Abstract: A method for lowering the iron content of calcium carbonate is disclosed. The method involves addition of an iron chelating agent to an aqueous calcium carbonate slurry, reducing the pH of the aqueous calcium carbonate by employing carbon dioxide containing gas, while maintaining the aqueous calcium carbonate slurry at an elevated temperature. The slurry is stirred, filtered, washed and dried. The calcium carbonate product resulting from the process of the present invention has a reduced iron content.Calcium carbonate produced according to the method of this invention is particularly suitable for use as food or pharmaceutical additives and may also be useful as a filler in papermaking processes or as additives in plastic products.

Abstract: The disclosed invention provides a method of forming refractory linings for maintaining refractory linings against attack by corrosive materials such as those present in steel manufacture. The method entails spraying an aqueous mixture of a refractory composition that includes at least one refractory material onto the working surface of a refractory lining. Spraying is performed to provide one or more layers of the refractory composition on the refractory lining after each exposure of the lining to corrosive materials such as those incurred in steel manufacture.

Abstract: This invention relates to a nozzle and a nozzle mix gunning system incorporating the nozzle for pneumatically propelling dry or wetted particulate gunning material toward a substrate a distance removed from the nozzle and at an angle to the line of sight of the operator. The nozzle comprises a plurality of substantially straight tubular sections. Each section is lined with an abrasion resistant material, and joined to the other sections in a manner that produces a curvature in the nozzle.

Abstract: A hydrophobic filler material for alkaline paper is disclosed. The filler material comprises finely divided particles of an inorganic material, a majority of particles having a surface all of which is substantially modified with a water soluble C.sub.12 -C.sub.22 fatty acid salt and a metal ion in an amount at least effective to complex all of the fatty acid salt present. An alkaline paper is disclosed. The alkaline paper comprises a hydrophobic filler material comprising finely divided inorganic material, a majority of particles having substantially all of their surface being modified with a water soluble C.sub.22 fatty acid salt. A method for improving sizing of alkaline paper is disclosed, comprising preparing a filler material and adding the same to cellulose fiber. The filler material is prepared by selecting finely divided particles of an inorganic material and substantially modifying all of the surface of a majority of the particles with a C.sub.12 -C.sub.

Abstract: The disclosed invention provides a method of forming refractory linings for maintaining refractory linings against attack by corrosive materials such as those present in steel manufacture. The method entails spraying an aqueous mixture of a refractory composition that includes at least one refractory material onto the working surface of a refractory lining. Spraying is performed to provide one or more layers of the refractory composition on the refractory lining after each exposure of the lining to corrosive materials such as those incurred in steel manufacture.

Abstract: The invention is directed to a low density material suitable for use as an expendable liner in a molten metal handling vessel such as tundish. The low density materials include a first component having at least one decomposable compound capable of producing gas, a second component having a reactable compound for reacting with the decomposable compound in the presence of water to cause the decomposable compound to generate a gas, and a refractory aggregate. The invention also relates to a method for making the low density material and to the resultant material as well.

Abstract: The disclosed invention relates to a composition comprising finely divided particles of an inorganic material treated with a cellulose derivative modified by or containing at least one ionic substituent. The disclosed invention further relates to a method of providing paper of improved brightness. The disclosed invention also relates to a method of providing finely divided particles of inorganic material, treating the particles with a cellulose derivative modified by or containing at least one ionic substituent, and adding the treated particles to cellulose fiber during an alkaline process for making paper. Also, an alkaline paper comprising the finely divided particles of inorganic material treated with the cellulose derivative is disclosed.

Abstract: The disclosed invention relates to a composition comprising finely divided cationically charged particles of an inorganic material treated with at least one of anionic polysaccharide or anionically modified polysaccharide. The disclosed invention further relates to a method of providing paper of improved strength. The method entails providing finely divided particles of inorganic material, treating the particles with at least one of anionic polysaccharide or anionically modified polysaccharide, and adding the treated particles to cellulose fiber during an alkaline process for making paper. Also, an alkaline paper comprising the finely divided particles of inorganic material treated with at least one of anionic polysaccharide or anionically modified polysaccharide is disclosed.

Abstract: A method and article of manufacture thereof is provided for reducing brightness reversion in bleached lignin-containing pulps or newsprint by the treatment of the bleached lignin-containing pulp or newsprint with 2,5-dihydroxydioxane. In one embodiment, calcium carbonate is added to enhance the activity of 2,5-dihydroxydioxane.

Abstract: An aggregated synthetic hydrotalcite having a substantially spheroidal shape and an average diameter of up to about 60 .mu.m is disclosed. The aggregates are composed of individual platy particles having plate diameters of from about 0.05 to about 10 .mu.m. The material has a low tapped density, a high pore volume and a high specific surface area. A process for producing the product is also disclosed. Product particle size is determined by controlling process parameters including reaction temperature and pH, stirring speed of the reaction mixture, and reactant addition rates and concentrations, including aqueous solutions of soluble magnesium and aluminum salts, which are mixed in a molar ratio of from about 2.5:1 to 4:1, and a basic solution containing excess carbonate and base to maintain the reaction mixture at a pH of from about 8.5 to about 9.5.

