Clean metallurgic method for preparing ammonium molybdate from molybdenite concentrates

Abstract

The invention discloses a clean metallurgic method for preparing ammonium molybdate from molybdenite concentrates. The traditional limestone roasting and ammonium carbonate solution leaching method is abandoned to ensure that an ammonium sulfate solution in a mother solution does not form a low-value ammonium sulfate byproduct to be discharged from a production system again, but is efficiently converted into an ammonium carbonate solution through adding cheap and available calcium carbonate, so that the circulation of ammonium / ammonia in the system is realized, and furthermore all the solutions in the system can be recycled; in addition, an intermediate product is ammonium polymolybdate obtained through acid precipitation so as to facilitate carrying out a preparation process for a subsequent molybdenum product. The clean metallurgic method concretely comprises the steps of raw material configuration; oxidizing roasting; pretreatment; ammonium salt leaching; purification and separation; acid precipitation and separation; ammonium salt conversion and separation; and recovery and absorption, wherein an ammonium salt solution leaching agent required in the leaching step is prepared by adding the NH3 and CO2 gases obtained in the production process and the ammonium carbonate solution obtained after absorption and replenishing a proper quantity of ammonia water. The clean metallurgic method is low in production cost and high in production efficiency.

Description

technical field [0001] The invention relates to a clean metallurgical method for preparing ammonium molybdate from molybdenite concentrate, belonging to the technical field of molybdenum smelting. Background technique [0002] Molybdenite concentrate is the most important mineral raw material for the preparation of ammonium molybdate. The methods of processing molybdenite concentrate to prepare ammonium molybdate products in the prior art mainly include oxidation roasting-ammonia leaching and full wet oxidation. [0003] Oxidation roasting-ammonia leaching method has mature technology, small investment, and is easy to master. More than 90% of ammonium molybdate is produced by this method, but this method has the following main problems: [0004] 1) A large amount of low-concentration SO is produced during oxidation and roasting of molybdenum concentrate 2 There is currently no economical and efficient treatment method for flue gas, which leads to serious environmental poll...

AI Technical Summary

Problems solved by technology

[0004] 1) A large amount of low-concentration SO is produced during oxidation and roasting of molybdenum concentrate 2 There is currently no economical and efficient treatment method for flue gas, which leads to serious environmental pollution;

[0005] 2) The oxidation roasting temperature is high (about 600°C), which is easy to cause MoO in the calcined sand 3 The volatilization loss of the molybdenite concentrate with low melting point and more impurities is easy to agglomerate during the sintering process, which will eventually lead to a low recovery rate of Mo in the concentrate;

[0006] 3) The rare element rhenium contained in the molybdenite concentrate is difficult to recycle, and almost all of it is discharged with the flue gas;

[0007] 4) The quality requirements for molybdenum concentrate are relatively high, and it is not suitable for processing complex ore and low-grade ore

[0012] 1) Due to the large amount of lime added, CaSO is generated 4 The amount of slag is large and the amount of slag is large;

[0013] 2) The clinker is leached under acidic conditions, the equipment is corroded seriously, and the operating conditions are poor;

[0014] 3) The amount of sulfuric acid is large, the circulation is difficult, and a large amount of difficult-to-treat acid-containing wastewater is produced;

[0015] 4) The molybdic acid obtained after calcium molybdate leaching by sulfuric acid also needs to be converted into ammonium molybdate product through ion exchange or solvent extraction, and the process is more complicated and the cost is higher;

[0016] 5) The process of ion exchange and solvent extraction produces a large amount of wastewater containing ammonia nitrogen, which increases the cost of treatment

[0018] 1) The solution is difficult to fully circulate;

[0019] 2) The ammonium carbonate that is continuously added to the system is eventually transformed into a by-product of ammonium sulfate with low value, which will inevitably lead to high production costs

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