Yellowcake 4 : Ammonium diuranate, the penultimate uranium compound in U3O8 production, but the form in which mine product was sold until about 1970. See: Uranium oxide concentrate
US Department of Labor, Electric Power eTool: Glossary of Terms, Occupational Safety & Health Administration OSHA, Washington, D.C., USA 2010. https://www.osha.gov/SLTC/etools/electric_power/gl ossary.html, (OSHA/ Electr Pwr - Amer) {618}