1. Most basic
The granulation device is tilted disk ,into which all the raw materials are sent after being mixed ,it rolls in a certain ways , the materials are granulated relying on their viscosity and the spraying water ,the finished particles after drying and screening are the fertilizers.
Advantages :Simple equipments ,only cost hundreds of thousands of dollors; the need of the viscous materials, a certain formula to limit the concentration ; production capacity is generally about 100 tons per day.
The granulation device is a tilted tube, just like several disc granulators overlap each other, whose efficiency is high, with the addition of the steam in the reactor between the materials,the materials whose viscosity is low can also be granulated in a high efficiency ,due to the water vapor increases the viscosity of the materials . Formulation limits are relatively small .
The largest type of equipment, a processing line costs 2-3 millions, daily production capacity is 280-400 tons, with good formula it can reach more than 500tons.
The above two kinds of fertilizers ,the ratio of nitrogen can not be too high, because if the concentration is greater than 40 , the materials contains to much water,which is difficult to live up to the drying standard.
Spraying is referring to the urea spraying, urea is sprayed during the process in the compound fertilizer granulation to reduce the process of crushing urea ,it would save the cost if connected through the urine pipeline of the urea plant . Fertilizer dissolved quickly, but most of them are high nitrogen formula whose nitrogen content is higher than 20. Low nitrogen fertilizer is not necessary to use urea.
Processing equipment should also be the drum granulator, the cost of the high-nitrogen formulation is low, whose particle shape is good.
The tower granulation : the raw materials are heated into the melt-solution and dispersed from the high position, scattered in the air to become the spherical pellets due to the surface tension ,and finally screened. Particles contains less water because of the high temperature , not easy to agglomerate, materials are fully mixed , good uniformity and appearance.
The tower granulation needs for high-purity materials, so there are many high concentration formula, the proportion of urea is relatively high.In addition: frequent replacement of the formula is not proper for the tower granulation due to the high cost , there are a lot of material in the production line ,the replacement of the formula will result in higher expenses.