Abstract: Disclosed is a microwave chemical method for totally extracting fluorine and rare earth from bastnaesite concentrate, including: alkaline conversion defluorination of bastnaesite through microwave irradiation, microwave-assisted leaching of fluorine, solid-liquid separation of leaching solution and microwave-assisted leaching of rare earth. The rare earth hydrochloric acid solution for leaching contains no fluorine ion, so that the fluorine interference of subsequent processes such as impurity removal can be completely avoided; the fluorine and the rare earth are leached with microwaves, which does not need the stirring, so that the automatic control is easy to implement; the fluorine and rare earth leaching speed is high, the leaching time is short and the complete leaching of fluorine and little residual alkali in the slag can be realized by two-time leaching; and no fluorine-containing waste water is discharged, and the total extraction of the rare earth can be realized by one-time leaching.

Abstract: Disclosed is a microwave chemical method for totally extracting fluorine and rare earth from bastnaesite concentrate, including: alkaline conversion defluorination of bastnaesite through microwave irradiation, microwave-assisted leaching of fluorine, solid-liquid separation of leaching solution and microwave-assisted leaching of rare earth. The rare earth hydrochloric acid solution for leaching contains no fluorine ion, so that the fluorine interference of subsequent processes such as impurity removal can be completely avoided; the fluorine and the rare earth are leached with microwaves, which does not need the stirring, so that the automatic control is easy to implement; the fluorine and rare earth leaching speed is high, the leaching time is short and the complete leaching of fluorine and little residual alkali in the slag can be realized by two-time leaching; and no fluorine-containing waste water is discharged, and the total extraction of the rare earth can be realized by one-time leaching.

Abstract: The present invention pertains to the technical field of energy resource chemical industry, and in particular relates to a continuous reaction device and process for synthesizing polyoxymethylene dimethyl ethers by using paraformaldehyde and methylal as feedstock or using trioxane and methylal as feedstock in the presence of an acidic catalyst. The continuous reaction device comprises multiple slurry bed stirred tank reactors connected in series or in combination of series connection and parallel connection, and also comprises an on-line solid-liquid separation device to perform separation of the reaction mixture from the catalyst. Each of the tank reactors is provided with an axial-flow stirring paddle having 2-6 blades per layer, to ensure sufficient mixing of the reactants with the catalyst.

Abstract: The present invention pertains to the technical field of energy resource chemical industry, and in particular relates to a process for producing polyoxymethylene dimethyl ethers by directly using concentrated formaldehyde aqueous solution as feedstock to catalytically react with methanol and/or methylal in a fixed bed reactor. The method of the present invention uses concentrated formaldehyde aqueous solution with a concentration of over 80% by weight to react with methanol and/or methylal, in the presence of an acidic catalyst, to produce the required polyoxymethylene dimethyl ethers.

Abstract: The present invention relates to a method for refining polyoxymethylene dialkyl ethers by catalytic hydrogenation using a slurry bed, wherein, using a slurry bed reactor for refining by hydrogenation, an equilibrium system containing polyoxymethylene dialkyl ethers products is refined by catalytic hydrogenation, so as to remove formaldehyde contained therein. The refining method by hydrogenation described in the present invention can remarkably increase the separation and purification efficiency of polyoxymethylene dialkyl ethers, and the polyoxymethylene dialkyl ethers obtained after subsequent rectification have a purity greater than 99.5%, a product yield greater than 97% and an atom utilization ratio close to 100%.

Abstract: The present invention relates to the field of chemical engineering and technology, in particular relates to the sub-field of synthesis of high quality alternative liquid fuel for engines from non-petroleum based feedstock, more particularly relates to a method for adjusting, controlling and optimizing the synthetic process of polyoxymethylene dimethyl ethers by utilizing chemical thermodynamic principle. The process of the present invention is achieved by conditions wherein the initial temperature of reaction is controlled at 100-120° C., then the temperature is reduced to 50-70° C. by successive stepwise cooling or programmed cooling, the reaction pressure is controlled at 0.1-4.0 MPa, and the molar ratio of paraformaldehyde or trioxane, metered in formaldehyde units, to methylal in the feedstock is 1.5:1-8:1.

Abstract: The present invention relates to a method for refining polyoxymethylene dialkyl ethers by catalytic hydrogenation using a fixed bed, wherein, using a fixed bed reactor for refining by hydrogenation, an equilibrium system containing polyoxymethylene dialkyl ethers products is refined by catalytic hydrogenation, so as to remove formaldehyde contained therein. The refining method by hydrogenation described in the present invention can remarkably increase the separation and purification efficiency of polyoxymethylene dialkyl ether products with various polymerization degree, and the polyoxymethylene dialkyl ethers obtained after subsequent rectification have a purity greater than 99.5%, a product yield greater than 97% and an atom utilization ratio close to 100%.

Abstract: The present invention relates to a method for refining polyoxymethylene dialkyl ethers by catalytic hydrogenation using a slurry bed, wherein, using a slurry bed reactor of refining by hydrogenation, an equilibrium system of products containing polyoxymethylene dialkyl ethers is refined by catalytic hydrogenation, so as to remove formaldehyde contained therein. The refining method by hydrogenation described in the present invention is able to remarkably increase the extracting rate of polyoxymethylene dialkyl ethers, and the polyoxymethylene dialkyl ethers obtained after subsequent rectification have purity greater than 99.5%, yield greater than 97% and atom utilization ratio close to 100%.

Abstract: The present invention relates to a method for refining polyoxymethylene dialkyl ethers by catalytic hydrogenation using a fixed bed, wherein, using a fixed bed reactor of refining by hydrogenation, an equilibrium system of products containing polyoxymethylene dialkyl ethers is refined by catalytic hydrogenation, so as to remove formaldehyde contained therein. The refining method by hydrogenation described in the present invention is able to remarkably increase the extracting rate of polyoxymethylene dialkyl ether products with various degrees of polymerization, and the polyoxymethylene dialkyl ethers obtained after subsequent rectification have purity greater than 99.5%, yield greater than 97% and atom utilization ratio close to 100%.

Abstract: The present invention relates to the field of chemical engineering and technology, in particular relates to the sub-field of synthesis of high quality alternative liquid engine fuel from non-petroleum based feedstock, more particularly relates to a method for regulating and optimizing the synthetic process of polyoxymethylene dimethyl ethers utilizing chemical thermodynamic principle. The process of the present invention Is achieved by conditions wherein the initial temperature of reaction is controlled at 100-120° C., then the temperature is reduced to 50-70° C. by successive stepwise cooling or programmed cooling,, the reaction pressure is controlled at 0.1-4.0 MPa, and the molar ratio of paraformaldehyde or trioxane metered in formaldehyde units to methylal in the feedstock is 1.5:1-8:1. In the process, higher overall yield of the target product can be achieved in the same reaction time, and selectivity of products with higher degree of polymerization of methoxy groups can be increased.