Showing papers on "Precipitated silica published in 1977"

Novel precipitated siliceous products and methods for their use and production

Abstract: A method for producing a precipitated silicon dioxide having a new combination of physical and chemical properties is disclosed. The pigments are produced by acidulating a solution of an alkali metal silicate with an acid under controlled precipitation conditions. The aqueous reaction medium comprising the precipitated silica is then post-conditioned by introducing a second silicate solution into the reaction vessel and thereafter adding additional acid to react with the said second silicate solution. By varying the amount of the silicate employed in the post-conditioning step, a product is obtained which has a unique combination of physical and chemical properties including reduced wet cake moisture content, high surface areas and oil absorptions, improved surface activity, friability, wetting characteristics, and the like. The product has particular utility for use as a rubber reinforcing agent because of its increased surface activity and oil absorption, etc. The product, however, may be used in paints, paper, detergents, dentifrice compositions, molecular sieves, and polymeric compositions. An unexpected discovery of the invention involves the production of a rubber reinforcing silica which has a decreased wet cake moisture content. In one particularly advantageous embodiment, an adduct material, such as aluminum, is added to control the refractive index and surface area of the product.

Novel precipitated siliceous products

Abstract: A method for producing a precipitated silicon dioxide having a new combination of physical and chemical properties is disclosed. The pigments are produced by acidulating a solution of an alkali metal silicate with an acid under controlled precipitation conditions. The aqueous reaction medium comprising the precipitated silica is then post-conditioned by introducing a second silicate solution into the reaction vessel and thereafter adding additional acid to react with the said second silicate solution. By varying the amount of the silicate employed in the post-conditioning step, a product is obtained which has a unique combination of physical and chemical properties including reduced wet cake moisture content, high surface areas and oil absorptions, improved surface activity, friability, wetting characteristics, and the like. The product has particular utility for use as a rubber reinforcing agent because of its increased surface activity and oil absorption, etc. The product, however, may be used in paints, paper, detergents, dentifrice compositions, molecular sieves, and polymeric compositions. An unexpected discovery of the invention involves the production of a rubber reinforcing silica which has a decreased wet cake moisture content. In one particularly advantageous embodiment, an adduct material, such as aluminum, is added to control the refractive index and surface area of the product.

Preparation of zeolite

Abstract: Crystalline aluminosilicate Type Y zeolite is prepared by reacting silica, alumina, sodium hydroxide and water to produce a slurry of Type Y zeolite and excess silicate containing mother liquor. Silicate is recovered from the mother liquor as precipitated silica/alumina hydrogel by the addition of an acid aluminum salt such as aluminum sulfate. The precipitated silica/alumina hydrogel is used in the zeolite reaction step as a source of silica and alumina.

Method of disposing of precipitated silica

Abstract: A method of disposing of silica dust precipitated from metallurgical furnaces producing products high in silicon content by making mechanically strong metal oxide pellets with the silica dust as a binder is disclosed.

Adsorption of polymers at the solution–solid interface. XIII. Adsorption and steric stabilization with styrene–2‐vinylpyridine copolymers

Abstract: Random and block copolymers of styrene and 2-vinylpyridine, covering the full range of composition, have been synthesized. The adsorption of these polymers from trichloroethylene solution on to precipitated silica has been studied and their ability to impart colloidal stability to the silica dispersions also investigated. Estimates of the layer thickness of adsorbed copolymers have been made. Polystyrene is not adsorbed from trichloroethylene and does not stabilize dispersions of precipitated silica. A random copolymer having 1% 2-vinylpyridine units is adsorbed but shows very little steric stabilization. Random copolymers of 2-vinylpyridine content greater than 10% and AB block copolymers of more than 6% 2-vinylpyridine behave very similarly in respect both of the quantity adsorbed and in their ability to stabilize silica suspensions. Layer thickness does not seem to depend on copolymer composition. Random copolymers with low to intermediate 2-vinylpyridine contents are better steric stabilizers in trichloroethylene than are the corresponding copolymers of methyl methacrylate with styrene: this is attributed in part to the longer sequences of adsorbable units in the vinylpyridine copolymers.

Soft-settling fluosilicate-treated silica flatting agent

Abstract: 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.

Silicone composition and its use

Abstract: A silicone composition with controlled rheological properties and a controlled specific gravity that may vary from 1.035 to 1.06 comprising a diorganopolysiloxane and blends of diorganopolysiloxanes which are compatible with each other which polysiloxanes have a viscosity that may vary anywhere from 10,000 to 500,000 centipoise at 25 DEG C, and a filler selected from the class consisting of fumed silica, precipitated silica, fumed silica treated with a silicone compound, precipitated silica treated with a silicone compound. Such compositions may be utilized with blood samples when the blood sample is treated to separate the blood clots from the blood serum which composition forms an integral barrier between such separated blood clots and the blood serum.