EP3325679A1 - Procédé de réduction de fer trivalent dans la production de dioxyde de titane dans le procédé au sulfate - Google Patents

Procédé de réduction de fer trivalent dans la production de dioxyde de titane dans le procédé au sulfate

Info

Publication number
EP3325679A1
EP3325679A1 EP16763441.9A EP16763441A EP3325679A1 EP 3325679 A1 EP3325679 A1 EP 3325679A1 EP 16763441 A EP16763441 A EP 16763441A EP 3325679 A1 EP3325679 A1 EP 3325679A1
Authority
EP
European Patent Office
Prior art keywords
reduction
iron
digestion solution
titanium
digestion
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP16763441.9A
Other languages
German (de)
English (en)
Inventor
Jan Klauset
Oystein RUUD
Asborn DAHL
Mitja Medved
Per Thoen
Thomas Pierau
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kronos International Inc
Original Assignee
Kronos International Inc
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 Kronos International Inc filed Critical Kronos International Inc
Publication of EP3325679A1 publication Critical patent/EP3325679A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
    • C01G23/0532—Producing by wet processes, e.g. hydrolysing titanium salts by hydrolysing sulfate-containing salts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/14—Sulfates
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
    • C22B3/08—Sulfuric acid, other sulfurated acids or salts thereof
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/22—Treatment or purification of solutions, e.g. obtained by leaching by physical processes, e.g. by filtration, by magnetic means, or by thermal decomposition
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/20—Treatment or purification of solutions, e.g. obtained by leaching
    • C22B3/44—Treatment or purification of solutions, e.g. obtained by leaching by chemical processes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/1236—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching
    • C22B34/124—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching using acidic solutions or liquors
    • C22B34/125—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching using acidic solutions or liquors containing a sulfur ion as active agent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B34/00—Obtaining refractory metals
    • C22B34/10—Obtaining titanium, zirconium or hafnium
    • C22B34/12—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08
    • C22B34/1236—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching
    • C22B34/1259—Obtaining titanium or titanium compounds from ores or scrap by metallurgical processing; preparation of titanium compounds from other titanium compounds see C01G23/00 - C01G23/08 obtaining titanium or titanium compounds from ores or scrap by wet processes, e.g. by leaching treatment or purification of titanium containing solutions or liquors or slurries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the invention is directed to the reduction of trivalent iron in the production of titanium dioxide in the sulfate process.
  • the so-called sulfate process for the production of titanium dioxide based on the digestion of iron-titanium raw materials in sulfuric acid, which forms after the addition of dilute sulfuric acid to the solid digestion cake a digestion suspension, the dissolved iron (II) sulfate and titanyl sulfate and a contains sparingly soluble pulping residue.
  • a digestion solution is formed, from which subsequently the dissolved iron (II) sulfate is crystallized out and likewise separated off.
  • the dissolved Titanylsulfat is hydrolyzed and the formed Titanoxidhydrat calcined to the final product titanium dioxide.
  • the commonly used raw materials such as llmeniterz or iron-titanium slags often contain larger amounts of trivalent iron, usually in the form of the minerals hematite and magnetite.
  • the dissolved trivalent iron in the form of Fe2 (SÜ4) 3 in the digestion solution has a negative influence on the intermediates and on the final titanium dioxide product.
  • Iron (III) sulphate also has in
  • CONFIRMED U NGSKOPI E made to divalent iron by adding metallic iron.
  • the metallic iron is usually added as iron scrap in bulk or in the form of pressed packets of defined density in the digestion suspension.
  • the speed of the exothermic surface reaction is dependent on the surface condition, the thickness of the iron material used and the
  • the injected air causes cooling of the suspension, which leads to lower reaction rates, and also acts as an oxidizing agent for bivalent iron and hydrogen in statu nascendi, whereby trivalent iron or water are generated.
  • the yield of the metallic iron used is reduced, which has an effect on the economy of the process.
  • trivalent titanium is also produced from the tetravalent titanium by the addition of the metallic iron.
  • the reduction step does not take place in the digestion suspension, but after separation of the insoluble digestion residue in the digestion solution, and preferably before
  • Ferrous sulphate crystallization takes place. The reduction is carried out by introduction of SO 2 gas, which reacts with Fe (III) sulfate and water to form Fe (II) sulfate and sulfuric acid. If necessary, residual iron (III) can subsequently be reduced by means of metallic iron (scrap metal).
