Summary for brightening of aluminium cookware Discussion
Brightening of aluminium cookware is the goal of a manufacturer asking how to get a bright finish on aluminium cooking pots using an automatic conveyorized washing line with pressurized spray sections. The excerpt only shows the question and the start of the process description, including manual loading, liquid caustic soda in bulk, and a conveyor speed of about 1 meter/min. No answers are included in the provided thread text, so there is no documented recommendation, chemical adjustment, or process change to summarize from named responders. Based on the available source, the page is mainly a request for help about achieving brightness in an aluminium cookware cleaning/finishing line rather than a resolved discussion.
July 10, 2014
Q. We manufacture aluminium cooking pots, and as part of the process we need to achieve a bright finish of the cookware. Our current "automatic conveyorized washing" line process is based on pressurised spray system for each section, as follows:
WORKING CYCLE (conveyor speed is about 1 meter/min)
1. Manual loading onto the conveyor
2. caustic soda ⇦liquid caustic soda in bulk on
Amazon [affil link]
etch at 65 °C – 3 minutes for 3 meter length of conveyor section
3. Dripping – about 1.4 min for 1.4 meter length of conveyor section
4. 1st Rinsing – about 1 min for 1 meter length of conveyor section
4. Dripping – about 1.2 min for 1.2 meter length of conveyor section
5. Neutralising with nitric acid at room temp (68% concentration) (10 parts nitric acid to 90 parts water) for 1 minute over 1 meter conveyor length.
6. Dripping – about 1.2 min for 1.2 meter length of conveyor section
7. 2nd Rinsing – about 1 min for 1 meter length of conveyor section
8. Dripping – about 1 min for 1 meter length of conveyor section
9. 3rd Rinsing – about 1 min for 1 meter length of conveyor section
10. Dripping – about 1 min for 1 meter length of conveyor section
11. Blower Drying with hot recirculated air – for 4 min to cover 4 meter conveyor length
12. Manual Offloading from conveyor
Despite the above, we are unable to obtain a shiny, bright finish of our cookware, and also the cookware is not anodized due to market requirements. All our pots/pans are come out with a dull, matte finish. The volume of cookware pieces sent thru the washing line can be anywhere between 8,000 to 10,000 pieces per 8 hours of various diameters and heights.
I would be grateful to receive any suggestions to help us improve the surface finish to make it appear shiny, bright. If there are any questions/additional info you require, please let me know.
Thanks you
Timir
TIMIR MAJITHIA
– MOMBASA, COAST, KENYA