Oxalic Acid

Oxalic acid is a chemical substance also known as Ethanedioic Acid.  It is a colourless compound which belongs to the family of dicarboxylic acids.  Oxalic acid is soluble in water, ether and alcohol, and melts at 187ºC.   It is naturally found in many plants like spinach as metal salts.  At high concentrations, it is an extremely dangerous poison.  No need for fright though as the amounts present in plants are not so toxic.  The only food that contains high concentrations of oxalic acid that can be harmful if consumed is the leaves of spinach or other dark leafy plants.  People normally eat the stalk of these plants and not the leaves so it is highly unlikely for it to pose any great danger.  One would have to eat an estimated eleven pounds of stalks at one time for it to pose a threat.  What we need to be concerned about is the contribution to the development of oxalate crystals in the body.  Since oxalic acid is not a useful nutrient to the body, it is processed as oxalates and excreted in the urine.

The crystals of oxalic acid can be very large to irritate the body.  Approximately 80 % of kidney stones or gall stones are derived from oxalate.  The individuals who are mostly at risk are people with kidney disorders and rheumatoid arthritis.  They need to be conscious of the amount of oxalic acid they intake.

Oxalic acid is highly corrosive and toxic, and has abundant uses.  Among its many uses are:

1. It is used in rare earth mineral processing.
2. It is used in photography as reducing agents.
3. It is widely used in the manufacture of bleaches and rust removal products especially
4. It is used in the pharmaceutical industry as a purifying agent.
5. It is in the textile and wood industry as a bleaching agent.
6. It is an excellent rust remover for metals.
7. It is used as a waste water treatment to remove calcium in the water.
8. It is used in laundries as an acid rinse.
9. It is used to remove scale from automobile radiators.
10. Rock collectors use it to clean minerals.
11. It is used in the home for sterilizing and cleaning home brewing equipment.
12. It is used to remove food stains from kitchen countertops and plumbing fixtures.
13. Mild solutions will remove ink from fabric.
14. Stains from driveways and painted surfaces are easily removed by using oxalic acid.
15. Also great for cleaning shower enclosures and patio furniture.

Oxalic acid like any other strong acid should and must be handled with great care.  Here are a few tips to bear in mind when handling oxalic acid:

• Always wear latex gloves when handling oxalic acid.
• Use only in well ventilated areas.
• Wear a dusk mask and always protect your skin.
• If swallowed, drink plenty water.
• If inhaled, get fresh air instantly.
• Always dispose of oxalic acid properly.