International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
Recovery of Gold, Silver, Palladium, and
Copper from Waste Printed Circuit Boards
Youssef. Chehade, Ameer. Siddique, Hisham. Alayan, Naveena. Sadasivam, Saeed. Nusri, and Taleb. Ibrahim

like the Waste Electrical and Electronic Equipment (WEEE)
Directive in Europe and the EPA in the US, is not present
locally. Table I shows some global statistics for e-waste. As an
extrapolation, it is reliable to compare electronic waste
amounts in the UAE to those of developed countries such as
Europe or the US since UAE is known to have a big share of
global electronic sales. Even by conservative estimates of
Dubai Municipality, about 10,000 personal computers (PCs)
were expected to be dumped by the end of 2007.
Abstract—Printed circuit boards (PCBs) are currently being
dumped in landfills or incinerated which is causing a serious
environmental harm in the form of toxic gases or leached hazardous
compounds. PCBs contain high amounts of precious metals; about 20
wt% copper, 0.04 wt% gold, 0.15 wt% silver, and 0.01 wt%
palladium. The extraction of these metals from PCBs is both
profitable and environmentally worthwhile. Hence, this study aims to
design a commercial process to extract these four metals from PCBs
of computers and mobile phones. This paper discusses the relevant
market analysis and research that led to the selection of these metals
and PCB sources. Furthermore, the proposed extraction process has
been sub-divided into three stages: (1) Physical separation, (2) metal
recovery, and (3) waste treatment. Stage 1 involves size reduction to
~1 mm diameter, followed by the corona electrostatic separator and
the hydro-cyclone which separate metals from nonmetals. Stage 2
separates individual target metals from each other by
hydrometallurgical processing. This stage involves the dissolution of
metals in sulphuric acid and aqua regia, followed by the application
of EMEW electrowinning technology which results in metal purities
of up to 99.99%. Stage 3 includes the treatment of byproducts
according to environmental, health, and safety standards.
TABLE I
E-WASTE STATISTICS
Place
Globally
USA
Europe
Amount of waste
in million tons (type)
20-50 (e-waste)
2.37 (electronic)
8.3-9.1 (e-waste)
Year of
Survey
2006
2009
2005
Surveying
Organization
UN [3]
EPA [4]
WEEE [5]
Recycling efforts in the UAE for e-waste are still in their
infancy [1]. Although several companies have started
campaigns to collect e-waste, initiatives have not been taken
for recycling it locally.
For instance, Etisalat held
EnviroFone, a mobile phone and e-waste collection campaign,
which collected 40,000 mobile phones and 23 tons of other
electronic wastes in the UAE in the beginning of 2009. These
numbers are a very small fraction of the potentially available
e-waste in the UAE. However, information could not be found
to indicate recycling within the UAE which might be the
reason of disinterest in collecting e-waste on a larger scale. It
was found that most of the collected e waste either end up in
landfills or are shipped off to third world countries like India
and China for inappropriate disposal [2]. However, with
increasing awareness, industrial development has become
intertwined with waste management practices. In November
2011, Bee’ah launched an e-waste pre-sorting and dismantling
facility at Al Saja'a, Sharjah [3]. However, the facility does not
process any of these dismantled parts for recovering the
materials, but it is a promising step towards proper e-waste
management in UAE.
Keywords—Electronic waste management, precious metals
printed circuit board (PCB), recovery
I. INTRODUCTION
E
LECTRONIC waste (e-waste) is a growing concern
globally as well as in the UAE. The UAE is known to
have one of the lowest life-expectancies of consumer
electronics which is around two years of use [1]. As a result,
electronic wastes are piling up in landfills which pose
potential environmental and health threats. The situation has
been deteriorating due to increasing industrial production
which has been culminating from a high consumer demand for
the newest and most powerful gadgets.
It is difficult to find reliable statistics about amounts of
electronic waste in the UAE because clear strategic surveying,
Youssef. Chehade is with the American University of Sharjah, Sharjah,
UAE (corresponding author to provide phone: +971503873785; e-mail:
[email protected]).
