Onoda Cement Co., Ltd.

Koyo Precision Instruments, Inc.

Hiroshi Uchikawa

Hajime Kato

Masao Shimoda

Mutsuo Munekata

Shigejiro Mori

Shunichiro Uchida

Hiroyuki Motohashi

Haruhiko Komatsu

A kinetofrictional force testing apparatus has a spindle rotated by a variable speed motor. A load cell is disposed in opposition to a disk coupled to the spindle and includes a test head for the disk, a rotational frequency controlling synthesizer, and a personal computer for general control. The rotational speed of the motor is varied on the basis of clock pulses from the rotational frequency controlling synthesizer associated with the personal computer. The rotational frequency and rotational acceleration/deceleration of the disk coupled to the spindle are digitally controlled by a predetermined program set in the personal computer. The test head is supported by a leaf spring having strain gauges mounted on its lateral surfaces. Frictional forces are measured by the output of the strain gauges.

Kinetofrictional force testing apparatus

The specification discloses a self-hardening mold sand having surface stability and high compressive strength yet containing a comparatively small amount of water. The mold sand is prepared by mixing a self-hardening binder of clinker powder, containing 11CaO.7Al.sub.2 O.sub.3. CaX.sub.2 (where X is a halogen atom) and a sulphate, with a binder additive consisting of a surface active agent of which the main component is .beta.-naphthalene-sulphonic acid formaldehyde condensate salt, and then mixing this binder and binder additive with sand, water and preferably a retarder consisting of an organic carboxylic acid or boric acid.

Self-hardening mold sand

A method of decreasing the content of nitrogen oxides in a combustion exhaust gas which comprises the steps of mixing the combustion exhaust gas with at least one material selected from the group consisting of ammonia, an ammonium salt, urea and an aqueous solution thereof, and bringing the resulting mixture into contact at a temperature of 600.degree. C. to 1,500.degree. C. with any of the baked materials obtained during the process extending from preparation of cement blending materials to production of cement clinker by baking said cement blending materials, thereby decreasing the content of, for example, nitrogen monoxide (NO) in the combustion exhaust gas.

Method of decreasing the content of nitrogen oxides in combustion

This invention relates to a process for treating a sludge or a drainage containing chromium (VI) compounds with a calcium haloaluminate bearing rapid hardening cement in a short period of time. The solidified material developes high strength and has shown a extremely Cr.sup.6+ fixation.

Process for treating a sludge or drainage containing chromium (VI)

This invention relates to mixtures of molding sand which comprise a mixture of a molding sand with a rapid hardening cement containing calcium aluminate as amorphous glass and/or crystals, and/or calcium haloaluminate, a polymer water holding agent and a lime, or mixture of a molding sand with the above-mentioned rapid hardening cement, a polymer water reducing agent, a lime, and, if necessary, a foaming agent, and in either case with water. The mixture also provides a method of mixing the ingredients except for water and then kneading the mixture with water.

Molding sand mixtures

A process for manufacturing a rapid hardening portland cement clinker containing a calcium halo-aluminate having the formula; 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2, in which X is a halogen, characterized by adding at least one sulfur compound selected from calcium sulfate, calcium sulfite and calcium sulfide to the mixed raw materials comprising mainly an aluminous material, a calcareous material, a silicious material, an iron source and a halogen source, and burning the obtained mixture in an oxidizing temperature.

Process for manufacturing rapid hardening portland cement clinker

This invention relates to a method for retarding the setting time of rapid hardening cement which comprises adding a boric compound to cement manufactured by adding insoluble anhydrite to clinker powder containing 11CaO.7Al.sub.2 O.sub.3.CaX.sub.2 or adding the clinker to insoluble anhydrite and intergrinding the mixture, and a method for still more retarding the setting time of rapid hardening cement which comprises adding a boric compound to cement containing a set-retarding agent other than the boric compound.

Method for retarding the setting time of rapid hardening cement

A sludge having a water/solid high ratio and containing a substance having a harmful influence upon the setting of portland cement is solidified by mixing the sludge with rapid hardening cement containing calcium haloaluminate.

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Funabashi, Japan

Hiroshi Uchikawa