Abstract: The present invention provides a composition for recovery of petroleum and gas, which comprises (a) a copolymer having a molecular weight of 100,000 or more, composed of 30-75 mole % of N-vinylpyrrolidone unit, 5-70 mole % of (meth)acrylamide unit and 0-20 mole % of (meth)acrylic acid unit or a salt thereof, (b) a water-soluble aldehyde, (c) a phenol compound, and (d) water. This composition can form a gel in a required gelling time even at high temperatures and even in the presence of bivalent metal ions and accordingly can be used for efficient recovery of petroleum and gas.

Abstract: Oxygen or a mixed gas containing oxygen, or a chemical flame produced by a mixture of a combustion gas and a combustion-assisting gas containing oxygen, is blown against the surface of molten iron to cause radiation emission. The radiations are divided into components of different wavelengths, and the resulting emission spectra are measured to determine the composition of the molten iron.

Abstract: A carbon-unsaturated molten metal or molten alloy containing elements more oxidizable than iron such as chromium and silicon is dephosphorized by addition of a flux composition comprising calcium carbide and a halide of alkali earth metal such as calcium fluoride in a non-oxidizing atmosphere, and thereafter the slag as a by-product is stabilized against formation of undesirable gases. This method when employed in refining ferrochromium or crude stainless steel makes feasible dephosphorization, and it is particularly suited for economical production of low phosphorus stainless steel.

Abstract: Cr alloy, Mn alloy or Mo alloy can be dephosphorized and denitrified simultaneously with a flux newly prepared. The flux comprises metallic Ca, Mg, Ba or Sr and halides thereof. There is no loss of valuable alloying component in this method.