US3336100A - Process for the production of molybdenum dioxide - Google Patents

Process for the production of molybdenum dioxide Download PDF

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Publication number
US3336100A
US3336100A US347388A US34738864A US3336100A US 3336100 A US3336100 A US 3336100A US 347388 A US347388 A US 347388A US 34738864 A US34738864 A US 34738864A US 3336100 A US3336100 A US 3336100A
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molybdenum
furnace
atmosphere
product
molybdenum dioxide
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Expired - Lifetime
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US347388A
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Cloppet Raymond
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Societe dElectro Chimie dElectro Metallurgie et des Acieries Electriques Dugine SA SECEMAU
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G39/00—Compounds of molybdenum
    • C01G39/02—Oxides; Hydroxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity

Definitions

  • This invention relates to prepartion of molybdenum dioxide for industrial uses'such as production of molybdenum steels and alloys.
  • I l I Present industrial practices for addition of molybdenum to a bath of liquid steel include placing a quantity of a molybdenum alloy, generally ferromolybdenum, which has the. amount of molybdenum required within a solid charge of a furnace before the charge is melted.
  • Another practice comprises adding the ferromolybdenum to the molten bath.
  • Such practices have disadvantages due to the high melting point and great density of ferromolybdenum, which is slow to dissolve in the steel bath because the temperature of the bath is generally lower than the melting point of the ferromolybdenum.
  • the ferromolybdenum remains on the bottom of the furnace and, after tapping out thesteel the furnace operator finds pieces of the ferromolybdenum on the bottom of the furnace. Consequently, the steel tapped out is deficient in molybdenum and residual molybdenum left in the furnace is liable to be incorporated into the next heat of steel in which it is unnecessary, or even unwanted, if the next heat requires a low molybdenum content. Thus, consecutive heats of steel may not havethe specified amount of molybdenum.
  • molybdic oxide, M00 which may or may not be accompanied by a reducing agent, onto a steel bath.
  • the reducing action of the iron, and contingently that of the reducing agent, frees the molybdenum which becomes incorporated into the has disadvantages which arise fromthe molybdenum oxhaving a considerable vapor pressure at the temperatures of application.
  • a substantial proportion is lost by sublimation or by entrainment in the pulverulent condition. Inlight of the cost of molybdenum, a sizable loss is encountered.
  • the amount lost'is variable and the steel or alloy may lack the specified amount of molybdenum.
  • M00 instead of M00 in this last method of operation ofiers considerable advantages.
  • M00 requires less reducing agent since it contains no more than 2 atoms of oxygen instead of 3 per atom of molybdenum.
  • This fixing of sulphur by molybdenum dioxide does not depend only upon the partial pressure of sulphur dioxide, but also'upon the length of time of subjection of the dioxide to presence of certain impurities.
  • My invention relates to a process which includes a reaction of M05 and M00, and renders it possible-to produce a molybdenum dioxide, M00 which has a very low 8 content and a low M00 content.
  • the process comprises intimately mixing finely divided products containing M00 and M08, in stoichiometrical amounts which allow for contingently presentimpurities liable to react with these two compounds.
  • the resulting mixture is very gradually heated within an enclosure wherein the advantage ofliered by the generated.
  • the following the particular atmosphere and upon the' 3 atmosphere is conditioned.
  • the reaction between M and M takes place between 600 C. and 700 C., and preferably between 650 C.
  • the mixture introduced into the reaction enclosure is the product from a molybdenite roasting kiln
  • the sulphur it contains must be measured to determine the proportions of the products which are to be mixed in order to practice my process.
  • the operation of a roasting kiln of this kind may be regulated so that the product obtained may be used directly in my process.
  • the physical condition and chemical composition of the products introduced into the kiln or furnace are adapted to the quality of the molybdenum dioxide to be manufactured.
  • molybdic oxide M00 whose grains are smaller than 2 mm.
  • the flotation concentrates are appropriate for the M08 however, it is desirable that this M05 have a high degree of fineness. Additionally, special attention is devoted to stirring of the M00 and MOS; to obtain an intimate mixture.
  • the reaction between the M00 and the M08 is performed in a hermetic rotary furnace which isequipped with devices for conditioning the atmosphere therein.
  • the reactive mixture is heated progressively and maintained at a temperature exceeding 650 C. for a certain time, such as several hours. Temperatures which exceed 700 C. are avoided so as not to efi'ectvfritting of the M00 and M08
  • the time of this heating or first stage depends upon the quality of the product one wishes to obtain, and upon certain characteristics of the reactive mixture, for example, grain sizes, mode of operation, the agitation of the mixture, or the thickness of a solid layer in the furnace. 1
  • the atmosphere of the furnace is under pressure in slight excess of that on the outside of the furnace (for instances 5 to 10 mm. of water) and is progressively enriched with S0; until the proportion of S0 exceeds 80%. Naturally, escape of. the gases to the outside occurs.
