Sciencemadness Discussion Board

Zinc Borate Production

vampirexevipex - 26-3-2012 at 11:28

I dont know if this really is what i've been after (zinc borate). Anyways here is what i did: I mixed zinc metal and boric acid at 900° F and the result was a slimy gray solution. Im not completely sure if this is zinc borate because when i was mixing both ingredients i noticed that the boric acid was hardly soluble with the zinc and had to let it sit for 30 minutes until it completely mixed, but i still see some pure zinc particles in it. So my question is: Is it possible to create zinc borate by mixing Boric Acid and Zinc at temperatures of 900° F?

A picture of it, in the attachment.



[Edited on 22-02-12 by vampirexevipex]

Zinc Bacon.png - 812kB

LanthanumK - 26-3-2012 at 16:40

You likely created what was known as a mixture. Maybe some zinc oxidized and this oxide reacted with the boron trioxide, but most of it probably did not react.

vampirexevipex - 26-3-2012 at 17:01

thanks, anyways i been breaking the big chunks of the mixture down until i made powder out of the mixture, its a gray silvery looking dust, and anyways how do i confirm if the mixture is zinc borate or not?

LanthanumK - 27-3-2012 at 03:36

If it is zinc and boric acid mixture, it will release large amounts of hydrogen when reacted with hydrochloric acid, and the resulting solid should be as white as the original boric acid. If it is zinc borate, no hydrogen should be emitted; probably no reaction will even occur in HCl.

barley81 - 27-3-2012 at 06:04

Which zinc borate do you want? Orthoborate? Boric acid forms many ions depending on pH (orthoborate at high pH and larger ions at lower pH).

Nicodem - 27-3-2012 at 07:30

Quote: Originally posted by vampirexevipex  
So my question is: Is it possible to create zinc borate by mixing Boric Acid and Zinc at temperatures of 900° F?

I doubt that. What is the reference you based that on? Which zinc borate are you after anyway?
I think you most likely got a mixture of mostly zinc and boric oxide (B2O3), perhaps with some oxidized zinc and residual metaboric acid. Zinc is in the wrong oxidation state anyway, so you would need to have some redox reaction first. Thus, zinc would have to either get oxidized by air's oxygen first, or somehow react with boric acid before this dehydrates to metaboric acid which is unlikely. Even if you would start with proper starting materials, such as zinc oxide and boric acid or boric oxide, the about 500 °C you used does not sound high enough for a monophasic product to form (assuming that you even used the correct stoichiometry which is the prerequisite to obtain a single compound).
Quote:
how do i confirm if the mixture is zinc borate or not?

This is generally done by powder XRD. Perhaps it also possible to get a confirmation by IR, but I think this is rarely used for such materials, so you might not even be able to find the reference spectra in the literature.
Additionally you need to confirm you have a monophasic product to declare it a compound. This can be done by SEM microscopy which can give you the elemental analysis of each particle (though B is on the verge of detection), or you can do it more primitively by sintering a sample, polishing it and checking under a microscope to see how many visually distinct phases compose the produced material. If you can only see one phase, then it is likely that your product is a compound.

ScienceSquirrel - 27-3-2012 at 07:54

Years ago I boiled a solution of boric acid with iron powder and the liquid became a pale green colour.
On dilution and cooling, addition of ammonia solution produced a pale green precipitate so some of the iron reacted.
I suspect that zinc powder would react in a similar way but I would hesitate to call the product a compound.

vampirexevipex - 28-3-2012 at 10:15

Quote:
What is the reference you based that on?


On the production of iron borate ( http://www.tirebor.com/download/bormadenimakaleler/65.pdf ) but instead of heating it over 900°C i though the C was an F and heated it to 900°F, anyways since i discovered the problem i heated the mixture to 1000°C and got a dark gray fully mixed liquid, after cooling i made it into a fine powder. It has a strong burned plastic odor.
Quote:

If it is zinc and boric acid mixture, it will release large amounts of hydrogen when reacted with hydrochloric acid, and the resulting solid should be as white as the original boric acid. If it is zinc borate, no hydrogen should be emitted; probably no reaction will even occur in HCl.


I'll be performing that test by the end of the day. Thanks.

solo - 28-3-2012 at 17:54

Reference Information


The Development of Zinc Borate Production Process
By H.Emre ELTEPE
A Dissertation Submitted to the Graduate School in Partial Fulfillment of the Requirement for the Degree of
November, 2004
MASTER OF SCIENCE

http://ifile.it/xhycz2t