Full Recovery End Life Photovoltaic

Technical progress – October 2014

FRELP: progress in October 2014

The four steps of the plan of development, the situation is as follows:


In September it was tested in continuous the prototype for detachment, trying to optimize performance.

There are some problems in the gluing system of the panels head to head because, in transit in the high temperature area, before the detachment of the glass from the sandwich, we had some problem of loosening of the joint due to the fact that the adhesive is very sensitive to temperature changes, and therefore, when the temperature rises beyond a certain limit, the disconnect occurs.

Let adhesives that are resistant to conditions of temperature higher than the operating temperature in order to have a certain margin of safety and to avoid problems in the continuity of the process of detachment.


Have been performed various tests on pyrolysis on centimeter portions of sandwiches to mediate the quantitative results of residual ashes on which we made of the chemical analyzes.

Have been analyzed different types of ashes of pyrolysis and the results of the chemical analyzes are quite variable, in particular depending on the presence of silver that is present in an amount ranging from 0,05% to 0,15% with respect to the total weight of entire panel.

Even the other metal components have a high variability according to the type of the panel and, for the same panel, depending on the portions of the wafer.

We have finalized the study of the ashes and in particular to the recovery of silver and copper, which are the elements to be recovered by electrolysis after dissolving in acid leaching through.

For aluminum, it is seen that, by milling and subsequent sieving thrust of the ash, it is possible to recover most of the aluminum as a residual overscreen.


In September it was also tested the process of acid leaching with different acids and mixtures of acids.

After numerous tests based on sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid and various mixtures of the same, considering the environmental problems relating to different dangerousness of the same, it was decided, also in function of the encouraging early results, to focus primarily on leaching with hot nitric acid.

Therefore we will proceed in this direction also in function of the subsequent stage of electrolysis, which will be object of study in the month of November and December when we have established the most suitable dilution ratios of the acid solution to be used for the selective electrolysis at different potentials.


September 23 took place simultaneously two conventions to which Sasil and SSV participated by presenting the project FRELP:

• 29th Conference on Solar Energy and Photovoltaic (EU PVSEC 2014) in Amsterdam in the “PV life cycle management & recycling”;

• 12th ESG (European Society of Glass) Conference, in Parma.

Both have attracted much interest because, in the recovery of the panels with silicon technology, there are currently no active treatment processes at industrial level; also at the level of research is still in the recovery phase little selective for the enhancement of the individual components.



Sasil S.p.A., Stazione Sperimentale del Vetro and PV Cycle are working on a 4 years project to test and demonstrate the application of innovative technologies for 100 % recycling of end-of-life PV  panels, mono and poly-crystalline in an economically and viable way. Two key environmental solutions are thereto proposed:

  • Recovery of high quality extra clear glass, to be employed in hollow and flat glass industry, implying very significant energy and CO2 emission saving in the glass melting process.
  • Recovery of (metallic) silicon, to be employed as ferrosilicon in iron silicon alloys or, if enough purity is obtained, transformed in amorphous silicon to be employed in the production of thin films, thus saving important energy cost and CO2 emission  for the production of primary silicon

On the 23rd of September, an overview of the project and its results obtained so far will be offered in two simultaneous events in the worlds of glass and photovoltaic:

Tuesday, September 23, 2014 the FRELP project featured in two simultaneous events in the world of glass and photovoltaics.

Tuesday, September 23, 2014 the FRELP project featured in two simultaneous events in the world of glass and photovoltaics.

presentazione sasil x pv_cycle - roma 28-02-2013 - italiano Here you can download the pdf of the presentation.


presentazione sasil x pv_cycle - roma 28-02-2013 - italiano Here you can download the pdf of the presentation.


Technical progress – June 2014

June 2014

FRELP: progress in June 2014

The four steps of the plan of development, the situation is as follows:

1st step Detachment of aluminum profiles and connector (ACTION B3)

This action has been fully resolved at the design level with the help of a robotics company that has already provided to the study of the components and has already budgeted also a possible industrialization of the process.

We have already contacted the other two manufacturers to have some alternative offers before to start comparative assessments and then proceed with the order.

