Provided is a method for industrially mass-producing a modified xylopolysaccharide from biomass. The biomass used as a raw material includes xylan in plant cell walls, having at least one kind of substituents selected from acetyl, feruloyl arabinofuranosyl and coumaroyl arabinofuranosyl groups in the side chains of xylan. A passage controlling mechanism is internally arranged to generate plug-flow onto a slurry containing the biomass at a solid content in 10 mass % to 30 mass %. The hydrothermal treatment is performed under the controlled conditions: at a temperature of 160 C. or more, at a pressure equal to or higher than the saturated water vapor pressure at said temperature, and with a reaction severity R.sub.0 ranging from 3000 to 7000. A modified xylopolysaccharide is obtained as preserving the substituents in the side chains of xylan by performing a continuous hydrothermal treatment in a cylindrical plug-flow reactor.

Selective flocculants for beneficiation of bauxite ore comprise one or more types of polysaccharides comprising one or more types of pentosan units. Also disclosed are processes for enriching aluminum hydroxide and alumina from bauxite ore comprising the aluminum hydroxide and alumina and clay materials and and/or siliceous gangue, wherein the process comprises carrying out a selective flocculation process in the presence of one or more of the selective flocculants.

The embodiments of the present disclosure provide a method for extracting xylose liquid and cellulose with high purity from corn straw. The method includes raw material screening, raw material preprocessing, alkali processing, acid hydrolysis, and gradient alkali processing. The embodiments of the present disclosure adopt a gradient selective refining method for extracting a high-purity xylose liquid and cellulose from the corn straw, so as to maximize the extraction of the xylose from the corn straw, and at the same time, to separate and extract a high-purity cellulose product from straw residue under a low-cost process processing.

Provided is a method for industrially mass-producing a modified xylopolysaccharide from biomass. The biomass used as a raw material includes xylan in plant cell walls, having at least one kind of substituents selected from acetyl, feruloyl arabinofuranosyl and coumaroyl arabinofuranosyl groups in the side chains of xylan. A passage controlling mechanism is internally arranged to generate plug-flow onto a slurry containing the biomass at a solid content in 10 mass % to 30 mass %. The hydrothermal treatment is performed under the controlled conditions: at a temperature of 160? C. or more, at a pressure equal to or higher than the saturated water vapor pressure at said temperature, and with a reaction severity R.sub.0 ranging from 3000 to 7000. A modified xylopolysaccharide is obtained as preserving the substituents in the side chains of xylan by performing a continuous hydrothermal treatment in a cylindrical plug-flow reactor.

The embodiments of the present disclosure provide a method for extracting xylose liquid and cellulose with high purity from corn straw. The method includes raw material screening, raw material preprocessing, alkali processing, acid hydrolysis, and gradient alkali processing. The embodiments of the present disclosure adopt a gradient selective refining method for extracting a high-purity xylose liquid and cellulose from the corn straw, so as to maximize the extraction of the xylose from the corn straw, and at the same time, to separate and extract a high-purity cellulose product from straw residue under a low-cost process processing.