Solder dross has gone from being a cost to be considered by large companies to a very high cost that must be tracked for all who assemble electronic devices. As much as 70% of bar solder can be wasted as solder dross and with SAC 305 now at the $25/Lb level and even leaded solder costing almost twice as much as in previous years it is a major issue.
Recovering your own dross could save you money but it is not an undertaking that should be done lightly. Besides the equipment, cost and manpower necessary here are a few thoughts to consider
To recycle dross some states require processing permits and the permits would need to comply with local regulations.lead treatment compliance issues are even more complex, they would apply include Blood lead testing for employees,ventilation issues, dust collectors and hoods, pollution insurance etc...
The bi-product generated from sweating dross or separating good metal from oxides and flux residues is typically not desirable and could become a disposal issue for the generating company. Typically only 50% of the metal can be recovered from dross recycled by pot sweating and the single wave unit squeezing machines are not much more effective.
There is more value to the company by simply selling the dross for the best price however sale of dross to a recycler is something that often makes more money for an employee selling it out the back door or a middle man than it saves for the company.
Many companies do not realize the value of dross, especially lead free dross. Many company senior managers would be amazed at the hundreds of thousands of dollars of company assets (bar solder dross) that just disappears from the balance sheet.
Because of the exponential increase in the cost of metals coinciding with the shift to lead free every company should be accurately tracking their solder usage and should get a handle on the cost of dross. So many do not really have a clue.
New in line processes such as MS2 from P. KAY Metal have been developed to actually halt the formation of dross right in the wave solder machine and therefore save 50% to 70% of the solder. Actual reductions in solder purchases of this magnitude have been proved.
This process saves a moderate sized company many hundreds of thousands of dollars a year. Because this is an in line process the using company is not a recycler and is therefore not required to do anything more on the regulatory side than they must do to solder boards.
One thing for sure, the old days of just letting a low level manager handle the sale of dross to a recycler and not tracking the entire bar solder usage/purchase life cycle is rapidly coming to a close if an assembly company is to remain profitable and competitive.