R&D

15

2023

-

02

Production process of molybdenum metal products

Classification:


【Summary Description】The overall domestic molybdenum market presents a pattern of high volatility. And do you know how molybdenum metal products are manufactured?

In 2022, the global molybdenum production is expected to be 250,000 tons, which is 1.96% lower than the actual value of 255,000 tons in 2021. Among them, the total output of China, Chile, the United States, Peru and Mexico accounts for about 93% of the global total. Specifically, China's molybdenum production is expected to be 100,000 tons in 2022, accounting for 40% of the world's total molybdenum production, ranking first; Chile ranks second at 44,000 tons, accounting for 17.6%; the United States ranks third at 42,000 tons, accounting for 17.6%. 16.8%.


At present, the prices of molybdenum products such as molybdenum concentrate, ferromolybdenum, and molybdenum oxide are still at a relatively high level, and the domestic molybdenum market as a whole presents a pattern of high volatility. So do you know how molybdenum metal products are manufactured?

 

Start with industrial molybdenum oxide. First, molybdenum oxide is dissolved in ammonium hydroxide or sodium hydroxide, and the solution is subjected to precipitation and filtration, solvent extraction or a combination of both to remove impurities. Extract high-purity ammonium molybdate or ammonium dimolybdate (ADM) by crystallization or precipitation and filtration. This high-purity chemical is the starting material for the production of molybdenum metal powder. Molybdate can be calcined (heated to high temperature in air) to produce high-purity molybdenum trioxide. Whether using ADM or calcined oxide as the starting material for molybdenum metal production, the subsequent process is the same. ADM or calcined oxide undergoes a two-stage chemical reduction reaction in hydrogen to produce pure molybdenum metal powder. The first-stage reduction reaction takes place in the temperature range of 450-650°C, reducing the material to MoO2, often referred to as a brown oxide because of its color. The second stage reduction reaction is carried out in the temperature range of 1000-1100°C, and this process produces molybdenum metal powder with a purity of typically 99.97%.

 

Because pure molybdenum melts at very high temperatures and oxidizes at relatively low temperatures, traditional smelting processes cannot extract the metal from the ore. The ore is processed in a series of grinding and separation steps to separate the MoS2 (molybdenum disulfide) in the ore from other components. This isolated material contains up to about 90% MoS2, which is calcined in air to form MoO3 (molybdenum trioxide) and SO2 (sulfur dioxide). The sulfur dioxide is converted to sulfuric acid and sold for chemical applications. The remaining unseparated mineral components are called gangue. The calcined product, called technical molybdenum oxide, contains about 57% molybdenum and less than 0.1% sulfur. The roasting process does not remove the gangue, which is not a problem with most commercial molybdenum oxides used to produce molybdenum-containing alloy steels. In the smelting process of alloy steel, gangue will eventually become slag. However, commercial molybdenum oxide must be chemically purified before it can be used to produce molybdenum metal.