The invention discloses a method for crystal seed precipitation of a sodium aluminate solution, comprising the following steps of: 1), mixing a sodium aluminate solution with Al(OH)3 crystal seeds, starting to stir and precipitate at 60 DEG C to 80 DEG C, wherein the causticity ratio of the sodium aluminate solution is 1.25 to 1.60 and the crystal seed coefficient is 1.0 to 4.0; 2), cooling the precipitation system to 40-50 DEG C; and 3), continuously heating the precipitation system within 5 hours to 20 hours, wherein the heating amplitude is 5 DEG C to 25 DEG C, and the final temperature is not higher than 65 DEG C. By adoption of the method provided in the invention, the crystal seed precipitation process of the sodium aluminate solution is effectively reinforced, and the technical and economical indexes of yield in the precipitation, cycle efficiency of aluminium oxide production, and the like are improved.

Method for crystal seed precipitation of sodium aluminate solution

The present invention addresses the problem of providing a method for producing vanadium dioxide-containing particles having excellent thermochromic performance and transparency. This method for producing vanadium dioxide-containing particles is a method for producing, using hydrothermal reaction, vanadium dioxide-containing particles having thermochromic performance, wherein the method is characterized in that the vanadium dioxide-containing particle surface is surface modified without causing separation of a solvent and the vanadium dioxide-containing particles.

Method for producing vanadium dioxide-containing particle and dispersion

The invention relates to a method for preparing a catalyst used for synthesizing ethyl alcohol through hydrogenation on dimethyl oxalate. The catalyst contains a carrier, a catalytic active componentloaded on the carrier, and an optional catalytic promoter, concretely the catalyst contains: (A) based on element, 1-50wt% of elements which are selected from Cu, Fe, Ni, Co, Ag and Au and taken as the catalytic active component; (B) based on element, 0-10wt% of elements which are selected from third main group elements, transition elements and lanthanide elements and taken as the catalytic promoter; and (C) the carrier. The catalyst is prepared by adopting a urea-assisted hydrothermal synthesis method, and CO2 supercritical drying is adopted, so that high ethyl alcohol selectivity can be obtained, and high dimethyl oxalate conversion rate also can be obtained when the prepared catalyst is used for producing ethyl alcohol through hydrogenation on dimethyl oxalate. The invention also relates to the catalyst prepared by adopting the method provided by the invention and application of the catalyst in production of ethyl alcohol through hydrogenation on dimethyl oxalate.

Preparation method of catalyst used for synthesizing ethyl alcohol through hydrogenation on dimethyl oxalate, catalyst obtained by adopting preparation method and application thereof

A gas extraction hole sealing method based on radial strong expansion comprises steps as follows: (1), determining the hole sealing position and the hole sealing depth; (2), determining a hole sealing material with four characteristics of good compactness, high strength, high expansibility and high permeability; (3), mounting a radial strong expansion extraction hole sealing device; (4), inserting the radial strong expansion extraction hole sealing device into a drill hole for expansion hole sealing; (5), connecting an orifice pipe and a gas extraction pipe for gas extraction after expansion of a polyurethane mixed liquid ladle ends. The adopted device is simple in structure, high in hole sealing speed and simple and convenient to operate, and a worker can rapidly and skillfully operate the device. The effective hole sealing length of an extraction drill hole is well increased; due to compactness of the hole sealing material, the hole sealing material can bear pressure difference between the drill hole and the outside roadway, and air in the roadway is prevented from entering the drill hole from the possible slit of the hole sealing material.

Gas extraction hole sealing method based on radial strong expansion

The invention discloses a surface-modified aluminum hydroxide and a preparation method thereof. The surface-modified aluminum hydroxide comprises, by mass, 30 parts of aluminum hydroxide and 0.3-1.2 parts of a modifier. The modifier is Span, a complex of Span and stearic acid, or a complex of Span and sodium stearate. The Span is Span 40, Span 60 or Span 85. The preparation method comprises the following steps of preparing an aluminum hydroxide aqueous suspension having a mass concentration of 10%, heating the aluminum hydroxide aqueous suspension to a temperature of 80-85 DEG C, preparing a modifier-ethanol solution having a modifier mass concentration of 1%, adding the modifier-ethanol solution into the aluminum hydroxide aqueous suspension, heating the mixed suspension to a temperature of 70-90 DEG C, keeping the temperature for 0.5-1.5h, and carrying out standing, suction filtration, washing, drying and grinding so that the surface-modified aluminum hydroxide which is conducive to uniform dispersion in a polymer base and improves base compatibility is obtained.

