WO2003095364A1 - Procede de clarification de liqueurs bayer - Google Patents

Procede de clarification de liqueurs bayer Download PDF

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Publication number
WO2003095364A1
WO2003095364A1 PCT/AU2003/000554 AU0300554W WO03095364A1 WO 2003095364 A1 WO2003095364 A1 WO 2003095364A1 AU 0300554 W AU0300554 W AU 0300554W WO 03095364 A1 WO03095364 A1 WO 03095364A1
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WO
WIPO (PCT)
Prior art keywords
particulate material
feed
layer
bayer process
process liquor
Prior art date
Application number
PCT/AU2003/000554
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English (en)
Inventor
Gerald Dunstan Roach
John Bernard Cornell
Philip Scott Heckley
Geoffrey William Riley
Denis Nicoli
Original Assignee
Alcoa Of Australia Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alcoa Of Australia Limited filed Critical Alcoa Of Australia Limited
Priority to AU2003223258A priority Critical patent/AU2003223258A1/en
Publication of WO2003095364A1 publication Critical patent/WO2003095364A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
    • C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
    • C01F7/0646—Separation of the insoluble residue, e.g. of red mud
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F7/00—Compounds of aluminium
    • C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
    • C01F7/46—Purification of aluminium oxide, aluminium hydroxide or aluminates
    • C01F7/47—Purification of aluminium oxide, aluminium hydroxide or aluminates of aluminates, e.g. removal of compounds of Si, Fe, Ga or of organic compounds from Bayer process liquors

