John said:
However, ferric chloride is very easy to chemically alter, so it is
almost completely inert in the environment. Just neutralize it with
washing soda (sodium carbonate) till it quits fizzing. Then all iron
and copper chloride will have been converted to almost insoluble iron
and copper carbonate mud. Then you can flush it down the toilet.
At that point, the proper thing to do would be to filter through some
paper towels, and throw the solids into the trash. Copper compounds are
extremely poisonous to fish and plants.
My whole point was that dumping the FeCl into a tank of used oil, just
because the stupid mechanic says you can is well... stupid. You, and
the environment would be better off if you dumped the waste onto the
ground, and let it kill some weeds, or trees, that you don't like.
Flushing it down the toilet isn't a real good idea either, the FeCl does
a number on the cast iron pipe that lives in many plumbing systems. Many
moons ago, I worked for a PCB manufacturing house. They wouldn't allow
me to recycle their spent FeCl (the supplier would give me about $1/gallon
for spent FeCl, two carboys was worth more than I made in a day's wages)
They dumped the waste FeCl down the floor drain in the building, and then
had to bust up the floor every other year to replace the sewer pipe.
If you dump the FeCl into a sink, it will eat out the brass traps, without
regard for how much water you flush down the sink... ask me how I know ;-)
-Chuck
