CN114031116B - Preparation method of beta-type ammonium tetramolybdate - Google Patents

Preparation method of beta-type ammonium tetramolybdate Download PDF

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CN114031116B
CN114031116B CN202111594411.4A CN202111594411A CN114031116B CN 114031116 B CN114031116 B CN 114031116B CN 202111594411 A CN202111594411 A CN 202111594411A CN 114031116 B CN114031116 B CN 114031116B
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ammonium
beta
water
tetramolybdate
ammonium tetramolybdate
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CN114031116A (en
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周秋生
杨利群
李小斌
彭志宏
刘桂华
齐天贵
向丽娟
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Central South University
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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
    • C—CHEMISTRY; METALLURGY
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    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/80—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70
    • C01P2002/88—Crystal-structural characteristics defined by measured data other than those specified in group C01P2002/70 by thermal analysis data, e.g. TGA, DTA, DSC

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Abstract

The invention belongs to the technical field of metallurgy, and discloses a preparation method of beta-type ammonium tetramolybdate. The method takes solid-phase ammonium molybdate as a raw material, adds a small amount of water in the thermal decomposition process, controls the decomposition temperature and time, and directly obtains the beta-type ammonium tetramolybdate solid phase with a single crystal form in one step. Only a little water is needed in the preparation process, no waste water is generated, the thermal decomposition temperature is low, and the prepared beta-type ammonium tetramolybdate has a single crystal form.

