Abstract: A method of reducing alkaline earth metals contamination of activated carbon by washing the contaminated product with an inorganic acid, preferably hydrochloric, and then rinsing the acid washed carbon with water. Preferably, the washing step is carried out from three to thirty minutes at a pH of 2.5 or less. The rinsing step is continued until a pH of 5 or greater is obtained, preferably for a time period of at least three to five minutes. The method is applicable to any alkaline earth metal but particularly calcium and magnesium. Any inorganic may be employed with those forming water soluble salts being preferred. The invention also encompasses a method of regenerating spent activated carbon employing the acid wash and rinsing steps noted above followed by separating the washed carbon from the rinse water followed by drying and then pyrolizing the dried carbon at a temperature of approximately 500 degrees C. to 1100 degrees C. so as to effect the water gas reaction.

Abstract: A method and apparatus for reactivating spent granular activated carbon is the subject of this invention. The carbonaceous material is to be activated is fed to a drying zone where it is dried until incoming air and recycle gases fluidize the drying zone thus causing the dried material to be pneumatically conveyed to the regeneration or activation zone. In this zone, the temperature is raised to effect the oxidizing reactions thereby volatilizing at least some of the contaminants while converting residual carbon to carbon monoxide and hydrogen. Some of the produce gases from the drying and regeneration zones are utilized to fluidize both of these zones and the remaining gases are directed to the afterburner where combustibles are consumed. The product gases from the afterburner are then directed to a conditioning zone where combustible fuel is introduced so as to consume any residual oxygen.

Abstract: In the isomerization of an O,O-dialkyl phosphoroamidothioate to an O,S-dialkyl phosphoroamidothioate by heating the O,O-dialkyl starting material in the presence of a catalyst, followed by recovery of the desired O,S-dialkyl end product, the improvement which comprises arresting the heating when about 40 to 70% of the O,O-dialkyl starting material has isomerized to O,S-dialkyl product, separating unreacted O,O-dialkyl starting material from the O,S-dialkyl isomerization product, and further treating the O,O-dialkyl starting material to effect further isomerization. The separation is effected either by cooling to crystallize out O,S-dialkyl isomer or by evaporating off the O,O-dialkyl starting material.

Abstract: In the production of thiosemicarbazide comprising the steps of reacting hydrazine and ammonium thiocyanate to form hydrazinium thiocyanate and by-product ammonia, and heating the hydrazinium thiocyanate to effect isomerization thereof to thiosemicarbazide, the improvement which comprises removing the ammonia from the hydrazinium thiocyanate prior to isomerization thereof, whereby the thiosemicarbazide is produced in high yield and purity. Advantageously at least about 80% of the ammonia is removed by steam stripping and/or vacuum distillation and the subsequent isomerization is effected by prolonged heating in the presence of a carbonyl compound such as acetone or acetaldehyde. The thiosemicarbazide is recovered by cooling to effect crystallization, followed by filtration, the mother liquor being recycled as solvent medium for the next batch.