  • the target size given in EP 2 064 355 B1 is an iron (III) content of 0 to 1 g / l while avoiding the formation of trivalent titanium.
  • the reduction with the help of scrap iron is carried out so that the digestion solution is stirred in batches and pumped around a scrap package.
  • the degree of reduction of the solution is determined by redox potential measurement on the cooled solution.
  • Digestion solution overreduced for example by adding metallic iron, and only in a second sub-step, the desired degree of reduction is set by the overreduced digestion solution is mixed in an appropriate ratio with unreduced digestion solution.
  • the method has the disadvantage of an additional process step.
  • the object is achieved by a sulfate process for the production of titanium dioxide from an iron-titanium raw material comprising the process steps:
  • Reduction vessel setting a desired degree of reduction
  • Reduction vessel is adjusted, the trivalent iron is completely reduced to divalent iron and tetravalent titanium partially converted to trivalent titanium.
  • FIG 1 Schematic process picture of the inventive method for the reduction of trivalent iron
  • the dissolved iron after clarification and before reduction is usually from 3% by weight to 9% by weight as trivalent iron in the form of Fe 2 (SO 4) 3 and at 5% by weight to 25% by weight. % as bivalent iron in the form of FeS0 4 .
  • the dissolved titanium is present as tetravalent titanium in the form of titanyl sulfate.
  • the inventive method allows the setting of a desired
  • the digestion solution after clarification is preferably conducted via a storage tank into a reduction vessel, which is preferably filled with metallic iron in the form of scrap iron.
  • the scrap iron is present, for example, as a bed or in the form of pressed scrap packets and is referred to below as "scrap.”
  • the pulping solution is preferably introduced from below, wherein a suitable liquid distribution system is preferably located at the bottom of the reduction vessel, for example sieve trays with suitable pressure loss or pipe distribution systems which are known and commercially available from the extraction and distillation technique, over which the digestion solution is passed evenly distributed through the scrap.
  • the digestion solution is at the other end of the reduction vessel, in this case at the top of the vessel e.g. deducted as overflow.
  • Reduction process dissolves the scrap iron in the digestion solution, and new scrap is refilled as needed.
  • the amount of metallic iron available for reduction which is permanently in contact with the digestion solution to be reduced, remains approximately constant during the progress of scrap consumption.
  • This can preferably be achieved in that, for example, the surface of the digestion solution in the vessel is always below the scrap filling by the scrap is correspondingly refilled so that it protrudes from the digestion solution.
  • a defined level of scrap filling may be maintained below the surface of the digestion solution by refilling the scrap to a suitable level measurement.
  • the digestion solution is preferably at empty tube speed through the
  • Promoted reduction vessel which corresponds to a Reynolds number of at least 200, preferably of at least 800 and more preferably of at least 1600.
  • the method according to the invention can be largely automated and run both in “batch mode” as in “continuous operation”.
  • the digestion solution overflowing from the reduction vessel is recirculated via line A (see Fig. 1) directly back into the reduction vessel and partially or completely via line B (see Fig. 1).
  • the decomposition solution passes through a heat exchanger (FIG. 1), with the aid of which the temperature of the solution is set to less than 85 ° C. in the entire process step of the reduction can.
  • the temperature of the solution in the entire process step of the reduction but in particular in the reduction vessel to a value below 85 ° C and above 50 ° C is set so that on the one hand no premature hydrolysis occurs and on the other hand, a sufficiently high reaction rate can be maintained to a to achieve the desired system capacity.
  • an automated temperature measurement of the solution takes place, both at the inlet into the reduction vessel (T1) as at the outlet from the reduction vessel (T2).
  • the temperature in the reduction reactor should be between 60 ° C and 70 ° C.
  • the heat exchanger can be installed in line A and / or in line B.
  • the temperature of the solution in the reduction vessel can also be controlled via the feed rate per unit time in the reduction reactor and the amount of cycle flow per unit time.
  • the progress of the reduction reaction in the overflow from the reduction reactor digestion solution can be determined continuously by means of redox potential electrode.
  • optionally automatable methods from the field of instrumental analysis for determining the concentration of trivalent iron and / or trivalent titanium compounds can be used to control the progress of the reduction.
  • optical, spectroscopic and electroanalytical determination methods which are used continuously in-line or discontinuously off-line are suitable.