Ameer. Siddique is with the American University of Sharjah, Sharjah,
UAE (e-mail: [email protected]).
Hisham. Alayan is with the American University of Sharjah, Sharjah, UAE
(e-mail: [email protected]).
Saeed. Nusri is with the American University of Sharjah, Sharjah, UAE (email: [email protected]).
Naveena. Sadasivam is with the American University of Sharjah, Sharjah,
UAE (e-mail: [email protected]).
Taleb. Ibrahim is with the American University of Sharjah, Sharjah, UAE
(e-mail: [email protected]).
A. Scope of Study
This paper discusses the recovery of gold, silver, palladium,
and copper from end-of-life printed circuit boards of
computers and mobile phones. The objective is to merge two
aspects of a successful project; sustainability in terms of
environment, resource and health protection, in addition to
profitability in terms of importance of recovered products.
226
International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
particle size distribution. Since PCBs have various
compositions, the average weight compositions obtained in
Table II will be assumed constant for the feed streams.
3. This study will focus on the recovery of the selected
valuable metals which are gold, silver, palladium, and copper.
Other metals present have been grouped together and labeled
as non target metals.
B. PCB Source Selection
Among all electronic components, PCBs contain relatively
high amounts of precious metals compared to the other
components. PCBs of computers and mobile phones are rich
in precious metal content and are the most abundant since they
are the backbone of most electronics [1], [4]. The values of
metal compositions of PCBs from different sources like
televisions, personal computers, DVD players, calculators and
others were obtained and analyzed to conclude that PCBs from
personal computers and mobile phones contain the highest
amounts of valuable metals [5].
B. Stage 1: Separation of Metals from Nonmetals
The separation of metals from nonmetals will provide
appropriate conditions for further processing which involve
the use of chemical reagents and solvents. There are different
possible approaches to separate metals from nonmetals in
PCBs which mainly involve incineration, acid washing or
physical separation. Incineration can be used to burn off the
nonmetallic parts of PCB and retain the metals from the ashes.
However, incineration causes release of hazardous gases such
as dioxins and furans which can cause severe harm the
environment [13]. Acid washing/bathing can be also used to
react with the nonmetallic parts of PCB and recover the metals
either from the rich solvent or as precipitates. However, the
process of acid washing is very difficult to control especially
when including the nonmetallic parts of PCBs as it causes
release of hazardous vapors and fumes. Physical separation
techniques can also be used to separate the metals and
nonmetals from PCBs. Such techniques are known to have
safe and eco-friendly operation. Although they are energy
intensive, physical separation technologies are able to produce
separate streams of metals and nonmetals. Such separation
paves the way either for more profit from sales of waste
plastics and ceramic, or for more future development in the
area of recycling of plastics.
C. Target Metals Selection
Printed circuit boards in computers and mobile phones
consist of epoxy resins, plastics, and glass, along with over
fifteen metals [5]. Composition values of these metals in the
literature varied due to differences in the sources from which
the PCBs were obtained. To minimize error, five different
sources were selected and their average composition was used
and is shown in Table II [6]-[10]. The average compositions of
the metals were multiplied with the average price of the metal
per kilogram. The prices were obtained from metalprices.com
by taking an average estimate over a 2-year period (20102011).
TABLE II
PCB FEED COMPOSITIONS
PCB Feed Compositions
Gold
Silver
Palladium
Copper
Other metals
Non-metals
(wt %)
0.039
0.156
0.009
18.448
9.35
72
Gold, silver, copper, and palladium contributed to more
than 91% of the total worth of metals found in PCBs, and thus
these four metals were selected for further study. The total
value of these metals added up to $24.3 per kg of PCB.
II. METAL RECOVERY PROCESS
The proposed approach for the recovery of valuable
metalsfromPCBsisdividedintothreegeneralstages.The
first stage involves the separation of metals from
nonmetals, the second stage is to separate the target
metals from other metals and the final stage is waste
treatment.
