Abstract: The invention relates to reinforcing and/or process fibers based on plant fibers, obtainable thereby that plant fibers from which the wood components have been removed are treated with an aqueous solution of at least one metal compound selected among metal oxides, hydroxides, carbonates, sulfates, thiosulfates, sulfites, silicates or phosphates, subsequently washed and treated with an inorganic or organic binding agent or the fibers which have not been washed are neutralized with a mineral acid or that plant fibers from which the wood components have been removed are treated with an oxidation agent or that non-pretreated plant fibers are treated at 250.degree. to 350.degree. C. with the controlled addition of air so that carbonization of the fibers takes place.

Abstract: Anfractuous cellulose fibers exhibiting exceptional high bulking properties are produced by treatment of dry hammermilled wood cellulose fibers with anhydrous liquid ammonia at substantially atmospheric pressure. Fibrous webs of enhanced bulk are produced by preparing an aqueous furnish comprising at least ten percent by weight ammonia treated anfractuous fibers in admixture with conventional papermaking fibers.

Abstract: A multistage process for bleaching high-yield and ultra high-yield pulps is described whereby the pulp is treated sequentially with a peroxygen compound, a reducing compound and a final peroxygen compound to achieve higher brightness levels.

Abstract: Cellulose fibres such as wood pulp are made more suitable for reinforcement of cement products by a treatment which reduces their swelling in aqueous and alkaline mediums. The fibres are dispersed in water, allowed to swell, and impregnated with a solution of a titanium and/or zirconium chelate compound. After drying, the fibres are heated to react the chelate compound(s) with the hydroxyl groups on the cellulose fibres, preferably to produce cross-linking between hydroxyl group residues.The treated fibres are more stable in cement media, and, despite their increased hydrophobicity, are dispersible in cement slurries to give good web formation in the manufacture of cement products such as sheet. They impart improved flexural strength and modulus to cement products compared with untreated cellulose reinforcing fibres.

Abstract: The present invention seeks to provide a method for treating the cellulose obtained from the cellulose cooking process for paper-making purposes. According to this method, the cellulose is separated from black liquor or other similar waste slurry produced in the cooking process by means of compression and washed, bleached and dried, and an essential feature of the present invention is that all the phases of treatment are carried out in a pressure filter (4). The treatment is performed so that black liquor or similar waste slurry is first compressed from the cellulose pulp slurry, whereafter the resulting cellulose cake is washed by conducting washing liquid into the filter, after which the cellulose is bleached by treating the cake with one or several bleaching chemicals led into the filter and by re-washing, if necessary, the cake between the various bleaching phases, and finally, the cellulose cake is dried and removed from the filter.

Abstract: In a two-stage cellulosic pulping and bleaching system having first-stage pulping using standard pulping chemicals and second-stage bleaching using an alkaline oxygen system, the addition of a protector occurs only in the first stage pulping instead of between the first and second stages or in the second stage bleach. A magnesium compound is normally used as the protector.

Abstract: A versatile process and apparatus is presented for producing, in high yields, many different grades of pulp from a single wood specie or for pulping any specie or type of woody material, and for storage and recycling of the by-product liquid and gaseous materials. The process of this invention is virtually pollution free, and the reactant chemicals are recoverable from the by-products. In the alternative, the by-products themselves have a commercial value which may forestall recovery of the reactants. The lignin constituent extracted from the pulp is usable as a resin binder, a wood rehardening agent, or a glue.

Abstract: Efficient lignin removal from cellulosic pulp with decreased cellulose degradation is attained by replacing chlorine with an acidic bromine-chlorine mixture in acidic chlorination of the pulp.

Abstract: A process is provided for the delignification of lignocellulosic material wherein the lignocellulosic material, prior to the delignification, is treated with water or an aqueous solution to remove compounds which catalyze the degradation of carbohydrates and then the delignification is carried out with oxygen and alkali in the presence of a manganese compound to improve the selectivity of the delignification and increase the rate of delignification.

Abstract: A three stage process for pulping lignocellulosic materials, preferably softwood chips comprising: as a first stage treating the lignocellulosic material with a cyanide ion-containing solution at a pH between 7 and 12 to form cyanohydrin groups; in a second stage digesting the thus treated lignocellulosic material with an alkali metal pulping solution containing hydroxyl ions; and as a third stage treating the thus digested lignocellulosic material with 1% to 12% by weight sodium hydroxide, as sodium oxide based on o.d. pulp from the alkaline pulping stage, in the presence of an excess of oxygen.