How do I dispose of used Ferric Chloride etchant?

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Discussion Overview

The discussion revolves around the disposal of used Ferric Chloride etchant, particularly focusing on the challenges faced by hobbyists in managing waste solutions containing copper chloride. Participants explore various disposal methods and the implications of these methods, considering both environmental and practical aspects.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant expresses uncertainty about the chemical composition of the waste solution, questioning whether it is copper chloride or cupric chloride.
  • Another participant suggests that the economic viability of refining the copper from the solution may be low due to the small amount present.
  • There is a proposal to react the waste solution to produce CuSO4, which could have applications in metal plating or as a soil additive.
  • Some participants mention the potential environmental impact of improper disposal, referencing practices of others who dispose of the solution irresponsibly.
  • A later reply mentions a recommendation to add sodium carbonate or sodium hydroxide to the Ferric Chloride to precipitate copper and iron, leaving sodium chloride in solution.
  • One participant shares a link to an external resource that discusses alternatives to using Ferric Chloride for etching.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best method for disposal, with multiple competing views and suggestions presented throughout the discussion.

Contextual Notes

The discussion highlights the lack of clear guidance on waste disposal for hobbyists in regions with limited access to proper waste management services. There are also uncertainties regarding the chemical processes involved in the proposed disposal methods.

NipunaG
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Hi everybody.
I'm an electronics hobbyist and use Ferric chloride to etch copper circuit boards. I'm left with a solution of copper chloride (or is it cupric chloride? Chemistry isn't my forte).
So my question is, how do I dispose of it? I already searched around on the internet and there was no clear answer except "contact the authorities", but I can't do that here because I live in a third world dump and the authorities are not to be trusted with waste disposal. I have to do everything myself, if possible.
I know some people who etch boards like this in large scale (a thousand boards a month or so) and these guys just throw the stuff wherever they can. One of them recently contacted me about disposal because he was worried about any damage he may be doing, which prompted my search.
 
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There is not much weight of copper in the solution, so it is probably uneconomic to refine into metallic Cu. Placing Al metal cans in a Cu solution will sometimes produce metallic Cu.

The chlorine is a problem as it digests wood and rusts steel, so maybe you can react the waste solution to produce CuSO4. That can be used to plate metals with copper, or to treat timber to stop it rotting.

Some soils are short of Cu as a trace element. You could treat those soils by adding a Cu compound to a fertiliser. What are your soils like?

Cu is used in anti-fouling paint on boat hulls, while molluscs use two Cu atoms to make their blue blood = haemocyanin, instead of the Fe that makes animals blood red = haemoglobin. Green trees use an Mg atom to make chlorophyll.

Have you thought of breeding and farming octopuses?
 
NipunaG said:
Hi everybody.
I'm an electronics hobbyist and use Ferric chloride to etch copper circuit boards. I'm left with a solution of copper chloride (or is it cupric chloride? Chemistry isn't my forte).
So my question is, how do I dispose of it? I already searched around on the internet and there was no clear answer except "contact the authorities", but I can't do that here because I live in a third world dump and the authorities are not to be trusted with waste disposal. I have to do everything myself, if possible.
I know some people who etch boards like this in large scale (a thousand boards a month or so) and these guys just throw the stuff wherever they can. One of them recently contacted me about disposal because he was worried about any damage he may be doing, which prompted my search.
One company recommends adding sodium carbonate and/or sodium hydroxide to the ferric chloride. Copper and iron would be precipitated and the NaCl (table salt) would be in solution.
https://www.mgchemicals.com/products/prototyping-and-circuit-repair/prototyping/ferric-chloride-415
 
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