A. Assumptions
1. PCBs might contain hazardous materials in electronic
components such as relays, switches, capacitors, or batteries.
Such materials include lead, mercury, and arsenic which are
very dangerous to handle. Magnetic materials can also be
found in such components which could cause harm to
physical separation equipment. Such components should be
manually dismantled by vendors and removed from the PCBs
before any processing [11], [12].
2. For the ability to process solid streams as described
before, the streams should be of uniform concentrations and
227
B.1. Comminution
The particle size of the crushed PCB has significant effects
not only on the efficiency of the physical separation
equipment, but also on the effectiveness of further treatments
involving chemical processes. According to Oliveira et al,
shredding of PCBs is a fundamental process which liberates
particles from different materials in order to allow further
processing by other physical and chemical technologies [12].
The PCB feed which consisted of discarded motherboards
from personal computers were shredded into 5x5cm plates,
and then grinded to an average diameter of 1.2 mm and
characteristic diameters d10=0.48 mm and d90=2.1 mm [14].
About 80-90% of the principal metals were recovered in that
size range [14]. The concentrations of metal content in grinded
PCBs vary with different particle sizes of the grinded output.
Higher concentrations occur in intermediate fractions in
particle size range of 0.4-1.7 mm [14]. This result has been
also supported by another study of PCBs stating that the fine
fractions were rich in plastic materials while the metals were
fundamentally present in the intermediate fractions with
particle size range of 0.3-1.5 mm [12].
International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
B.2. Physical Separation
Chemical behaviors of metals and nonmetals are
extensively different when using chemical reagents or
extraction solvents. For this purpose, the separation of metallic
materials from other plastics and ceramics that are found in
PCBs is sought prior to any further processing stages through
physical means.
C.2. Reduction
The process of reduction should be selective, controllable,
and have low energy consumption. Electro-refining would be
the most suitable for its high selectivity and controllability,
especially with the advancement of EMEW technology. Since
gold, silver, and palladium are available in low amounts,
electrolysis is to be used for metal recovery due to its
selectivity and ease of control. Electrowinning can eliminate
the need of filtration or recovery of metals from salts, as the
EMEW technology results in metals of high purity that can be
collected easily as powder or plates [15].The new aspect of the
EMEW technology is the setup that makes it continuous,
increasing the efficiency of electrolysis. The setup of the
EMEW cell is composed of a tube that usually acts as the
cathode where deposition of the metal occurs and a rod that
runs along the center of the tube and acts as the anode. The
electrolytic solution then continuously moves in the tube
rather than staying static such as in a lab-scale electrolytic cell.
This technology was first introduced in Brisbane, Australia, in
1995, and has been tested, verified and implemented in
industry especially for copper recovery [16]. EMEW
technology can provide continuous operation, ease of
harvesting deposited metals, controlled safe and eco-friendly
operation, selective electrowinning of metals, and has
effective ability to tolerate contaminants [15], [17]. EMEW
might require a large capital investment and a need of special
materials to handle highly corrosive agents such as aqua regia.
However, the outcome of recovery can compensate its capital
cost.
B.3. Proposed Process for Stage 1
For the process of comminution, the proposed design will
involve shredding of the PCBs into 5x5 cm plates following
by crushing into an average diameter of 1.5 mm. After that,
for physical separation of metals from nonmetals, electrostatic
separation using the corona separator will separate metals
from nonmetals. This method is highly recommended in PCB
recycling because of significant differences in conductivity
and electrostatic properties of the different components in
PCB. Corona electrostatic separation process is known to have
an eco-friendly operation and low energy cost. The corona
separator will produce a middlings product which can be
further crushed into an average particle diameter of less than
0.07 mm and sent to a Falcon concentrator for further
separation of metals from nonmetals. Magnetic separation can
be further used to separate ferromagnetic from nonferromagnetic metals. The target streams of Stage 1, which
would contain gold, silver, palladium, copper, zinc, tin, and
other nonferrous metals will be further processed in Stage 2
for recovery of valuable metals.
