Abstract: A system includes a measured value storing device in which a product measured value acquired periodically and a manufacturing condition measured value are stored, a product threshold value setting device that sets a product threshold value for determining whether a product is normal or not, an abnormality accumulating device that acquires a product abnormality cumulative frequency where the product abnormality measured value exceeds the product threshold value, a product threshold value changing device that changes the product threshold value, a condition threshold value setting device that sets a condition threshold value to be compared with a manufacturing condition measured value, a condition abnormality accumulating device that acquires a condition cumulative frequency, a condition threshold value changing device that changes a condition threshold value, and a cause identifying device that identifies a cause of abnormality based on the distribution of the product abnormality cumulative frequency and a man

Abstract: A system includes a measured value storing device in which a product measured value acquired periodically and a manufacturing condition measured value are stored, a product threshold value setting device that sets a product threshold value for determining whether a product is normal or not, an abnormality accumulating device that acquires a product abnormality cumulative frequency where the product abnormality measured value exceeds the product threshold value, a product threshold value changing device that changes the product threshold value, a condition threshold value setting device that sets a condition threshold value to be compared with a manufacturing condition measured value, a condition abnormality accumulating device that acquires a condition cumulative frequency, a condition threshold value changing device that changes a condition threshold value, and a cause identifying device that identifies a cause of abnormality based on the distribution of the product abnormality cumulative frequency and a man

Abstract: The slurry subjected to aggregation processing by a line mixer is supplied to a slurry feed member via a slurry supply passage and then fed radially outward from slurry fed outlets within a sedimentation tank. Therefore, liquid flow hardly takes place below the slurry feed member and the settling velocity of the solid is increased. The slurry feed member is arranged close to the boundary face of the thickened slurry zone, and thus the settling distance of the solid is shortened. Accordingly, the residence time of the solid is shortened to a great extent. In addition, the sedimentation tank can be constructed to be sealed and solid-liquid separation can be also performed under the pressurized state.

Abstract: A process for the production of aluminum hydroxide from an alumina-containing ore comprising, in a process for the production of aluminum hydroxide involving extraction of alumina from an alumina-containing ore by an aqueous alkaline solution, supplying a slurry containing the alumina-containing ore at a high solid content which is prepared from a small amount of an alkaline solution together with an aqueous alkaline solution which is so preheated to a temperature that a preheated temperature is enough high to have a temperature after the mixing with the slurry which is higher than an extraction temperature of alumina, simultaneously or after the mixing them, to an extraction apparatus comprising of a tube reactor, extracting alumina from the alumina-containing ore under extraction conditions of a temperature of 120.degree.-160.degree. C.