Abstract:
An apparatus for selective particle flotation includes a static mixer connected to a flotation section in lieu thereof of the apparatus. The static mixer is disposed upstream of the flotation section in lieu thereof with respect to a direction of fluid flow through the apparatus. The static mixer mixes sludge with small gas bubbles. A flotation cyclone is disposed in an upstream portion of the flotation section in lieu thereof with respect to the direction of fluid flow through the apparatus. The flotation cyclone is the initial separation device through which the sludge flows.
Abstract:
A deinking system for use with recycled paper pulp includes a number of gas sparged hydrocyclones mounted around the outer periphery of a foam separation vessel, with the slurry outlet from each hydrocyclone introducing slurry into the vessel below the level of liquid in the vessel, and above the accepts outlet from the bottom of the vessel. An annular trough is provided adjacent the top and outer periphery of the vessel, and has a bottom sloping to one or more drain outlets. The hydrocyclone discharge conduits into the vessel are tangential to cause bubble-releasing swirling of the slurry in the vessel. The cyclone preferably is pedestal-less, and has a single gas inlet, and a deflector within the annular air jacket of the hydrocyclone. At least one substantially conical substantially uniform back pressure generator may be disposed in the hydrocyclone slurry outlet, a foam conveyance and breaking device may be associated with the drain outlet from the trough, and a foam and rejects handling tank connected to the foam conveyance and breaking device and including a substantially spiral downwardly extending feed ramp may also be provided.
Abstract:
A suitably conditioned slurry feed is introduced to a trough from which it is distributed into a slurry layer-flow forming chamber provided with a discharge weir which discharges an evenly spread layer of slurry onto an inclined plate feeding into a mixing passage and then into a vessel. Recirculated slurry from the vessel is also fed into the mixing passage via a recycle gate which forms it into a layer of slurry. An array of clean liquid jets accelerates thin gas envelopes and impinges between layers of slurry and causes intensive mixing of all streams in the mixing passage. A high shear rate produces high intensity turbulence and shears gas into very small bubbles. A multiphase mixture flow is discharged from the mixing passage into the vessel, where it flows past one or more longitudinal stabilizing baffles. Gas bubbles loaded with hydrophobic particles disengage from the stream, rise toward the liquid surface and are diverted by bubble-diverting guides toward a froth discharge end of the vessel. A layer of froth travels toward a froth weir where it is discharged. Residual slurry leaves a discharge launder via a weir to a following flotation cell or process stage.
Abstract:
A method and several embodiments of apparatus are disclosed for use in foam flotation separation. The method discloses performing the separation in a module operated at nonatmospheric pressure, and the apparatus disclosed are suitable for use as the module of the method. Both the method and the apparatus contemplate positive and negative pressure operation.
Abstract:
A method of separating an aqueous solids containing suspension includes (a) subjecting a first solids containing suspension to centrifugal forces so as to separate the suspension into a first gas containing flow, a second gas-free flow and a third flow; (b) feeding the third flow into a flotation cell having a bottom; (c) introducing air at the bottom of the flotation cell into the third flow for separating from the third flow a fourth partial flow; (d) withdrawing the air containing third flow after the separation of the fourth partial flow from the flotation cell; and (e) subjecting the third flow to the centrifugal forces of step (a). An apparatus for the separation of gas and lightweight material from a gas and lightweight material containing aqueous solids suspension is also described and includes a centrifugal pump for separating the gas and lightweight material from the solids suspension with a suspension inlet and an outlet for the lightweight material; a flotation cell for separating the lightweight material from a solids suspension; and a circulation loop connecting the outlet of the centrifugal pump, the flotation cell and the suspension inlet of the pump.
Abstract:
A method for the deinking of recycled fibers, in which the macerated fibers are slurried with water; introduced to a deinking cell which has a central anode and a perimetal cathode; subjected to a direct current electric field applied between the anode and the cathode, causing the ink to be attracted away from the fibers and to electrocoagulate the ink then floating to the surface of the slurry with the aid of gas bubbles generated during the application of the electric field; and washed to recover a cleaner, brighter pulp of recycled fibers.
Abstract:
The invention relates to a flotation-deinking-device comprising a flotation vessel and at least one inlet for introducing the suspension into the flotation vessel, the inlet being a staged diffusor (12) in which in a region of the stage transition (26) an air inlet opening (20) is arranged. A turbulence generator (28) without an air supply is arranged upstream of the stage transition (26) as seen in the direction of flow.
Abstract:
In froth flotation apparatus for separating solid particle impurities from a liquid suspension stock in a flotation cell, provision is made for aerating the stock flowing through the inlet conduit leading to the cell by positioning a drum-shaped rotor having an irregular outer surface in the conduit on an axis extending transversely of the conduit, directing a supply of air against the rotor surface on the upstream side of its rotational axis, and causing the rotor to rotate at a linear speed of its outer surface which is substantially higher than the linear flow rate of the stock in the conduit so that the rotor surface breaks up the air impinging thereon into bubbles and distributes those bubbles in the stock flowing therepast to create foam within the cell.
Abstract:
A method and several embodiments of apparatus are disclosed for use in foam flotation separation. The method discloses performing the separation in a module operated at nonatmospheric pressure, and the apparatus disclosed are suitable for use as the module of the method. Both the method and the apparatus contemplate positive and negative pressure operation.
Abstract:
Wastepaper is treated by a ink-removing process in which an aqueous wastepaper pulp slurry is introduced into a treating vessel, air is blown into the wastepaper pulp slurry preferably through a number of air-blowing orifices formed on a peripheral surface of at least one horizontal cylinder located in the bottom portion of the vessel to absorb ink particles floating in the wastepaper pulp slurry by air bubbles ejected from the orifices and rising toward the wastepaper pulp slurry surface. The resultant ink-absorbed froth is then removed. In this process, air is blown in an amount satisfying the relationship (I)G/L.gtoreq.5.0 (I)wherein L is the volume (m.sup.3) of the wastepaper pulp slurry in the treating vessel and G is the total volume (Nm.sup.3) of the air bubbles blown into the vessel, to promote the contact of the air bubbles with the ink particles in the wastepaper pulp slurry.