Definitions

  • the present invention relates to a method for clarifying Bayer Process liquors.
  • the method of the present invention is particularly suited to the clarification of primary settler overflow liquor.
  • the Bayer process is widely used for the production of alumina from alumina containing ores, such as bauxite.
  • the process involves contacting alumina- containing ores with recycled caustic aluminate solutions, at elevated temperatures, in a process commonly referred to as digestion.
  • the sodium aluminate solution so produced also contains insoluble residues from the bauxite ore, and the solids are separated from the solution in a thickener or clarifier.
  • the solids known as 'red mud', are taken as underflow from the thickeners, then typically washed to recover caustic values and render such suitable for disposal.
  • the overflow typically still contains finely divided red mud particulates, comprising iron oxides, iron hydroxides, silica and the like.
  • the presence of these compounds in the final alumina product is highly undesirable and the settler overflow is often passed through one or more filters to remove such, before being seeded with aluminium hydroxide to induce the precipitation of further aluminium hydroxide therefrom.
  • the precipitated aluminium hydroxide is separated from the caustic aluminate solution, with a portion of the aluminium hydroxide being recycled to be used as seed and the remainder recovered as product.
  • the remaining caustic aluminate solution is recycled for further digestion of alumina containing ore.
  • the filters remain operable for relatively short periods of time prior to blinding. Periods of operation of approximately 8 hours are typically achieved before maintenance is required. This typically involves opening the filter assembly, removing the solids, and back flushing the filter medium with clean spent liquor. This causes considerable disruption in an otherwise largely continuous process, and demands considerable labour.
  • Connelly et al. United States Patent number 5,387,405 dated Feb. 7, 1995 disclose a secondary 'polishing' process for Bayer Process liquors in which bio- carbohydrates such as dextran are used in conjunction with an inert insoluble solid as a filter aid to treat a primary settler overflow before passing such to a secondary settling stage, and the contents of the Connelly patent are herein incorporated by reference.
  • the Connelly patent states (at column 2, lines 58-60) that 'a Bayer Process operation may accomplish suspended solids ranging from essentially zero to no more than 5 mg/L'.
  • the patent includes experimental data in which 500 mL samples of primary settler clarifier overflow were combined with a filter aid before adding varying concentrations of bio-carbohydrate flocculant in a magnetically stirred 600 mL beaker with acceptable results.
  • attempts to apply the method disclosed by Connelly in test apparatus approximating a conventional clarification vessel have met with limited success.
  • Emmett, R.C. et al. in a paper titled 'Recent Developments in Solid/Liquid Separation Technology in the Alumina Industry', (Light Metals 1992) describes recent improvements in various separation steps used in Bayer refineries, including some experimental use of a solids contact clarifier having a top-fed combination feed well and flocculant compartment. Incoming feed is mixed with recirculated settled solids, recirculation being achieved using an underflow pump.
  • inert is used in relation to a substance to indicate that the substance is not substantially chemically acted upon by the Bayer Process Liquor, or substantially dissolved, therein under the typical conditions of the Bayer Process.
  • the method also comprises the step of:
  • the steps of introducing an inert particulate material into a clarifier vessel and introducing a first flocculating agent into the clarifier vessel more specifically comprise the steps of:
  • the first flocculating agent and the inert particulate material may pass through an in-line mixing device before being introduced to the clarifier vessel.
  • Flocculating agents may be generally divided into two types, being those that predominantly clarify a suspension (a clarifying flocculating agent), and those that predominantly cause settling rates to increase (a settling flocculating agent).
  • the first flocculating agent is a clarifying flocculating agent.
  • the method of the present invention may include the step of:
  • the second flocculating agent may comprise the same agent as the first flocculating agent.
  • the second flocculating agent may be introduced directly to the clarifier vessel, or be mixed with the inert particulate material and or the Bayer Process liquor prior to being introduced into the clarifier vessel.
  • the point at which the second flocculating agent is introduced will be determined, at least in part, by the nature of the flocculating agent and the nature of the inert particulate material.
  • the steps of introducing the feed Bayer Process liquor into the lower portion of the clarifier vessel such that the feed Bayer Process liquor passes through at least a portion of the first layer of particulate material comprises:
  • the feed Bayer Process liquor and the at least a portion of the inert particulate material pass through an in-line mixing device before being introduced to the clarifier vessel.
  • the method may comprise the further step of: mixing a portion of the underflow with the feed Bayer Process liquor to provide at least a portion of the inert particulate material added to the clarifier vessel;
  • the method of the present invention may comprise the step of:
  • the inert particulate material so introduced to settle to form a second layer of particulate material beneath the first layer of particulate material, the second layer of particulate material having a higher concentration of particulate material than the first layer of particulate material.
  • the step of introducing the feed Bayer Process liquor into the lower portion of the clarifier vessel such that the feed Bayer Process liquor passes through at least a portion of the first layer of particulate material more specifically comprises the step of:
  • the step of introducing the feed Bayer Process liquor into the lower portion of the clarifier vessel such that the feed Bayer Process liquor passes through at least a portion of the first layer of particulate material more specifically comprises the step of:
  • the method of the present invention may comprise the step of:
  • the method of the present invention comprises the step of:
  • the step of controlling the extent to which the first layer of particulate material extends above the point at which the feed Bayer Process liquor is introduced into the first layer of inert particulate material and the density of the first layer of particulate material comprises:
  • the step of controlling the extent to which the first layer of particulate material extends above the point at which the feed Bayer Process liquor is introduced into the first layer of inert particulate material and the density of the first layer of particulate material further or alternately comprises:
  • the step of altering the thickness and density of the first layer of particulate material may comprise:
  • the step of altering the thickness and density of the first layer of particulate material may comprise:
  • the step of altering the thickness and density of the first layer of particulate material may comprise:
  • the method may further include the step of:
  • gibbsite concentrations may include systems primarily involving solid-liquid separation (by gravity, enhanced gravity, filtration, classification or other), followed by dissolution of the gibbsite using fresh caustic or other Bayer Process Liquors to an appropriate level for gibbsite nucleation control.
  • the step of removing an overflow from an upper portion of the clarifier vessel, said overflow comprising a liquor with reduced solids content relative to the feed Bayer Process liquor more specifically comprises the step of:
  • the concentration of solids between the first layer of inert particulate material and the point at which the overflow is removed is below about 0.080 g/L.
  • the invention comprises the steps of introducing a feed Bayer Process liquor with a flocculating agent and an inert particulate material into the lower portion of the clarifier vessel such that the feed Bayer Process liquor-flocculating agent-particulate material mixture passes through at least a portion of a layer of suspended inert particulate material in the lower portion of the clarifier vessel, removing an overflow from the clarifier vessel, said overflow comprising a liquor with reduced solids content relative to the feed Bayer Process liquor, removing an underflow from the clarifier vessel, said underflow including solids from the feed Bayer Process liquor, and inert particulate material, mixing a portion of the underflow with further feed Bayer Process liquor; and disposing of a portion of the underflow wherein the steps are performed substantially simultaneously, in a continuous process.
  • the step of introducing the feed Bayer Process liquor agent into the lower portion of the clarifier vessel such that the feed Bayer Process liquor passes through at least a portion of the first layer of particulate material may be performed using any feed arrangement, including sparging or piping into feed distribution equipment. These arrangements might include a tangential feed entry into the bottom or side of the clarifier vessel, or a bottom, central feed arrangement. However, in a preferred form of the invention, the feed Bayer Process liquor is distributed radially from a central discharge sparge.
  • a rotating rake assembly is provided in the second layer of particulate material, the rotating rake assembly being adapted to agitate the second layer of particulate material providing a relatively consistent underflow density.
  • the Bayer Process liquor has an initial alkali concentration of up to 400g/L TA, where TA represents total alkali concentration expressed as g/L sodium carbonate.
  • the Bayer Process liquor has a temperature below its boiling point.
  • the Bayer Process liquor has an initial solids concentration of up to 1000mg/L.
  • the Bayer Process liquor may be a green liquor, supersaturated in alumina.
  • the Bayer Process liquor is provided in the form of a primary settler overflow liquor.
  • the inert particulate material is preferably selected from the group calcium oxide, limestones, calcium hydroxides, slaked limes, calcium carbonate, calcite, calcium aluminate, cellulose, crushed carbon, graphite, cellulose based filter aids, alumina, alumina species and other materials such as plastics, or mixtures thereof.
  • the inert particulate material is selected from the group: CaO, limestone, Ca(OH) 2 , slaked lime, calcite, calcium aluminate, Ca(AIO 2 ) 2 .
  • the inert particulate material is provided in the form of tricalcium aluminate.
  • the inert particulate material comprises particles in the size range 0.5 to 200 ⁇ m.
  • the inert material is introduced at a concentration of approximately 1 to 10g/L. However, higher concentrations, such as approximately 20 g/L may be used.
  • Appropriate flocculating agents may include low molecular weight anionic polymers, particularly bio-carbohydrates such as dextran.
  • a dextran flocculant is used.
  • the dextran flocculant is provided in the form of H152, as supplied by Ondeo-Nalco (product code 85711).
  • an acrylate, acrylamide, hydroxamate terpolymer flocculant, such as HXPAM200, from Cytec is used.
  • the appropriate density and thickness of the first layer of inert particulate material will be a function of factors including but not limited to: the particle size distribution of the inert particulate material, the density of the inert particulate material, the particle size distribution and density of flocculated particles (entering either as Bayer Process liquor, inert particulate material or a combination of both), the rise rate of Bayer process liquor to the overflow, local fluid velocity as impacted on by vessel geometry and internals and the properties of Bayer Process liquor reporting to the overflow (density, viscosity, presence of other phases such as air, etc).
