Ppg Industries, Inc.

Roger A Crawford

Paritosh M Chakrabarti

Robert H Juda

Cletus N Welch

Clifford E Loehr

John E Carbaugh

Thomas G Krivak

Robert B Simmons

Howard H Hoekje

Laurence E Jones

Patrick G Malloy

Da-Hung Yang

Hubert J Golden

Described are high solids aqueous slurries of amorphous precipitated hydrated silica, which slurries are of relatively low viscosity. The slurry typically contains from about 40 to about 60 weight percent of hydrated precipitated high structure silica. The viscosity of the high solids slurry is less than about 1000 centipoises. Processes for producing the aqueous high solids silica slurry are disclosed. In one embodiment, a wet cake of amorphous precipitated hydrated silica is liquified and the liquified wet cake charged to a high intensity mill wherein the silica is wet milled until the median agglomerate particle size of the silica is between about 0.3 and about 3 microns. In a further embodiment, finely-divided dry amorphous precipitated silica is slurried in a dispersion mill to the desired solids level and this slurry charged to a high-intensity mill and wet milled therein until the aforesaid agglomerate particle size range is attained. The resulting high solids slurry can be shipped in bulk with only mild agitation to prevent setting. A dispersant may also be added to the slurry prior to milling to retard settling of the silica.

High solids aqueous silica slurry

Described is a titanium dioxide-containing resin saturable paper sheet in which from about 5 to about 40 weight percent of the titanium dioxide filler is replaced with amorphous precipitated silica having an essentially neutral to slightly alkaline, e.g., 6.5 to 8.5, pH and a medium agglomerate particle size of less than 30 micrometers, e.g., 3 to 10 micrometers. The BET surface area of the silica may vary from about 25 to about 200 m.sup.2 /g, e.g., 50 to 100 m.sup.2 /g. Also described are decorative laminates in which the core of the laminate contains at least one of such saturable paper sheets.

Saturating grade paper

Halophors of a complex of bromine or iodine, a tertiary amide, e.g., dialkylformamide or dialkyl acetamide, and a halide, e.g., alkali metal or alkaline earth metal bromide or iodide, are described. The alkyl groups of the tertiary amide are typically lower alkyl groups, i.e., groups containing from 1 to 4 carbon atoms. Also described are solid biocidal compositions, e.g., fumigants, of particulate, free-flowing inert amorphous siliceous carrier having at least a biocidal amount of halophor admixed with said carrier.

Halophor composition

Halophors, e.g., bromophors, comprising a complex of sulfone, e.g., sulfolane, halide ion, e.g., sodium bromide, and halogen, e.g., bromine, are described. Solid, free-flowing halophor compositions of the aforesaid complex and an amorphous siliceous carrier are also described.

Described are free-flowing particulate bromophor compositions of a siliceous carrier having absorbed therein from 1 to 80 weight percent of a bromophor that is a complex of (a) bromine, (b) alkali metal halide and (c) nonionic, anionic or cationic surfactant-type organic material.

Bromophor composition

Halophor biocidal compositions, e.g., bromophors, comprising a complex of N-alkyl substituted-2-pyrrolidone, e.g., N-methyl pyrrolidone, halide ion, e.g., sodium bromide, and halogen, e.g., bromine, are described.

Halophor biocidal compositions

Complexes of bromine and/or iodine, the dihalide of poly(ethylene glycol) and alkali metal or alkaline earth metal halide are described. In particular, complexes of bromine with poly(ethylene glycol) dichloride and alkali metal halide, e.g., lithium or sodium bromide, are described.

A continuous integrated process for the production of neutral calcium hypochlorite in which crystals of by-product sodium chloride are more easily separated from the calcium hypochlorite product is described. The process includes diluting an aqueous slurry of sodium hydroxide, lime and bleach mother liquor with aqueous salt solution saturated with calcium ion and sodium chloride and chlorinating the resulting aqueous admixture in the presence of a seed bed of sodium chloride crystals and calcium hypochlorite crystals at temperatures less than 35.degree. C., e.g., 15.degree.-20.degree. C. A suspension of readily separable, sodium chloride crystals and calcium hypochlorite crystals in chlorinator liquor is conveyed to a classification zone where the sodium chloride and calcium hypochlorite crystals are separated.

Process for producing calcium hypochlorite

A continuous integrated process for the production of calcium hypochlorite in which crystals of by-product sodium chloride are more easily separated for the calcium hypochlorite product is described. The process includes: (a) introducing with agitation into a vessel an aqueous slurry of dibasic calcium hypochlorite, sodium hydroxide, and aqueous salt solution saturated with calcium ion and sodium chloride in amounts at least sufficient to substantially dilute the sodium hydroxide; (b) forwarding the resulting aqueous mixture of step (a) to a chlorination zone containing a seed bed of calcium hypochlorite and sodium chloride crystals; (c) introducing chlorine into the chlorination zone, thereby producing an aqueous suspension containing further quantities of calcium hypochlorite crystals and readily separable significantly larger sodium chloride crystals; and (d) removing aqueous suspension containing such calcium hypochlorite and sodium chloride crystals from the chlorination zone to a classification zone. Calcium hypochlorite crystals are maintained in suspension in and removed from the upper portion of the classification zone; while the larger and more dense crystals of sodium chloride settle and are removed from the lower portion of said classification zone.

Disclosed is a hypochlorite decomposition catalyst of nickel (II) oxide and NiCo.sub.2 O.sub.4 spinel, a hypochlorite destruction process using the catalyst, and a method of synthesizing the catalyst on a porous support.

Method of decomposing hypochlorite ion in a basic solution

Finely divided silica is used as a flattening agent to reduce gloss in lacquers and varnishes, but untreated silica tends to settle out of certain lacquers and varnishes to form a hard layer that is resistant to redispersion. Treatment of the silica with a reactive organopolysiloxane such as methyl hydrogen polysiloxane reduces the tendency of the silica to settle and renders it more easily redispersible. The treated silica may be incorporated into known lacquers, varnishes, and other coating compositions.

Soft-settling silica flatting agent

Novel silica gels are disclosed, as well as their formation from aqueous sodium silicate solutions by neutralizing the hydroxyl ion by electrolysis at a rate whereby the concentration of hydroxide ion is maintained within the range wherein silica gel forms.

Silica gels and their formation by electrolysis of silicate solutions

Finely divided, fluosilicate-treated silica, such as silica flatting agent for use in coating formulations, is prepared by blending in a dry, finely divided state, silica and divalent metal fluosilicate, notably magnesium fluosilicate. In a preferred embodiment, dry pellets of amorphous, precipitated silica and dry magnesium fluosilicate are milled together to produce the fluosilicate-treated flatting agent. In another embodiment, an aqueous solution of magnesium fluosilicate is applied to silica pellets which are then milled.

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Wadsworth, OH, United States of America

Roger A Crawford