The dimensioning of the system was made on the basis of the dismantling of about 45 panels/hour, corresponding to a weight of 1000 kg/hour, and such as to allow a power supply to the next step on the basis of a feed rate of about 2 cm/second.

2nd step Detachment of glass by sandwich (ACTION B3)

This action, which was the crux of the whole project, is now settled in brilliantly through the creation of a pre-prototype capable of handling a range of panels equal to 25% of that provided in the pilot plant.

After a month of testing, changes, implementations, technological innovations, practice tests, has now reached a level of reliability that allows us to confirm that the correct choice of the pre-prototype design object.

In June, it was also proven automation, which still needs fine-tuning, especially in relation to the variability of the panels to be treated, because, for the moment, we are limited to three types of the 18 considered by SSV phase characterization.

In any case we will also dedicate the month of July to complete the tests on all types available in order to evaluate each type of variable to which you may suffer.

In summary, the technology used is based on three innovations:

1 – Heating differentiated on the two sides of the sandwich (glass side and side wafer) with three different heating devices which ensure a delta of 20-30 degrees in temperature between the glass side and the side of the wafer. This delta is essential to ensure a perfect separation of the glass from the surface of EVA in contact with the glass itself.

2 – Mechanical Detachment of the glass by means of a pulsating knife, leveled at a fixed distance from the intrados side of the glass, result of an experiment on the field, which has allowed to minimize the effort of dragging of the panel and to maintain a perfect alignment of the detachment line with tolerances on the order of 0,1 mm. Both the oscillation that the amplitude of the pulsating movement are adjustable in an automatic way, depending on the characteristics of the panel.

3 – Complete automation of the progress of the panel as a function of 5 parameters:

  • frequency of the pulsations of the knife;
  • temperature in the transport section;
  • temperature in the cutting section;
  • thickness of the glass;
  • typology of the backsheet.

Based on a few hours of steady state operation it can be said that the specific total energy used throughout the separation phase is well below the 100 kWh/t, provided as an objective in the presentation of the project.

In July, we will test the prototype also the gluing device in continuous of the panels to be treated, in order to evaluate also any problems due to the discontinuity in the longitudinal phase of contact with the pulsating knife.

3rd step Pyrolysis (ACTION B4)

There have been several tests of pyrolysis, for now in ambient not inertized with nitrogen to problems of delay in delivery of the equipment.

This, however, has served to complement the quantitative and qualitative data on the size of the silicon wafer, and this has already allowed you to change almost on a final mass flow.

It was also verified the ease of extracting, by simple sieving, after the pyrolysis, the strings of aluminum, inside of the ashes of pyrolysis, maintain dimensions significantly larger than the rest of the ashes.

The B3 action on the pyrolysis, whose term was scheduled to end in June 2014, will be completed by September, 2014, due to the delay in the receipt of laboratory equipment and the delay in obtaining the silicon wafer recovered through the operation of the pre-prototype.

4th step Leaching, Nanofiltration, Pyrolysis (ACTION B5)

The leaching has been studied only in the context of the possible reactive in particular on the need to send anything but the silicon in solution, and not to affect the nano silver particles which should be removed for nanofiltration before or after electrolysis. The type of electrolysis will be chosen based on the results of the nanofiltration.

These experiments will be the subject of thorough investigations and laboratory tests in the coming months. The action B5 will be completed by September 2014.


The project, passed the hurdle of detachment of the glass from sandwich, proceeds according to the programs, with a delay of three months on the actions B4 and B5.

Currently there aren’t obstacles in the way of good continuation.

Technical progress – May 2014

May 2014

FRELP: progress in May 2014

Methodology of detachment EVA GLASS

During the month of May has solved the most important problem related to the detachment of the glass of the photovoltaic panel from the “sandwich” EVA + silicon.

As anticipated in April, through the prototype developed by Sasil, several options have been tested, both from the point of view of the heat treatment, which, under the appearance of the actual posting.

At the end is a good result was achieved with the use of three systems of preliminary heating and two technical solutions for the phase of final separation of the glass.

The purpose of separating the pure glass was obtained with the use of total energy less than 100 kWh/t.


You will need to optimize the system by the end of June 2014 in order to collect all the data for the final design of the pilot plant will be sized as expected for a flow rate of 1 t/h, and processed for whole panels 1 meter long.