  • the inert particulate material is provided in the form of tricalcium aluminate, with a particle size distribution in the range 0.5 to 200 micron, being mixed with H152 dextran flocculant, treating a Bayer Process liquor in the form of primary settler overflow with density of approximately 1.27g/cm 3 and viscosity of approximately 1.9cP with clarifier feed being introduced into a 1.8m tall clarifier by a radial sparge to achieve an effective up flow in the range of 2 to 4m/hr in the first layer of inert particulate material, it is preferable that the concentration of solids in the first layer of inert particulate material is between 40 and 120g/L.
  • the first layer of inert particulate material extends at between about 200-900mm above the point at which the feed Bayer Process liquor is introduced into the first layer of inert particulate material.
  • first layer of inert particulate material will vary, however a certain density of first layer of inert particulate material will be required to remove solid particulates (from both Bayer process liquor and inert particulate material) introduced into the clarifier vessel. This density will be a function of the factors mentioned previously.
  • the density of the second layer of inert particulate material is between about 220g/L to 450 g/L.
  • the density of the second layer of inert particulate material will be highly dependent on the type of inert particulate material chosen and the height available between the point at which the Bayer Process liquor is introduced into the first layer of inert particulate material and the point at which the underflow is removed from the vessel. These heights will impact on the density and compaction achievable with a specific type of inert particulate material and those skilled in the art will be able to determine the density and height of second inert particulate material to best suit the conditions for a particular application.
  • the point at which the overflow is removed from the clarifier vessel relative to the first layer of particulate material is also dependent on at least some of the factors described above. However, for the same operating conditions and treating the same Bayer Process Liquor as above it is preferred that the overflow is removed from between about 600 and 1400 mm above the first layer of particulate material.
  • a block diagram/flow-sheet illustrating some features of the best method comprises Figure 1.
  • a Bayer Process liquor in the form of a primary settler overflow liquor containing residual solids is combined with a flocculant in the form of Nalco H152 at a dosage of 10-20ppm or lower, the primary settler overflow-flocculant combination then being combined with an inert particulate material in the form of tricalcium aluminate of a size range 0.5 to 200 ⁇ m at a concentration of 10g/L, the combination then being introduced into a clarifier vessel.
  • the clarifier vessel has an upper portion, having a peripheral overflow weir and launder and a lower portion, having a conical floor sloping towards a central underflow outlet.
  • the conical floor section of the clarifier also has a rake assembly as can best be seen in Figure 2.
  • Feed to the clarifier is introduced by way of a radial sparge arrangement that can be raised or lowered. Feed is introduced from the top via the sparge and the sparge exit is located in the bottom part of the clarifier vessel. Feed is evenly distributed in a radial fashion into the body of surrounding fluid/slurry.
  • a relatively dense layer of tricalcium aluminate with a density of approximately 300 g/L and a thickness of 300 mm below the feed point is allowed to form.
  • a loose bed of tricalcium aluminate, with a solids concentration of approximately 40-120g/L and a thickness of about 500-900 mm is allowed to form.
  • a region of solids concentration between about 0.005 and 0.080 g/L, and a thickness of about 500-1000 mm is allowed to form.
  • the various layers are illustrated in Figure 3.
  • the relatively dense layer is continuously agitated by way of the rake assembly to ensure relatively constant solids concentration, and thus underflow density, and to assist in consistent withdrawal of solids from the vessel.
  • Introduced primary settler overflow liquor-H152 flocculant-tricalcium aluminate mixture passes through at least the loose bed of tricalcium aluminate, substantially reducing the residual solids content thereof.
  • An underflow is removed from the clarifier vessel, the underflow including a substantial portion of the residual solids from the primary settler overflow liquor, with the dense tricalcium aluminate.
  • the thickness of the respective layers, and most importantly the loose bed of tricalcium aluminate may be maintained in the desired range by varying the rate at which the underflow is taken, the rate at which Bayer Process liquor is introduced and/or the point at which the sparge exit is positioned in the clarifier vessel with respect to the dense and loose layers of tricalcium aliuminate.
  • a portion of the underflow is mixed with the feed primary settler overflow liquor to provide at least a portion of the tricalcium aluminate fed therewith, and a portion is disposed of.
  • the portion of the underflow Prior to mixing with the feed primary settler overflow liquor, the portion of the underflow is subjected to washing to assist in controlling gibbsite precipitation by dissolution of solid gibbsite into solution.
  • the overflow from the clarifier vessel has a substantially lower solids content relative to the feed liquor.
  • a pilot clarifier vessel was constructed, 600mm in diameter and 1.8m high, with feed lines and pumps to allow the addition of tricalcium aluminate and flocculant to the Bayer Process Liquor.
  • An underflow system was installed to allow recycling of settled solids back to an agitated feed tank.
  • Inert particulate solid was able to be added into the agitated feed tank at up to 10g/L Bayer Process liquor flow.
