Seven examples of flotation cells utilized in waste paper deinking industry are reviewed to show the variety of approaches used to optimize the characteristics of a flotation system In attempting to identify the key fundamental parameters it is noted that comparisons of flotation effectiveness on the basis of bubble surface area flux bsaf
In particular flotation deinking is a separation process used to remove ink and other contaminant particles from reclaimed cellulose fibre Despite the many differences between mineral flotation and flotation deinking all flotation cells operate on similar principles In modern flotation cells three separate processes take place in tandem
The existing vertical cylinder flotation cell that is used for floatation and ink removing is when flotation and air can not mix with slurry is full and uniform makes bubble fully not arrest printing ink and deinking efficiency is poor; In addition the foam that has printing ink is short in the slurry liquid level time of staying and the fiber that rises to the slurry liquid level with
The contribution of the froth removal height on the flotation deinking of a 50% old magazines/50% old newsprint mixture was investigated by using a laboratory flotation cell prototype
In addition to ink removal valuable materials such as fibers and minerals will be lost in flotation deinking which lowers yield and thus decreases the profitability of the process
The development of deinking flotation cells has been an evolutionary one starting with a transfer of the Denver cell from the mineral processing industry in the 1950s It can be seen that the pace of major developments has increased since the end of the 1970s TABLE 1 History of flotation deinking cells modified from McCool [3] en er Veu er
The results in Fig 1 were obtained in the frame of laboratory flotation studies which first showed experimental evidence concerning the first order kinetics of the deinking process Julien Saint Amand and Perrin 1991 Deinking furnish containing small microscopic ink particles from magazines and large flat shaped specks thickness about 5 μm from UV
Flotation experiments were conducted using both nylon and wood fibers in column and commercial bench scale flotation deinking cells It was found that increased froth stability resulted in a lower
The technological parameters relating to the aeration mixing and separation steps of the flotation cells currently used in the field of waste paper recycling are reviewed in this paper A laboratory flotation cell was designed to study the effects of the hydrodynamic flotation parameters and tested on different deinking furnish The physico chemical aspects of flotation
Applications Versatile use for primary and secondary deinking flotation as well as filtrate flotation General technological assessment of full scale mill flotation systems Process optimization in the laboratory thus avoiding cost intensive full scale trials in the mill Preliminary trials in the laboratory for minimizing process risks at
4 sized flotation cell based on the designed concentrate tonnages and solids content of the concentrate Wash water addition is commonly measured as a ratio with the water in the concentrate A wash water ratio of means that theoretically all the „dirty‟ water in the concentrate containing the entrained ash particles is replaced by
SelectaFlot flotation combines both primary and secondary flotation in one compact unit resulting in advantages for inspection and maintenance In order to save floor space different configurations and cell arrangements are available such as double decker or piggy back Simple and stable control concept
The use of flotation in large scale to remove printing ink from wastepaper followed the development of deinking flotation cells This started with the employment of the Denver Cell from the mineral processing industry in the 1950s and has increased steadily Finch and Hardie 1999 Over the last two decades the removal of ink from paper pulp
Flotation separation relies on the wettability difference between feedstock particles; therefore these particles with hydrophobic properties will be separated from hydrophilic particles when
SelectaFlot flotation inline arrangement Efficient deinking is primarily about two things how to maximize brightness while minimizing the loss of fibers SelectaFlot does both The ANDRITZ SelectaFlot flotation is avail able in eight sizes featuring capacities up to 985 t/d 1 Primary flotation cell 2 Secondary flotation cell 3 FoamEx foam
Deinking LowEnergyFlotation LEF is a patented low energy deinking flotation with minimal fiber loss It effectively removes inks and hydrophobic contaminants from recovered paper and reduces the energy demand by up to 50% compared to a standard application Existing flotation plants can be rebuilt to LEF technology
In the early 1980s froth flotation was introduced to the paper industry to remove ink particles during the paper recycling process While the deinking flotation process is widely used it also
In the second step deinking takes place in the flotation cell where hydrophobic collector attaches air bubbles to ink particles after which bubbles rise and are finally collected as foam on the
By using the optimized flotation conditions the deinked pulp brightness can reach ISO 01SO higher than that of the control the effective residual ink concentration reduction is mg/kg actual deinking efficiency is up to % The deinking experiments confirmed its superior performance of the laboratory cell REFERENCES
Flotation deinking is one of the steps in deinking which usually consists of dislodging ink from the fibers during repulping followed by ink separation from the suspension by flotation and washing A schematic of a flotation deinking cell is shown in Fig 1 It consists of a chamber in which the pulp suspension is introduced together with air
The results in Fig 1 were obtained in the frame of laboratory flotation studies which first showed experimental evidence concerning the first order kinetics of the deinking process Julien Saint Amand and Perrin 1991 Deinking furnish containing small microscopic ink particles from magazines and large flat shaped specks thickness about 5 μm from UV
Applications Versatile use for primary and secondary deinking flotation as well as filtrate flotation General technological assessment of full scale mill flotation systems Process optimization in the laboratory thus avoiding cost intensive full scale trials in the mill Preliminary trials in the laboratory for minimizing process risks at
An Example of flotation cell capacity and circuit retention time approximation Estimate the volume of conditioners and flotation cells required to handle 9100 dry tons of ore per 24 hours at 30% pulp solids by weight with an ore specific gravity of Five minutes conditioning time and 15 minutes flotation time are desired
© Copyright 2024 By Ore Crushing Equipment Manufacturer
