Abstract: The present invention provides new process for preparing inorganic fine particles, which suppresses agglomeration and adhesion of particles due to heat when preparing powder from a raw material liquid such as a slurry of zirconia hydrate fine particles in order to obtain inorganic raw material powder having sharp particle size distribution. Furthermore, the present invention provides a new process for preparing inorganic fine particles, which can make the chemical structure homogenous among the produced particles and inside the particles even in a multi-component system. The present invention provides a process for preparing inorganic fine particles, which comprises heating and applying impulse waves to a raw material liquid.

Abstract: This method relates to a non-draining type human waste disposal by pulse combustion drying. In the method, a pulsating combustion gas is discharged downward into a vertically cylindrical dryer from a pulse combustor disposed at the top of the dryer, and making contact the pulsating combustion gas with residue-removed human waste, digester chamber sludges or their mixtures charged therein, turning the charged matters to dried powder and steam under the dryer conditions of 120.degree.-150.degree. C., withdrawing the dried powder from the bottom of the dryer and the combustion gas containing steam from a lower side of the dryer, dust-removing the combustion gas containing steam maintained at 120.degree.-150.degree. C., deodorizing the dust-removed combustion gas, and exhausting the deodorized gas into the air. As an alternative method, the dried powder and the combustion gas containing steam are withdrawn from the bottom of the dryer, the withdrawn material maintained at 120.degree.-150.degree. C.

Abstract: A low bulk density hollow fine powder of alkali metal compound can be produced from an aqueous solution of the compound by one step. The method for producing a low bulk density hollow fine powder of alkali metal compound according to the present invention comprises a step of contacting an aqueous solution of an alkali metal compound with a pulsating combustion gas.

Abstract: A heat recovery system is disclosed for a pulse combustion drying system in which the exhaust gas of combustion from a pulse combustor passes successively through a dryer, a product collector and a scrubber. The heat of the exhaust gas is recovered in the scrubber by spraying with water or other liquid and transferring by heat exchange the heat absorbed by the water to compressed air, and passing the heated compressed air successively through a membrane heat exchange tube on the wall of the product collector and a membrane heat exchange tube on the wall of the dryer. The air is discharged finally in an air-injection nozzle of the pulse combustor.

Abstract: It is an object of the present invention to provide a pulse combustion method and a valveless pulse combustor in which the strong sound wave energy and the combustion gas generated by explosions in the combustion chamber are effectively used for drying of a substance with no waste of sound wave energy and heat of the combustion gas.A pulse combustion method according to the present invention is characterized by a step of pushing the sound wave energy and the combustion gas which flow toward the air intake back to the combustion chamber by jetting a compressed gas toward the air intake. By means of this step, the sound wave energy and the combustion gas which were generated at the time of explosion in the combustion chamber and flow toward the air intake are pushed back to the combustion chamber and further to the exhaust pipe by a stream of the compressed gas. This enables the sound wave energy and the combustion gas which have been conventionally wasted to be used for drying of a substance.

Abstract: This disclosure relates to a rotary kiln for heating and calcining lime, waste, etc. and to a method of direct reduction of metal oxide using such a kiln. A cylindrical outer shell is mounted for rotation on its axis, and a stationary inner tube extends into the interior of the shell. Fuel and/or combustion air flow passages extend within the tube, and burner nozzles are supported by the tube and are connected to the passages. The tube is concentrically or eccentrically mounted adjacent the upper side of the space within the shell, thereby positioning the burner nozzles at the optimum positions.