C. Stage 2: Separation of the Individual Valuable Metals
The feed to Stage 2 consist of a mixture of different metal
and this stage is where all the metals of interest will be
separated from the mixture and extracted as pure metals which
can be sold. The metals selected for recovery in this study are
gold, silver, palladium and copper. Therefore, a process is
needed which can selectively and quantitatively separate each
of these metals from the mixture, taking into consideration all
other possibly present metals. Pyrometallurgical processes are
not selective, require major amounts of energy and can form
uncontrolled harmful products. Physical processes do not
satisfy the needs for Stage 2 of obtaining high purity metals as
output and hence cannot be used. Hydrometallurgical
processes can provide high selectivity, high purity output,
controlled environment, and good recovery. Stage 2 acts as
integral part in the recovery process as it involves separation
and extraction of metals from the solid metal effluent mixture
from Stage 1. Hydrometallurgical processes have been
proposed as the most beneficial process for this stage.
C.3. Proposed Process for Stage 2
The non-ferromagnetic metallic streams from Stage 1 are to
undergo dissolution in sulfuric acid to dissolve the non-target
metals. This effluent is to be separated from the remaining
target metals (Au, Ag, Pd, and Cu) and is to be considered as a
byproduct liquid stream. The target metals are to be further
dissolved using aqua regia. After complete dissolution, the
stream of aqua regia which contains the dissolved target
metals enters a series of four EMEW electrowinning
operations, each for the reduction of a specific target metal
(Au, Ag, Pd, and Cu). According to the applied potential and
the setup of the EMEW, copper is to be deposited in the first
EMEW cell because of the lowest required applied potential
and the highest amount, followed by gold, then palladium, and
silver finally. The spent aqua regia is then either recycled for
reuse or is to be treated as a byproduct.
The products of Stage 2 are the separated individual metals
in solid form, as well as liquid byproduct streams. Endproducts of stage 2 are as follows:
 Byproduct liquid stream which contains the non-target
non-ferromagnetic metals dissolved in sulfuric acid.
 Nonmetallic residue stream resulting after dissolution.
 Byproduct liquid stream of spent aqua regia.
 Separated individual target solid metals (gold, silver,
palladium, and copper) of high purity.
C.1. Dissolution
Dissolution of the metallic mixture is crucial because the
subsequent processing steps are largely dependent on the
reagents or methods that will be implemented for dissolution.
In this study, the non-ferromagnetic metallic streams are to be
dissolved and separated from the non-target metals using
sulfuric acid. Then copper, palladium, silver, and gold are to
be dissolved all together from the non-ferromagnetic metallic
mixture using aqua regia.
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International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
Fig. 1 Proposed proccess for recovery
y of target metalls
229
International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
III. MATERIAL BALANCE
The streams of concern that contain the metallic bulk in
Stage 1 are streams 10 and 16 which are combined together to
form Stream 18 which is to be dissolved in sulfuric acid. Since
the amount of sulfuric acid needed to dissolve the non-target
metals was not found in literature, it was assumed to be
equivalent to the ratio of aqua regia to metals which was found
to be about 20 ml of acid for every gram of metal dissolved
[6]. Hence the amount of sulfuric acid that is required in
Stream 19 is given by (6).
The material balance is shown in Tables V and VI. The
description of the material balance is based on the proposed
metal recovery process illustrated in Fig. 1.
A. Stage 1 Material Balance
For Stage 1, the PCB feed was assumed to have uniform
composition. The feed basis was selected as 1000 kg per day.
