The invention discloses a preparation method and an application of a magnetic X type 
molecular sieve. The preparation method comprises steps as follows: after 
grinding, 
coal gangue is subjected to high-temperature 
roasting and activating with 
sodium carbonate; the 
coal gangue is oxidized at the low temperature, 
hydrochloric acid is added, soaking is performed at the temperature of 90 DEG C, a mixture is filtered, 
oxalic acid is added to a filtrate, and the filtrate is standby; solids are washed and then dried, 
sodium hydroxide solids are added, a mixture is ground to be uniformly mixed, and then the mixture is subjected to low-temperature alkali fusion; deionized water and 
citric acid are added, the mixture is aged at the temperature of 60 DEG C, the standby filtrate is added, a 
mixed solution is subjected to ultrasonic 
crystallization, and iron-doped 
molecular sieve is synthesized; an iron-doped 
molecular sieve sample is put in a tubular furnace and subjected to high-temperature reduction, and the magnetic X type molecular 
sieve is prepared. The prepared magnetic X type molecular 
sieve has the advantages that specific surface area is large, adsorptive property is high, 
solid-liquid separation of a product can be realized easily through an external applied 
magnetic field and the like, the problem of high synthesis cost of the molecular 
sieve is solved, meanwhile, a new way is provided for recycling, refining and efficient utilization of the 
coal gangue, waste is changed into wealth, and the environment-friendly and low-carbon requirements are met.