50 results about "Soda pulping" patented technology

This invention provides an improved process for recovering chemicals from black liquor in alkaline pulping, which is achieved by introducing depuration treatments of green liquor and lime before causticization reaction and a two-step-causticization procedure in the causticization procedure of the conventional chemical recovery process. The process of this invention not only avoids the generation of the waste residue (lime mud) from the beginning and saves the recovery and treatment of lime mud, but also can directly produce a series of precipitated calcium carbonate products with various particle sizes by regulating process conditions while the alkali is recovered, said CaCO3 products including a CaCO3 suitable for making coated paper, wherein ≧50% of the CaCO3 has a particle size below 2 μm; a CaCO3 suitable for making neutral sized paper, wherein ≧90% of the CaCO3 have a particle size below 2 μm; a superfine CaCO3 having an average particle size <1 μm. The present invention can be used for treatment of pollution of black liquor in the alkaline pulping.

Calcium carbonate in the form of aragonite crystals suitable for use as a filler for papermaking to give useful properties for bulk, whiteness, opacity, wire abrasion and yield is obtained by taking advantage of the causticization step. Herein disclosed is a process for producing calcium carbonate in the form of aragonite crystals which is useful as a filler for papermaking via the causticization step of the sulfate or soda pulping process, comprising adding an aqueous alkaline solution having a hydroxide ion level of 3 mol / l or less and containing 0.25 mol or less of carbonate ion per 1 mol of quick lime to quick lime and / or slaked lime at a quick lime concentration of 1–60% by weight with stirring to prepare milk of lime, and then adding green liquor to said milk of liquor at a loading rate of 0.002–0.12 g (sodium carbonate) / min / g (quick lime) to perform a causticization reaction at a temperature of 30–105° C.

The invention relates to the field of recovering black liquor in alkaline method pulping in the technical field of pulping and papermaking, in particular to a process for preparing white mud calcium carbonate from green liquor recovered from wood pulp sulfate-method pulping alkali. The process comprises the following steps of: (1) purifying the green liquor; (2) purifying calcined lime; (3) pre-causticizing the green liquor; and (4) causticizing the green liquor. According to the process, most of divalent ferrum ions in the green liquor are masked by adding an aid, trivalent ferrum ions in the calcined lime are masked by purifying the calcined lime, reaction of the trivalent ferrum ions in the calcined lime and the divalent ferrum ions in the green liquor is inhibited, and the generation quantity of hydroxides or sulfides of divalent ferrum in the causticizing process is reduced, so that the high-whiteness white mud calcium carbonate is obtained. The green liquor recovered from the wood pulp sulfate-method pulping alkali is treated by the process, a process flow is simple, and used chemicals are clean and environment-friendly.

The invention discloses a preparation method for a hemp stem-based paper straw, and belongs to the technical field of straw production. The raw paper of the paper straw provided by the invention is made of a hemp full-stem pulp obtained by pulping through a solid oxygen-alkali method, wherein the quantification of inner-layer raw paper is 80 to 120 g / m2; and the quantification of outer-layer raw paper is 50 to 70 g / m2. According to the invention, the raw paper is cut after single-face sizing treatment; straw rolling is then performed on a straw mold, wherein oblique-angle wrapping is adopted for rolling, and the angle is in a range of 30 to 50 degrees; two layers of straw paper are bonded through a synthetic casein environmentally-friendly degradable paper straw hot-water-resistant adhesive; drying treatment is then performed at 110 DEG C for 5 min; and cutting is performed according to set parameters. The hemp stem pulp used for straw paper making is obtained by adopting a solid oxygen-alkali pulping technology which is mild in conditions and friendly to the environment, so natural antibacterial components of hemp stems are greatly retained; the load of environmental pollution isreduced; the paper straw is endowed with a natural antibacterial effect and caters to a sustainable development strategy advocated by the nation; and the paper straw has good economic effect and social effect.

The invention discloses a method for producing an organic fertilizer from reed soda pulping process black liquor and corn fermentation glutamic acid waste liquor and belongs to the field of organic fertilizers. The method comprises the procedures of mixing the black liquor collected from the reed soda pulping process with the waste liquor collected from the process of producing glutamic acid through corn fermentation and producing the organic fertilizer. The procedure of mixing the black liquor collected from the reed soda pulping process with the waste liquor collected from the process of producing the glutamic acid through corn fermentation comprises the steps of storage of the black liquor, storage of the waste liquor and mixing of the black liquor and the waste liquor. The procedure of producing the organic fertilizer comprises the steps of evaporation and concentration, spraying granulation, cooling, sieving and film coverage, so that an organic fertilizer finished product is obtained. According to the method, the black liquor generated through the reed soda pulping process is alkaline and rich in organic matter, natural fulvic acid and other elements; the waste liquor generated in the process of producing the glutamic acid through corn fermentation is acidic and high in nitrogen content. The black liquor and the waste liquor are mixed in a certain proportion, so that the PH values and nutrition of the two types of liquor supplement one another, and after the concentration is raised through evaporation and concentration, the organic fertilizer high in content of the organic matter and nutrition is produced through the spraying granulation technology.

