A Study of the Physico-Mechanical Properties in Short Bleaching Sequences

Ferraz, Ana Paula Costa Rodrigues; Ventorim, Gustavo

doi:10.1590/1806-90882018000500005

Cited by 3 publications

(1 citation statement)

References 7 publications

(12 reference statements)

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“…The higher H 2 SO 4 load in the acid hydrolysis stage A (Table 1) of the pulps in relation to the control sequence was due to the carryover alkalinity (Sixta 2006). The increased in pH negatively impacted the chlorine dioxide stage and increased its consumption (Sevastyanova et al 2012, Ferraz & Ventorim 2018. It was caused by the chlorite (ClO 2 -) formation in pH 4.0 and reducing the delignification rate of chlorine dioxide.…”

Section: Alkaline Filtrate (Carryover) Recirculation and Chemical Reagent Consumptionmentioning

confidence: 99%

Post-O2 Eucalyptus Pulp in a/D(ep)dp Bleaching Sequence Washed With Recirculation of the Alkaline Filtrate

Souza¹,

Zanuncio²,

Colodette³

et al. 2021

JTFS

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Circuit closure in the pulp manufacturing process may mitigate water scarcity. This work aimed to analyse the feasibility of reusing the alkaline filtrate (carryover) from the (EP) stage of producing hardwood pulp in the A/D(EP)DP bleaching sequence. Pulp from Eucalyptus grandis and Eucalyptus grandis × Eucalyptus urophylla wood and the alkaline effluent from (EP) bleaching stage were collected in a pulp mill. Bleaching was conducted both without this effluent (as a control) and with 15 kg odt -1 of the alkaline filtrate from the (EP) stage. The consumption of reagents during bleaching and the chemical, physical, mechanical and optical pulp properties were evaluated. The alkaline filtrate increased the pulp kappa number from 1.4 to 2.2 with a fixed reagent dosage. The consumption of chlorine dioxide, sulfuric acid and the brightness reversion were 13.7, 17.3 and 20.1% higher in treatments using carryover, respectively to achieve a brightness level of 89 ± 0.2% ISO in the bleaching process. The viscosity, hemicelluloses content and the pulp properties did not vary between these two treatments. The adoption of effluent recirculation should consider the environmental and economic gain of reducing the water consumption and the negative effect of pulp chemical changes and the increase in reagent consumption.

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Section: Alkaline Filtrate (Carryover) Recirculation and Chemical Reagent Consumptionmentioning

confidence: 99%

Post-O2 Eucalyptus Pulp in a/D(ep)dp Bleaching Sequence Washed With Recirculation of the Alkaline Filtrate

Souza¹,

Zanuncio²,

Colodette³

et al. 2021

JTFS

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Aspen Plus simulation for effluent reuse in thermomechanical pulp mills

Caldeira

Silva

Rodrigues

et al. 2023

Water Science &Amp; Technology

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The objective of this study was to evaluate the closing of the water circuit and reusing the treated effluent in the production of TMP, using simulations performed with the Aspen Plus®. The treated effluent was reused to replace 50, 75 and 100% of the well water. An adaptation of the Aspen Plus® program simulating the TMP production process and a dynamic simulation test to verify the accumulation of non-process elements (NPEs) in industrial processes at different proportions of reuse were evaluated. The quality of the final product was assessed in laboratory bleaching tests for pulp brightness and brightness reversion. The concentrations of the NPE were 0.00097, 0.00122 and 0.00145 kmol/h for Mn2+, 0.012929, 0.018368 and 0.023595 kmol/h for Fe3+ and 0.000542, 0.000722 and 0.000948 kmol/h for Cu2+, with the recycling of the treated effluent of 50, 75 and 100%, respectively. The brightness and brightness reversion of the pulp were similar with the different proportions of effluent reuse and with the use of fresh industrial water, with values ranging from 83.37 to 83.97% ISO and 5.43 to 6.38 ISO units, respectively. The use of treated effluent did not affect the pulp quality, which could diminish the water use in a pulp mill.

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Valorization of Grass Clipping Waste: A Sustainable Approach to Cellulose Extraction and Paper Manufacturing

Taurbekov,

Kaidar,

Baltabay

et al. 2024

Applied Sciences

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This study investigates the physical, mechanical, and structural characteristics of handmade paper samples derived from cellulose extracted from grass clippings using two distinct methods as follows: (1) alkali treatment and (2) alkali treatment followed by bleaching, coupled with the incorporation of barium sulfate as a mineral filler. Our investigation revealed that the handmade paper samples’ densities, moisture contents, and thicknesses varied within the ranges of 0.436 to 0.549 g/cm3, 5.60 to 2.51%, and 0.41 to 0.50 mm, respectively. The tensile strength and folding endurance of the papers produced through alkali treatment with barium sulfate were notably superior to those produced from bleached pulp and barium sulfate. Our analysis indicates that several critical factors, including paper density, thickness, the crystallinity index, and the microfibrillar structure of cellulose, intricately influence the mechanical and strength properties of the samples. Using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques, we identified characteristic cellulose bonds and examined cellulose’s crystalline and amorphous phases. Additionally, the crystallinity index of the samples was determined using both the Segal and peak deconvolution methods. Scanning electron microscopy (SEM) micrographs revealed interconnected networks of cellulose fibers with varying thicknesses and lengths, along with incorporated mineral filler within the cellulose fiber structure. Variations in mineral particle retention were attributed to the presence or absence of cellulose microfibrils. These findings contribute to our understanding of the observed strength characteristics of the paper samples and underscore the potential applications of cellulose derived from grass clippings, especially when combined with barium sulfate as a mineral filler in paper production.

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A Study of the Physico-Mechanical Properties in Short Bleaching Sequences

Cited by 3 publications

References 7 publications

Post-O2 Eucalyptus Pulp in a/D(ep)dp Bleaching Sequence Washed With Recirculation of the Alkaline Filtrate

Post-O2 Eucalyptus Pulp in a/D(ep)dp Bleaching Sequence Washed With Recirculation of the Alkaline Filtrate

Aspen Plus simulation for effluent reuse in thermomechanical pulp mills

Valorization of Grass Clipping Waste: A Sustainable Approach to Cellulose Extraction and Paper Manufacturing

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