  • the yield from my process varies according to the operating conditions and may reach 95%.
  • this first stage is terminated when the reaction products contain less than 0.5% S and less than M003.
  • my invention includes commencing the desulphurization, or second stage, earlier and also covers extending the first stage until release of S0 becomes insignificant, i.e. until the pressure inside the furnace stops being superior to the atmospheric pressure, thereby avoiding air entering the furnace.
  • the residual sulphur content results predominantly from the action of an atmosphere rich in S0 upon the M00 of the reaction product; half the residual sulphur I the M00 product while a very low percentage of S is results from this action when the S0 content in the atmosphere of the furnace ranges about
  • the product is maintained at a moderately high temperature, 400 C. to 600C, within an enclosure under a pressure close to atmospheric pressure, in which partial S0 pressure is as low as possible and generally lower than 10%.
  • the reaction product is maintained at a moderately high temperature, 400 C. to 600C, within an enclosure under a pressure close to atmospheric pressure, in which partial S0 pressure is as low as possible and generally lower than 10%. In this enclosure, the
  • This second stage may be carried out between the end required, the furnace of the second stage is scavenged with a slightly oxidizing current of gas, e.g., one containing a limited quantity of air.
  • a slightly oxidizing current of gas e.g., one containing a limited quantity of air.
  • the quantity of air -therefore oxygen-to be admitted obviously depends upon the reoxidization of. the product which may be tolerated for substantially the whole oxygen so introduced oxides M00 into M00 This lowers the amount of sulphur but increases the content of free M00 due to a slight reoxidization of the surface of the M00 product.
  • the desulphu'rization may also be performed at a temperature comprised between 600 C. and 700 C. However, one must wait until the emission of S0 has become sufficiently low so that the required rate of flow of the diluent gas necessary for maintaining under 10% the partial S0 pressure in the atmosphere of the furnace is not economically prohibitive.
  • the reaction between thev M00 and the MOS may continue to a certain extent with the last traces of reducing sulphur in the reaction product. If in this case the gaseous scavenging necessary to lower the concentration of sulphur dioxide is performed with air, the resulting oxidization on the surface of the molybdenum dioxide may even hasten the end of the reaction.
  • the cooling of the product rich in M00 is carried out in a non-oxidizing atmosphere, neutral or reducing, to about 250 C., to prevent its reoxidization.
  • a non-oxidizing atmosphere neutral or reducing
  • the inert atmosphere employed for the desulphurization stage is particularly suitable.
  • the second stage desulphurization, occurs in the same furnace as the first stage, wherein the atmosphere is modified so that it contains 'less than 10% S0
  • the reaction products are withdrawn from the furnace at the end of the first stage and introduced into another enclosure in which are conditions favorable for desulphurization.
  • the process may be conducted continuously from the mixing to the extraction of the final cooled M00 product. It is further possible to practice the process by forming within an identical apparatus two enclosures separated by a partition wherein the lower extremity is immersed in the product which is being processed.
  • Example I kg. of molybdic oxide of technical quality, containing 92% M00 and 14 kg. of molybdenite concentrate containing 86% MoS were carefully mixed and then treated in a rotary furnace in which they progressively reached a temperature of 650 C. In this furnace, they were maintained at this temperature for approximately 3 hours under a pressure close to atmospheric pressure.
  • the furnace was equipped with devices for temperature control and atmosphere conditioning. When the atmosphere in the furnace contained 80% of S0 the release of sulphur dioxide had practically stopped. Thereafter, the temperature of the furnace was allowed to drop to 500 C.
  • This product was then introduced into a second furnace substantially identical with the first and equipped with devices for the conditioning of the atmosphere. There it remained for approximately 2 hours at 600/ 650 C. while subjected to an atmosphere whose sulphur dioxide content was maintained at 10% by blowing in approximately 2 m. of air per 100 kg. of product.
  • Example 111 In this example, I employed an oxide direct from roasting of molybdenite concentrates within a specially controlled furnace. The oxide contained:
  • a process for the production of molybdenum dioxide comprising:
  • the process of claim 1 characterized by carrying out said heating and maintaining until the atmosphere of a furnace in Which said heating and maintaining is performed is more than 80% S0 4.
  • the process of claim 1 characterized by carrying out said heating and maintaining until the sulphur content of the reaction product is less than 0.5% sulphur and less than 15% M00 5.
  • the process of claim 1 characterized by during said desulphu-rizing subjecting said reaction product to flows of an inert gas to maintain the S0 content of said atmosphere less than 10%.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)
  • Manufacture And Refinement Of Metals (AREA)
US347388A 1963-02-28 1964-02-26 Process for the production of molybdenum dioxide Expired - Lifetime US3336100A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR926277A FR1357784A (fr) 1963-02-28 1963-02-28 Procédé de fabrication de dioxyde de molybdène

