Process for rendering waste from electric furnace production of phosphorus non-hazardous

A process for treating a waste slurry generated in the electric furnace production of phosphorus, the process comprising the steps of:

• a) heating a mixture of the waste slurry and alkali, the waste slurry comprising one or more materials selected from the group consisting of UTS metals, cyanides, elemental phosphorus, and phosphides to produce a treated slurry;
• b) cooling the treated slurry and separating the gases formed;
• c) adjusting the pH of the treated slurry to at least 11;
• and
• d) filtering the treated slurry to produce a wet cake and a filtrate:
• in which step a) is carried out in the presence of oxygen.

A process for treating a waste slurry generated in the electric furnace production of phosphorus, the process comprising, in order, the steps of:

• a) heating a mixture of the waste slurry and alkali in the absence of oxygen, the waste slurry comprising one or more materials selected from the group consisting of UTS metals, cyanides, elemental phosphorus, and phosphides to produce a treated slurry;
• b) heating the treated slurry in the presence of oxygen;
• c) adjusting the pH of the treated mixture to at least 11;
• and
• d) filtering the treated slurry to produce a wet cake and a filtrate.