[StevT2008]

Hi

I bought some zinc metal powder from Ebay for "cold" galvanisation purpose. The powder is grey but I want to be sure the powder is real zinc metal but not zinc phosphate. Do somebody know how to test the powder with "household" products ? I don't need anything fancy.

Thanks.

[billnotgatez]

melting point?
reaction with muriatic acid (HCl)?

You can look at the properties of the suspected items and select a difference
https://en.wikipedia.org/wiki/Zinc
https://en.wikipedia.org/wiki/Zinc_phosphate

GOOGLE will provide information - for instance reactivity with acids and bases
http://www.npi.gov.au/resource/zinc-and-compounds

[Enthalpy]

Zinc phosphate is white.
You can check if the powder conducts electricity. It may need to press on it.

[Corribus]

Melting point is probably the easiest analytical way. Throw it on a DSC, find where the melting point is, done. Assuming you don't have a DSC at home, acid test is probably the easiest way to do it.

[StevT2008]

Zinc phosphate is white.
You can check if the powder conducts electricity. It may need to press on it.

I test the powder with a multimeter and there is no conductivity.

[StevT2008]

Melting point is probably the easiest analytical way. Throw it on a DSC, find where the melting point is, done. Assuming you don't have a DSC at home, acid test is probably the easiest way to do it.

I don't have DSC. The problem with acid is almost all metal reacts with acid.

[Intanjir]

I test the powder with a multimeter and there is no conductivity.

You might melt it into a convenient chunk to make it easier to test the conductivity. Easy enough to do as the melting point is quite low for a metal. There are some videos of people melting US pennies (which are mostly zinc) with just the burner flame on their stove.
Of course it should be readily obvious that you have a metal after melting it and not something like zinc phosphate. If you need some zinc to compare properties to, just melt a penny 

Note: The boiling point of zinc is also quite low. So ventilation and not being overzealous with the heat is recommended.

[Enthalpy]

I test the powder with a multimeter and there is no conductivity.

Try to press on the powder. If you have authentic zinc powder too, just compare.

Hydrochloric and sulphuric acids let zinc powder react swiftly. Easy to find and try, but please take precautions.

[Corribus]

The problem with acid is almost all metal reacts with acid.

Regardless of whether or not that is true, zinc phosphate is not a metal and will behave quite differently from zinc powder when exposed to a strong acid (like, battery acid).

[StevT2008]

I tested the powder with acid (HCL) todays. The powder is likely metal zinc. The reaction was pretty violent. I say likely because I didn't pour the solution to my skin to confirm it was HCL nor flamed the gas from the reaction to confirm it was H2. I was too lazy today.

[Borek]

I didn't pour the solution to my skin to confirm it was HCL

Huh?