The invention discloses a synthetic method of high-purity low-temperature phase cristobalite, wherein noncrystalline silica is made into suspension having a solid content of 40% to 50% with a 1% to 5%ammonium fluoride solution, and pH of the suspension is adjusted to 7-8 with 25% ammonia water and sealed into a high pressure reaction kettle Temperature in the reaction kettle is increased to 80 DEG C-200 DEG C, pressure in the reaction kettle is 1-25MPa, and constant temperature and constant pressure are maintained for 4h-24h; crystallized silica suspension is cooled and filtered, filtrate containing ammonium fluoride is used in step 1) for recycling in pulping, and filter cakes are repeatedly washed 3 to 6 times with high-purity water with a conductivity being less than 10 mu s/cm to remove impurity ions; pre-crystallized filter cakes after washing are dried under a vacuum degree of -1MPa to -2MPa and at temperature of 105 DEG C for 3-6h to obtain pre-crystallized silica powder; the silica powder is charged into a high-temperature muffle furnace with the temperature being raised to 900 DEG C-1200 DEG C at a heating rate of 2-5 DEG C, insulated for 5h-7h, and naturally cooled toobtain high-purity cristobalite micro powder Crystal structure of the cristobalite provided by the invention is a tetragonal phase, and no other crystal phases are mixed, and the purity is as high as 9990% to 9999% 

Synthetic method of high-purity low-temperature phase cristobalite

The invention discloses cristobalite, a preparation method of the cristobalite and application of the cristobalite serving as a carrier of a catalyst The cristobalite has a porous structure; the specific pore volume of the cristobalite is 05 to 07ml/g, the average pore size is 400 to 900nm, most probable pore size is 400 to 850nm, and the cristobalite contains 70 to 999 weight percent of silicon dioxide and 01 to 30 weight percent of tungsten component counted by oxide The cristobalite serving as the carrier of the catalyst has a stable property at high temperature; the cristobalite disclosed by the invention has intrinsic properties of cristobalite prepared by other methods, the porous structure and potential industrial application value, and is expected to develop a new industrial application field of the cristobalite The method for preparing the cristobalite, disclosed by the invention has the advantages of simplicity, low requirement on equipment and low energy consumption; in addition, the silicon dioxide raw material is easily obtained and abundant in reserves, so that the production cost is low

Cristobalite as well as preparation method and application thereof

The invention relates to the field of petrochemical catalysts, and discloses an alumina extrusion molding method, a strip-shaped alumina agent prepared by the method, and application of the strip-shaped alumina agent in catalysts. The alumina extrusion molding method includes the steps of (1) kneading alumina powder, protein-containing starch, dilute nitric acid and optional water to obtain a plastomer; (2) performing extrusion molding on the plastomer to obtain a wet molded body; (3) drying and calcining the wet molded body to obtain the strip-shaped alumina agent. The strip-shaped alumina agent prepared by the method has the advantages of uniform surface, less proneness to bonding and high mechanical strength.

Strip-shaped alumina agent, and extrusion molding method and application thereof

The invention relates to a dichromium trioxide catalyst for catalyzing ethane to prepare ethylene. The dichromium trioxide catalyst comprises porous dichromium trioxide, pores and the external surface of the porous dichromium trioxide are grafted by Si-O-like groups. The invention also relates to a preparation method of the dichromium trioxide catalyst for catalyzing ethane to prepare ethylene and relates to application of the dichromium trioxide catalyst to preparation of ethylene through dehydrogenation of ethane oxidized by carbon dioxide. According to the catalyst provided by the invention, high ethane conversion rate and high ethylene selectivity can be achieved when the catalyst is applied to reaction of catalyzing dehydrogenization of ethane to prepare ethylene.

Ke Li

Papers

Cristobalite as well as preparation method and application thereof

Strip-shaped alumina agent, and extrusion molding method and application thereof

Dichromium trioxide catalyst for catalyzing ethane to prepare ethylene and preparation thereof