12 ENESSCO Dealing with wax in


board manufacturing The performance of a containerboard line can be adversely affected when wax changes the substrates surface friction. Here’s a product that helps solve the problem. PPL reports


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urface friction of the outside ply of a linerboard is a critical characteristic.


Commonly measured as the ‘slip’ or ‘slide’ angle, it can have an impact on production and converting operations, along with contributing to stacking and handling difficulties. A second major issue is the


effect that wax absorbed on the surface of fibres has on board strength characteristics. Typically, ‘suspended’ wax will attach to the surface of individual fibres and adversely impact fibre/fibre bonding. This results in lower overall sheet strength. Wax enters the system from


the recycling plant when old corrugated containers (OCC) are used. Furnish associated with wax includes curtain-coated and wax- cascaded corrugated boxes. Half of all petroleum-based paraffin waxes that are generated are used in curtain-coated applications or cascaded-corrugated containers to provide moisture and water resistance. Few mills are able to remove this wax contamination. The mill recycling operation


is often carried out at elevated temperatures. The typical operating temperature range is 125-160 deg F. The majority of paraffin waxes have melting points in the 122-132 deg F range. Dispersed wax is a stable suspension that has the ability to permeate off the fibre into the water phase. Dispersed wax particles measuring 5-100 microns


January/February 2019


significantly reducing absorbed wax.


Cold pulping: Stock pulped at 120 deg F has shown reduced concentrations of wax in the water from 60ppm down to 4ppm. Under such conditions a typical board mill producing around 350 tons per day can expect to see: ● 0.6 ton/day wax entering system ● 0.37 ton/day at the decker ● 0.02 ton/day wax in water feeding machine


in a suspended state make for poor removal in typical stock preparation systems. Wax can be present in three potential forms: 1. Free wax 2. Suspended wax 3. Absorbed wax


Free wax: At low operating temperatures (less than 120 deg F) this form of wax is maximised. Wax has not been absorbed onto the fibre and can be found as large particles that float. This is the only form of wax that can be removed by using reverse-type cleaners, through flow cleaners, centrifuge methods and the like, due to its large size and low specific gravity. Screening equipment is not effective in removing suspended and absorbed wax forms. Free wax removal is around 10 per cent of the total. It is then logical to assume that cleaning equipment is only operating at 10 per cent efficiency for wax removal; 90 per cent of wax stays in the system in the following forms.


Suspended/dispersed wax: Not much suspended wax is generated at lower temperatures. However, in the range of 122- 160 deg F fine wax dispersion is increased. Upon cooling the dispersed wax is stabilised and coats fibre on contact. Suspended wax does not agglomerate to form large particles unless reacted with other types of contaminants or control chemistry. Particle size for typical suspended/dispersed wax is in the 5-100 micron range.


Absorbed wax: This wax attaches itself to the fibre but can continue to be liberated as suspended wax under the high temperature and mechanical sheer action within the system. Absorbed wax and suspended wax will continuously shift from the ‘absorbed’ form to the ‘suspended’ form and back again under these conditions. Addition of Enessco’s 1000 agglomeration technology initiates the development of ‘suspended wax agglomerations,’ while


● 0.04 ton/day removed at reverse cleaners


Enessco: the mechanism Enessco International’s approach to combat stickies and wax problems is unique in that three different methods are utilised to obtain maximum reduction of contaminant loading in the recycled paper process system. The Enessco product is a 100 per


cent active dry powder, a blend of wetting agents and inorganic polymers fed to the recycled fibre pulper. It is available in 2.27kg or 22.7 kg repulpable bags or make down systems, deink dosage rates of approximately 0.6kg per ton of recycled furnish in the pulper.


Pulper treatment: Enessco begins to work in the pulper by interacting with the wax/ fibre and stickies/fibre interface. This maximises initial ‘macro- stickies & free wax’ particle size and rigidity during repulping. When reductions in temperature and caustic are possible this will


Pulp Paper & Logistics


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