In order to follow the metal compositions after the corona
electrostatic separator, the average weight percent of the
metals in the outlet was calculated. The distribution of the
different components in the PCB is as follows: 6% metals,
72% non-metals, 6% ferromagnetic metals and 22% nonferromagnetic metals. The assumptions that were made about
the efficiency and dust formation in the equipment are:
 Dust Formation: The shredder and crusher 1 were
assumed to produce 0.1% dust
 Efficiency: The two magnetic separators were assumed to
work at an efficiency of 98%
In order to operate the Falcon concentrator, the necessary
water supply was calculated using (1):
∗
∗
∗ 1
80%
(2)
B.3. Electrolysis Reduction
Stream 24, which contains the metals of interest, then goes
through the electrolysis reduction stage. Since the metals of
interest are gold, silver palladium and copper, four different
electrolytic cells are needed to carry out cathodic reduction for
each of these metals. Since copper has the highest flow rate, it
will be removed first. Following this, the sequence was
decided based on ease of separation depending on the
principle of reactivity where gold is the least reactive and will
therefore be the easiest to deposit, followed by palladium, and
then silver. Stream 24 passes through the first cell, which has
been designed to extract the copper, and most of copper is
removed into Stream 25.
The remaining solution (Stream 26) is then sent to the next
cell which has been designed to reduce gold. Gold is deposited
on the electrodes, is removed as Stream 27. Similar processes
would be followed for palladium and silver as shown in Fig. 1.
Finally, streams 25, 27, 29 and 31 are the streams of the target
metal which have been recovered. The final resulting liquid
byproduct (Stream 32) will consist mainly of the unreacted
excess acid and small amounts of unreacted metals.
Regeneration and recycling possibility of this stream needs to
be investigated. It is important to note that steams 25, 27, 29
and 31 are cathodic depositions of the respective metals and
are to be removed in batches.
(3)
Furthermore, the corona electrostatic separator will split the
streams into metals, nonmetals, and middlings. The efficiency
of this separation was taken as 90%. Since a minor percentage
of the metal stream will be present in the nonmetal stream, this
was taken as 5%. The same can be said for nonmetals in the
metal stream. For Stream 7, which predominantly consists of
nonmetals, (4) and (5) were used to determine the metal flow
rate.
∗
(4)
Where xmn is the percentage of metals in the nonmetal stream.
Similarly, for Stream 8, the metal flow rate is based on the
separation efficiency:
∗
(6)
B.2. Dissolution of Target Metals
The outlet stream from the reactor that dissolved the nondesired metals (Stream 21) contains all the metals of interest
and is then sent to treat with the second reagent which is aqua
regia. In this reactor, 97%, 98%, 93% and 100% of gold,
silver, palladium and copper respectively were found to
dissolve with the ratio of 20 ml of acid for every gram of
metal [6].
The residue from this reactor (Stream 23) would contain
slurry of non-metals which have been left over from Stage 1
and also insoluble salts which were assumed to be zero.
Where cfs is the mass concentration of the solids required in
the Falcon concentrator feed and ρw is the density of water.
Assuming streams 16 and 17 are totally dried, the mass flow
rates of metals and non-metals are calculated using (2) and (3).
∗ 85%
Where
is the amount of acid volume needed to dissolve
1kg of non-target metals.
Also, to reduce the margin of error, 1% copper has been
assumed to dissolve in sulfuric acid due to the presence of
oxygen [18]. Moreover, PCBs contain highly non-reactive
metals other than the metals of interest, such as platinum,
which will not dissolve in sulfuric acid. These metals form
approximately 2% of the undesired metallic bulk.
(1)
∗
(5)
Where ηs is the separation efficiency of corona electrostatic
separator.
B. Stage 2 Material Balance
B.1. Dissolution of the Non-Target Metals
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International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
IV. ENERGY BALANCE
Where:
A: atomic mass of the species
3600: conversion factor between hours and seconds
CE: current efficiency, the ratio of actual extent of reaction
to the theoretical one
A. Stage 1 Energy Balance
The description of equipment in Stage 1 and their
corresponding energy consumption are listed in Table III. The
data has been obtained from vendors and literature.
Estimates were made in using (7), (8), and (9), which are:
1. VI = E (standard potential).
2. Assume activities equal to concentration in mol/L.
3. As a safety factor for a conservative estimate, take a
low CE=0.1 (10% current efficiency) to account for the
previous estimates.