Description

Preparation method of beta-type ammonium tetramolybdate
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a preparation method of beta-type ammonium tetramolybdate.
Background
At present, the ammonium tetramolybdate preparation in the industry mainly adopts an acid precipitation process, ammonium molybdate solution after concentration and filtration is placed into an acid precipitation tank, the temperature of the solution is controlled to be 40-45 ℃ before acid precipitation, stirring is started, acid liquor is added, the acid adding speed is higher before the solution is cloudy, the acid adding speed is reduced after the solution is cloudy and crystallized, the pH value of the solution is detected, and the acid adding is stopped when the pH value is =1.5 to 2.5. When the pH value is kept constant between 1.5 and 2.5, discharging and filtering immediately, and leaching twice by using ammonium chloride or ammonium nitrate solution with the pH value being the same as the final pH value of acid precipitation. The highest reaction temperature in the acid precipitation process is not more than 60 ℃; if molybdenum blue appears in the solution in the acid precipitation process, a proper amount of hydrogen peroxide is added to oxidize the low-valence molybdenum into high-valence molybdenum, so that the molybdenum blue disappears. Ammonium molybdate solution before acid precipitationThe pH value is kept to be 7-7.5 generally, and a small amount of free ammonia is ensured to be in the solution, so that the formation of ammonium tetramolybdate is facilitated when acid is added for neutralization and precipitation; the acid precipitation reagent is generally HNO 3 Or HCl, HNO in industrial nitric acid 3 The content is 40 to 68 percent, and the HCl content in the industrial hydrochloric acid is 30 to 35 percent.
Neutralizing the ammonium molybdate solution with an acid, and hydrolyzing molybdenum in the form of anions in the solution to precipitate ammonium polymolybdate, wherein the reaction formula is as follows:
4(NH 4 ) 2 MoO 4 +6H + →(NH 4 ) 2 O·4MoO 3 ·2H 2 O↓+6NH 4 + +H 2 O
the ammonium molybdate neutralization crystallization process conditions mainly comprise pH value, inorganic acid type, temperature, original concentration of ammonium molybdate solution and the like.
The production of ammonium tetramolybdate by the acid precipitation process must be carried out in an aqueous solution, the use of a large amount of water not only causes the shortage of water resources, but also the recovery and the reuse of waste water after the process is finished are also problems needing attention. Reducing agents such as stannic chloride and the like generally exist in hydrochloric acid, hexavalent molybdenum can be reduced into divalent molybdenum in the acid precipitation process, molybdenum blue appears, a proper amount of hydrogen peroxide needs to be added, and if the hydrogen peroxide is added excessively, the product can turn yellow; nitric acid and hydrochloric acid also react with the acid precipitation vessel (typically stainless steel), thereby discoloring the solution and corroding the vessel; the use of large amounts of acidic reagents results in large amounts of nitrate or chloride salts, and the disposal of such waste water after the reaction is complete is problematic. The ammonium polymolybdate precipitated by acid precipitation is a mixture mainly comprising ammonium tetramolybdate and containing multiple components of ammonium trimolybdate, ammonium paramolybdate and ammonium decamolybdate, and the ammonium tetramolybdate is also a mixture of alpha-type or several crystal forms of ammonium tetramolybdate.
The alpha-type ammonium tetramolybdate has uneven grain size and poor thermal stability, and the qualification rate of molybdenum bars produced by using the alpha-type ammonium tetramolybdate as a raw material is low. The beta-type ammonium tetramolybdate is an ideal crystal form, has large and uniform crystal grains and good thermal stability, does not generate intermediate compounds in the thermal evolution process, and has good processing performance on the molybdenum powder reduced.
Many researchers have studied the thermal decomposition process of ammonium molybdate, such as the Master's academic thesis ammonium molybdate thermal decompositionThe phase transition behavior and dynamics research of (1) indicates that the sample has obvious change when the temperature of ammonium dimolybdate is increased to 170 ℃, and the composition change is quite obvious when the temperature is increased to 180 ℃, and (NH) may appear 4 ) 4 Mo 8 O 26 、4MoO 3 ·2NH 3 ·H 2 O and the like; since the starting material does not carry crystal water and the reaction takes place by evolution of NH 3 And H 2 The reaction of O gas, the largest possible reaction product being (NH) 4 ) 4 Mo 8 O 26 . The thermal decomposition of several heterogeneous ammonium molybdates published in Yi Zhou lan et al shows that heterogeneous ammonium molybdate generates a series of thermal decomposition reactions in the heating process to release NH 3 And H 2 O, to form various ammonium molybdate intermediate phases. With the continuous rise of the reaction temperature, the molybdenum content of the intermediate phase is increased, and the final product is MoO 3 The main thermal decomposition reactions are as follows: (NH) 4 ) 6 Mo 7 O 24 ·4H 2 O→（NH 4 ） 4 Mo 5 O 17 （110℃）→(NH 4 ) 2 Mo 4 O 13 （220℃）；(NH 4 ) 2 Mo 4 O 13 And beta- (NH) 4 ) 2 Mo 4 O 13 →(NH 4 ) 2 Mo 14 O 43 （290℃）→(NH 4 ) 2 Mo 22 O 6 （290℃）→MoO 3 (290 ℃ C.). Pure phase of beta-form ammonium tetramolybdate cannot be obtained by thermal decomposition.
Disclosure of Invention
Aiming at the problems in the prior art, the invention mainly aims to provide a preparation method of beta-type ammonium tetramolybdate.
In order to achieve the purpose, the invention adopts the following technical scheme.
The method takes solid-phase ammonium molybdate as a raw material, a small amount of water is added in the thermal decomposition process, the decomposition temperature and time are controlled, and the beta-type ammonium tetramolybdate solid phase with a single crystal form is directly obtained in one step.
Ammonium molybdate gradually loses NH when being heated 4 + And H 2 O, thereby gradually changingTo generate 'low ammonium' ammonium molybdate solid phase.
It is preferable to select high ammonium molybdate as the raw material.
The high-ammonium molybdate of the invention refers to: NH when the total Mo of the ammonium molybdate chemical formula is 1 4 + In an amount greater than the NH in ammonium tetramolybdate 4 + Ammonium molybdate.
In the thermal decomposition process of ammonium molybdate, a small amount of water is added, so that the decomposition reaction temperature can be reduced, the dissolution of ammonium molybdate on a microscopic level is facilitated, and NH during heating is facilitated 4 + And escape.
Specifically, the method for preparing beta-type ammonium tetramolybdate comprises the following steps:
(1) Mixing high-ammonium molybdate with a small amount of water to obtain a material A;
(2) Heating the material A to 140-240 ℃, and reacting for 1-3 hours to obtain a material B;
(3) And drying the material B to obtain the beta-type ammonium tetramolybdate.
Further, in the step (1), the ammonium molybdate with high ammonium content is mixed with water according to the liquid-solid mass ratio of 1.
Further, the high ammonium molybdate is selected from one or more of ammonium orthomolybdate, ammonium dimolybdate, ammonium paramolybdate and ammonium decamolybdate.
Further, in the step (2), water is supplemented every 10 to 30min in the reaction process. The mass ratio of the supplemented water to the added water in the step (1) is 1 to 3:1.
further, the drying temperature is 50 to 70 ℃, and the drying time is 5 to 7h.
Further, the whole process of recovering the produced NH 3 。
The technical scheme provided by the invention can be used for preparing the beta-type ammonium tetramolybdate product with single crystal form.
Compared with the prior art, the technical scheme provided by the invention has the following obvious advantages:
(1) Only a very small amount of water is used, and no waste water is generated;
(2) The thermal decomposition temperature is low, and the cost is low;
(3) The product prepared by the method has a single crystal form, only beta-type ammonium tetramolybdate exists in the reaction product, and no other crystal forms exist;
(4) The process is simple and short, and the operation is simple.
Drawings
FIG. 1 is a process flow diagram of the production of ammonium tetramolybdate by acid precipitation.
Fig. 2 is a flow chart of the technical scheme adopted by the invention.
Figure 3 is an XRD pattern of the product prepared in example 1.
FIG. 4 is a thermogravimetric-differential thermal profile of the product prepared in example 1.
Figure 5 is an XRD pattern of the product prepared in example 2.
Figure 6 is an XRD pattern of the product prepared in example 3.
Figure 7 is the XRD pattern of the product prepared in example 4.
Detailed Description
The present invention is described in detail below with reference to the attached drawings, and the description in this section is only exemplary and explanatory and should not be construed as limiting the scope of the present invention in any way.
It is to be noted that, unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the invention pertains.
Example 1:
mixing ammonium dimolybdate and secondary distilled water according to a liquid-solid mass ratio of 15:1, placing the mixture in a flat-bottomed crucible, reacting for 2 hours in a muffle furnace at the reaction temperature of 140 ℃, taking out a material layer and supplementing water every 30min during the reaction, wherein the mass ratio of the water supplementing amount to the initially added secondary distilled water is 1:1, taking out the product to be dried after the reaction is finished, wherein the drying temperature is 50 ℃, and the drying time is 7 hours.
Fig. 3 is an XRD pattern of the product prepared in this example, from which it can be seen that the product is β -form ammonium tetramolybdate with a single crystal structure.
FIG. 4It can be seen that, in the process of temperature rise, only one endothermic peak, which represents (NH), exists in beta-type ammonium tetramolybdate 4 ) 2 Mo 4 O 13 Loss of NH 3 And H 2 O to MoO 3 The process of (1). .
In summary, the reaction equation for example 1 is: 2 (NH) 4 ) 2 Mo 2 O 7 =(NH 4 ) 2 Mo 4 O 13 +2NH 3 ↑+H 2 O
Example 2:
mixing ammonium orthomolybdate and secondary distilled water according to a liquid-solid mass ratio of 30:1, placing the mixture in a flat-bottomed crucible, controlling the reaction temperature in a muffle furnace to be 240 ℃, reacting for 1h, taking out a material layer and supplementing water every 10min during the reaction, wherein the mass ratio of the water supplementing amount to the initially added secondary distilled water is 3:1, taking out the product after the reaction is finished, and drying at 70 ℃ for 5h.
Fig. 5 is an XRD pattern of the product prepared in this example, from which it can be seen that the product is β -form ammonium tetramolybdate with a single crystal structure.
Example 3:
uniformly mixing ammonium decamolybdate and secondary distilled water according to the liquid-solid mass ratio of 20, placing the mixture in a flat-bottom crucible, controlling the reaction temperature in a muffle furnace to be 190 ℃, reacting for 2 hours, taking out a material layer every 15min during the reaction, and supplementing water, wherein the mass ratio of the water supplementation amount to the initially added secondary distilled water is 1:1, taking out the product after the reaction is finished, and drying at 70 ℃ for 7h.
Fig. 6 is an XRD pattern of the product prepared in this example, from which it can be seen that the product is β -form ammonium tetramolybdate with a single crystal structure.
Example 4:
uniformly mixing ammonium paramolybdate and secondary distilled water according to the liquid-solid mass ratio of 25, placing the mixture into a flat-bottom crucible, controlling the reaction temperature in a muffle furnace to be 180 ℃, reacting for 3 hours, taking out a material layer every 20min during the reaction, and supplementing water, wherein the mass ratio of the water supplementation amount to the initially added secondary distilled water is 1.5:1, taking out the product after the reaction is finished, and drying at 70 ℃ for 5h.
FIG. 7 is an XRD pattern of the product prepared in this example, from which it can be seen that the product is β ammonium tetramolybdate having a single crystal structure.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (3)

