Method for preparing molybdenum powder by ammonium molybdate

Abstract

The invention provides a method for preparing molybdenum powder by ammonium molybdate. The method includes the steps: firstly, screening the ammonium molybdate by a 40-mesh screen to obtain an oversize product and placing the screened oversize product into a ball mill for ball-milling to obtain ammonium molybdate powder; secondly, performing primary hydrogen reduction treatment for the ammonium molybdate powder by the aid of a primary reduction furnace in hydrogen atmosphere to obtain molybdenum dioxide; thirdly, performing secondary hydrogen reduction treatment for the molybdenum dioxide by the aid of a secondary reduction furnace in the hydrogen atmosphere to obtain rough molybdenum powder; and fourthly, placing the screened rough molybdenum powder into a mixer for uniform mixing to obtain finished molybdenum powder. Preparation technology is simple, and the method is safe, reliable and suitable for industrialized mass production. The molybdenum powder prepared by the method can meet technical requirements of a national standard GB / T3461-2006, and can be widely used for preparing raw materials for molybdenum and molybdenum alloy products such as molybdenum slabs, molybdenum bars, molybdenum piercing mandrels and molybdenum fabricated parts.

Description

technical field [0001] The invention belongs to the technical field of rare metal powder metallurgy, and in particular relates to a method for preparing molybdenum powder by using ammonium molybdate. Background technique [0002] In the process of industrial production, ammonium molybdate is usually prepared by using industrial molybdenum oxide as raw material and adopting sequential methods of ammonia leaching, acid precipitation and crystallization. Because ammonium molybdate has the physical characteristics of deliquescence and agglomeration, it is necessary to sieve ammonium molybdate. In the industrial production process, ammonium molybdate is generally passed through a 40-mesh sieve. [0003] After the ammonium molybdate is passed through a 40-mesh sieve, the under-sieve is no deliquescence, no agglomeration, low moisture content, white loose crystals, which can be widely used in petroleum refining catalyst fields such as hydrodesulfurization and chemical fertilizer in...

AI Technical Summary

Problems solved by technology

However, the ammonium molybdate passed through a 40-mesh sieve has more crystal water, severe agglomeration and hardness, and obvious color difference, which seriously affects the follow-up production of molybdenum products.

The above sieve cannot be prepared according to the conventional process to obtain high-quality molybdenum powder. There are two main reasons. One is that the rotary tube type reduction furnace is usually used to prepare the molybdenum powder in the industrial production process. The feeding method, and the sieve after the ammonium molybdate passes through the 40-mesh sieve, the larger block particles often get stuck in the screw feeder and cause damage to the equipment, resulting in paralysis of production; the second is that even if the push-type multi-tube Furnace, because the particle size of the sieve is too large, and the core of the particles is hard due to the existence of a large amount of crystal water and free water, so that the hydrogen reduction process cannot fully react, resulting in oxygen, potassium, sodium, etc. in the molybdenum powder produced The content seriously exceeds the standard and cannot meet the technical requirements of molybdenum processed products

[0004] The method commonly used in the current industrial production is to return the ammonium molybdate through the 40-mesh sieve to the ammonium molybdate production line for ammonia leaching, acid precipitation and crystallization, which leads to increased energy consumption and lower costs. raised

Images