Process for drying potash magnesium sulphate fertilizer

Abstract

A process for drying a potash magnesium sulphate fertilizer comprises the following steps: (1) wet material feed: feeding water-containing potash magnesium sulphate fertilizer into a strengthened airflow dryer; (2) hot air feed: heating the air, and pressurizing and feeding the heated air into the cone bottom of the strengthener of the strengthened airflow dryer; (3) drying process: keeping the wet material to be dried in the strengthened airflow dryer for 2-7 seconds, thereby obtaining the finished potash magnesium sulphate fertilizer containing less than or equal to 2wt% of free water; and (4) discharge, and tail gas treatment and emission: feeding the dried material into a discharge device along with the air flow, performing cyclone dust removal or removing dust through a water film or a cloth bag, and then collecting the dried potash magnesium sulphate fertilizer and emitting the tail gas. The process for drying the potash magnesium sulphate fertilizer provided by the invention is easy to control the drying temperature, simple and short in process, high in drying strength, good in adaptability, high in thermal efficiency, continuous, stable and reliable in drying process, even and reliable in quality of product, good in drying effect, and suitable for mass production and for drying heat sensitive materials.

Description

technical field [0001] The invention relates to a drying process for potassium-magnesium sulfate fertilizer, in particular to a drying process for potassium-magnesium sulfate fertilizer with high water content, small particles, poor fluidity and heat sensitivity. Background technique [0002] The definition of potassium-magnesium sulfate fertilizer in the national standard GB / T20937-2007 is: potassium-magnesium sulfate is a kind of magnesium, sulfur, etc., which is extracted from salt lake brine or solid potassium-magnesium ore by physical methods or directly removed impurities. A compound potassium fertilizer of trace elements. The molecular formula is K 2 SO 4 (MgSO 4 ) m nH 2 0, m=1-2, n=0-6. [0003] In the prior art, there are two drying processes for potassium and magnesium sulfate fertilizers. [0004] (1) Rotary drum drying method: the wet potassium magnesium sulfate fertilizer is sent to the kiln head of the rotary drum dryer through the feeder, and sent...

AI Technical Summary

Problems solved by technology

[0004] (1) Drum drying method: send the wet potassium and magnesium sulfate fertilizer into the kiln head of the drum dryer through the feeder, and send it into the hot air drying through the hot air stove. The disadvantage of this method is that the drying time is long and the drying temperature is not easy. Control, the material is easy to agglomerate, and the product particle size is not easy to control

[0005] (2) Fluidized bed drying method: the wet potassium and magnesium sulfate fertilizer is evenly fed into the fluidized bed through the distributor, and the hot air is sent into the fluidized bed by a high-pressure blower, and the wet potassium and magnesium sulfate fertilizer is blown up to form A drying method in a fluidized state. The disadvantage of this method is that the adaptability of the material is poor, and it is easy to produce a "press bed" phenomenon for materials with high moisture content and high viscosity.

The existing drum drying method is not suitable for drying such heat-sensitive materials due to the long residence time of the material, the drying temperature is difficult to control, and the moisture content of the product is also difficult to control.

The fluidized bed drying method has high requirements on the moisture content and fluidity of the material, and the wet potassium magnesium sulfate fertilizer has a large difference in particle size and moisture content due to different production processes. If the particle size is small and the moisture content is high, the fluidity Therefore, this method cannot be applied to the drying of potassium and magnesium sulfate fertilizers with small particle size and high moisture content.