1. A method for preparing beta-type ammonium tetramolybdate, comprising the steps of:
(1) Mixing high-ammonium molybdate with a small amount of water to obtain a material A; mixing high-ammonium molybdate with water according to the liquid-solid mass ratio of 1;
(2) Heating the material A to 140-240 ℃, and reacting for 1-3 hours to obtain a material B;
(3) Drying the material B to obtain beta-type ammonium tetramolybdate; the drying temperature is 50 to 70 ℃, and the drying time is 5 to 7h;
the high ammonium molybdate refers to: NH when the total Mo of the ammonium molybdate chemical formula is 1 4 + In an amount greater than the NH in ammonium tetramolybdate 4 + Ammonium molybdate in an amount of material (b); the high ammonium molybdate is one or more of ammonium orthomolybdate, ammonium dimolybdate and ammonium decamolybdate.
2. The method for preparing beta ammonium tetramolybdate according to claim 1, wherein in the step (2), water is replenished every 10 to 30min during the reaction.
3. The method for preparing beta ammonium tetramolybdate according to claim 2, wherein the mass ratio of the water replenishing amount to the water added in the step (1) is 1 to 3:1.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2644624A1 (en) * 1976-10-02 1978-04-06 Bergwerksverband Gmbh PROCESS FOR THE MANUFACTURING OF BETA-ISOPROPYL-NAPHTHALIN
CN102126756A (en) * 2011-04-20 2011-07-20 中南大学 Method for producing industrial grade ammonium paramolybdate
CN105220050A (en) * 2015-09-29 2016-01-06 河南科技大学 A kind of doped with rare-earth oxide molybdenum-copper matrix material and preparation method thereof
CN105374577A (en) * 2015-11-23 2016-03-02 太原理工大学 Preparation and application of molybdenum oxide powder electrode material with high specific capacitance characteristics
CN113458405A (en) * 2021-06-09 2021-10-01 郑州大学 Preparation method of large-particle-size metal molybdenum powder

