When I end up with a batch of Iron chloride, usually old copper chloride leach contaminated with iron, I will use it in a corning ceramic dish on a hot plate to dissolve low grade scrap copper or iron, I use heat and let the solution concentrate, adding more Iron chloride solution as the water vapors off, and solution thickens and becomes more acidic, letting solution concentrate strengthens its acid property's, and it will dissolve copper and iron with a vengeance, when solution is highly concentrated I will decant thicker solution to a jar, on cooling some copper chloride precipitates out.
This recovery process helps me reduce my large volume waste copper/iron chloride solution, and gives me a way to dissolve large volume of thick copper or thin iron from scrap at the same time.
After solution cools and as much copper I chloride settles out that will in my settling jar, I can return liquid back to the ceramic dish to dissolve more copper with additions of more of my old copper chloride/iron chloride solution, and keep repeating this process, reducing the volume of my used solution of copper chloride/Iron chloride, and forming copper salts of the copper and iron I am working on to dissolve. (I can have two of or more of these cooling jars going at one time).
Using a suction tool to transfer liquids, I will not remove the solid metals or insoluble powders at the bottom of the ceramic dish, or the cooling settling jars.
My goal here is forming copper chloride salts out of the copper metal, and dissolving iron into solution.
This is continued till I have dissolved the metals (most of the gold, will remain as powders in the bottom of the casserole dish, but some will be carried over to the settling and cooling jar with the copper salts, most of the iron tends to stay in solution, any silver will normally get carried over in decanting as silver chloride is fluffy and takes time to settle.
in this settling jar I will have a dark brown powder of copper, and an dark brown almost black thick solution, this thick concentrated solution will also hold a lot of copper, diluting the solution with water will precipitate the copper from the iron chloride, the water will also dissolve acid from the dark brown copper powders making them white, ( if much silver in these white copper powders it will normally darken again in sunlight later) now this lighter green iron chloride solution can be decanted, the powders washed in more water, after stirred powers are settled, a few more water washes are done, leaving me with copper I chloride salts, with some gold or silver in the jar, I can keep these powders stored under a layer of water, to use to make copper chloride solution later, or I can use these copper powders in a type of sludge for a stock pot collector of values where the copper chloride powders go into solution when acidic waste is added to this stock pot, the copper chloride powders replace more noble metals from solution in this stock pot leaving me with more valuable powders in my stock pot over time.
I do not add hydrogen peroxide to the iron chloride (old copper chloride) solution when I use it to dissolve copper or iron, with strong heat the oxygen makes the iron in solution form hydroxides of iron, the iron hydroxides will be in the form of a red rouge powder.
This red rouge iron powder when formed will not dissolve in acids, to much of any extent at all, even in aqua regia, I have dissolved gold from a batch of the red rouge iron hydroxide powder and most of this red iron hydroxide stays insoluble.
I have also used this to dissolve copper pipe pieces where they were silver soldered to recover the silver.