Raw material: Take wet salted cow hide (good selection).

Trimming: By hand knife. Take salted weight (All % based on this salted weight)
Now see the chart of the operations step by step of the tanning with chemical used, time required and analytical test.
Tannery







Operation % of chemical use Time Analytical test
Pre-soaking 300% water
0.2% soda ash
0.2% LD 600
Run 60 minutes
Drain
Main soaking 300% water
0.4% soda ash
0.3% LD 600
0.2% preservative
Run 30 minutes
Leave overnight,
next day drain
wash well
Liming 300% water
4% lime
3.5% sodium sulphite
1% liming auxiliary
0.2% LD 600
Run 30 minutes
Leave the bath for 2-3 days
Then scudding by hand
Chemical wash 200% water
0.25% meta bi-sulphate
Run 20 minutes
Drain
Deliming 100% water
1.5% ammonium chloride
1.5% ammonium sulphate
0.5% meta bi-sulphate
Run 45 minutes Check with phenolphthalein
Bating 100% water
1% batting agent
0.5% wetting agent
Scudding, wash well
Run 60 minutes
Drain
Check: Thumb and Bubble test
Pickling 80% water
8% salt
0.2% impropel CO
0.5% formic acid
1.2% sulphuric acid
0.5% hypo
Leave ovewnight
Run 15 minutes
Run 30 minutes
Run 2 hours
Run 30 minutes
Drain half pickle bath
Check pH
Chrome tanning 4% Basic chromium powder+ 4% basic chromium powder
1% sodium formate
0.5% OCS
50% water
Run 30 minutes


Run 60 minutes
Check: Penetration
100%
Basification 1.2% sodium bi-carbonate
0.2% preservative
Run 90 minutes


Run 60 minutes
Check final temperature 28 - 40 degree celcius
pH = 3.7 - 3.8


After completing the above operations, assess the wet blue.
Assessment:
1. Boil test
2. Shrinkage temperature
3. Chromic oxide estimation
4. Grading and selection
5. pH check

Goat hides: The process of manufacturing technology if standard wet blue from salted goat hides is same as Cow hides except that there is an additional operation  in goat hide called Painting. 
Paiting chemicals that required are as follows -





Painting 8% lime
2% sodium sulphite
0.2% LD600
water requires to make as paste. 4-6 hours or overnight

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