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US3336100A true US3336100A (en) 1967-08-15

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US (1) US3336100A (en&quot)
BE (1) BE643941A (en&quot)
CH (1) CH417552A (en&quot)
DK (1) DK111202B (en&quot)
FR (1) FR1357784A (en&quot)
GB (1) GB1016237A (en&quot)
NL (1) NL6401327A (en&quot)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833352A (en) * 1968-05-21 1974-09-03 M Vojkovic Process for beneficiating molybdenate concentrate to produce molybdenum trioxide
US3928240A (en) * 1971-09-01 1975-12-23 Standard Oil Co Ohio Process for the preparation of molybdenum-containing oxidation catalysts
US4462822A (en) * 1983-11-08 1984-07-31 Amax Inc. Molybdenum dioxide-molybdenite roasting
US4551312A (en) * 1984-11-13 1985-11-05 Atlantic Richfield Company Process for converting molybdenite to molybdenum oxide
US4552749A (en) * 1985-01-11 1985-11-12 Amax Inc. Process for the production of molybdenum dioxide
US20080260612A1 (en) * 2007-04-18 2008-10-23 Orchard Material Technology, Llc Oxidation of metallic materials as part of an extraction, purification and/or refining process
US20140161715A1 (en) * 2012-12-12 2014-06-12 Orchard Material Technology Sulfide oxidation process for production of molybdenum oxides from molybdenite
CN113148960A (zh) * 2021-04-13 2021-07-23 郑州大学 钼精矿短流程制备高纯度含硫产物的方法
CN113234940A (zh) * 2021-04-13 2021-08-10 郑州大学 钼精矿短流程制备钼金属产物的方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1637838A (en) * 1925-01-27 1927-08-02 Fillmore Hyde A Method of treating ores
US2398114A (en) * 1942-09-12 1946-04-09 Westinghouse Electric Corp Reduction of molybdenum trioxide
US2817583A (en) * 1956-05-10 1957-12-24 Basf Ag Working up of sulfidic raw materials
US2987392A (en) * 1960-02-02 1961-06-06 Lester D Supiro Method of rapidly producing metallic powders of high purity

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1637838A (en) * 1925-01-27 1927-08-02 Fillmore Hyde A Method of treating ores
US2398114A (en) * 1942-09-12 1946-04-09 Westinghouse Electric Corp Reduction of molybdenum trioxide
US2817583A (en) * 1956-05-10 1957-12-24 Basf Ag Working up of sulfidic raw materials
US2987392A (en) * 1960-02-02 1961-06-06 Lester D Supiro Method of rapidly producing metallic powders of high purity

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833352A (en) * 1968-05-21 1974-09-03 M Vojkovic Process for beneficiating molybdenate concentrate to produce molybdenum trioxide
US3928240A (en) * 1971-09-01 1975-12-23 Standard Oil Co Ohio Process for the preparation of molybdenum-containing oxidation catalysts
US4462822A (en) * 1983-11-08 1984-07-31 Amax Inc. Molybdenum dioxide-molybdenite roasting
US4551312A (en) * 1984-11-13 1985-11-05 Atlantic Richfield Company Process for converting molybdenite to molybdenum oxide
US4552749A (en) * 1985-01-11 1985-11-12 Amax Inc. Process for the production of molybdenum dioxide
US20080260612A1 (en) * 2007-04-18 2008-10-23 Orchard Material Technology, Llc Oxidation of metallic materials as part of an extraction, purification and/or refining process
US20140161715A1 (en) * 2012-12-12 2014-06-12 Orchard Material Technology Sulfide oxidation process for production of molybdenum oxides from molybdenite
US9187340B2 (en) * 2012-12-12 2015-11-17 Orchard Material Technology Sulfide oxidation process for production of molybdenum oxides from molybdenite
CN113148960A (zh) * 2021-04-13 2021-07-23 郑州大学 钼精矿短流程制备高纯度含硫产物的方法
CN113234940A (zh) * 2021-04-13 2021-08-10 郑州大学 钼精矿短流程制备钼金属产物的方法

Also Published As

Publication number Publication date
FR1357784A (fr) 1964-04-10
DK111202B (da) 1968-07-01
NL6401327A (en&quot) 1964-08-31
BE643941A (en&quot) 1964-06-15
GB1016237A (en) 1966-01-05
CH417552A (fr) 1966-07-31

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