2754.     PRIVALOV, S. I., CHAUKAVIN, M. K., ZUEVA, V. P., AND OGARKOV, N. P.  [Synthesis of Gas Suitable for Cementation Operations.]  Vestnik metallopromy-shlennesti, vol. 19, No. 1, 1939, p. 85-91; Chem. Abs., vol. 34, 1940, p. 1286.

        Gas suitable for cementation of steel was prepared by synthesizing CH₄ from CO, CO₂, and H₂ in the presence of a catalyst comprising pumice stone impregnated with a solution of Ni(NO₃)₂ containing 15% powdered Cr₂O₃ and reduced with H₂ at 350°.  The life of the catalyst was indefinite provided the temperature did not exceed 500°-600° and its surface remained clean.  The temperature in the retort was maintained at 400°.  If the starting gas has 4-5 times as much H₂ as CO+CO₂, the resulting gas did not have to be scrubbed of the CO₂.