For now the prototype is able to work on strips of panel of 250 mm and have already been obtained significant samples of glass and of “sandwich”. The glass has already been further purified with a separator with excellent optical results.


The “sandwich” destined to pyrolysis has been chopped into small pieces of centimetric size and tested in pyrolysis at the laboratory Sasil, with the current equipment, which, however, proved to be not entirely suitable.

We decided to purchase new laboratory equipment for testing of pyrolysis, suitable to process the “sandwich” in nitrogen atmosphere and with appropriate measuring instruments to control the outflows.

In any case, by preliminary tests were obtained significant information on the procedures pyrolysis suitable in this particular type of pyrolysis expected in discontinuous and in space inertized with nitrogen.


Were made attemps to solubilize the ashes of pyrolysis but due to lack of adequate standard elements to be searched, we postponed further such tests, when we have the appropriate standard.

Technical progress – April 2014

April 2014

FRELP: progress at the end of APRIL 2014

In particular, we dealt with thoroughly investigate the following systems:

a- heating different test with infrared of panel EVA + GLASS;

b- EVA detachment from the glass after heat treatment;

c- separation optical glass polluted by contact seals in the glass / aluminum;

d- recognition of the composition of the backsheet as a function of pyrolysis behavior;

e- mode-gripping of the panels with suckers;

f- mode cutting of aluminum profiles;

g- mode breakout of aluminum profiles once cut corners.


Below we describe briefly how it’s operated:

a1- were tested three types of infrared, shortwave, medium, long. The solution will be the combination of these three sources of infrared as each has characteristics that are functional to the four important parameters for the preliminary heat treatment of the EVA detachment from the glass:

– Rapid heating;

– Heating differentiation between EVA and glass;

– Maintaining the temperature at the time of posting;

– Speed ​​of temperature regulation.

It is expected to complete the test of detachment within the month of June.


b1-Preliminary tests of detachment with four technologies:

– Detachment with fixed knife;

– Detachment with high-pressure water;

– Detachment at high pressure air;

– Separation tape with water-cooled.


c1- Optical separation of the glass recovered from the edges and polluted by rubber (gasket).

Tested the optical separation on the particle size of 5 mm.

Evidence of screening and crushing of the glass.


d1- It was identified with a tool pointing to distance for the recognition of the plastic as in the pyrolysis step is necessary to separate any plastics containing chlorine type pvc.


e1- Were tested different ways of taking on the “backsheet” in order to maneuver the panel according to the following phases of tearing of aluminum profiles and the connector. There are no particular problems.


f1- They tested two techniques:

– Cutting with a circular saw;

– Cutting with abrasive disc.

The best results for now are with circular saw, but it is expected to structure the system so you can make the interchangeable cutting devices, in order to adapt to any changes in the composition of the outer profiles of the panels.


g1- Were performed positively evidence of tearing of the outer profiles of aluminum, after the preliminary cutting of the edges, so as to have separated the four profiles, two short sides and two long sides.


Almost all systems have now been defined and partially made ​​of pre-reduced scale prototypes that have allowed to test the solutions provided.

The technology that has not yet been completely defined is that of point “b” as within the month of May will be ready for the pre-prototype that will test the two technologies, compressed air and high pressure water, including we will choose the most suitable practical application in the prototype.

The prototypes that have to perform CDEFG-phases have been identified, designed and evaluated.

The prototypes that need to perform the steps ab are in pre-prototype to be tested by the end of May and approved by the end of June.

The main difficulties, as expected, related to the phase b, but the preliminary results indicate that we have the solution handy.

SASIL presents the FRELP project at the International Conference on the recovery of photovoltaic panels

SASIL presents the FRELP project at the International Conference on the recovery of photovoltaic panels

Thursday, February 28, 2013, in the beautiful setting of the Sheraton Hotel De Medici in Rome, Lodovico Ramon presented the Project FRELP (Full Recovery End of Life Photovoltaic) during the afternoon session of the conference on the recovery of photovoltaic panels organized by PV Cycle.

presentazione sasil x pv_cycle - roma 28-02-2013 - italiano Here you can download the pdf of the presentation.