I do not have the pH in ...

I do not have the pH in front of me, but I believe it is much higher than 8.5 to 9. to get free OH alkalinity you need to be above a pH of 10.5; for the metal precipitation..  The first course in Qualatative Analysis taught us that by raising the pH will precipitate a lot of things, including metals; not to be confused with the precipitation of carbonates and bicarbonates as found in the soda ash & lime  (calcium oxide) process.  Depending upon your requirements calcium oxide, calcium hydroxide, sodium hydroxide or potassium hydroxide may be used.  It depends upon your process and the cost one can tolerate to get the precipitation you want.;  you just need to get the pH up to 10.5 or higher for a free OH radical to be present for metal precipitation.   

I am using the pH elevation to drop most of the nickel, copper, silver and gold out of the rinse water for a plating operation.  The first step of raising the pH is kinda simple.  The final removal of nickel is done with a product we developed called Nickout.  It pulls the last amount of precious metals down so that theymeet the requirements for discharged.  After the process we bring the pH back down to about 9 for discharge to keep the goveernment  happy.

The precipitated precious mental are then filtered, dried and sold. They get about $200K for every filtered sludge that is sent in.  We comfirm the final discharge of the waste water by ICP analysis.  We get to sell them Nickout, and do the confirming analysis for the waste water regulations.  If you need some nickout solution, to remove a low ppm  (below 1 ppm) of these mental, contact me at wh@bluevalleylabs.com.