Name | Hexaammonium molybdate |
Synonyms | Hexaammonium molybdate Ammonium heptamolybdate Molybdate, hexaammonium Ammonium hepta molybdate ammonium heptamolybdrate Molybdate(6-),hexaammonium MOLYBDIC ACID AMMONIUM SALT PHOSPHATE MONITOR FIRST REAGENT PHOSPHATE MONITOR SECOND REAGENT PHOSPHATE MONITOR REDUCTION REAGENT PHOSPHATE MONITOR REDUCTION SOLUTION |
CAS | 12027-67-7 |
EINECS | 234-722-4 |
InChI | InChI=1/Mo.2H3N.4H2O.4O/h;2*1H3;4*1H2;;;;/q;;;;;;;;;2*-1/p+2/rMoO4.2H3N.4H2O/c2-1(3,4)5;;;;;;/h;2*1H3;4*1H2/q-2;;;;;;/p+2 |
Molecular Formula | H24Mo3N6O12 |
Molar Mass | 588.04 |
Density | 2,498 g/cm3 |
Melting Point | 190°C |
Water Solubility | Freely soluble in water. |
Solubility | H2O: soluble |
Appearance | White to white-like powder |
Specific Gravity | 2.498 |
Color | Clear light colored |
Exposure Limit | ACGIH: TWA 0.5 mg/m3NIOSH: IDLH 1000 mg/m3 |
Merck | 14,533 |
Storage Condition | Store at RT. |
Stability | Stable. |
MDL | MFCD00064633 |
Physical and Chemical Properties | White crystals |
Use | For the preparation of catalysts, metal molybdenum, pigments, metal surface treatment, corrosion inhibitors, trace element fertilizers |
Hazard Symbols | Xi - Irritant |
Risk Codes | R22 - Harmful if swallowed R36/38 - Irritating to eyes and skin. R52/53 - Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment. R36/37/38 - Irritating to eyes, respiratory system and skin. |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36 - Wear suitable protective clothing. |
UN IDs | UN 3264 |
WGK Germany | - |
RTECS | QA4900000 |
TSCA | Yes |
HS Code | 28417010 |
Toxicity | mic-esc 2 mmol/L MUREAV 31,185,1975 |
Raw Materials | ammonium molybdate |
colorless or light yellow-green columnar crystals. Soluble in 2.3 water, insoluble in ethanol, acid decomposition. When heated to 90 °c, one molecule of crystal water is lost and decomposed when heated to 190 °c. The pH value of 5% aqueous solution is 5.O ~ 5.5. The relative density was 2. 498.
The pulverized industrial molybdenum trioxide, water and ammonia water were stirred and dissolved. After filtration, the insoluble matter was washed with aqueous ammonia. Ammonium sulfide solution was added to the filtrate, heated, and filtered. Upon concentration by evaporation to a relative density of 141, aqueous ammonia was added and stirring was continued until there was a strong ammonia odor. Cooling, Suction filtration, pure ammonium molybdate.
It is used as a reagent for measuring phosphate, nickel, germanium, selenium dioxide, arsenate, alkaloid, lead and the like. Reagents for chromatographic analysis. Industrial as a catalyst for the oil industry, but also Powder Metallurgy molybdenum, photography, ceramic glaze, pigment industrial raw materials.
EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
overview | ammonium heptamolybdate is an important intermediate product in the molybdenum metallurgy process, is the main raw material for the production of molybdenum powder, molybdenum wire and molybdenum-based products, and is used in chemical and petroleum catalysts, flame retardants, dyes, pigments and trace element fertilizers and other industries and fields. With the rapid development of molybdenum high-tech products, ammonium heptamolybdate has become an indispensable material in high-tech fields such as superconductivity, cermet, laser, computer, polymer synthesis and testing. |
preparation process | 1. the traditional preparation process recrystallization method recrystallization method uses the different distribution ratio of impurity components in solution and in crystals, and uses multiple dissolution and crystallization to gradually reduce the impurity content in crystals, thus meeting the technical requirements of products. In recrystallization, the impurity components are circulated in the system, and the impurities are either in solution or in crystallization. Therefore, it is difficult to obtain products with high purity in this production method. In addition, the recrystallization method is a mixture of ammonium molybdate with a variety of crystal structures. After filtration and separation, the surface of the product has more water, which must be dried to meet the technical requirements of the product. At present, the domestic manufacturers of ammonium heptamolybdate all adopt the traditional intermittent production method and adopt the evaporation crystallization method. In the process of evaporation crystallization, due to the unreasonable structure of the traditional evaporation crystallization equipment, such as the heating jacket of the evaporation crystallization tank is too high, the speed of the stirring motor cannot be controlled, etc., resulting in the product particle size distribution is too wide and uneven, and the production of ammonium seven molybdate The finished product contains high impurities, poor crystal form, and low product direct yield. Moreover, the concentration of free ammonium, the specific gravity of the solution, the evaporation temperature, and the stirring speed in the production process have a greater impact on ammonium heptamolybdate. Therefore, transforming traditional equipment, strictly controlling production conditions, and improving the quality of ammonium heptamolybdate products are currently domestic The primary task of ammonium ammonium molybdate manufacturers. The recrystallization process is shown in Figure 1. Figure 1 is a flow chart of the recrystallization process. The ion exchange method uses ammonium cation exchange resin. When the ammonium molybdate solution flows through the ion exchange column, the impurity metal in the solution replaces ammonium and is adsorbed on the resin, and the molybdenum is left in the solution with MoO42-negative ions. The exchanged solution can be directly used for the preparation of pure ammonium heptamolybdate crystals. However, due to the different adsorption capacity of the resin to different impurities and cations in the solution, it is difficult to completely remove the metal impurities in the solution with a single resin. In actual production, different resin multi-column cascade exchange methods are used for purification. Although the ion exchange process can obtain higher quality products, the production cost is relatively high because the ion exchange cycle is relatively long and the resin must be regenerated after a period of production. The process flow is shown in Figure 2. Figure 2 is the flow chart of the ion exchange process 2. The improvement of the preparation process The improved ion exchange process has the following characteristics:(1) The molybdenum calcine is leached with liquid alkali, and a higher leaching rate can be obtained by only one leaching (2) The exchange process is both a transformation process and a impurity removal process, so the purification process in the classic process (except copper and iron) can be omitted;(3) The process does not require an acid precipitation process, therefore, hydrochloric acid is not used in the whole process, so the consumption of ammonia can be reduced accordingly;(4) The production cost can be greatly reduced. If the process can be used in industrial production, it will greatly improve the technical and economic indicators of molybdenum smelting. |
use | used as a reagent for the determination of phosphate, alkaloid, arsenate and lead, chromatographic analysis reagent, and used for the extraction of metal molybdenum, photography industry and pottery glaze manufacturing. (2015-11-16) Used in petroleum cobalt, molybdenum catalysts, pigment chemicals and trace fertilizers, and a few powder metallurgy companies use ammonium heptamolybdate as raw material. used to make catalyst, metal molybdenum, pigment, metal surface treatment agent, corrosion inhibitor, trace element fertilizer, etc. used to make catalyst, metal molybdenum, pigment, metal surface treatment, corrosion inhibitor, trace element fertilizer, etc. |
production method | pulverized industrial products molybdenum trioxide, water and ammonia are stirred to dissolve. Filter and wash the insoluble matter with ammonia water. Add ammonium sulfide solution to the filtrate, heat and filter. When evaporating and concentrating to a relative density of 1 41, add ammonia water and stir continuously until there is a strong ammonia smell. Cooling, suction and filtration to obtain pure ammonium molybdate. |
category | toxic substances |
flammability hazard characteristics | toxic molybdenum and ammonia fumes produced at high temperatures |
storage and transportation characteristics | warehouse ventilation and low temperature drying |
fire extinguishing agent | dry powder, foam, sand, carbon dioxide, mist water |
occupational standard | TWA 10 mg (molybdenum)/m3 |
toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |