you can see this Article Separation and Recovery of Fine Particles from Waste Circuit...

https://www.epa.gov/sites/production/files/2014-05/documents/handout-10-circuitboards.pdf

There are some ways that may be partially effective. There is a way of ligand exchange for REE's; find the following paper below, within which there are many references.

A Study on Removal of Rare Earth Elements from

U.S. Coal Byproducts by Ion Exchange

PETER L. ROZELLE, ADITI B. KHADILKAR, NUERXIDA PULATI,

NARI SOUNDARRAJAN, MARK S. KLIMA, MORGAN M. MOSSER,

CHARLES E. MILLER, and SARMA V. PISUPATI

Thanks for you reference

Refer to this particular article

A new technology for separation and recovery of materials from

waste printed circuit boards by dissolving bromine epoxy resins

using ionic liquid

Journal of Hazardous Materials (2012), vol. 239-240,

pp. 270–278.

Can you find this article useful? with respect

http://www.irjes.com/Papers/vol3-issue5/B350517.pdf

I think you can try supercritical metal extraction process or-else you can try pyro based process. Even some paper published based on the alkali leaching.

Article Fast copper extraction from printed circuit boards using sup...

Article Review of Pyrometallurgical Treatment of Electronic Scrap

Even you can try alkali fusion methods also but complication will arise during the separation process

thanks for your

reply