The Dow Chemical Company

Exxon Research and Engineering Company

Battelle Development Corporation

Silag, Inc.

Bhupendra K Parekh

William M Goldberger

Harold M Epstein

Bobby P Faulkner

A two-step method for separating mineral grains from their ores is practised by first applying a shock discharge directly through the ore sample producing shock waves emanating from along the discharge path and reflected shock waves (tension waves) from grain boundaries and other discontinuities in the ore, such tension waves resulting in tensile stresses in the ore greater than the strength of the boundary or discontinuity whereby to gross spall the sample generally along the discharge path and to microfracture the region near the discharge path. The second step comprises comminuting the microfractured ore by impact or non-impact means to further reduce the ore generally along microfractures wherein considerably less energy is expended in the second step than would be required to reduce the ore to the same condition without the first step. A second non-impact step is preferably the application of acoustic energy to the microfractured region of the ore resulting in enlargement of microfractures and subsequent spalling of these microfractured regions.

Two stage comminution

The present invention is directed to silicon carbide whisker recovery from a mixture of silicon carbide whiskers and carbonaceous silicon carbide particles. The invention involves shredding the mixture down to a specified particle size, dispersing the mixture in water to form an aqueous mixture, agitating the aqueous mixture, adding surface active reagents to the aqueous mixture, agitating the resulting water-reagent mixture, subjecting the water-reagent mixture to froth flotation having at least three stages, removing tailings therefrom containing water and silicon carbide whiskers and removing float therefrom containing reagents and carbonaceous silicon carbide particles, performing a solid-liquid separation on the tailings and the float, thereby obtaining from the aqueous solution the desired silicon carbide whiskers and obtaining from the reagent solution a carbonaceous silicon carbide particle product.

Recovery of silicon carbide whiskers from coked, converted rice hulls by

The present invention is directed to silicon carbide whisker recovery from a mixture of silicon carbide whiskers and carbonaceous silicon carbide particles. The invention involves shredding the mixture down to a specified size, dispersing the mixture in water to form an aqueous mixture, agitating the aqueous mixture, mixing the aqueous mixture with an immiscible organic solvent which is lighter than water, agitating the resulting water-organic solvent mixture, allowing the organic solvent and its contents to rise above the water and its contents, separating the two liquid phases into an organic solvent phase and an aqueous phase and, lastly, performing a solid-liquid separation on each of the two phases, thereby obtaining from the aqueous solution the desired silicon carbide whiskers and obtaining from the organic solvent solution a carbonaceous silicon carbide particle product.

Metal beads, e.g., magnesium beads, or Mg alloy beads, having a high degree of rotundity, and having a thin coating of sludge or slag ingredients, are recovered from entrapment in a friable contiguous material of sludge or slag material by (a) a primary milling of the friable matrix in a hammer mill or impact mill, (b) screening the material to collect the desired particle sizes, (c) attriting the material in a secondary milling operation to further, and gently, grind sludge material from around the beads, and (d) separating the rotund beads from the pulverized matrix material by using a shape-classifier, such as a slanted shaker table. The material may be treated beforehand by melting the metal-containing sludge or slag, adding a flux or emulsifier material with stirring to cause dispersion of the metal into a relatively narrow particle size range and then freezing the molten mixture. The invention is especially useful in the case of Mg beads, since Mg beads are malleable and pyrophoric.

Growing community of inventors

Columbus, OH, United States of America

Bhupendra K Parekh