Abstract: When low-quality iron ore is used as a coal liquefaction catalyst, in order to improve its catalytic activity it is subjected to one or a combination of reduction, heat-treatment, or washing with or immersion in water for a long period of time so as to remove catalyst poisons before it is used as a catalyst. When high-quality iron ore is used, it is first reduced with carbon monoxide and then used as a catalyst.

Abstract: When low-quality iron ore is used as a coal liquefaction catalyst, in order to improve its catalytic activity it is subjected to one or a combination of reduction, heat-treatment, or washing with or immersion in water for a long period of time so as to remove catalyst poisons before it is used as a catalyst. When high-quality iron ore is used, it is first reduced with carbon monoxide and then used as a catalyst.

Abstract: A plurality of different types of raw material coal fines are sieved to a size not exceeding 1.5 mm; said sieved raw material coal fines are blended so as to satisfy the following conditions:(a) AP index: 75 at the minimum,(b) Mean maximum reflectance: 1.20% at the minimum, and(c) A [dilatation] - [contraction] value of from -2 to +5% when carbonized under conventional conditions in a horizontal type coke oven battery at a heating rate of 5.degree. C/min. (350.degree. - 600.degree. C);said blended raw material coal fines thus obtained are mixed with a binder and formed to produce a formed coal; and then, said formed coal thus obtained is charged into a horizontal type coke oven battery and carbonized, whereby a high-strength formed coke for blast furnace is a slight mutual agglomeration is manufactured.

Abstract: A method for reducing NO.sub.x gas contained in an exhaust gas to harmless N.sub.2 gas with NH.sub.3 gas using an iron oxide catalyst, characterized in that said iron oxide catalyst comprises a substance consisting essentially of hematite crystals (.alpha.-Fe.sub.2 O.sub.3), and the peak intensity of X-rays diffracted on the (110) plane of the lattice of said crystal has a ratio of 0.6 to about 1.0 to that of X-rays diffracted on the (104) plane of said crystal lattice.

Abstract: A method of removing nitrogen oxides from an exhaust which comprises the steps of contacting an exhaust containing nitrogen oxides and ammonia with a reducing catalyst received in a reactor to reduce the nitrogen oxides to nitrogen gas, wherein iron ore catalyst lumps having a particle size of 25 mm or less and forming a catalyst bed in the reactor are used as a reducing catalyst; the iron ore lumps of the catalyst bed are let to fall gravitationally through the reactor continuously or intermittently; and the iron ore catalyst lumps discharged from the reactor are either used as raw material for iron manufacture or fed back to the reactor to be reused as a reducing catalyst after being sieved.

Abstract: Powder and/or fine particles containing mainly oxides of iron or ferroalloys, which are used or generated in ironworks, steelworks, etc. are sieved to a grain size range between about 32 mesh and about 10mm and used as reduction catalyzer. A reactor is filled with said reduction catalyzer. Exhaust gas containing nitrogen oxides and with added ammonia is passed in contact with said reduction catalyzer through said reactor, while heating said reduction catalyzer to a temperature between about 300.degree. C and about 370.degree. C, whereby nitrogen oxides are removed from said exhaust gas by reduction. Said reduction catalyzer can be used as material for ironmaking, without requiring any further treatment, after use as catalyzer.

Abstract: A method of removing a nitrogen oxide from an exhaust containing the same which comprises preparing an absorbent solution by adding divalent copper ions alone or a mixture of the divalent copper ions and divalent manganese ions to an acid aqueous solution containing sulfites or acid sulfites of ammonium, alkaline metals, or alkaline earth metals or a mixture of two or more of these compounds; and introducing the plant exhaust into the absorbent solution to carry out reaction between the sulfite radical of the absorbent solution and the nitrogen oxides contained in the exhaust to reduce the nitrogen oxides to nitrogen gas.