John Cameron

Bio: John Cameron is an academic researcher from Western Michigan University. The author has contributed to research in topics: Kraft paper & Black liquor. The author has an hindex of 6, co-authored 15 publications receiving 90 citations.

Production of a single coated glossy inkjet paper using conventional coating and calendering methods

Abstract: The unique structure of precipitated and gelled silicas provides an internal and packing porosity that enables the rapid diffusion of liquid inks into the coating layer. The rapid uptake of the ink immobilizes the anionic dyes at the surface of the coating, allowing high optical print densities to be achieved. However, precipitated and gelled silicas are primarily used in matte grades since the particle size of them is typically 3-16 μm range. This study focused on the use of non-porous fumed silicas and alumina in glossy inkjet media. The coating process was a single coat blade application on a cylindrical lab coater (CLC) at speeds up to 920 m/min. The use of fumed alumina enabled gloss values of almost 70% to be achieved after 3 passes through a sheet fed soft nip calender at 60 C and 123 kN/m. The work is significant because it demonstrates the ability to produce glossy inkjet coated papers by applying a single pigmented coating layer on a blade coater and finishing with a soft nip calender. The research described herein examines the contribution of coating structure influences on inkjet print quality. The pigments used are commercially available and are currently being employed in this application.

Decarbonization reactions between sodium metaborate and sodium carbonate

Abstract: Autocausticizing, used for the recovery of kraft pulping chemicals, is nearing commercialization. This technology produces sodium hydroxide directly on dissolving the molten salts produced in the kraft recovery furnace in water. Thus, the dependence on the lime cycle for sodium hydroxide is reduced. Ongoing trials in several kraft mills are in progress to implement this technology. In this study, the reactions between sodium metaborate (NaBO2) and sodium carbonate (Na2CO3)the anticipated reactantswere studied in a tubular reactor heated in an electric furnace. It was found that the reaction begins in the solid phase, followed by a liquid phase reaction. The reaction rate is extremely rapid once the system melts. It was proposed that these reactions could proceed through the intermediate formation of sodium diborate (Na4B2O5).

Comparative studies of kraft and kraft-borate pulping of black spruce

Abstract: L'autocaustification au borate peut remplacer le cycle de chaux du procede kraft (autocaustification totale) ou y apporter un complement (autocaustification partielle). Le procede d'autocaustification partielle a recemment ete commercialise dans une usine kraft et est en cours d'essai dans plusieurs autres. Bien qu'on sache que le borate reagit avec la lignine, on en sait peu sur les effets des borates sur le rendement des pâtes kraft ou les proprietes de la fibre. La presente etude visait a determiner l'effet du metaborate de sodium, le produit borate de l'autocaustification, sur la mise en pâte kraft et les proprietes des pâtes d'epinette noire. Les principaux resultats de cette etude suggerent que le borate permet d'accroitre le rendement, de reduire la quantite de refus et d'ameliorer la selectivite lors de l'extraction de la lignine, qu'il n'a aucun effet sur la delignificantion et qu'il peut accroitre la viscosite de la pâte au meme indice Kappa.

Some properties of kraft and kraft-borate pulps of different wood species

Abstract: Comparative analyses were carried out on the properties of birch, maple, and spruce for conventional kraft pulping and kraft pulping with sodium metaborate added to correspond to 35% autocausticizing. A 1.8% increase was noticed in the screened yield for the kraft-borate pulping of spruce at H-factors higher than 1000. Also, at kappa numbers lower than 50, sodium metaborate increased the total yield in spruce pulping. Sodium borate did not affect the brightness nor the contents of extractives and hexenuronic acid groups (HexA) of the kraft pulps for the species studied. The kappa number corrected for the HexA component, which is a more accurate estimate of the lignin content, showed that kraft delignification was not changed by sodium metaborate at the increasing H-factor. An increase of holocellulose retention was found for the kraft-borate pulps of spruce at the kappa numbers lower than 60, indicating that sodium metaborate has the potential to protect carbohydrates in kraft pulping. Application: With no detrimental effects observed for maple, spruce, and birch pulps, autocausticizing with sodium metaborate added in the white liquor appears to be an easy way for a causticizing-limited mill to increase its capacity without new equipment.

Direct Capture of CO2 from Ambient Air

Abstract: The increase in the global atmospheric CO2 concentration resulting from over a century of combustion of fossil fuels has been associated with significant global climate change. With the global population increase driving continued increases in fossil fuel use, humanity’s primary reliance on fossil energy for the next several decades is assured. Traditional modes of carbon capture such as precombustion and postcombustion CO2 capture from large point sources can help slow the rate of increase of the atmospheric CO2 concentration, but only the direct removal of CO2 from the air, or “direct air capture” (DAC), can actually reduce the global atmospheric CO2 concentration. The past decade has seen a steep rise in the use of chemical sorbents that are cycled through sorption and desorption cycles for CO2 removal from ultradilute gases such as air. This Review provides a historical overview of the field of DAC, along with an exhaustive description of the use of chemical sorbents targeted at this application. Solv...

Sorbents for the Direct Capture of CO2 from Ambient Air.

Abstract: The urgency to address global climate change induced by greenhouse gas emissions is increasing. In particular, the rise in atmospheric CO2 levels is generating alarm. Technologies to remove CO2 from ambient air, or "direct air capture" (DAC), have recently demonstrated that they can contribute to "negative carbon emission." Recent advances in surface chemistry and material synthesis have resulted in new generations of CO2 sorbents, which may drive the future of DAC and its large-scale deployment. This Review describes major types of sorbents designed to capture CO2 from ambient air and they are categorized by the sorption mechanism: physisorption, chemisorption, and moisture-swing sorption.