Development of cellulose-based toys with moulded fibre production method

In this work, a toy was developed from bleached sulphate pulp via a moulded fibre production technique. Moulded fibre products are generally used to preserve main products from damage during transportation and stow them in a particular order. This work investigated the use of moulded fibre products in daily life as final products. Bleached softwood sulphate pulp was used for the experiments to avoid the potential hygiene problems of using recycled paper for toy production. The physical properties of different degrees of refined sulphate pulp were evaluated during toy sample production. The results indicated that toys produced with bleached softwood sulphate pulp had optimum compression strength (22 kpgf) at the 35 SR° freeness level. Produced prototypes satisfied EN 71-3:2013+A1(2014) in terms of migration element limits.

Absorption of H2S with sodium hydroxide from the black liquid of sulfate pulp production

При обработке черного щелока сульфат-целлюлозного производства серной кислотой (с целью частичного или полного высаждения сульфатного лигнина) происходит выделение сероводорода и других серосодержащих газов. Рассмотрен процесс поглощения этих газов путем абсорбции водным раствором гидроксида натрия. Процесс подкисления черного щелока серной кислотой сопровождается выделением сероводорода, который должен подвергаться абсорбции. Промышленные методы получения сульфатного лигнина предусматривают применение абсорбции сероводорода водными растворами гидроксида натрия. В качестве абсорбентов при поглощении серосодержащих газов применяют растворы щелочи или воду в зависимости от состава сероводородных газов и дальнейшего использования продуктов абсорбции. Водные растворы гидроксида натрия применяются для абсорбции в тех случаях, когда обработке подвергаются значительные объемы газов, содержащих преимущественно сероводород. При этом в процессе абсорбции получается раствор сульфида натрия. В случае подкисления черного щелока серной кислотой абсорбции подвергается сероводород, который содержит и другие примеси. Для того чтобы абсорбция сероводорода гидроксидом натрия прошла с образованием конечного продукта сульфида натрия, необходимо использовать определенную концентрацию щелочи. Для достижения необходимого результата использовался симплекс-метод по целочисленной матрице, который позволил выбрать оптимальные параметры проведения процесса абсорбции сероводорода гидроксидом натрия. В результате получен раствор белого щелока с высокой сульфидностью, что является положительной характеристикой процесса варки сульфатной целлюлозы, так как уменьшает продолжительность варки до определенной степени провара, облегчает процесс делигнификации, а также увеличивает выход целлюлозы. Это позволяет уменьшить расход реагентов при приготовлении белого щелока, подаваемого на варку технологической щепы. По предложенному методу осаждение лигноуглеводного комплекса из черного щелока проводят без применения содорегенерационных котлов, где процесс получения белого щелока связан с получением плава щелочей и последующим получением из него зеленого щелока, с дальнейшей регенерацией белого щелока, используемого для варки сульфатной целлюлозы. В результате установлена принципиальная возможность абсорбции сероводорода раствором гидроксида с выполнением требований, предъявляемых к белому щелоку. While black liquor from sulfate pulp process treatment with sulfuric acid (for partial or full sulfate lignin precipitation) emission of hydrosulfide and other sulfur containing gasses happens. It is reviewed process of the gasses absorption by sodium hydroxide solution. The process of acidification of black liquor with sulfuric acid is accompanied by the release of hydrogen sulfide, which must undergo absorption. Industrial methods for producing sulphate lignin involve the use of hydrogen sulfide absorption by aqueous solutions of sodium hydroxide. Alkali solutions or water are used as absorbents for absorption of sulfur-containing gases, depending on the composition of hydrogen sulfide gases and the further use of absorption products. Aqueous solutions of sodium hydroxide are used for absorption in cases where significant volumes of gases containing predominantly hydrogen sulfide are processed. In the process of absorption is obtained a solution of sodium sulfide. In the case of acidification of black liquor with sulfuric acid, hydrogen sulfide is subjected to absorption, which contains other impurities. In order for the absorption of hydrogen sulfide by sodium hydroxide to form the final product of sodium sulfide, it is necessary to use a certain concentration of alkali. To achieve the required results, a simplex method was used for the integer matrix, which allows choosing the optimal parameters for the process of hydrogen sulfide absorption by sodium hydroxide. As a result of the experiment, a solution of white liquor with high sulfidity is obtained. which is a positive characteristic of the sulphate pulp boiling process, as it reduces the cooking time to a certain degree of penetration, facilitates the delignification process, and also increases the cellulose yield. This allows reducing the consumption of reagents in the preparation of white liquor fed to the cooking chips. According to the proposed method, the precipitation of the black liquor lignohydrocarbon complex is carried out without the use of soda recovery boilers, where the process of obtaining white liquor is associated with obtaining alkaline water and subsequent production of green liquor from it, with further regeneration of white liquor used for cooking sulphate pulp. As a result of the experiment, the principal possibility of hydrogen sulfide absorption by a hydroxide solution was established with the fulfillment of the requirements for white liquor.