Modified aluminum hydroxide and preparation method thereof

The invention discloses a preparation method of a copper-based catalyst for selective hydrogenation of dimethyl oxalate. The catalyst is prepared from an active component, an auxiliary and a carrier, wherein metal copper serves as the active component, orthosilicate serves as a silicon source, alcohol serves as a cosolvent, the auxiliary prepared through a sol-gel method is used for modifying the silicon-copper catalyst for solvothermal aftertreatment, the type of the solvent is changed to realize selective hydrogenation of oxalate, and methyl glycolate or glycol or ethanol is synthesized in an oriented mode. Compared with a sol-gel ammonia distillation method, it can be achieved that the dimethyl oxalate conversion rate is 100% at a low reaction temperature (180 DEG C), the selectivity of glycol is 98% or above, and meanwhile the use quantity of ammonia sources is reduced. Compared with a conventional precipitation method, there is no need to wash a catalyst precursor, so that a large quantity of water resources are saved, meanwhile, wastewater treatment capacity and difficulty are lowered, and environment friendliness of the whole process is improved.

Preparation method of copper-based catalyst for selective hydrogenation of dimethyl oxalate

Method for preparing high-whiteness aluminium hydroxide micropowder from Bayer process sodium aluminate solution

A gas-extraction hole-sealing material is composed of dual components A and B. The component A is polyisocyanates. The component B comprises: by volume, 28-30 parts of hard-foam polyether, 15-17 parts of high-resilience polyether, 5-6 parts of stable polyether, 8-12 parts of polyaspartic acid ester, 20-28 parts of a fire retardant, 2-3 parts of a foam stabilizer, 2-3 parts of amine-terminated polyether, 5-6 parts of a foaming agent, and 5-6 parts of a catalyst. When in use, the component A and the component B are used according to the volume ratio of 1:1 to be mixed in a gas-extraction sealing hole through a grouting pump, so as to form a compact seal coat. In comparison with polyurethane, the Gutejie composite material has better mechanical strength, wear resistance, corrosion resistance, oil resistance, water resistance, aging resistance and temperature cycling and compression resistance, will not contract, is not sensitive to water and moisture like polyurethane, and is not easily influenced by environmental temperature and humidity during construction.

Gas-extraction hole-sealing material

The utility model discloses a blowout prevention device for safety drilling in a coal bed, which mainly comprises four parts, namely a hole sealing device, a gas and water slag separation channel, a while drilling rotation device and a gas and water slag separator, wherein the hole sealing device is arranged in a drilling hole, an expanding rubber cylinder structure is arranged at the periphery of the hole sealing device, is arranged between a hole sealing sleeve and a wall face of the drilling hole, and is used for sealing, the tail part of the hole sealing device is connected with the gas and water slag separation channel, the separation channel has a three-way structure comprising a main sleeve pipe and a bypass, the main sleeve pipe is used for a drilling rod to pass through, a drilling stop protection device is arranged on the main sleeve pipe, the bypass is connected with the gas and water slag separator, the end part of the main sleeve pipe is provided with the while drilling rotation device, the while drilling rotation device has a three-layer structure, an outer layer is provided with a shell, a bearing is embedded into the inner layer of the shell, a drilling rod sleeve is embedded into the inner layer of the bearing, and a sealing gasket is arranged between the inside of the drilling rod sleeve and the drilling ord. By the blowout prevention device, sprayed coal powder and gas can enter an arranged system during drilling, the problem of bad sealing of the traditional blowout prevention device in allusion to various drilling rods, particularly a triangular drilling rod is solved, and potential safety hazards such as orifice spraying during drilling or transfinite gas particularly brought by drilling and the like are eliminated.

Blowout prevention device for safety drilling in coal bed

The utility model discloses a hole sealing device for gas extraction. The hole sealing device comprises a gas extraction pipe, wherein a sealing cylinder is sleeved on the gas extraction pipe, a glue outlet of a glue solution injection pipeline is sleeved in the sealing cylinder, two ends of the sealing cylinder are provided with clips for fixing and sealing, a front sealing and clamping baffle and a rear sealing and clamping baffle are respectively sleeved at two ends of the extraction pipe. According to the utility model, a polyurethane hole-sealing material is adopted to seal the hole for the coal mine gas extraction device in a section of closed space and foams in the closed space by using the hole sealing device, so that the compactness of the hole sealing material and the plugging effect on gasp around a drilled hole are enhanced, and gas leakage points can be reduced under the condition of negative pressure extraction, so that the concentration of gas extracted through hole drilling is increased and the gas extraction time is prolonged.

Chen Tao

Papers

Preparation method of copper-based catalyst for selective hydrogenation of dimethyl oxalate

Method for preparing high-whiteness aluminium hydroxide micropowder from Bayer process sodium aluminate solution

Gas-extraction hole-sealing material

Blowout prevention device for safety drilling in coal bed

Hole sealing device for gas extraction