Abstract: The method of the present invention is one for efficiently obtaining a condensed adsorbable gas from a gas containing a low concentration of the adsorbable gas by subjecting the original gas to the process of adsorption and desorption using adsorption columns packed with an adsorbent and then condensing the exhausted desorbed gas containing a higher concentration of the adsorbable gas, in which the adsorption column after adsorption is subjected to desorption after a desorbed gas exhausted from the second adsorption column to be mentioned later is introduced into the adsorption column to make the adsorbable gas contained in the desorbed gas be adsorbed by the column; an exhaust gas exhausted during the condensation of a desorbed gas and containing the noncondensed adsorbable gas is introduced into the second adsorption column to make the adsorbable gas contained in the exhaust gas be adsorbed by the column; and the desorbed gas containing the adsorbable gas and exhausted during the desorption of the second co

Abstract: Magnesium hydroxide of a substantially spherical particle form having an average particle size of from 5 to 500 .mu.m and a specific surface area of from 25 to 1 m.sup.2 /g.

Abstract: Magnesium hydroxide of a fine plate-like particle form having an average particle size (d) of from 0.2 to 0.8 .mu.m as measured by a light transmission type liquid phase sedimentation method, wherein the proportion of particles having a particle size of d+0.5 .mu.m or larger is not higher than 50% by weight based on the weight of the total particles, and the particle thickness distribution is such that the proportion of particles having a thickness of 0.05 .mu.m or less is not higher than 5% by number and the proportion of particles having a thickness of 0.2 .mu.m or more is not higher than 20% by number.

Abstract: A process for producing highly pure magnesium hydroxide, which comprises reacting magnesium hydroxide starting material containing impurities, with an aqueous solution containing a water-soluble calcium salt and carbon dioxide to form an aqueous solution containing a magnesium salt and calcium carbonate precipitates whereby said impurities are transferred to the precipitates, filtering off the precipitates, then reacting the aqueous solution containing the magnesium salt, with ammonia to form a slurry comprising magnesium hydroxide solid and an aqueous solution containing an ammonium salt, and filtering the slurry to obtain highly pure magnesium hydroxide solid and an aqueous solution containing the ammonium salt.

Abstract: A method for treating a waste gas containing a fluorine component and/or a chlorine component, which comprises contacting the waste gas with magnesium oxide particles having a specific surface area of from 100 to 200 m.sup.2 /g.

Abstract: A process for producing anhydrous sodium carbonate by the pyrolysis of wet sodium bicarbonate, which comprises (a) a step of forming a complex salt selected from the group consisting of Na.sub.2 CO.sub.3.3NaHCO.sub.3 and Na.sub.2 CO.sub.3.NaHCO.sub.3.2H.sub.2 O by the pyrolysis of wet sodium bicarbonate under such temperature and pressure conditions that said complex salt is stable, and (b) a step of forming anhydrous sodium carbonate by the pyrolysis of said complex salt under such temperature and pressure conditions that the anhydrous sodium carbonate is stable.

Abstract: A fire retardant polyolefin composition comprising from 40 to 70% by weight of magnesium hydroxide and from 30 to 60% by weight of a polyolefin, wherein from 0.3 to 10% by weight, based on the magnesium hydroxide, of at least one N-hydroxyalkylamide of a higher fatty acid selected from the group represented by the general formulas: ##STR1## where R is a C.sub.11 -C.sub.17 alkyl or alkylene group and R' is C.sub.n H.sub.2n where n is an integer of 1 to 6, is incorporated.

Abstract: A process for producing calcium hypochlorite hydrate crystals, which comprises continuously supplying a basic calcium hypochlorite slurry and chlorine gas, and reacting them at a temperature of from 20.degree.-50.degree. C. and at a chlorination rate of from 92 to 98.5% to precipitate calcium hypochlorite crystals at a crystallization velocity of not greater than 200 kg/m.sup.3 per hour.

Abstract: A process for producing hydrogen fluoride with use of fluorite as starting material and by conducting reactions in a first reactor and a second reactor wherein a reaction of fluorite with sulfuric acid, sulfuric anhydride and steam in the first reactor is conducted at a conversion of from 35 to 90% while maintaining the reaction temperature within a range of from 140.degree. to 240.degree. C. by controlling the respective amounts of the sulfuric anhydride, steam and sulfuric acid.

Abstract: An anhydrous sodium carbonate crystal is produced by crystallizing a sodium carbonate hydrate crystal from an aqueous solution of sodium carbonate in a sodium carbonate hydrate crystallizing zone and transforming said sodium carbonate hydrate to an anhydrous sodium carbonate crystal in the presence of a crystal habit modifier in an anhydrous sodium carbonate crystallizing zone and recycling a separated mother liquor into said sodium carbonate hydrate crystallizing zone.

Abstract: An anhydrous sodium carbonate crystal is produced by crystallizing an anhydrous sodium carbonate crystal from an aqueous solution of sodium carbonate in the presence of 0.5 to 10 wt. % of sodium chloride and 0.3 to 20 wt. % of sodium hydroxide and separating the crystal from a mother liquor.

Abstract: Sodium bicarbonate is produced in an apparatus comprising a reactor system for the production of sodium bicarbonate which comprises a housing having a plurality of reaction zones being placed in sequence from a last zone to a first zone, each being in liquid and gas flow communication with each adjacent zone; carbon dioxide inlet means being disposed at the bottom of the last zone so that carbon dioxide introduced into said last zone moves upwardly through said zone, and is discharged through a gas-liquid separator at the top of said zone and is then introduced into the bottom of the next adjacent zone, until said gas reaches the top of the first zone where it is discharged through a carbon dioxide gas outlet; inlet means for feeding an ammoniacal brine or a mother liquor to be carbonated into the top of the first zone, counter-currently to the upward movement of the carbon dioxide gas in said first zone, wherein said brine or mother liquor is passed downwardly through said first zone and flows sequentially i

Abstract: An aqueous solution of sodium hydroxide containing soluble impurities such as a concentrated catholyte produced by a diaphragm electrolysis is cooled by a coolant or a heat-exchanger to form a slurry containing sodium hydroxide hydrate crystals and fine impurity crystals. The fine impurity crystals are adsorbed on bubbles which are formed by vaporizing a dissolved coolant or introducing a gas in the slurry and separated from the slurry.

Abstract: An aqueous solution of sodium hydroxide containing soluble impurities such as a concentrated catholyte produced by a diaphragm electrolysis is cooled by a coolant or a heat-exchanger to form a slurry containing sodium hydroxide hydrate crystals and fine impurity crystals. The fine impurity crystals are adsorbed on bubbles which are formed by vaporizing a dissolved coolant or introducing a gas in the slurry and separated from the slurry.