrap

• Similarly, experiment is carried out for the high speeds and different weight samples. Also, further experiments includes the PVC material on the wires and burning them to recover the metals.

Aluminum Wire

Solder

Copper Wire

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Conversion

• To keep the comparison same between without PVC and with PVC samples, conversion factor of insulated material is calculated.

Material

5g

10g

15g

20g

Aluminum

7.0271

14.0542

21.0813

28.1084

Copper

17.98

35.96

53.94

71.92

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Workpiece Heating

Smoke due to burning of PVC

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PVC Waste

Burnt PVC ash

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Recovered metals

Aluminum RecoveredSolder Recovered

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Experimented Samples

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Results And Discussions

• Metals are recovered by heating process and the collected samples are weighed and compared with the original values and the percentage of metal recovered is calculated.

S. No

Solder Recovery (%) Low Speed

Aluminum Recovery (%) Low Speed

Copper Recovery (%) Low Speed

1 96.13848719 97.31426578 99.24096478

2 96.73573603 98.25139183 100.7921999

3 98.38726017 98.02434644 100.0399042

4 98.93716059 97.16130794 99.55209348

5 95.89335207 97.63796477 99.78634535

Percentage Recovery Of 5g Samples Without Cap Low Speed

percentage recovery of 5g samples without cap High Speed

S. No

Solder Recovery (%) HIGH Speed

Aluminum Recovery (%) High Speed

Copper Recovery (%) High Speed

1 98.89348134 98.63857214 102.2958531

2 98.62140946 98.86288621 100.8116046

3 97.08064792 99.00033256 100.5539754

4 98.67584142 99.08471509 100.712671

5 97.13957094 99.25144573 100.7695788

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5g Samples

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10g Samples Without cap

S. NoSolder recovery (%) Low

speed Aluminum recovery (%) Low speed Copper recovery (%) Low speed

1 87.38761775 98.99979849 100.0002924

2 98.67364225 97.19985345 100.0000068

3 98.51829214 97.99983542 100.0000258

4 98.91830852 98.30788884 100.000079

5 98.55990439 97.99987582 100.0000472

S. NoSolder recovery (%) HIGH speed

Aluminum recovery (%) High speed

Copper recovery (%) High speed

1 88.0595058 98.14729145 106.6323502

2 98.25876064 98.92451899 102.1095135

3 99.07396088 99.29885629 100.5047667

4 99.23220898 99.03540535 100.5013778

5 99.48756368 98.19198828 100.8065393

Percentage Recovery Of 10g Samples Without Cap Low Speed

Percentage Recovery Of 10g Samples Without Cap High Speed

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10g Without PVC

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15gm Without PVC

S. NoSolder recovery (%) Low speed

Aluminum recovery (%) Low speed

Copper recovery (%) Low speed

1 96.77589949 97.41466938 101.9423497

2 97.82605842 96.19371225 100.8101622

3 97.65933401 98.79287765 100.9131542

4 98.18895142 98.85580488 100.967604

5 98.09560184 98.79330607 101.2527128




1 95.96780425 97.45363093 107.9811586

2 96.60701169 98.03592988 105.1598013

3 99.04508936 98.69272424 102.6069117

4 99.27079968 98.54485799 102.4541163

5 99.45247338 98.75633808 103.4352881

Percentage Recovery of 15g Samples Without Cap Low Speed

Percentage Recovery of 15g Samples Without Cap High Speed

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15g Sample Without PVC

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20g Samples Without PVC




1 94.9927058 95.19322914 103.738916

2 93.50108124 96.74508618 102.48265

3 94.34259749 95.62392213 104.5125

4 94.20766044 95.76492465 104.031094

5 94.27843506 96.36286393 104.594802




1 96.89348134 96.63857214 104.2958531

2 95.62140946 97.86288621 103.8116046

3 96.08064792 98.00033256 103.5539754

4 96.67584142 96.08471509 102.712671

5 95.13957094 97.25144573 104.7695788

Percentage Recovery of 20g Samples Without Cap Low Speed

Percentage Recovery of 20g Samples Without Cap High Speed

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20g Samples Without PVC

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5g Samples With PVC

S.noSolder recovery (%) Low speed



1 96.3981462 95.44621639 102.1795485

2 95.9696824 97.32100351 103.6982523

3 97.9448529 96.53079901 103.3552624

4 97.5549214 97.53256425 102.3686813