Abstract: A hydrophobic filler material for alkaline paper is disclosed. The filler material comprises finely divided particles of an inorganic material, a majority of particles having a surface all of which is substantially modified with a water soluble C.sub.12 -C.sub.22 fatty acid salt and a metal ion in an amount at least effective to complex all of the fatty acid salt present. An alkaline paper is disclosed. The alkaline paper comprises a hydrophobic filler material comprising finely divided inorganic material, a majority of particles having substantially all of their surface being modified with a water soluble C.sub.12 -C.sub.22 fatty acid salt. A method for improving sizing of alkaline paper is disclosed, comprising preparing a filler material and adding the same to cellulose fiber. The filler material is prepared by selecting finely divided particles of an inorganic material and substantially modifying all of the surface of a majority of the particles with a C.sub.12 -C.sub.

Abstract: An aggregated synthetic hydrotalcite having a substantially spheroidal shape and an average diameter of up to about 60 .mu.m is disclosed. The aggregates are composed of individual platy particles having plate diameters of from about 0.05 to about 10 .mu.m. The material has a low tapped density, a high pore volume and a high specific surface area.A process for producing the product is also disclosed. Product particle size is determined by controlling process parameters including reaction temperature and pH, stirring speed of the reaction mixture, and reactant addition rates and concentrations, including aqueous solutions of soluble magnesium and aluminum salts, which are mixed in a molar ratio of from about 2.5:1 to 4:1, and a basic solution containing excess carbonate and base to maintain the reaction mixture at a pH of from about 8.5 to about 9.5.

Abstract: A method and article of manufacture thereof is provided for reducing brightness reversion in bleached lignin-containing pulps or newsprint by the treatment of the bleached lignin-containing pulp or newsprint with 2,5-dihydroxydioxane. In one embodiment, calcium carbonate is added to enhance the activity of 2,5-dihydroxydioxane.

Abstract: The present invention discloses an alkali oxide free low density refractory material especially adapted for use as a disposable liner material for molten metal containing vessels. This material includes about 0.1 to about 2 weight percent of a stiffening agent, about 0.1 to about 2 weight percent of a set retarding agent, about 0.1 to 6 weight percent of density reducing materials, about 0.1 to about 5 weight percent of a plasticizer, up to about 2 weight percent of a secondary binder, and the balance of a refractory aggregate which is preferably MgO. The stiffening agent and set retarding agent are used in substantially the same amounts to provide the disclosed refractory material with increased resistance to slumping while, at the same time, allowing spraying apparatus residence times of up to 30-40 minutes without clogging. The composition includes less than about 0.

Abstract: A process for adsorbing gold from a leach pulp by means of activated carbon is described in which the leach pulp (the leach solution together with the subdivided gold bearing ore) is diluted to a specific gravity of less than that of the activated carbon and is subsequently passed upwardly through a multistage liquid/solid contacting column. The contacting column is of the type having perforated plates or trays defining a series of vertically adjacent stages and the operation of the column has a cycle which includes a first part during which upward flow of diluted pulp fluidizes the activated carbon, a second part in which the carbon is allowed to settle on the trays and a third part during which a reverse flow of diluted pulp carries carbon downwardly through the column from one stage to another. In the third part of the cycle, loaded carbon is removed from the lowermost stage and treated to recover adsorbed gold therefrom.

Abstract: A liquid/solid contacting column and method of operating same is provided. The column is of the type in which a vertical series of stages is defined by vertically spaced perforated plates or trays which allow for forward flow up the column during which solid adsorbent in a fluidized state is contacted by liquid flowing up the column, and flow of solid adsorbent and liquid down the column during a reverse flow part of the operating cycle. The column is provided with outlet means in the form of one or more ports or ducts for a stream of liquid and solid adsorbent from the space above the lowermost plate or tray and wherein such outlet means is located at a predetermined height above said lowermost plate or tray.

Abstract: A relatively solid, stable biomass reaction product is provided produced from microorganisms having metal uptake properties when contacted by an aqueous solution containing metal cations. The biomass reaction product is produced by treating cells thereof with a caustic solution, whereby the biomass reaction product after drying is characterized in the particulate state of having substantially enhanced uptake of metal cations from aqueous solutions as compared to the metal uptake property of the microorganism before treatment. The biomass reaction product in the particulate state is preferably immobilized in an insoluble binder.

Abstract: A relatively solid, stable biomass reaction product is provided produced from microorganisms having metal uptake properties when contacted by an aqueous solution containing metal cations. The biomass reaction product is produced by treating cells thereof with a caustic solution, whereby the biomass reaction product after drying is characterized in the particulate state of having substantially enhanced uptake of metal cations from aqueous solutions as compared to the metal uptake property of the microorganism before treatment.

Abstract: A method is provided for the recovery of precious metals, such as gold and silver, from refractory sulfidic material and refractory carbonaceous sulfidic material. The sulfidic material is pulped and bioleached using either facultative or obligate thermophiles at temperatures in excess of about 45.degree. C. and ranging up to about 90.degree. C. The residue remaining from the bioleach is neutralized and washed and the precious metals therein recovered by dissolution.

Abstract: The invention provides a magnetic separator for the separation of a fluid mixture into a more magnetic portion and a less magnetic portion wherein the magnetic field generator comprise a pair of solinoid coils located opposite each other and between which a conveyor assembly carrying a matrix of magnetic elements and the fluid material to be treated passes during use of the magnetic separator.