The invention discloses a treatment method of digesting waste steam produced by soda pulping process. The digesting waste steam produced by the soda pulping process is fed into a de-sulfurizing tower to be mixed with lime emulsion sprayed by the de-sulfurizing tower and boiler smoke entering the de-sulfurizing tower in the de-sulfurizing tower, thereby enabling Na content in the smoke discharged from the de-sulfurizing tower is less than 100mg / m3 and enabling K content in the smoke is less than 50mg / m3. The method is simple and easy to operate, de-sulfuration of the lime emulsion is further assisted while eliminating alkaline air peculiar smell of the digesting waste steam, and de-sulfuration effect to the smoke is improved.

The invention provides a nano-iron oxyhydroxide gel composite material and a preparation method and application thereof. The present invention uses alkaline pulping and papermaking black liquor and acrylamide, maleic anhydride, crosslinking agent and initiator to prepare a gel composite material with crosslinked interpenetrating network macromolecules and high permeability, and passes the The method of in-situ synthesis produces nano-iron oxyhydroxide, and the preparation method is simple and feasible, and innovatively realizes the recycling and utilization of alkaline pulping and papermaking black liquor, saves costs and reduces environmental pollution. The nano-iron oxyhydroxide is evenly distributed in the composite material obtained by the present invention, and the interpenetrating network structure of the composite material effectively prevents the aggregation and shedding of the nano-iron oxyhydroxide, and provides a suitable place for the dispersion and fixation of the nano-iron oxyhydroxide , the adsorption and removal effect on heavy metals is obvious, and it has broad application prospects in the field of heavy metal removal.

The invention discloses a treatment method of digesting waste steam produced by soda pulping process. The digesting waste steam produced by the soda pulping process is fed into a de-sulfurizing tower to be mixed with lime emulsion sprayed by the de-sulfurizing tower and boiler smoke entering the de-sulfurizing tower in the de-sulfurizing tower, thereby enabling Na content in the smoke discharged from the de-sulfurizing tower is less than 100mg / m3 and enabling K content in the smoke is less than 50mg / m3. The method is simple and easy to operate, de-sulfuration of the lime emulsion is further assisted while eliminating alkaline air peculiar smell of the digesting waste steam, and de-sulfuration effect to the smoke is improved.

The invention provides a gas-liquid two-phase sulfonated alkali method for preparing a coal water slurry additive from slurry-preparing waste alkali liquor and relates to the fields of resource utilization and environmental protection. The coal water slurry additive comprises the following raw materials in parts by weight: 80-90 parts of waste alkali liquor, 40-48 parts of sulfur dioxide, 65-85 parts of phenol wastewater, 5-9 parts of hydrogen peroxide, 25-45 parts of formaldehyde and 10-20 parts of liquid caustic soda. The used sulfonated alkali method comprises the following steps: adding the waste alkali liquor into a reactor, heating to a temperature of 50-60 DEG C, slowly introducing sulfur dioxide while stirring, and introducing for 20-30 minutes until introduction is completed; adding phenol wastewater and hydrogen peroxide into the reactor, raising the temperature to 70-80 DEG C, maintaining the temperature for 1-2 hours, continuously dropping formaldehyde into the reactor for20-30 minutes, maintaining the temperature for 2-3 hours after dropping completion, and regulating the pH value to be 10 with liquid caustic soda, thereby obtaining the product. According to the method for preparing the coal water slurry additive provided by the invention, the waste alkali liquor and phenol wastewater is recycled for preparing the coal water slurry additive, and recycling and environmental protection can be realized.

The invention relates to a method for preparing bagasse dissolving pulp and pre-extracting hemicelluloses. The method comprises the following steps: bagasse preparation, wherein bagasse is subjected to depithing and washing; prehydrolysis carried out in a globe digester or a hydrolysis boiler with the process conditions during the process for depithing and oven-drying bagasse as follows: 1:0.4-8.0 adopted as the solid-to-liquid ratio, 100-200 DEG C adopted as the hydrolysis temperature, 15-240 minutes adopted as the hydrolysis time, 2-5 adopted as the pH value of the end point of hydrolysis so as to control the hydrolysis process and obtain the hydrolysate with xylo-oligosaccharide as the main component thereof and a small amount of xylose; solid-to-liquid separation and washing, wherein the filtrate is collected to prepare an extracting solution; dissolving pulp prepared by residue alkali method. By adopting the method, bagasse dissolving pulp and bagasse extracting solution which is used to prepare oligosaccharides are obtained. Most of pentosan in bagasse can be extracted by controlling the process conditions of the prehydrolysis. The technical route and the process conditions have strong pertinence, so that the reactivity and the uniformity of bagasse dissolving pulp can be improved. By improving the traditional dissolving pulp alkali method for pulping, bagasse biorefinery based on dissolving pulp pulping can be realized in engineering, so that the production costs for preparing bagasse dissolving pulp and pre-extracting hemicellulose are reduced.

The present invention provides a method for rapidly evaluating advantages and disadvantages of a poplar soda-AQ pulping process. The method comprises: a) determining the lignin content X (%) of a poplar raw material; b) adopting soda-AQ pulping to prepare a poplar pulp, wherein the alkali consumption Y (%) is calculated as Na2O; c) determining the residual alkali content A (%) of the obtained waste liquid and the Kappa number K of the pulp; and d) calculating the advantages and the disadvantages of the poplar soda-AQ pulping process according to the following formula, wherein the process is qualified if K<=Z1=X*21.7+Y*38.9 and A<=Z2=X*0.19+Y*0.2, otherwise the process is unqualified. The method has characteristics of simplicity, efficiency and strong practicality, is suitable for promotion, and provides a new method for rapid adjustment of the poplar soda-AQ pulping process.