  • the slurry so formed could be pumped via a line to the clarifier vessel at controlled flow using a flow control valve. Flocculant was added into the line.
  • the flocculated slurry could then be passed through an in-line spiral mixer before being introduced into the clarifier vessel.
  • the clarifier vessel was equipped with two feed systems, being (i) a sparge with outlet located 100mm from the bottom of the conical base of the clarification vessel, such that the feed Bayer Process liquor was distributed radially, and (ii) a feed well that was located off-centre to the cone (not ideal) with the outlet at the top of the conical base.
  • Figure 4 is a top view of the clarifier vessel, showing both the sparge and feed well.
  • Figure 5 is a schematic flow diagram for the test system. The flow to the clarifier was set at 1 kL/hr for the majority of the testwork. This relates to an upflow velocity of 3.5m/hr in the main body of the vessel when using the sparge and an up flow of 3.7m/hr in the main body of the vessel when using the feed well.
  • the feed well was fed via bifurcate arms to give tangential flow to the feedwell.
  • the feedwell extended down to the top of the cone.
  • Standard tests were carried out using 20 ppm Nalco H152, 1000 L/hr flow and 10 g/L filter aid fed to the feed tank. Results were disappointing after 6 hours of operation with overflow clarities >100 g/kL. It was hoped that the feedwell system would run without the need for a bed, but the results indicate that the existence of a bed is critical. Further feed well tests are described below.
  • the filter aid was changed to source B, at an increased dose, and the flocculant was changed to Nalco H152 (a dextran bio-polycarbohydrate) at 20ppm.
  • the overflow solids concentration (measured as NTU) decreased significantly after a period of time as seen in Figure 6 for tests at 5g/L and 10 g/L filter aid. During these tests no underflow solids were removed so the bed height increased over time. From these experiments it became apparent that a certain bed height was required for the liquor to pass through to effectively remove most of the fine mud solids.
  • the bed height was measured to be ⁇ 800mm above the feed position. Bed height was measured using a conductivity probe but also by withdrawing a sample at different levels using a thin tube and syringe. From Figure 6, it can be seen that good overflow clarities were achieved after the bed height reached ⁇ 600mm above the feed position.
  • the bed height was very high (1100 mm above the cone) for most of this test and this caused the overflow solids to be very high also (20-30 g/kL). A three-fold increase in flocculent dosage to 30 ppm did not lower the bed height.
  • a decrease in flow from 1000 L/hr to 500 L/hr reduced the bed height to 600 mm above the cone within half an hour. There was a corresponding increase in the bed solids concentration from 50 g/L to 65 g/L. With the reduction in bed height, overflow clarities in the order of 5 g/kL were observed. An increase in flow back to 1000 L/hr increased the bed height and poor clarities returned.
  • the 'Underflow Zone' (corresponding to the second layer in the description of the invention) had a solids concentration of -220 g/L and extended from the discharge point to the height of the cone.
  • a 'Suspended Zone' (corresponding to the first layer in the description of the invention), which consisted of a flocculated 'bed' of tricalcium aluminate and mud solids at a concentration of 50-60 g/L. The height of this bed was found to be critical to the efficiency of the clarifier. A suspended bed of -600-900 mm in height above the cone was found to give excellent overflow clarities.
  • the 'Clear Zone' was the upper zone immediately above the bed. Samples taken from this zone indicated that the solids concentration was slightly higher than the overflow concentration, suggesting that there may have been some turbulent action (or further settling) between the bed interface and the overflow. It was important that the clear zone was high enough to prevent the unsettled solids from entering the overflow.
  • Clarifier feed consisted of 10 g/L tricalcium aluminate sourced from source B, with 95% of the underflow solids flow recycled back to the feed tank and the remaining flow sent to waste. Fresh filter aid was added to maintain the mass balance. 10 ppm of Nalco H152 was added as the flocculent. Flow in the clarifier was set at 750 L/hr in an attempt to achieve reasonable overflow clarities. The initial bed height was 750 mm above the cone of the clarifier vessel.
  • Overflow clarities ranged between 7 and 40 g/kL and averaged 22 g/kL, much higher than the target overflow clarity of ⁇ 10 g/kL.
  • the major contributing factor for this was believed to be the higher than target bed height of 700-900 mm.
  • Figure 8 shows the relationship between overflow clarities and the bed height.
  • the aim of this experiment was to obtain the best overflow clarity for as long as possible using recycled solids.
  • the sparge used in the initial extended pilot plant experiments, having a simple radial feed, was modified by adding a four-armed rake to enable consistent underflow densities for recycling.
  • the underflow solids were injected into the suction side of the pump rather than the feed tank. By doing so, the tricalcium aluminate solids were not immersed in green liquor for long periods in the feed tank. (This method of addition would be preferable to delay gibbsite precipitation in the bed).
  • Figure 11 shows the solids concentration of the feed and clarifier overflow during the 15 hour run with the modified sparge. Higher feed solids from the thickener overflow did not affect the clarity of the clarifier overflow, indicating the robustness of the clarifier. Clarifier overflow solids of less than 5 g/kL were maintained during periods where thickener performance was very low.
  • pilot clarifier vessel may not be ideal, it has shown that overflow solids of less than 10 g/kL can be achieved using the method of the present invention. Modifications and variation such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