5 97.661928 97.49257296 102.792179

S.noSolder recovery (%) High speed



1 96.5526581 97.16631351 106.279914

2 96.8745722 94.27287328 107.202756

3 95.5577763 96.76269752 106.0993794

4 96.3567355 94.72578795 107.5379049

5 97.2138365 94.58424128 106.982931

Percentage Recovery of 5g Samples With Cap Low Speed

Percentage Recovery Of 5g Samples With Cap High Speed

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5g Samples With PVC

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10g Samples With PVC

S.noSolder recovery (%) Low speed



1 92.6307147 94.74527464 103.5756547

2 95.19278868 93.2706595 105.6023362

3 95.19521404 94.63244383 103.8294695

4 94.41624862 92.17918276 104.5960853

5 93.22480131 93.17244604 104.4316428

S.noSolder recovery (%) HIGH speed



1 96.8423219 94.44365029 103.0089546

2 92.3142846 94.12613445 105.5944654

3 95.8230883 95.8591443 101.6632694

4 94.1187557 92.68395708 102.6535641

5 94.0960554 94.02725386 103.7070149

Percentage Recovery of 10g Samples With Cap High Speed


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10g samples with PVC

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15g Samples with PVC




1 91.62945311 88.24994046 103.5756547

2 89.19002741 89.69882272 105.6023362

3 92.05756539 91.72398749 103.8294695

4 88.54890916 91.47039019 104.5960853

5 88.19590983 88.92116712 104.4316428




1 92.750475 93.174818 110.027927

2 90.593454 93.90464 110.1983181

3 92.286784 92.114485 109.3294309

4 93.920315 94.556955 105.7078773

5 92.088539 95.501658 105.0190731

Percentage Recovery Of 15g Samples With Cap High Speed


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15g Samples with PVC

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Effect of Speed

• All the experiments are attempted at high and low speeds and the variations are clearly drawn and almost all the samples with the high speed are resulted in greater metal recovery rates when compared with the low speed samples. So speed of the spin has greater effects on the metal recovery rates.

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Effect of Time

• Heating of the workpiece beyond the melting point of the metal results in mixture of the metals i.e. if a solder is heated beyond its melting point and if the temperature reaches the melting point of the any other metal then that metals gets melted and it mixes with the already melted solder.

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Variations Due To Area of The Workpiece

• High weight samples have the low recovery rates when compared with the low weight samples. And the area of the workpiece corresponds to the recovery rates.

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Effect of PVC material on metal recovery rates

• PVC material insulated on the wires are high in weight which results in less metal recovery

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Conclusion

• Burning of metals in open environment is reduced.

• Uncontrolled heating processes are completely eliminated.

• Metal recovery rates are high compared to the other processes that are presently using.

• By smelting process that are presently in existence have given a 86% metal recovery rates, where as the current process have a recovery rates of 90%.

• All recovery techniques that are presently in existence will be able to recover one metal at a time and for the other kind of metal another technique has to applied.

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Cont.

• Even though 100% recovery is not happened, but on each and every sample the recovery rate is more than 90%, which is a clear indication of the greater recovery rates.

• Metal recovery depends on various factors like RPM, weight of the sample, uniform heating, and time rate.

• A new design is created for the recovery process and the design has reflected in great recovery rates.

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• Easily available wire metals are chosen for the experimentation.

• Induction furnace that was used is a 15kw induction heater furnace, more kW machine would give greater results and metals with high melting points can also be recovered easily.

• Insulated material (PVC) extraction involves complex steps to recover yet not an impossible process, so the possibilities of PVC before extracting the metals has to studied.

Future Work

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