The present invention is related to a method for: reducing metals content in a Kraft pulping process comprising adding magnesium to a black liquor that is returned to the pulping operation; reducing aluminum content in a pulping process by adding magnesium to the black liquor to provide a green liquor having a specific molar ratio of magnesium:aluminum; producing or treating a green liquor having a specific molar ratio of magnesium:aluminum by adding magnesium to the black, weak black, strong black liqueurs; and producing hydrotalcite by the addition of at least 0.04-5.0 mols of magnesium:aluminum present at the weak black, strong black liqueurs, or a combination thereof. It is also provided a pulp mill comprising a digester (1), a washer (2), an optionally pulp bleaching, a weak black liquor concentrator (4), among other parts.

The present invention relates to a method for increasing the rate of enzymatic hydrolysis of a polysaccharide substrate, said method comprising at least one step of: enzymatic hydrolysis of said substrate with a mixture of enzymes, said mixture comprising at least one enzyme selected from lytic polysaccharide monooxygenases; in the presence of chemically modified lignin, wherein during at least part of the time of said step of enzymatic hydrolysis, H.sub.2O.sub.2 is supplied to the reaction mixture comprising said substrate, said mixture of enzymes and said chemically modified lignin, either from an external source or by generation in situ.

The present invention relates to a method for increasing the rate of enzymatic hydrolysis of a polysaccharide substrate, said method comprising at least one step of: enzymatic hydrolysis of said substrate with a mixture of enzymes, said mixture comprising at least one enzyme selected from lytic polysaccharide monooxygenases; in the presence of chemically modified lignin, wherein during at least part of the time of said step of enzymatic hydrolysis, H.sub.2O.sub.2 is supplied to the reaction mixture comprising said substrate, said mixture of enzymes and said chemically modified lignin, either from an external source or by generation in situ.

The present invention relates to a process for the controlling the sodium and sulfur levels in a pulp mill, comprising the steps of: a) providing a pulp mill stream comprising sulfide and having a total alkali concentration of at least 2 Molar; b) supplying a portion of the pulp mill stream to a reactor comprising sulfide oxidizing bacteria and removing sulfide from the pulp mill stream by subjecting said stream to sulfide oxidizing bacteria in the presence of oxygen, and at a pH in the range 8 to 11, to oxidize the sulfide to elemental sulfur, c) withdrawing from the reactor a treated pulp mill stream comprising sulfur, wherein the portion of the pulp mill stream is mixed with a portion of the sulfide oxidizing bacteria present in the reactor prior to supplying the pulp mill stream to the reactor in step b).

The present invention relates to separation of lignin from an aqueous slurry containing lignocellulosic biomass material comprising providing the aqueous slurry having an initial pH level to at least one precipitation phase for precipitating lignin, performing said precipitation phase during a reaction time including adding at least one acidifier, wherein a decrease in the pH value of the aqueous slurry to a lower ph level is created, separating the lignin in a first separation phase, performing an acidification phase including, performing a re-slurry step including mixing lignin from the first separation phase with an acidifier to form an acidic slurry, establishing a reaction temperature in a range of 65-95 degrees Celsius. and performing a retention step including maintaining the acidic slurry at the reaction temperature for a reaction time period of 30-60 minutes, and separating the treated lignin content from the acidic slurry in a second separation phase.

Discloses are a method for preparing fluff pulp from bamboos, and the fluff pulp prepared thereby. The method comprises the following steps: treating the bamboos with high-concentration alkali at a relatively mild temperature, after a certain period of treatment, replacing a treatment liquid for separating hemicellulose with a weak black liquor; Kraft cooking the treated bamboos to obtain unbleached bamboo pulp, removing rejects in the unbleached bamboo pulp by using a slotted screen; then removing miscellaneous cells by using a microporous sieve; carrying out two stages of oxygen delignification on the screened pulp; carrying out ECF bleaching treatment of a D.sub.0EpD.sub.1P process; and finally obtaining the bamboo fluff pulp which has high whiteness, low DCM extract content, low ash content and long fiber length, contains 4.2-4.6 million fibers per gram, and has relatively high bulkiness.

Discloses are a method for preparing fluff pulp from bamboos, and the fluff pulp prepared thereby. The method comprises the following steps: treating the bamboos with high-concentration alkali at a relatively mild temperature, after a certain period of treatment, replacing a treatment liquid for separating hemicellulose with a weak black liquor; Kraft cooking the treated bamboos to obtain unbleached bamboo pulp, removing rejects in the unbleached bamboo pulp by using a slotted screen; then removing miscellaneous cells by using a microporous sieve; carrying out two stages of oxygen delignification on the screened pulp; carrying out ECF bleaching treatment of a D.sub.0EpD.sub.1P process; and finally obtaining the bamboo fluff pulp which has high whiteness, low DCM extract content, low ash content and long fiber length, contains 4.2-4.6 million fibers per gram, and has relatively high bulkiness.

The present invention describes a method intended for lignin recovery, said method comprising: a step of mixing a stream of black liquor with an acidic biomass stream for providing a mixed heterogenous stream; a step of separating the mixed stream in a separation unit for providing one aqueous light phase stream and one lignin-containing heavy phase stream.

The present invention describes a method intended for lignin recovery, said method comprising: a step of mixing a stream of black liquor with an acidic biomass stream for providing a mixed heterogenous stream; a step of separating the mixed stream in a separation unit for providing one aqueous light phase stream and one lignin-containing heavy phase stream.

Discloses are a method for preparing fluff pulp from bamboos, and the fluff pulp prepared thereby. The method comprises the following steps: treating the bamboos with high-concentration alkali at a relatively mild temperature, after a certain period of treatment, replacing a treatment liquid for separating hemicellulose with a weak black liquor; Kraft cooking the treated bamboos to obtain unbleached bamboo pulp, removing rejects in the unbleached bamboo pulp by using a slotted screen; then removing miscellaneous cells by using a microporous sieve; carrying out two stages of oxygen delignification on the screened pulp; carrying out ECF bleaching treatment of a D.sub.0EpD.sub.1P process; and finally obtaining the bamboo fluff pulp which has high whiteness, low DCM extract content, low ash content and long fiber length, contains 4.2-4.6 million fibers per gram, and has relatively high bulkiness.