  • any other measuring method should also be included, with which the progress of the reduction or the concentration of trivalent iron and trivalent titanium in the digestion solution can be determined.
  • the complete reduction of the trivalent iron and the partial Ti (IV) reduction are carried out so that in the
  • Digestion solution a content of trivalent titanium from 1 to 5 wt .-%, particularly preferably from 1, 2 to 2.3 wt .-%, based on the total titanium concentration is achieved.
  • a batch of the unreduced digestion solution is circulated through the reduction vessel (line A, see Fig. 1) or through the reservoir tank and the reduction vessel (line B, see Fig. 1) until the desired Redox potential value of the digestion solution is reached, which corresponds to a complete reduction of trivalent iron and a partial reduction of tetravalent titanium.
  • the feed quantity of unreduced digestion solution is controlled via the ORP measurement by measuring the redox potential and / or the temperature at the outlet of the reduction vessel (T2) in the unreacted digestion solution into the reduction vessel regulates that at the outlet of the reduction vessel the target value for the concentration of trivalent titanium in the solution and / or the desired
  • Temperature can be achieved without a circulation on the line A and / or line B of the digestion solution is required. After the target value for the concentration of trivalent titanium at the outlet of the reduction vessel has been reached, the thus reduced digestion solution can be transferred to the subsequent process steps.
  • the digestion solution is circulated at a selected constant inlet from the reservoir tank through the reduction vessel and via the line A (see Fig. 1), where the volume flow through the line A Guided solution so regulated that the desired
  • Redox potential value is reached, which corresponds to a complete reduction of trivalent iron and a partial reduction of tetravalent titanium.
  • Redox potential value is reached, which corresponds to a complete reduction of trivalent iron and a partial reduction of tetravalent titanium.
  • the quality of the overflow can also be controlled in a controlled manner by the regulation of the quantity conducted in the circuit via line A, even in the case of fluctuating concentrations of the fractions to be reduced in the clarified digestion solution.
  • This control is carried out as in the embodiments described above via the measurement of the redox potential at the outlet of the reduction vessel.
  • the targeted reduction of the digestion solution i. the setting of the desired degree of reduction in the
  • the process according to the invention can be automated as far as possible and run in batch mode, in particular in continuous operation.
  • the reduction reaction can proceed evenly and controlled, so that a defined degree of reduction in the digestion solution in the sense of a redox potential, measured against a standardized reference potential, can be achieved.
  • the digestion solution contains fewer accompanying elements, e.g. must be separated in the subsequent crystallization and which adversely affect the quality of the final titanium dioxide product.
  • Example 1 continuous operation without recycling
  • a 20 m 3 reduction reactor (reduction vessel) with a height of 5 m was filled with about 9 tons of metallic iron in the form of a mixture of scrap press packages and scrap bed so that above the overflow at a height of 4 m a 0, 5 to 1 m projecting bed was formed.
  • the reduction reactor was initially unreduced with the clarified, about 55 ° C warm
  • a concentration of 1, 2 g / L trivalent titanium corresponding to about 1, 5 wt .-% trivalent titanium based on total titanium content
  • Reactor output of about 3 ° C set The power of the heat exchanger, which could be delivered to the circulated solution was up to 500 KW and was automatically retrieved depending on the desired temperature at the reactor outlet both for cooling and for heating.
  • Digestion solution at the reactor outlet was subsequently transferred to the subsequent process steps in the process.
  • Example 2 continuous operation with circulation
  • the reduction reactor from Example 1 was filled with clarified digestion solution after the same start-up procedure as described in Example 1 and then fed continuously from the feed tank at a constant volume flow rate of 50 m 3 / h.
  • the reactor was recirculated via a
  • Example 3 continuous operation with circulation
  • the reduction reactor from Example 1 was filled with clarified digestion solution after the same start-up procedure as described in Example 1 and then continuously fed with a volume flow of 70 m 3 / h from the feed tank.
  • the volume flow in the circuit via a heat exchanger and via line A was set to 45 m 3 / h, so that an outlet temperature of 63 ° C was established at the overflow. Under these conditions, the temperature difference between the reactor bottom and the reactor outlet was about 5 ° C.
  • the rate of dissolution of the metallic iron was about 1400 kg / h, which resulted in the complete reduction of trivalent iron and the desired trivalent titanium concentration of 1.2 g / L in the digest solution at the reactor exit.
  • the reduced digestion solution became the following

