Electricity gold-plated recovery method of solution

Aug. 7, 2011 - PRLog -- Gold is the most stable metal in chemistry, it has good adornment sex, corrosion resistance and reduce friction resistance, resistance to change color and of high temperature oxidation ability, also has small contact resistance and excellent brazing sex. Because its production is few, so in the use of it, want to consider how to the least amount to maximize its properties. Here are some simple recovery method and process:
A: will contain gold. Waste heated to 80 ℃--90, continuously mix slowly chloride solution, ferrous reaction are as follows;
Au3 Fe2 + + 3 + = = 3 Fe3 + + Au with gold ions press has been restored, the color of the solution by yellow gradually become ensemble red, gold drowned in the bottom. Continue to add too much the ferrous oxide solution, and let rest for a few hours. Take two drops of liquid static stratification, plus 1% salt two drops of blood red, blue, and gold now that had all been restored. Pour the liquid to clear, the reduced pressure method, the lower suction filter for yellow gold deposits.
2. Pickling, washed: take 1:2.5 hydrochloric acid in solution in powders simmer, stirring 5 minutes to the upper solution, and pour out so repeated 3-5 times, so far, to no present yellow. DuoCi with distilled water to wash washing powders, the water out of the pH value of about seven so far when
Drying: will the powders after wash in drying case of drying, have to orange sponge granular gold slag.
Solution: will cast alloy powder in quartz crucible inside, in high temperature tube in electric furnace heated to 1200 ℃ or so, melted into graphite mould casting for the gold bullion. If not, when melting blunt alloy powder can be added, but should not use borax quartz crucible, can buy graphite crucibles profiles of alloy powder.

2. In good ventilated condition, scrap gold plating, porcelain dish into heated evaporation to viscous, with five times, stirring constantly in distilled water dilute joined with hydrochloric acid acidification of ferrous sulfate, until no longer exhalation precipitation so far. On the black gold powder precipitation in porcelain dish the bottom. Will first hydrochloric acid, sediment after nitric acid, then cook with a dry cleaning. If can in 700-800 ℃ roasting 30 minutes better.

3. In good ventilated condition, hydrochloric acid waste of the gold plating PH = 1 or so. The solution heated to 70 ℃--80 in stir us, to become the transparent solution zinc alloy powder is, there are large with yellowish-white precipitation down so far. In the process, keep PH = 1 or so. Since then the processing methods and two the same.

Four. Not qualified gold out of the coating, not qualified in gold plating coating should as far as possible, for only in cannot save until except when back. PCB unqualified gold plating containing cyanide 50-60 available g/l of alkaline retreat back in addition to gold liquid. This return gold plating liquid back speed is quick and does not damage the nickel substrate, dissolve gold quantity can amount to 25 g/l, operating temperature 30 ℃--50 back after gold of the nickel after after may continue to gold-plated
Source from PCB manufacturer: http://www.raypcb.com  
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