Long-term-stability and synergistic ammonium chloride fertilizer with combined-soda process, and preparation method thereof

The invention relates to a long-term fertilizer and a preparation method thereof, and specifically a long-term-stability and synergistic ammonium chloride fertilizer and a preparation method thereof. According to the invention, ammonium chloride crystallized from cold precipitation and salting in a process for producing soda ash with a combined-soda process is mixed with the added ammonium stabilizer and/or synergist before entering a separation and drying process. The fertilizer comprises ammonium chloride, an ammonium stabilizer, and/or a synergist. According to the weight, ammonium chloride: ammonium stabilizer: synergist=1:0.001-0.1:0.0001-0.05; ammonium chloride: ammonium stabilizer=1:0.001-0.1. The ammonium chloride is a by-product ammonium chloride obtained in a process for producing soda ash with a combined-soda process. The long-term or stable/synergistic ammonium chloride fertilizer preparation method has the advantages of process saving, low cost, high quality, and stable effect. With the method, the long-term or stable/synergistic ammonium chloride has the advantages of uniform texture and stable effect. Nitrogen utilization rate of ammonium chloride is improved by 10-20 percentage points, and ammonium chloride utilization amount is reduced by more than 50%. Ammonium chloride fertilizer effect time is prolonged from 20-30 days to 80-100 days. After one time of fertilizing, top dressing can be avoided.