Hydrazine residues, recovery

Hydrazine dihydrochloride, 92 Hydrazine residues, recovery of, 92 Hydrazine sulfate, 90, 92 Hydrazoic acid, 77, 78 Hydriodic acid, 157, 159 by action of iodine on hydrogen sulfide, 157 constant boiling, 158 fuming, 162 stabilization of, 159 Hydrobromic acid, 151, 152, 155 constant boiling, 155... 

RECOVERY OF HYDRAZINE RESIDUES AS HYDRAZINE DIHYDROCHLORIDE OR HYDRAZINE SULFATE... 

Although it has long been known that benzaldehyde reacts with hydrazine in alkaline solution to give a yellow, insoluble precipitate of benzalazine1 and that the latter when steam distilled in the presence of mineral acids is hydrolyzed to give the corresponding hydrazine salts,2 no previous attempt has been made to apply these facts to the recovery of hydrazine residues. This reaction is practically quantitative and can be applied not only to the recovery of residual hydrazine left in solution in the Raschig synthesis (No. 31) but to all solutions where the detection and recovery of hydrazine in the presence of ammonia, or hydroxylamine, are of interest. In the process of formation of hydrazine salts from benzalazine, 95 per cent of the benzaldehyde can be recovered. 

Barium hexafluorosilicate, preparation of, for decomposition to silicon tetrafluoride, 4 145 Barium paraperiodate (orthoperiodate), Ba3H4(I06)2, 1 171 Barium dezZro-tartrate, for resolution of tris(ethylenediamine)-cobalt(III) ion, 6 184 Barium thiocyanate, 3 24 Benzalazine, in recovery of hydrazine residues, 1 92 Benzoylacetone, beryllium derivative of, 2 19... 

Hexamminenickel(II) iodide, 3 194 Hydrates, nomenclature of, 2 264 Hydrazidicarbamide, 4 26 Hydrazine, 1 90 and derivatives, from hydroxyl-amine-O-sulfonic acid, 5 124 derivatives of, by reduction of A -nitrosohydroxylamine-Ar-sulfonates, 6 121 residues, recovery of, 1 92 Hydrazine dihydrochloride, 1 92 Hydrazine urazolate, formation of, in preparation of urazole, 5 53, 54... 

The objective of this effort was the initial recovery of Sc with subsequent process steps to separate and recover the other metallic constituents. The initial step was the acid digestion of the tungsten ore tailings, which produced an insoluble residue containing W and a solution rich in most of the other metals. The steps in the overall separation scheme are outlined by the flow sheet presented in Figure 3. The hydrazine/ sulfuric acid solution was chosen as the reductant/solvent reagent based on the following considerations ... 

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