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9005357B2 (en) * 2012-05-24 2015-04-14 Agency For Science, Technology And Research Method of preparing molybdenum oxide films

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2644624A1 (en) * 1976-10-02 1978-04-06 Bergwerksverband Gmbh PROCESS FOR THE MANUFACTURING OF BETA-ISOPROPYL-NAPHTHALIN
CN102126756A (en) * 2011-04-20 2011-07-20 中南大学 Method for producing industrial grade ammonium paramolybdate
CN105220050A (en) * 2015-09-29 2016-01-06 河南科技大学 A kind of doped with rare-earth oxide molybdenum-copper matrix material and preparation method thereof
CN105374577A (en) * 2015-11-23 2016-03-02 太原理工大学 Preparation and application of molybdenum oxide powder electrode material with high specific capacitance characteristics
CN113458405A (en) * 2021-06-09 2021-10-01 郑州大学 Preparation method of large-particle-size metal molybdenum powder

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
"Study on the thermal decomposition of a commercial";Z.L.Yin et al.;《Thermochimica Acta 》;19941231;第244卷;第283-289页 *
"几种多相钼酸铵的热分解";尹周澜等;《有色金属》;19940831;第46卷(第3期);第61-65页 *
β型四钼酸铵的制备及结晶过程;吴争平等;《中南工业大学学报(自然科学版)》;20010430(第02期);第135-138页 *
仲钼酸铵热分解过程及其形貌演变的研究;傅小明等;《稀有金属》;20110115(第01期);第113-117页 *

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