Seitetsu Kagaku Co., Ltd.

Saburo Hayashi

Kazuo Haruna

Tohru Okabe

Hiroo Tsuchiya

Masahiro Inoue

Thoru Okabe

Takeo Tanabe

Mitsuji Adachi

Kazuyoshi Okamoto

Toshio Osada

Syohiti Okada

Shigeaki Mizutani

Mochifumi Mizutani

Mitsukazu Mukai

Teizo Isono

Akira Otsuji

In production of high concentration oxygen by a pressure-swing-adsorption method using air as a raw material, air is introduced into a first step adsorption apparatus packed with a zeolite molecular sieve and is subjected to a pressure-swing-adsorption operation to obtain a non-adsorbed gas comprising oxygen as the major component, argon and nitrogen; the non-adsorbed gas is introduced into a second step adsorption apparatus packed with a carbon molecular sieve and is subjected to a pressure-swing-adsorption operation to separate argon and nitrogen from oxygen as a non-adsorbed gas; and the desorbed oxygen is obtained as high concentration oxygen.

Process for producing high concentration oxygen by a

A process for the removal and recovery of mercury and, if desired, other heavy metals from incinerator waste water produced by washing waste gases from incinerators, which comprises adding to the waste water a reducing agent or a combination of oxidizing and reducing agents, subjecting the thus added waste water to stripping treatment in the presence of ferrous ion to obtain a mercury vapor-containing gas and simultaneously form spinel type crystalline compounds and then cooling said gas to separate and recover the mercury. If desired, said spinel type crystalline compounds are also removed from the mercury-free waste water.

Process for removal of mercury from waste water

A process for obtaining high concentration argon from air by means of pressure-swing-adsorption, characterized by passing air through a zeolite molecular sieve-packed adsorption apparatus and a carbon molecular sieve-packed adsorption apparatus in this order, subjecting the air to pressure-swing-adsorption operation independently in the above pieces of adsorption apparatus, thereby obtaining concentrated argon and high purity oxygen simultaneously.

Process for obtaining high concentration argon by

A tanning process comprising pickling a hide which has previously subjected to beamhouse works such as depilation if necessary, decalcification and beating, in the presence of urotropin and at least one tanning improver selected from chromium and aluminum salts as well as from phenolic compounds, organic compounds containing nitrogen and sulphur or halogen atoms, organic carboxylic acids, organotin compounds, copper compounds and arsenic compounds.

Tanning process and tanning compositions

By subjecting a hide which has completed beamhouse work to a pickling treatment in the presence of urotropin (hexamethylenetetramine) and then to a chrome-tanning treatment, pH control of chrome-tanning bath becomes simpler and easier, the combination between hide and basic chrome complex increases, and the amount of residual chromium in the waste water can be minimized. Further, by treating the formed leather which has completed tanning treatment with ammonia or ammonium salt of weak acid in the chrome bath after use, the workability in the finishing steps improves, quality of the leather additionally improves, and the chromium content of the residual solution can be made nearly zero.

Tanning method

A catalyst for removal of nitrogen oxides which shows extremely good catalytic activity and is excellent in durability and is low in the activity of oxidizing SO.sub.2 into SO.sub.3 be prepared at a low cost by impregnating a titanium oxide carrier with a vanadium sulfate, a vanadyl sulfate or a mixture thereof and then reacting a mixed gas consisting of 0.05 to 100% by mole of ammonia and 99.95 to 0% by mole of an inert gas which is inert to both ammonia and vanadium and vanadyl sulfates with the impregnated carrier while the reaction mixture is maintained at a temperature of 300.degree. to 520.degree. C., and preferably 370.degree. to 450.degree. C., or by shaping a mixture of titanium oxide and a vanadium sulfate, a vanadyl sulfate or a mixture thereof into a desired shape and then reacting a mixed gas consisting of 0.05 to 100% by mole of ammonia and 99.95 to 0% by mole of an inert gas which is inert to both ammonia and vanadium and vanadyl sulfates with the shaped mixture while the reaction mixture is maintained at a temperature of 300.degree. to 520.degree. C., and preferably 370.degree. to 450.degree. C.

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Kakogawa, Japan

Saburo Hayashi