52 results about "Soda pulping" patented technology

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.

This invention relates to the delignification of lignocellulosic pulp. More particularly, the invention relates to sulfonation and bleaching of the alkali pulping produced by Kraft pulp processes or produced through combination of alkali pulping processes and extended delignification stages.

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.