What is Chromium?

About Chromium: 

• It is a naturally occurring element found in rocks, animals, plants, soil, and in volcanic dust and gases.
• It is a very hard gray solid with a metallic luster.
• There are two forms: trivalent chromium, which is safe for humans, and hexavalent chromium, which is a toxin.
• Properties
  • It does not tarnish in air, when heated it borns and forms the green chromic oxide.
  • Chromium is unstable in oxygen, it immediately produces a thin oxide layer that is impermeable to oxygen and protects the metal below.
• Applications
  • Chromium use in iron, steel, and nonferrous alloys enhances hardenability and resistance to corrosion and oxidation.
  • The use of chromium to produce stainless steel and nonferrous alloys are two of its more important applications.
  • Other applications are in alloy steel, plating of metals, pigments, leather processing, catalysts, surface treatments, and refractories.

Where is Sukinda Valley?

• It is in the State of Orissa.
• It contains 97% of India's chromite ore deposits and one of the largest open cast chromite ore mines in the world.
• Approximately 70% of the surface water and 60% of the drinking water contains hexavalent chromium.
• The Brahmani River is the only water source for the residents and treatment facilities are extremely limited.

Q1:What is an alloy?

A metal alloy is a substance that combines more than one metal or mixes a metal with other non-metallic elements. For example, brass is an alloy of two metals: copper and zinc.

Source: Get clean water for Sukinda Valley residents, NGT orders Odisha government