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Compounds Of Iron (AREA)

Abstract

L'invention concerne l'étape de procédé consistant à réduire du fer trivalent dans la production de dioxyde de titane dans le procédé au sulfate. Selon l'invention, la réduction se produit après séparation du résidu de digestion faiblement soluble par utilisation du fer métallique de sorte que le fer trivalent est totalement réduit en fer divalent et le titane tétravalent de manière sélective partiellement en titane trivalent. De préférence, la teneur souhaitée en Ti(III) va de 1 % en poids à 5 % poids par rapport au titane total. De préférence, l'étape de procédé de l'invention est réalisée dans une opération en continu à une température allant de >50°C à <85°C dans un réacteur de réduction, la progression de la réduction étant contrôlée au moyen du potentiel d'oxydoréduction ou de la teneur de la solution en fer (III) ou en titane (III). Le procédé de l'invention est caractérisé par les avantages suivants : il peut être largement automatisé, la réaction de réduction se déroule de manière uniforme, on peut utiliser différentes qualités de ferraille, on obtient une amélioration de la qualité du produit TiO2.
EP16763441.9A 2015-07-23 2016-07-18 Procédé de réduction de fer trivalent dans la production de dioxyde de titane dans le procédé au sulfate Withdrawn EP3325679A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP15002178.0A EP3121295A1 (fr) 2015-07-23 2015-07-23 Procede de reduction de fer trivalent lors de la fabrication d'oxyde de titane selon le procede au sulfate
PCT/EP2016/001251 WO2017012710A1 (fr) 2015-07-23 2016-07-18 Procédé de réduction de fer trivalent dans la production de dioxyde de titane dans le procédé au sulfate

Publications (1)

Publication Number Publication Date
EP3325679A1 true EP3325679A1 (fr) 2018-05-30

Family

ID=54010794

Family Applications (2)

Application Number Title Priority Date Filing Date
EP15002178.0A Withdrawn EP3121295A1 (fr) 2015-07-23 2015-07-23 Procede de reduction de fer trivalent lors de la fabrication d'oxyde de titane selon le procede au sulfate
EP16763441.9A Withdrawn EP3325679A1 (fr) 2015-07-23 2016-07-18 Procédé de réduction de fer trivalent dans la production de dioxyde de titane dans le procédé au sulfate

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP15002178.0A Withdrawn EP3121295A1 (fr) 2015-07-23 2015-07-23 Procede de reduction de fer trivalent lors de la fabrication d'oxyde de titane selon le procede au sulfate

Country Status (9)

Country Link
EP (2) EP3121295A1 (fr)
JP (1) JP2018523014A (fr)
KR (1) KR20180031758A (fr)
CN (1) CN107849635A (fr)
AU (1) AU2016295915A1 (fr)
BR (1) BR112017025794A2 (fr)
MX (1) MX2017015435A (fr)
RU (1) RU2692544C1 (fr)
WO (1) WO2017012710A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112795784B (zh) * 2020-12-29 2022-04-05 中国科学院过程工程研究所 一种赤泥中有价组分综合回收的方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3524053A1 (de) * 1985-07-05 1987-01-08 Bayer Antwerpen Nv Verfahren zur herstellung von hochwertigem titandioxid nach dem sulfatverfahren
DE4339975C2 (de) * 1993-11-24 1996-08-29 Bayer Ag Verfahren zur Herstellung einer Ti(III)haltigen Lösung und deren Verwendung
AU2002952155A0 (en) * 2002-10-18 2002-10-31 Bhp Billiton Innovation Pty Ltd Production of titania
DE102007032417A1 (de) * 2007-07-10 2009-01-15 Tronox Pigments Gmbh Verfahren zur Herstellung einer reduzierten titandioxidhaltigen Aufschlusslösungsmischung
RU2487836C1 (ru) * 2012-04-18 2013-07-20 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Московский государственный машиностроительный университет (МАМИ)" Способ получения диоксида титана

Also Published As

Publication number Publication date
CN107849635A (zh) 2018-03-27
JP2018523014A (ja) 2018-08-16
KR20180031758A (ko) 2018-03-28
MX2017015435A (es) 2018-05-07
WO2017012710A8 (fr) 2018-01-11
AU2016295915A1 (en) 2017-12-14
BR112017025794A2 (pt) 2018-08-07
RU2692544C1 (ru) 2019-06-25
WO2017012710A1 (fr) 2017-01-26
EP3121295A1 (fr) 2017-01-25

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