Abstract: A carbon substrate manufacturing method includes a hot molding step, a burn-carbonizing step, a hot isostatical pressure treatment step, and a mirror polishing step. In the hot molding step, molding is performed while heating thermosetting resin powders to be a hard carbon substrate after burn-carbonizing, where the thermosetting resin powders are of a particle size 150 .mu.m or more, HPF 80-150 mm, a moisture content 1.0-3.0 weight %, Fe, Ni, Si and Ca respectively 5 ppm or less. In the burn-carbonizing process, a disk shaped resin molded body is filled into a graphite cylinder and burn-carbonized by heating from the external while the condition therefor is maintained in that the disk shaped resin molded body is stacked holding therein a graphite spacer at every one sheet basis or at every plurality of sheet basis and is loaded on its top with a tungsten carbide weight, where the graphite spacer has a heat conductivity 100 kcal/m.hr..degree. C. or less, a bulk density 1.70-1.85, and a flatness degree 10 .mu.

Abstract: The surface of a blank for a textured amorphous carbon substrate is polished in a surface with a predetermined surface roughness, and then the blank with a polished surface is heated at a predetermined temperature in an oxidizing atmosphere to form minute irregularities in the polished surface through a reaction expressed by C+O.sub.2 =CO.sub.2 so that the surface is textured in an appropriate surface roughness. A randomly textured amorphous carbon substrate has a randomly textured surface with a surface roughness Ra in the range of 20 to 100 .ANG. and the ratio Ra.sub.2 /Ra.sub.1, where Ra.sub.1 is the surface roughness with respect to a circumferential direction, and Ra.sub.2 is the surface roughness with respect to a radial direction, in the range of 0.75 to 1.25 .ANG.. A concentrically textured amorphous carbon substrate has a concentrically textured surface with a surface roughness Ra in the range of 30 to 100 .ANG. or in the range of 40 to 200 .ANG., and the ratio Ra.sub.2 /Ra.sub.1 of 1.75 or greater.

Abstract: The present invention relates to a process for separating 2,7-DMN, characterized in that a mixture containing at least 50% by weight of 2,7-DMN and the other DMN isomers obtained by preliminarily concentrating a fraction in the range of 250.degree.-270.degree. C. of catalytically cracked petroleum oil is preliminarily adjusted to a temperature of 60.degree.-90.degree. C. to form a slurry containing the crystal of 2,7-DMN, which is placed in a tightly sealed pressure vessel, adiabatically pressurized to the range of 500-2,500 kgf/cm.sup.2 and solidified to form a state of co-existing of solid and liquid phases, liquid is then discharged under pressure from the solid-liquid co-existing system, the solid remaining in the vessel is pressed to discharge the liquid remaining between the solid particles, which are integrated to give 2,7-DMN having a purity of 98% by weight or more.

Abstract: The invention intends to separating a methyl derivative of naphthalene (2,6-dimethyl naphthalene or 2-methyl naphthalene) from a mixture material in a high purity more than 98 weight %. The starting material is preliminarily treated at a raised temperature up to 220.degree. c. at the highest and with LHSV of 0.1-6 Hr.sup.-1 in the presence of an acid catalyst usually used for olefin polymerization. The treated material is distillated to remove the polymerized impurities and to raise the naphthalene derivative content at least up to 50 weight %. And then the obtained material is subjected to the crystallization under a pressure of 500-2500 kgf/cm.sup.2 at a temperature of 80.degree.-150.degree. C. (for 2,6-DMN) or 10.degree.-35.degree. C. (for 2-MN).

Abstract: The present invention provides a method of converting NO.sub.3.sup.- ions which are contained in denitration waste liquids to nonpoisonous N.sub.2 gas or to valuable by-products. In the method of the invention, concentrated sulfuric acid is added to the waste liquid which results from denitration of exhaust gases which contains calcium nitrate and calcium chloride to obtain a mixed solution of nitric acid, hydrochloric acid, sulfuric acid and calcium sulfate. The ratio of the chloride ions to nitrate ions in the mixed solution is adjusted within the range of Cl.sup.- /NO.sub.3.sup.- = 2-3; the mixed solution is heated to 110.degree. to 150.degree. C after adjusting the concentration of sulfuric acid in the solution to 10 to 70% by weight to thereby convert the mixed solution to a mixed gas essentially including NOCl, Cl.sub.2 and nitrogen oxides. The mixed gas is then passed through concentrated sulfuric acid having a concentration higher than 80% which is maintained at a temperature of 80.degree. to 150.

Abstract: Exhaust gases are denitrated by a method comprising removing NO from exhaust gases which comprises washing the exhaust gas with a first aqueous solution containing a chloride of Mg or Ca, and a hypochlorite of Mg or Ca, and washing said washed gas with a second aqueous solution of an alkali.