TABLE III
POWER CONSUMPTION/UTILITY COSTS IN STAGE 1
Description
Power
Cost
Equipment
(KWh)
(AED/hr)
SHREDTECH ST-75E
2-Shaft Shredder
100
43
Crusher 1
Crusher 2
Corona
Electrostatic
Separator [13]
EUROPEAN
HAMMER MILL
EHM4008-75 (KEFID)
TRAPEZIUM MILL
TGM100 (KEFID)
Single Roll Type
Magnetic
Separator [19]
-
Falcon SB40
Concentrator
Model L40
TOTAL
65
27.95
100
43
0.2
0.086
0.02
0.0086
0.4
0.172
265.6
114.2
For each cell, only the concentration of the metal which it is
designed to extract was calculated. Mass of the metal and
solution was taken from the mass balance and the density was
assumed to be the density of the acid solvent because it makes
up the major part of the solution (>97 wt%). Table IV shows
the energy requirement of electrolysis.
TABLE IV
ELECTROLYSIS DATA
EC 1
EC2
(Cu)
(Au)
A
(ion activity)
z
(ionization state)
B. Stage 2 Energy Balance
Equations (9), (10) and (11) govern the electrowinning of
metals and are used to obtain energy requirements for the
deposition of certain amounts of the metal [20].
∗
∗
Nernst
Equation
(7)
∗ ln
Where:
E: half-cell potential of the reaction in Volts
E0: standard half-cell potential at STP and molarity of 1
R: universal gas constant, 8.314 J/mol-K
z: number of moles of electrons transferred in the reaction
F: Faraday’s constant, 96,485 Coulombs/mol of electrons
a: chemical activity of the species
VI = (Ea+Ec)+ηa+ηc+(IR)electrolyte+(IR)contacts
∗
∗
∗
EC 4
(Ag)
7.54E-4
5.18E-07
2.12E-07
3.82E-06
2
3
4
1
E0
0.3419
1.498
1
0.7996
E
0.2498
1.3741
0.9014
0.4793
VI
0.2498
1.3741
0.9014
0.4793
A
63.546
196.967
106.42
107.868
CE
(in fraction)
0.1
0.1
0.1
0.1
Energy (kWh/kg)
2.11
5.61
9.08
1.19
Total Energy (kWh/hr)
44.381
0.2449
0.0877
0.210
V. CONCLUSION
The recovery of precious metals can be achieved using the
proposed process, which has been divided into three main
stages. The first stage aims to achieve the maximum
separation of metals from nonmetals in order to eliminate the
bulk of nonmetals in further processing. The second stage
involves the dissolution of metals followed by selective
extraction of metals through reduction in EMEW cells. The
third stage includes treatment of the waste streams which
contain aqua regia, sulfuric acid, heavy metals and organic
slurry. With this process gold, silver, palladium and copper
with high purity can be recovered from waste PCBs that are
obtained from personal computers and mobile phones.
Calculations using the data obtained from current statistics
showed that 0.044 kg of gold, 0.18 kg of silver, 0.010 kg of
palladium and 21 kg of copper can be recovered from 125 kg
of PCBs.
Possible challenges that have been recognized include:
• Lack of reliable statistics in UAE and the region
(8)
Where:
VI: applied potential needed for electrolysis, in Volts
Ea & Ec: half cell-potentials (in reduction form) of the anodic
and cathodic reactions, obtained from Eq. 1, in Volts
ηa & ηc: over-potentials at the anode and cathode, in Volts
(IR)electrolyte & (IR)contacts: potentials required to overcome the
resistance of electrolytes in solution and the electrical
contacts of the cell
EC 3
(Pd)
(9)
231
International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
[20] S. R. Rao. (2006). Resource Recovery and Recycling from Metallurgical
Wastes. Amsterdam: Elsevier.
