THORIUM FURNACE RESIDUES

MOLTEN METAL EXPLOSIONS, PRECIOUS METAL DERIVATIVES PYROPHORIC METALS, REACTIVE METALS STEEL WOOL, THORIUM FURNACE RESIDUES... 

See also metal dusts (reference 3), thorium furnace residues... 

Textile clothing static charges, 394 Theory without detailed thought, 394 Thermal explosions, 394 Thermal stability of reaction mixtures and systems, 394 Thermite reactions, 395 Thermochemistry and exothermic decomposition, 396 Thiatriazoles, 400 Thionoesters, 401 Thiophenoxides, 401 Thorium furnace residues, 401 Tollens reagent, 401 Toxic hazards, 402 Trialkylaluminiums, 402 Trialkylantimony halides, 403 Trialkylbismuths, 403... 

Many furnace residues (fine powders and salts) deposited in the upper parts of furnaces used for thorium melting operations, are highly pyrophoric and often ignite as the furnace is opened. Such residues may be rendered safe by storage under water for 60-90 days. If the water is drained off early, ignition may occur. 

This is a way to do this procedure without having to use one of those crazy tube furnaces stuffed with thorium oxide or manganous oxide catalyst [21]. The key here is to use an excess of acetic anhydride. Using even more than the amount specified will insure that the reaction proceeds in the right direction and the bad side reaction formation of dibenzylketone will be minimalized (don t ask). 18g piperonylic acid or 13.6g phenylacetic acid, 50mL acetic anhydride and 50mU pyridine are refluxed for 6 hours and the solvent removed by vacuum distillation. The remaining residue is taken up in benzene or ether, washed with 10% NaOH solution (discard the water layer), and vacuum distilled to get 8g P2P (56%). 

After the reactor was cooled to room temperature, it was opened and the mass of metal was mechanically freed of frozen slag. Ninety percent of the zinc in the alloy was removed by distillation in a retort heated to 1150°C at a vacuum lower than 0.2 Torr. The retort was then filled with argon or helium to prevent oxidation of the spongy thorium and cooled to room temperature. The thorium was transferred to a beryllia crucible in an induction-heated vacuum furnace for melting, evaporation of the residual zinc, and casting into a graphite mold. Thorium metal yield was 94 to 96 percent. 

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