Raw material effects on fibres

Raw material effects on fibres Paper usually consists of wood fibres, though non-wood fibres can be important locally. In specialty papers, non-wood fibres have global use. Fibre properties vary considerably with the wood species (Figure 1) and growth site and with the pulping and papermaking treatments that the fibres undergo. Because of the stochastic nature

To access this post, you must purchase All themes or Natural fibre products. Do you already have a membership or are you part of an organization? log in

Design of collection systems

Design of collection systems Collection systems exist in two general types, as pick-up and as drop-off systems, sometimes with both types in parallel. In most countries, the collection systems is defined by the authorities, often on municipality or department level. Particularly in regions where an officially organised collection system does not exist to a large

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Dry sorting of paper for recycling

Dry sorting of paper for recycling Mixed post-consumer paper for recycling which is not thoroughly monitored during collection typically contains unwanted material and should be sorted before the recycling process. Sorting also adds value by enabling the sorting company to create higher priced qualities. After separating the mix into pure packaging and graphic grades, both

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Collection systems of paper for recycling

Collection systems of paper for recycling Challenge and organisation Collection of paper and board for recycling takes place from various sources. These sources are printers and converters, offices, retailers as well as other industrial users and private households. The key to a high collection rate of paper for recycling is an efficient collection from households

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Machines for fine screening and fractionation

Machines for fine screening and fractionation   Andritz fine screening  ©ANDRTIZ   Basic physical mechanisms in pressure screens In a pressure screen several sub-processes occur in parallel: The deflocculation of the pulp in order to singularise particles, the passage of fibres through the apertures, the periodic cleaning of the screen plate by suction pulses caused

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Process design for market deinked pulp

Process design for market deinked pulp Market DIP is pulp produced for sale on the open market to paper mills to replace virgin fibres. The production of Market DIP from RCF is the most demanding process. A prerequisite is using wood-free grades as furnish, i.e. in the form of sorted office waste. The mechanical fibre

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Alternative bleaching processes

Alternative bleaching processes The search for new, more efficient bleaching processes has produced laboratory results on alternative bleaching chemicals. These primarily refer to peroxy acids, including peracetic acid and Caro’s acid. Peracetic acid (CH3COOOH) has a high oxidation potential and is therefore very acid. Produced from concentrated acetic acid (CH3COOH) and peroxide (H2O2), it exists

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Ozone bleaching (Z)

Ozone bleaching (Z) Ozone bleaching is a recent development for bleaching recycled fibre pulp. In contrast to its use for bleaching chemical pulp, where it serves exclusively to degrade residual lignin further, in the bleaching of deinked pulp it destroys dyes and optical brighteners 1-3. The strength gains that accompany the treatment have secondary importance.

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

Bleaching with oxygen chemicals – oxygen bleaching (O)

Bleaching with oxygen chemicals – oxygen bleaching (O) For some years, there has been a trend — not only in chemical pulp bleaching but also in recovered paper processing — towards replacing chlorine-containing bleaching chemicals by oxygen-based chemicals. The driving forces behind this trend are as follows 1: Changed consumer demands: Demand for products manufactured

To access this post, you must purchase All themes. Do you already have a membership or are you part of an organization? log in

0