Comparison of the usage of fines and PCC pigment in handsheets

Purpose This paper aims to investigate the influences of fines and precipitated calcium carbonate (PCC) pigment and their contents on the fundamental properties of handsheets and also evaluate these results in terms of mechanical and chemical data. Design/methodology/approach A design research approach has been based on the production of various laboratory handmade papers. Any of the paper additives were not added to the paper web to compare the results of the effects of fines and PCC pigment in a literal way. For this purpose, the target grammages of handsheets and the production variables such as pulp consistency, temperature and other variables of formation, pressing and drying processes were kept constant and studied meticulously. Findings This study is confirmed that with the addition of fines to the pulp of the control handsheets, an increase of up to 125% has been observed in the tensile index values, while a decrease of up to 30% has been observed with the addition of PCC pigment as filler. The tensile results have been changed depending on the pulp content and hence chemical bonds formed in the paper web. These mechanical changes have been explained by correlating with the data of FT-IR spectrums. Especially, the variations have been seen at 950–1150 cm−1, which referring to C-OH and C-O-C stretching vibrations. Originality/value The originality of this work is based on understanding and comparing the effects of fines and the effect of PCC pigment as a paper filler on the structural and chemical characteristics of laboratory-made handsheets.

EFFECT OF MICROCRYSTALLINE CELLULOSE AS A FILLER AND/OR FILLER RETENTION AID ON THE MECHANICAL PROPERTIES OF BAGASSE PAPER SHEETS

Microcrystalline cellulose (MCC), as a green material derived from bagasse, was investigated as an additive (0-3 wt%) in the preparation of bagasse paper sheets, in comparison with cationic starch. The effect of MCC addition, in the presence of 15% kaolin or 15% calcium carbonate as paper filler, was also studied. The properties of bagasse paper sheets loaded with MCC or cationic starch, in the presence or absence of 15% kaolin or 15% calcium carbonate as paper filler, were evaluated in terms of breaking length, burst, tear, opacity and filler retention values. Also, SEM and thermal analyses of the paper sheets were performed. It was found that all the properties of the bagasse paper sheets were improved as a result of MCC or cationic starch addition and, in general, the observed improvement increased as the percent of addition increased. Calcium carbonate and cationic starch, in general, gave superior properties, compared to kaolin and MCC, respectively. Overall, MCC could be considered as an alternative economically viable paper additive.

Optimization of the microstructure of carbonized lime mud by sodium polyacrylate

Lime mud (LM) is a by-product originated from the causticization process of papermaking industry. Microscopic structural changes of LM in carbonization process lead to defects on its performance. Regulating the growth of calcium carbonate obtained from the carbonization process and preventing its influence on the surface microstructure of LM has become the key to achieve the self-digestion of this solid waste. In this study, microscopic structural changes of LM co-carbonized with sodium polyacrylate (PAAS) were investigated. The results showed that, compared with traditional carbonation, the microstructure of LM co-carbonized with PAAS was changed remarkably. The newly calcium carbonate formed in the carbonization process would be solidified and coated on the LM surface. Then LM co-carbonized with PAAS would have a smaller specific surface area, pore volume and pore size, which significantly improved its application performance when it was used as paper filler. In addition, a potential technique for improving the surface microstructure of calcium carbonate particle was proposed.

TG/DTA-FTIR Study on Total Resource Recovery from Tetra Pak Waste by Pyrolysis under a CO2 Environment

Pyrolysis of Tetra Pak waste under CO2 was investigated using a thermogravimetric/differential thermal analyser coupled with a Fourier transform infrared spectrometer. Experimental results showed that cellulose was decomposed between 270 and 390 °C, leading to the formation of aldehydes, ketones, carboxylic acids and levoglucosan. Thermal cracking of polyethylene occurred between 440 and 530 °C and the main products were aliphatic hydrocarbons. CO can be produced by the gasification of pyrolytic char by CO2 at temperatures ranging from 860–970 °C. Aluminium (Al) foil remained in a “thin layer shape” despite melting above 660 °C. CaO was generated from the decomposition of CaCO3 used as a paper filler at 722 °C. The reaction between CaO and the CO2 atmosphere during the cooling process led to the formation of new CaCO3 which was the main component of ash after gasification and was easy to separate from Al foil.

Engineered porous calcium silicate as paper filler: effect of filler morphology on paper properties

Developing engineered filler with special morphology to increase filler content and deliver paper desirable properties has been deserved much concern. In this work, two engineered calcium silicate fillers with different morphology, namely fly ash based calcium silicate (FACS), fibrous calcium silicate (FCS) were adopted to investigate the effect of filler morphology on paper properties, and natural wollastonite was used for comparison. It is found that FACS exhibits a wrinkled, porous surface while FCS reveals spherical agglomerates composed of needle-like particles. Physical tests demonstrated that in comparison with natural wollastonite with discrete shape, the aggregated porous structure of FACS and FCS showed noticeable improvement in bulk and opacity due to their high specific surface area (112 m2/g v.s 29 m2/g). At around 40 % filler content, the bulk of FACS and FCS filled handsheets increased 59.6 % and 43.8 %, respectively. The findings suggested that the engineered porous calcium silicate can be potentially used as paper filler in light weighted paper.

Global occurrence, geology and characteristics of tubular halloysite deposits

Halloysite with tubular morphology is formed in a wide range of geological environments from the alteration of various rock types. Intrusive acidic coarse-grained rocks, such as granites, pegmatites and anorthosite, with large potash and sodic feldspars contents, are subsequently altered to kaolinite, halloysite and other clay minerals by weathering or shallow hydrothermal fluid activity. Processing to separate the halloysite-kaolinite fraction from the altered host rock provides a product which can be used as a paper filler and in ceramics and fibreglass, among other uses, with various deposits in Brazil, China, Thailand and elsewhere. In the Kerikeri-Matauri Bay district of Northland, North Island, New Zealand, volcanic alkali rhyolite was extruded as domes and cooled rapidly with fine-grained feldspar subsequently altered to halloysite. The IMERYS plant in Matauri Bay separates the clay from the quartz-cristobalite matrix with an ∼20% yield of halloysite. The principal market is for high-quality porcelain and bone china that require low levels of Fe2O3 and TiO2. Deposits with high levels of halloysite occur in China, Turkey and the USA. The Dragon mine in Utah, USAwas recently reopened by Applied Minerals Inc. and now produces halloysite from zones of up to 100% white halloysite. Smaller occurrences of tubular halloysite are mined in China, Turkey and elsewhere from masses of comparatively pure clay that appear to have crystallized directly from solutions in which Al and Si were soluble.