• Special equipments are needed for PCB processing
• Lack of proper simulation software that can handle solid
processing
• EMEW technology is still relatively new
• Material of construction of Stage 2 should handle the
highly corrosive reagents
• Evolution of hydrogen which is highly flammable
To conclude, the goal of the study is an initiation of proper
e-waste management and resource recovery in the UAE and
the region that can boost the productivity of local economy.
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for Recovering Resources and Products from Waste Printed Circuit
Boards. School of Environmental Science and Engineering. Shanghai,
China.
P. C. Oliveira, F. C. Taborda, F. Margarido and C. A. Nogueira,
“Physical and Chemical Processing of Printed Circuit Boards Waste,”
presented at the World Recycling Forum, Shanghai, China, Nov. 2009.
“EMEW Electrowinning," Kurion Technologies Limited, Northants
T. Treasure, "Commercialisation of the EMEW Cell," Electrometals
Mining Limited.
(2011) Electrometals Technologies Limited. [Online].
http://www.electrometals.com.au/how-it-works.html
H. Yang, J. Lui, and J. Yang, "Leaching copper from shredded particles
of waste printed circuit boards," Journal of Hazardous materials, vol.
187, no. 1-3, pp. 393-400, March 2011.
Parsons, D. (2006) Printed circuit board recycling in Australia. 5th
Australian Conference on Life Cycle Assessment, 22-24 November
2006, Melbourne, Australia.
232
International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
TABLE V
STAGE 1 MATERIAL BALANCE DATA SHEETS
Basis (Kg PCB/day)
1000
Feed
(wt %)
Dust Generation - Crusher 1
Corona Specifications
Falcon Concentrator Specifications
Hours per shift
8
Metals
28
Equipment
Dust
Released (wt
%)
Shifts per day
1
Non metals
72
Shredder
0.1
Nonmetals in Metal
Outlet (%)
5
Metal Grade of Product (%)
80
Working hours
8
Ferrous
10
Crusher 1
0.1
Metals in Nonmetal
Outlet (%)
5
Nonmetal Grade of Product
(%)
20
125
Non ferrous
90
Feed Density (kg/m3)
30
Density of Water (kg/m3)
1000
(Kg PCB/Working hr)
Separation Efficiency
(%)
90
Metal Recovery (%)
85
Magnetic Separator 1
Efficiency
(%)
98
Magnetic Separator 2
Efficiency
(%)
98
Stream Flow Summary Table
Water Supply (kg/hr)
203.4
Feed Compositions
In PCB feed
Gold
Property
(wt %)
0.039
Mass
Flow
Rate
Total Flow
Metal
Units
1
3
4
5
6
kg/hr
125
0.125
0.125
124.750
6.238
kg/hr
35
0.035
0.035
34.930
1.747
89.820
Silver
0.156
Palladium
0.009
Copper
18.448
Iron
5.15
Nickel
0.918
In Metal Stream
Ferromagnetic
(wt %)
21.671
Non-ferromagnetic
78.329
Total Target Metals
66.614
Target Metal
kg/hr
Gold
0.139
Other Metals
kg/hr
Silver
0.557
Palladium
0.032
Copper
65.886
Element
Mass
Flow
11
14
15
16
17
29.251
6.238
0.3858 6.1016 1.459
4.64
1.747 31.437 6.677
24.760
1.747
0.3858 1.4307 1.216
0.215
4.491
80.83
8
4.491 0.000
4.491
4.491
0 4.6709 0.243
