recovery of aluminum from industrial and electronic waste via melting with salt flux
DESCRIPTION
ESCUELA POLITÉCNICA NACIONAL Quito - Ecuador. Facultad de Ing . Química y Agroindustria Departamento de Metalurgia Extractiva. Recovery of aluminum from industrial and electronic waste via melting with salt flux. Ernesto de la Torre, Santiago Yépez, Alicia Guevara. - PowerPoint PPT PresentationTRANSCRIPT
RECOVERY OF ALUMINUM FROM INDUSTRIAL AND ELECTRONIC
WASTE VIA MELTING WITH SALT FLUX
Ernesto de la Torre, Santiago Yépez, Alicia Guevara
ESCUELA POLITÉCNICA NACIONALQuito - Ecuador
Facultad de Ing. Química y Agroindustria
Departamento de Metalurgia Extractiva
ALUMINUM PRODUCTION FROM BAUXITE
ALUMINUM RECYCLING
ENERGY CONSUMPTIONEnergy Consumption [kWh/ton]
Aluminum Production from Bauxite (Primary
Production) Aluminum Recycling
(Secondary Production)
17000 750
ALUMINUM RECYCLING ALLOWS TO OBTAIN A 95 % SAVE OF THE ENERGY CONSUMED IN ALUMINUM PRIMARY PRODUCTION
KCl – NaCl SYSTEM
Eutectic Point
Tem
pera
ture
[ºC
]
Concentration [mol %]
Liquid
KCl – NaCl – NaF SYSTEM
MELTING MECHANISM
ALUMINUM INDUSTRIAL AND ELECTRONIC WASTES
EXPERIMENTAL PROCEDURE
CHEMICAL CHARACTERIZATION OF ALUMINUM WASTES
Aluminum wastes
Concentration [%]
Al Mg Fe CuProfile cutting swarf 98,45 0,30 0,23 0,01Extrusion swarf 98,59 0,59 0,30 0,06Heat sinks 98,33 0,52 0,30 0,05Dross 98,13 0,97 0,30 0,05
[Pb], [Ni], [Zn], [Cr], [Mn], [Sn], [Si] = 0,01 < [Concentration] < 0,06 [%]
ALUMINUM DROSS CHARACTERIZATION
Aluminum Oxygen Magnesium
ALUMINUM DROSS Semiquantitative Analysis using
SEMElement Concentration [%]
Al 58,47O 31,24
Mg 9,34Fe 0,94
X Ray Diffraction Analysis
Mineral Formula Concentration [%]
Aluminio Al 97Hierro Fe 1Espinel Al2MgO4 1Óxido de cobre, aluminio y níquel (Cu, Ni)Al2O4 1
ALUMINUM WASTES MELTING WITHOUT SALT FLUX
ALUMINUM WASTES MELTING USING SALT FLUX
ALUMINUM WASTES MELTING USING DIFFERENT CHLORIDES
ChloridesAluminum yield [%]
Profile cutting swarf
Extrusion swarf Heat sinks Dross
KCl 79,2 89,0 91,5 54,0NaCl 74,4 86,0 87,3 51,2MgCl2 9,2 9,5 69,8 39,2
CaCl2, MnCl2, BaCl2, NH4Cl 0 - 5 0 - 5 0 - 50 0 - 40
ALUMINUM SWARF MELTING APPLYING AGITATION
Agitation applyed using a wooden rod
Agitation applyed using a stainless steel
rod
Rod used to apply agitation
Concentration [%]
Al O C
Wooden rod 79,79 5,02 15,19Stainless steel rod 95,85 4,15 Not detected
ALUMINUM SWARF MELTING PROCESS
Aluminum wastes
Temperature [ºC]
Composition [mol %]
Amount of salts[wt %]
Time [hr]
Aluminum yield [%]
Profile cutting swarf 850 KCl = 100
NaCl = 0 100 0,50 93,6
Extrusion swarf 850 KCl = 70
NaCl = 30 50 0,33 98,5
Extrusion swarfProfile cutting swarf
HEAT SINKS MELTING PROCESS
Aluminum wastes
Temperature [ºC]
Composition [mol %]
Amount of salts[wt %]
Time [hr]
Aluminum yield [%]
Heat sinks 850 KCl = 90NaCl = 10 100 1 97,6
ALUMINUM DROSS MELTING PROCESS
Aluminum wastes
Temperature [ºC]
Composition [mol %]
Amount of salts[wt %]
Time [hr]
Aluminum yield [%]
Dross 750 KCl = 50NaCl = 50 30 2 71,6
INFLUENCE OF FLUORIDES ADDITION TO THE SALT FLUX
0 2 4 6 8 100
20
40
60
80
100Sodium fluoride (NaF)
Heat sinks Profiles cutting swarf Extrusion swarf Aluminum drossNaF Concentration [mol %]
Alu
min
um y
ield
[wt %
]
ALUMINUM QUALITY ANALYSIS
Aluminum wastes Concentration [%]Al Mg Fe Si
Profile cutting swarf 99,20 0,01 0,20 0,44Extrusion swarf 99,10 0,04 0,22 0,41Heat sinks 99,10 0,17 0,13 0,46Dross 99,20 0,01 0,20 0,41
[Cu], [Ni], [Zn], [Mn], [Cr], [Ti], [Pb], [Li], [Ga], [V], [Ag]0,0001 [%] < [Concentration] < 0,02 [%]
CONCLUSIONS
Aluminum wastes, (electronic and industrial)
Melting process allows to obtain a product with a concentration of Al > 99 %.
This product meets market requirements.
CONCLUSIONSUsing salt flux that contains mixtures of KCl and NaCl during the melting process, prevents the oxidation of the material and, in the case of the dross, the salt flux allows to remove the spinel layer.
Aluminum wastes
Temperature [ºC]
Composition [mol %]
Amount of salts[wt %]
Time [hr]
Aluminum yield [%]
Profile cutting swarf 850 KCl = 100
NaCl = 0 100 0,50 93,6
Extrusion swarf 850 KCl = 70
NaCl = 30 50 0,33 98,5
Heat sinks 850 KCl = 90NaCl = 10 100 1 97,6
Dross 750 KCl = 50NaCl = 50 30 2 71,6
Fluorides addition causes that the aluminum yield decreases.
Due to an increase in the melting temperature of the salt mixture.
CONCLUSIONS
Ernesto de la Torre , Santiago Yépez, Alicia Guevara
ESCUELA POLITÉCNICA NACIONALQuito - Ecuador
Facultad de Ing. Química y Agroindustria
Departamento de Metalurgia Extractiva
RECOVERY OF ALUMINUM FROM INDUSTRIAL AND ELECTRONIC
WASTE VIA MELTING WITH SALT FLUX