Abstract:
This work was undertaken to investigate the
applicability of recycling pickling and chrome solutions in
order to save chemicals and protect the environment from
there polluted solutions.
Experimental work which was investigated through
statistical analysis shows that the PH and salt content are quite
significant and must be always maintained at the standard
levels of 2.2 and 3.0 as shown in tables 4.1 and 4.2. The
solutions were recycled for seven runs, each run was adjusted
to the required levels as shown in tables 4.4, 4.5 and 4.6, the
leather produced was subject to both physical and chemical
analysis, the results which are shown in tables 4.9 and 4.10,
agreed with the standard specifications of these types of
leathers which are in the range of (e.g. tensile strength 200-
210gr/cm). No work has so far been carried out for recycling
of picking solutions. Previous work (Tuck 1981) used the
picking solution for chrome tannage and adjusted the chromebath
accordingly.
On the other hand the process of recycling picking solution
was delayed to be carried out in chrome tanning stage.
(F)
Seven runs were investigated, in each run the spent liquor was
analyzed for Cr2 O3 content and the results are shown in tables
4.7 and 4.8. The solution was adjusted to the required level
and the process of tannage was continued until completion.
The leather produced was processed from chrome tannage
through shaving, retannage, drying to finishing. The leather
produced was subjected to physical and chemical analysis
which were satisfactory as compared to the standard
specifications of the British Official Methods of specifications
(JSLTC, 2002). It is concluded that both picking and chrome
solutions can be recycled indefinitely without loss of quality.
The saving in chemicals is 60%, and 90% of water float, no
liquid wastes need to be discharged giving a clean
environment.
(