4.428
kg/hr
90
Gold
kg/hr
0.049
4.88E-05 4.87E-05
0.049
0.002
0.002
0.044 0.001
0.043
0.002
5.0602E‐05 0.0025 0.002
0.000
Silver
kg/hr
0.195
1.95E-04 1.95E-04
0.195
0.010
0.010
0.175 0.004
0.172
0.010
0.0002 0.0099 0.008
0.001
Palladium
kg/hr
0.011
1.13E-05 1.12E-05
0.011
0.001
0.01
0.010 0.000
0.010
0.001
1.1677E‐05 0.0006 0
0
Copper
kg/hr
23.060
23.014
1.151
1.151 20.713 0.414
20.298
1.151
0.0239 1.1729 0.997
0.176
0.0131 0.0406 1.163
0.0525 0.1625 1.008
0.178
0.583
0.0030 0.0094 0.208
0.037
11.685
0.023
0.023
0.012
0.090
10
Non-metal
23.315
0.090
7
8
9
82.58
35.928 6.677
5
0.023
0.023
0.012
233
23.268
11.662
1.163
0.583
1.163 20.942 0.419
0.583 10.495 6.258
20.523
4.238
International Conference on Chemical, Civil and Environment engineering (ICCEE'2012) March 24-25, 2012 Dubai
TABLE VI
STAGE 2 MATERIAL BALANCE DATA SHEETS
Solvents
Aqua Regia
Sulfuric Acid
Density(kg/L)
1.76
1.8305
Liters added/kg of Metal dissolved
Prices/metric ton
20
20
Nitric Acid 60%
Hydrochloric Acid 36%
Exchnage Rates
Dollars to Dirhams
UK Pounds to Dirhams
3.67
5.68
Sulfuric acid 98%
Molar Flow
Rates
(tons/hr)
Price Range
$350-420
£85
Average Price(AED)/ton
$350
£125
$100-200
£55
Efficiencies
Undesired Metal Separation
Gold Dissolution
947.875
997.25
431.45
Cost of Reagents
(AED)/hr
%
98
97
Silver Dissolution
Palladium Dissolution
Copper Dissolution Aqua Regia
Copper Dissolution Sulfuric Acid
Gold Eletrolytic Reduction
98
93
100
1
100
Silver Eletrolytic Reduction
100
Nitric Acid
0.1884
178.56
Palladium Eletrolytic Reduction
100
Hydrochloric Acid
0.5651
563.58
Copper Eletrolytic Reduction
100
Sulfuric Acid
0.1628
70.22
Stream Flow Summary Table
22
23
24
753.514
4.740
774.915
0
0.006
21.312
0
0
0.089
753.514
0
753.514
0
0
0
0
4.734
0
Property
Total Flow
Precious Metal
Other Metals
Aqua Regia
Sulfuric Acid
Non-Metals
Units
kg/hr
kg/hr
kg/hr
kg/hr
kg/hr
kg/hr
18
30.711
21.531
4.446
0
0
4.734
19
162.762
0
0
0
162.762
0
20
167.332
0.213
4.357
0
162.762
0
21
26.141
21.318
0.089
0
0
4.734
Element Mass
Flow
Gold
Silver
Palladium
Copper
kg/hr
kg/hr
kg/hr
kg/hr
0.045
0.180
0.010
21.295
0
0
0
0
0
0
0
0.213
0.045
0.180
0.010
21.082
0
0
0
0
0.001
0.004
0.001
0.000
Average
Composition
of Target
Metals
Gold
Silver
Palladium
Copper
%
%
%
%
0.147
0.586
0.034
69.341
0
0
0
0
0
0
0
0.127
0.172
0.689
0.040
80.649
0
0
0
0
0.028
0.076
0.015
0.000
Mass Flow
Rate
234
25
21.082
21.082
0
0
0
0
26
753.832
0.230
0.089
753.514
0
0
27
0.044
0.044
0
0
0
28
753.789
0.186
0.089
753.514
0
0
29
0.010
0.010
0
0
0
30
753.779
0.176
0.089
753.514
0
0
31
0.176
0.176
0
0
0
32
753.603
0
0.089
753.514
0
0
0.044
0.176
0.010
21.082
0
0
0
21.082
0.044
0.176
0.010
0
0.0437
0
0
0
0
0.176
0.010
0
0
0
0.010
0
0
0.176
0.000
0
0
0.176
0
0
0
0
0
0
0.006
0.023
0.001
2.721
0
0
0
100.000
0.006
0.023
0.001
0
100
0
0
0
0
0.023
0.001
0
0
0
100
0
0
0.023
0
0
0
100
0
0
0
0
0
0