Urea 46-0-0 Prilled Aqua Regia Gold Refining"Greenway Biotech Brand" 20 Pounds 20 Pounds of Greenway Biotech Brand Urea 46-0-0 (46% Nitrogen) 99.9% Pure Great to Improve Nitrogen Deficiency Neutralizing Acid in Aqua Regia Gold Recovery Process Great as a Humectant (Dye Color, Moisturizer, etc.)