A contribution to the resistance of combined plywood materials to abrasion

The aim of the paper was to propose the methodology of testing the abrasion resistance of combined water-proof plywood materials with the phenol-formaldehyde foil surface finish and to assess the surface resistance of a new combined plywood material of a given construction to abrasion. For sheathing, phenol-formaldehyde foils with the low content of resins were used, which are combined with unwoven and woven glass fibres highly resistant to mechanical wear. The paper for phenol-formaldehyde foils manufactured of sulphate pulp (basis weight 60 g/m²) was impregnated by a low-molecular resin with the resin deposit 150% DM (dry matter) per paper DM. To evaluate the newly designed material our testing methodology was prepared in such a way that it will conform to related European standards. It is completed by the method of sampling and preparation of samples for tests including their acclimation. According to our proposal, measurements were carried out of selected constructions of water-resistant plied veneer materials with jackets of various basis weight combined with glass fibres. Data on the abrasion resistance were acquired which can be considered to be reliable. The values of abrasion resistance were assessed with respect to standards valid in the EU which determine fields of their use.

Willow wood (Salix alba) as a raw material for pulp production

The properties of willow wood (structural-physical and mechanical properties and chemical composition) were investigated to determine the parameters of the technological process of semichemical and sulphate pulp manufacture. The experimental material was willow wood Salix alba cl. 107/65/7. Semichemical and sulphate pulp were obtained in the laboratory. The yield, chemical properties and physical-mechanical properties of the obtained intermediate products intended for paper manufacture, were determined. The properties of poplar wood Populus deltoides Bartr. cl.725, were studied and its pulp production performed with the aim of comparison.

High yield CTMP fibres as a possibility of the more efficient yield of wood raw material

The evident shortage of wood as a raw material has become a limiting factor in the pulp and paper industry which is the greatest consumer of wood in Europe. The situation in our country is similar. During the few past years, the production of poplar and willow pulpwood was 220.000 m3 per year, which is insufficient for the planned increase in the production of sulphate pulp (175.000 tons till 2005). This paper deals with the aspects of the more efficient yield of raw material, based on the significantly higher yield of CTMP fibres, as well as with the significance of the lower adverse effect on the environment. It also analyses the conditions of production and the quality of the obtained fibres, as a possible substitute for chemical pulp and secondary fibres in papers of different quality. The main reasons for the production and use of CTMP fibres in our country are reported.

Kinetic Models for Describing Degradation of AOX in the Waste Water of a Mill Producing Bleached Sulphate Pulp

In the study, submodels for describing degradation of organic chlorine (measured as AOX) coming from a mill producing bleached sulphate pulp were developed. The submodels coupled to a hydrodynamic model can then be used in assessing the behaviour of AOX in receiving waters. The data used in developing the models was based on mesocosm-scale experiments carried out in two lakes. Waste waters of two mills were used at two dilutions (2% and 10%). Part of the mesocosms were darkened in order to study the effect of light on degradation. In the first phase of the modelling first-order kinetics with a constant coefficient were used. The next steps were to include the effect of temperature and light in the model. Including temperature and light did not much contribute to the modelling results. It was found that more than half of the degradation was caused by the light-dependent component of the degradation reaction. The reaction obeys first order kinetics satisfactorily. However, the reaction coefficient is greater in the beginning of the experiment than later. A correction function describing the decrease of the reaction coefficient was included in the model. The correction function is based on the idea that the most readily decaying components of AOX disappear from the solution in the beginning and therefore the apparent reaction coefficient decreases. Only data on AOX was available in this study but the approach can be applied for different chloro- organic compounds and also for other organic substances.