L'invention concerne un procédé de réduction de la teneur en solides d'une liqueur Bayer d'alimentation contenant des solides résiduels. Ce procédé comprend les étapes consistant: à introduire un matériau particulaire inerte dans un récipient de clarification présentant une partie supérieure et une partie inférieure; à introduire un premier agent de floculation dans ledit récipient de clarification; à permettre à au moins une partie du matériau particulaire inerte de former une première couche de matériau particulaire inerte en suspension dans la partie inférieure du récipient de clarification; à introduire la liqueur Bayer d'alimentation dans ladite partie inférieure du récipient de clarification de façon que celle-ci passe au moins dans une partie de la première couche de matériau particulaire inerte; et à retirer un trop-plein de la partie supérieure dudit récipient de clarification, ledit trop-plein comprenant une liqueur à teneur réduite en solides résiduels par rapport à la liqueur Bayer d'alimentation.
PCT/AU2003/000554 2002-05-10 2003-05-09 Procede de clarification de liqueurs bayer WO2003095364A1 (fr)

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Application Number Priority Date Filing Date Title
AU2003223258A AU2003223258A1 (en) 2002-05-10 2003-05-09 Method for clarifying bayer process liquors

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AUPS2248 2002-05-10
AUPS2248A AUPS224802A0 (en) 2002-05-10 2002-05-10 Method for clarifying bayer process liquors

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012003578A1 (fr) * 2010-07-09 2012-01-12 Rio Tinto Alcan International Limited Ajout de floculant et vitesse de mélange permettant de séparer une boue
CN113603123A (zh) * 2021-07-13 2021-11-05 靖西天桂铝业有限公司 一种拜耳法氧化铝生产中碳酸钠免苛化的方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4603000A (en) * 1984-09-05 1986-07-29 Fabcon Incorporated Process and apparatus for flocculating and clarifying a solid-liquid slurry
US4997573A (en) * 1987-08-17 1991-03-05 Golconda Engineering And Mining Services Pty. Ltd. Clarification process for mining liquors
WO1994026383A1 (fr) * 1993-05-07 1994-11-24 Alcan International Limited Ameliorations apportees a un decanteur sous pression
US5387405A (en) * 1992-03-25 1995-02-07 Nalco Chemical Company Bayer liquor polishing

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4603000A (en) * 1984-09-05 1986-07-29 Fabcon Incorporated Process and apparatus for flocculating and clarifying a solid-liquid slurry
US4997573A (en) * 1987-08-17 1991-03-05 Golconda Engineering And Mining Services Pty. Ltd. Clarification process for mining liquors
US5387405A (en) * 1992-03-25 1995-02-07 Nalco Chemical Company Bayer liquor polishing
WO1994026383A1 (fr) * 1993-05-07 1994-11-24 Alcan International Limited Ameliorations apportees a un decanteur sous pression

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012003578A1 (fr) * 2010-07-09 2012-01-12 Rio Tinto Alcan International Limited Ajout de floculant et vitesse de mélange permettant de séparer une boue
US20130168326A1 (en) * 2010-07-09 2013-07-04 Rio Tinto Alcan International Limited Flocculent addition and mixing rate for separating a slurry
CN113603123A (zh) * 2021-07-13 2021-11-05 靖西天桂铝业有限公司 一种拜耳法氧化铝生产中碳酸钠免苛化的方法

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