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John Otti
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Join Date: Feb 2008
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Reuse of Leather Shavings

02/14/2011 6:39 AM

The leather shavings is a solid waste produced during the tanning of hides. This waste contains chromiun (harzadous waste). I would like to know if does exist any technology to recovery and reuse of this waste, avoiding the disposal on hazardous waste landfill.
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Yusef1
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#1

Re: Reuse of Leather Shavings

02/14/2011 11:06 PM

I have seen "leather" which is actually vinyl with ground leather in it. If it exists in the market place, there is somebody making it.

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Lehman57
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#2

Re: Reuse of Leather Shavings

02/14/2011 11:36 PM

In the wood world there is chipboard and particleboard. Is a similar idea possible with leather?

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corelite
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#3

Re: Reuse of Leather Shavings

02/15/2011 1:15 AM

If "avoiding the disposal on hazardous waste landfill" is you main concern why not find a way off separating the chromium from the leather and reuse the Cr?

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vincentwade
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#4

Re: Reuse of Leather Shavings

02/15/2011 7:00 AM

Since when? Tannic acid tans hides. Comes from tree bark. We drink tannic acid with every cup of hot or cold brewed tea. No "chromiun" involved. Who told you this?
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kramarat
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#5
In reply to #4

Re: Reuse of Leather Shavings

02/15/2011 7:47 AM

Chromium has been the industry standard around the world in leather tanning. It is the best and fastest, but they are attempting to phase it out. See link in post #1.

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vincentwade
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#9
In reply to #5

Re: Reuse of Leather Shavings

02/19/2011 11:22 PM

Wow, that's crazy! I never knew that. I went to the Hoopa reservation near Willow Creek California and watched them tan elk hides, and they used cottonwood and oak bark soaked/boiled in fresh water to make an acidic tea-like concentrate and used it to tan hides. I guess the use of the chromium is somehow faster and cheaper. Figures.
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Apothicus
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#7
In reply to #4

Re: Reuse of Leather Shavings

02/15/2011 11:42 AM

Seems they use quite a bit of the stuff actually. The items below are from IULTCS.

Chrome (v); chromingTreat hides and skins with chrome liquor for tanning.
Chrome complex dyestuffAnionic dyestuff containing metal chrome complexes, type 1:1 or 1:2.
Chrome complex, (chromium) (cationic, anionic, neutral)Complex formed by the co-ordination of various ligands to one or more Cr

+++ ions, which may have a net positive (cationic), negative (anionic) or zero (neutral) charge.

Chrome leatherLeather tanned either solely with chromium salts or with chromium salts together with quite small amounts of some other tanning agent used merely to assist the chrome tanning process, and not in sufficient amount to alter the essential chrome-tanned character of the leather.
Chrome liquorBasic chromium sulphate liquor prepared by reduction of a dichromate by glucose in the presence of sulphuric acid.
Chrome mordant dyeDye, which needs a mordant to fix.

Note: Chrome as a metallic salt could be a mordant.

Chrome oxideDark green, amorphous powder, forming hexagonal crystals on heating that are insoluble in water or acids; used as a pigment to colour wares and as a catalyst. Also known as chrome green.

The chromium content of a chrome tanned leather and of a chrome tanning material is usually expressed as chrome oxide (Cr2O3) content.

Chrome retanned leatherSecond tannage treatment of a leather tanned with chrome tanning salt, and then with other tanning materials.

Note: As vegetable tanning.

Chrome stainIrregular shaped darker coloured area on chrome leather, seen after tannage, due to increased deposition of chromium compounds, often related to too rapid basification.
Chrome tanningChrome tanning using a single solution of a basic trivalent chromium salt, usually primarily the sulphate.
Chrome tanning salt, (liquid; powder)Commercial preparation of basic chromium sulphate, of a certain basicity, containing more or less of neutral salts; in the liquid, or powder, form.
Chrome-alum liquorBasic chromium sulphate liquor prepared from chrome alum by addition of an alkaline substance, usually sodium carbonate.
ChromiumMetallic chemical element, symbol Cr, atomic number 24, atomic weight 51,996.

· Hexavalent: the hexavalent form (Cr+6 or CrVI) of chromium ion as in chromates and bichromates. It has no tanning properties.

· Trivalent: the trivalent form (Cr+3 or CrIII) of chromium ion as in chrome sulphate, chloride, etc. This is the chrome tanning form.

· Total: The chromium content in leather, float, wastewaters, etc. in whatever form it is.

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DAG
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#6

Re: Reuse of Leather Shavings

02/15/2011 10:01 AM

I use an old school alum tan. This may not be economically viable for you, but there are other methods that may be. What kind of volume do you tan?

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John Otti
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#8
In reply to #6

Re: Reuse of Leather Shavings

02/15/2011 11:46 PM

The issue is how to deal with the savings which has large amounts of chromium. When put in landfills, it is an environmental hazard and hence the challenge and the endeavor to find a technology to help in reducing the volumes sent to landfills.
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Apothicus (1); corelite (1); DAG (1); John Otti (1); kramarat (1); Lehman57 (1); vincentwade (2); Yusef1 (1)

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