March, 2018
www.us-tech.com
Clean and Efficient Recycling for SMT/PCB Metals Waste
By Jack Scott, Ph.D., Steve J. Butler and Thomas Mitchell, Conecsus, LLC F
rom solder dross to paste residues on con- sumable products, such as used stencil wipes, solder paste jars and syringes, electronics
manufacturing produces metal-bearing resi - dues and wastes in all kinds of forms. Even though RoHS has taken most of the lead out of the PCB manufacturing process, the alloys that have replaced lead-containing solders are hard- ly nontoxic. These byproducts must be responsibly
managed and disposed of. Doing so can cost a mid-size manufacturing facility between $12,000 and $20,000 per year, depending on manufacturing volumes. One solu- tion to the metals residue waste problem was developed in 2013 by Conecsus, LLC, and is called RACS (Reducing Agent: Coke Substitute). Conecsus processes industrial
metal-bearing residues and wastes in a sophisticated recycling facility, con- verting them into reusable metal products using patented technologies that minimize air emissions and con- serve energy. Wastes that the company
processes primarily contain tin and lead, with varying amounts of silver, gold, antimony, indium, bismuth, and copper. Raw materials are sourced from a variety of manufac- turing industries in North America and finished products are shipped around the world.
Reducing Hazardous Waste The RACS process is focused on
the waste stream known colloquially as “contaminated trash.” This mate- rial is generally made up of under- stencil wipes, spent paste, tubes and jars, gloves, rags, finger cots, and similar items that are, from a regula- tory standpoint, a characteristically hazardous and regulated waste. Toxic metals are what cause
this material to be considered haz- ardous by regulatory agencies, and these cannot be processed or trans- ported in the same fashion as solder dross when a company has small or large quantity generator status. As such, they are expensive to manage and to dispose of, and a great deal of record keeping is required to remain compliant with state and federal reg- ulations. The RACS technology allows
Conecsus to take that material and reuse it as a reagent ingredient in the processing of other materials, such as solder dross, filter cakes, detinning dross, and other tin or lead residues. This small, but important, distinction often gives generators in most states the ability to ship it to Conecsus with on a common carrier with a bill of lading, along with their solder dross. This may eliminate the need for an expensive hazardous waste carrier, or processing the material through a hazardous waste management firm. This allows generators to send
their solder-contaminated waste to Conecsus as a reagent replacement, rather than as hazardous waste. As a result, this reduces the amount of hazardous waste that the client is responsible for, because they no longer have to report it as such. RACS allows the refiner to reuse the carbon units, which con-
See at APEX, Booth 1119
Paste and wipes waste before shredding (left) and after (right).
tain metal, as a reagent in other pyrometallurgical processes. This reduces the amount of coal prod-
ucts needed for their reagent values in refining impure metals. RACS material is up to 30 percent more effective than coal products in reducing oxidation in impure metals. This further reduces the purchase of coal
products, while reducing the amount of carbon dioxide that is released from the refining process where RACS is used. In short, it can lessen a generator’s carbon footprint, as well as its reportable waste streams. Both of these are significant benefits from both an environmental and financial perspective.
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