Kureha Kagaku Kogyo Kabushiki Kaisha

Shigeru Saitoh

Tetsuya Watanabe

Koji Konno

Tadashi Nakamura

Toshiya Mizuno

Naohiro Murayama

Shinsuke Yoshikawa

Nobuhiro Moriyama

Tamotsu Miyamori

Masahiro Segawa

Mitsuo Onozuka

Kunihide Yaguchi

Masaaki Shimada

Ichiroh Ishibashi

Takeshi Imura

Masaki Shimada

Katsutoshi Komahashi

Kenji Kodama

Noboru Suzuki

An apparatus for purifying crystals comprises a crystal purifying tower having a transverse cross-section of two partially overlapping circles, stirrers each comprising a rotational shaft passing through the center of each of the circles and having blade members disposed spirally on its surface, a solid-liquid separation plate disposed at the bottom portion of the tower, a liquid take out means disposed below the separation plate, a starting crude crystal feed means disposed above the separation plate, a purified crystal take out means disposed at the upper portion of the tower, heating means disposed in the tower in a multistage manner along the longitudinal direction of the tower, and purified crystal circulation means for cooling a portion of purified crystals taken out from the tower and feeding back the cooled crystals to the tower at at least one portion of the tower.

Apparatus for purifying crystals

Ultrafine fiber of an ethylene tetrafluoride copolymer having an orientation degree (.pi.) of at least 0.6 and an average fineness of 0.0001 to 0.9 denier. A process for producing such fiber or a porous membrane thereof is also disclosed.

Ultrafine fiber of an ethylene tetrafluoride copolymer and a process for

Crystals containing a molten liquid at the bottom of a purifying tower are cooled, so that three effects i.e., washing, sweating and recrystallization are improved while maintaining a heat balance within a tower to thereby obtain highly pure crystals. The apparatus according to this invention comprises a crystal purifying tower of a transversal cross sectional configuration in which two circles are partially joined to each other and in which a stirrer having blade members spirally attached around the surface of a rotational shaft is disposed at the center for each of the circles, the purifying tower having a starting material feed means about at the middle thereof, a heating means and a product take out port at the upper portion thereof, a cooled crystal feed means, a low purity crystal component take out means and a means for extracting a portion of the crystal component at low purity out of the system at the bottom thereof, wherein the crystal component at low purity taken out by the low purity crystal component take out means is crystallized and then cooled by a means disposed outside the purifying tower for crystallizing and then cooling the crystal component at low purity, and the crystals thus crystallized and then cooled are fed by means of the cooled crystal feed means to the purifying tower.

The invention relates to a furnace assembly adapted for the combustion of wastes. Its grating is arranged tiltable and a mass of mineral particles is mounted on the latter and for acting as a provisional and stationary furnace bed.

Furnace adapted for burning city-, industrial and the like wastes

Oxides of nitrogen can be removed efficiently from a gas containing such oxides of nitrogen by bringing said gas into contact with an aqueous solution containing an organic acid alkali salt and a salt of metal selected from the group consisting of Fe, Co, Ni, Cu and Mn in the presence of a sulfurous acid alkali salt. The efficiency for removing oxides of nitrogen is much improved by use of a polybasic acid alkali such as ethylenediamine tetracarboxylic acid alkali salt or nitrilo-tricarboxylic acid alkali salt as said organic acid alkali salt.

An absorbing solution for the removal of nitrogen oxide form a gas

A method of removing nitrogen oxides from a gas containing nitrogen oxides and converting same to a salt of imidodisulfonic acid, wherein the gas containing nitrogen oxides is brought into contact with an aqueous solution which contains at least one ferrous salt and at least one sulfurous acid alkali salt to absorb the nitrogen oxides in solution in the form of imidodisulfonic acid alkali salts.

Method of removing nitrogen oxides from a gas as a salt of

Disclosed is a method for removing hydrogen chloride from an exhaust gas containing same without discharging any waste water from the system, which method includes bringing the exhaust gas into contact with a slurry containing calcium carbonate or calcium hydroxide to absorb the hydrogen chloride in the form of calcium chloride and then recovering the calcium chloride as solid calcium chloride hydrate.

Method for removing hydrogen chloride from exhaust gas containing same

A melt-molded polyvinylidene fluoride or polymonochlorotrifluoroethylene sheet having a thickness of about 20 .mu. to 2 mm and a spherulite size of less than about 10 .mu., whereby the sheet transmits more than about 40% of the dorno rays in a wavelength region of about 2,800 to 3,300 A, and a sun room using as a light admitting plate a sheet or plate of the polyvinylidene fluoride or the polymonochlorotrifluoroethylene permitting transmission of the physiologically active rays in sunlight.

Dorno ray transmitting sheet

A method of effectively removing nitrogen oxides which are entrained in a gas, wherein a nitrogen oxide-containing gas is brought into contact with an aqueous solution which contains at least one ferrous salt and one sulfurous acid alkali salt to absorb the nitrogen oxides in the solution in the form of imidodisulfonic acid alkali salt, hydrolyzing the imidodisulfonic acid alkali salt to obtain a hydrolyzate-containing solution, and adding nitrous acid, nitrous acid anhydride, or nitrite to the hydrolyzate-containing solution to generate nitrogen.

Method of removing nitrogen oxides from a gas containing nitrogen oxides

A method of removing nitrogen oxides from a gas containing nitrogen oxides and converting same to ammonium sulfate, wherein the gas containing nitrogen oxide is brought into contact with an aqueous solution which contains at least a ferrous salt and a sulfurous acid alkali salt to absorb the nitrogen oxides in the solution in the form of imidodisulfonic acid alkali salts, and the imidodisulfonic acid alkali salt is converted into ammonium sulfate by hydrolysis at a temperature higher than 100.degree. C after separation and recovery of the salt from solution.

Method of removing nitrogen oxides from a gas and for converting same to

A sulfur dioxide-containing exhaust gas is scrubbed by contact with an aqueous solution containing an alkali salt of an organic acid to dissolve sulfur dioxide in the aqueous solution in the form of alkali sulfite. The alkali sulfite in the solution is converted by oxidation into alkali sulfate, which is contacted for reaction with a calcium compound to form calcium sulfate. The calcium sulfate so formed is separated by filtration from the aqueous solution for recovery while the filtrate is recycled for use as the aqueous solution for scrubbing the exhaust gas. The concentration of alkali sulfite in the scrubbing aqueous solution is maintained at a level of less than 1% to ensure efficient removal of sulfur dioxide from the exhaust gas in the form of calcium sulfate.

Growing community of inventors

Iwaki, Japan

Shigeru Saitoh