Removing Zinc

Two things come to mind, neither one is environmentally friendly.

Sand or glass bead blasting or HCl.

Milo will know.

H2SO4 will generate hydrogen and bubble off quickly. Woody Maybe get std muratic acid if the coating is not thick, ie hot dipped.

Check dumps and battery recyclers or dealers. Old battery acid is difficult to dispose of safely and legally. Using it to remove zinc will consume it, and if you're smart, you may be able to market the hydrogen you produce. Just take care, it blows up, you know.

http://www.google.ca/#hl=en&safe=off&q=remove+zinc+plating&aq=0c&aqi=g-c2&aql=&oq=remove%2Bzinc&gs_rfai=&fp=2d2515cdb106b4e2

Theobrown -- I keep a gallon of swimming pool acid (HCl-Hydrochloric acid) around for removinf the zinc plating drom small items I'm going to weld or just have a plain steel finish like on antique machinery. An old Chlorox bottle with the top cut off or a 5 gallon plastic bucket for bigger stuff works well. Also works for brightening copper or brass.

When finished I fill another bigger container partly full of water, rinse the stripped part in it and put it aside to dry in the sun. Then I pour the spent acid into that large volume of waterfollowed by slowly adding powdered sodium carbonate (swimming pool pH increaser) to the dilute acid, stirring with a wood stick until the fizzing stops and the solution shifts color indicating the acid is neutralized. I used pH test strips to verify the end point. They are cheap and easy to get.

What's left is a pretty benign solution and if at pH 7-8 is mostly a suspension of insoluble metal salts, carbonates, oxides and chlorides. I live in a rural area and feel OK about dumping the stuff. A small volume could be put in a plastic concrete mixing tub an allowed to dry completely and mix with a little sand or reduce to a volume that would be easy or at least cheap to go through a hazmat collection process.

Ideally you could find some large size plastic pipe (and a suitable cap for one end) close to the diameter of your cylinders to minimize the amount of acid you'd need to strip each half of a cylinder while standing vertically. Or possibly cut the pipe in half lengthwise, dam each end, lay it horizontal on some wood block stands and add a pouring outlet at one end for emptying it. Then lower the cylinder into it using some plastic strap or rope, invent a way to rotate it to do the top, then the bottom and a way to stand it up afterward to drain the acid off it and move it into the rinse tank.

Ed Weldon

Why do you think zinc is toxic? When heated, it will oxidize to zinc oxide, which is nonvolatile at wood-fire temperatures. Traces of zinc actually have a nutritional value.

Removing the zinc depends on what is underneath. If it's steel, careful, supervised treatment with acid will remove the zinc before the steel. The removal process itself will generate mists of acid vapors that actually are dangerous.

DB

wpenrose -- The problem with zinc comes when you weld steel with zinc present. The fumes are the bad stuff. You don't want to breath it any more than you have to.

The following is from an OSHA web page: http://www.osha.gov/doc/outreachtraining/htmlfiles/weldhlth.html

"ZINC

"Zinc is used in large quantities in the manufacture of brass, galvanized metals, and various other alloys. Inhalation of zinc oxide fumes can occur when welding or cutting on zinc-coated metals. Exposure to these fumes is known to cause metal fume fever. Symptoms of metal fume fever are very similar to those of common influenza. They include fever (rarely exceeding 102o F), chills, nausea, dryness of the throat, cough, fatigue, and general weakness and aching of the head and body. The victim may sweat profusely for a few hours, after which the body temperature begins to return to normal. The symptoms of metal fume fever have rarely, if ever, lasted beyond 24 hours. The subject can then appear to be more susceptible to the onset of this condition on Mondays or on weekdays following a holiday than they are on other days."

Ed Weldon

Large amounts of inhaled zinc have been shown to kill off smell receptors in the sinuses. higher doses can be toxic. Zinc is an important nutrient but too much is bad for you.

If you are in an outer area you could pile them along with some waste timber and just burn them, and work with them once cooled.

We have used old fridge racks for BBQ grills after burning them thoroughly. Easy!

Do not use acid , a strong solution of caustic soda will do the job and will not corrode the steel. Fill tank with water and sit in a bath of caustic solution.You will find the solution slowly neutralises so depending on how many you are doing disposal at the end of the job wont be such a headache mix in vinegar to neutralise the solution.

The steel is not very thick for a long life as a burner still you can only see by trial.

1/2 " well casing pipe.. That's what I used for the burner shown in my picture..

you can grind it off.

I do suggest to continue with fire to remove the zinc. The brass or zinc fever is not so dangerous and the good news is that worker who subjected to this fever will recover and will develop a resistance so somebody will experience the sickness once in his life. Do professional respiration protection that all. If you use acids you will be in trouble. if the acid used is HCl, zinc chloride would be formed and it is more toxic than zinc oxide fumes and need lot of operations for its disposal.