[IanJ]

In my vast experience of chemistry (not) I have unintentionally mixed these two liquids with one another in a ratio of approx Ferric:Sodium 10:1

Oops.

They are in a screw-top container (lid isn't too tight); and hoping for advice as to how I should dispose of them... now they've calmed down.

Thanks

[Intanjir]

Neutralize the pH. You should be left with only iron oxide, silica, and chloride salt. I like to use washing soda to neutralize excess acid since it is cheaper and easier to handle than NaOH (other than the bubbles).

You should have a precipitate already. Is it white?

[IanJ]

Neutralize the pH. You should be left with only iron oxide, silica, and chloride salt. I like to use washing soda to neutralize excess acid since it is cheaper and easier to handle than NaOH (other than the bubbles).

You should have a precipitate already. Is it white?

Hi, thanks for your reply, no it's a clear colourless liquid underneath a brown foam (from the copper PCB boards I guess). After a while it all calmed down. Including the foam it occupies about 1.5 litres of volume. It's in a screw top 5 litre container; screw is sufficiently tight to allow breathing.

Should I add soda to this? How much?

[Intanjir]

Sounds like there may have been more involved than just ferric chloride and sodium metasilicate. The foam is the precipitate I was looking for but I didn't expect it to float! I guess it was bubbling while it reacted and the silica trapped in bubbles as it was precipitating? However I don't know what would have caused the bubbling. Maybe your sodium metasilicate is old and has accumulated a fair amount of carbonate from the atmosphere?

When you gave the ratio of 10:1 was that the ratio of liquid volume or the ratio of metal ions? If you were giving the ratio of the liquids it tells us very little since we don't know the concentration of the liquids. I assumed that you would have residual acidity given that you gave a 10:1 ratio of acid to base but I now doubt this.

Since the solution below the foam is clear it sounds like the iron has precipitated along with the silica which suggests that pH is near neutral or above. The brown is presumably iron oxide/hydroxide and not copper. Copper would make for blue-greens.
If the pH is near neutral or above then there wouldn't be any hazard from the ferric chloride any longer.

Do you have any pH indicator strips or solution?