Process for producing molybdenum trioxide through spiral flow fluidized calcination

Abstract

The invention discloses a process for producing molybdenum trioxide through spiral flow fluidized calcination. The process mainly comprises the following steps of: preheating molybdenum concentrate to make the materials in a gas-solid mixed state; conveying the preheat molybdenum concentrate to a fluidized rotary calciner to make the gas-solid mixed ratio in the calciner to be 40: 0.5-1 and temperature to be 50 to 800 DEG C; allowing the calcined smoke to enter an air-cooled heat exchanger to cool the smoke to below 300 DEG C; and collecting dust by using a cloth bag to perform gas-solid separation to recycle the calcined sand. Due to the process, the molybdenum metal grade reaches over 60 percent and the recovery rate reaches 99.5 percent after the molybdenum concentrate is calcined. Compared with the convention calcination, the process has more complete oxidation so as to be beneficial for producing molybdate and improve leaching rate and recovery rate. The process is performed in a fully-sealed system and has the advantages of high recovery rate, environmental friendliness, convenient automatic control, simpliness, little time consumption, low energy consumption, good calcining quality, improvement on production efficiency and reduction in labor intensity of operators.

Description

technical field [0001] The invention relates to a process for preparing molybdenum trioxide, in particular to a process for preparing molybdenum trioxide by swirling boiling calcining. Background technique [0002] Molybdenum concentrate is calcined to produce molybdenum trioxide calcined sand. Now the commonly used calcining equipment includes: rotary kiln, multi-hearth furnace and fluidized fluidized furnace. Both heat the molybdenum concentrate to above 500°C, and pass air into the furnace to burn the molybdenum concentrate and decompose it into molybdenum oxide and sulfur dioxide. Other impurities in molybdenum concentrate are oxides and salts. Due to the small specific surface area of ​​gas-solid contact in the furnace, temperature control is difficult, melting agglomeration is easy to occur, and the reaction is uneven. The time is as long as 8 to 10 hours, and the production capacity is low. The concentration of sulfur dioxide produced by the reaction is lower than 1....

AI Technical Summary

Problems solved by technology

Other impurities in molybdenum concentrate are oxides and salts. Due to the small specific surface area of ​​gas-solid contact in the furnace, temperature control is difficult, melting agglomeration is easy to occur, and the reaction is uneven. The time is as long as 8 to 10 hours, and the production capacity is low. The concentration of sulfur dioxide produced by the reaction is lower than 1.0-1.5%, which is not conducive to the recovery of sulfuric acid. It is difficult to protect the environment, the cost is high, and the equipment maintenance cost is high.