auses And Solutions For Agglomeration, Flatulence And Precipitation In The Production Of Water-soluble Fertilizers

One, the problem of agglomeration

The problem of agglomeration of fertilizers generally occurs in the process of fertilizer processing, storage, transportation, and transportation. It is mainly caused by the moisture absorption, surface dissolution (deliquescent), evaporation, and recrystallization of the microscopic fertilizer grains. Crystal bridges are formed in this process. , Causing small particles to become large particles and agglomerate.

First, the materials we usually use in the production of fertilizers are: ammonium salt, phosphate, trace element salt, potassium salt, etc., most of which contain crystal water and are easy to absorb moisture and agglomerate. For example, ammonium sulfate is easy to agglomerate, phosphate and trace amounts. When the elements meet, it is easy to agglomerate and become insoluble in water. Urea is easy to precipitate water and agglomerate when encountering trace element salts. The main reason is that urea replaces the crystal water in the trace element salt to become a paste, and then agglomerates. .

Second, fertilizer production is generally non-sealed production. During the production process, the higher the air humidity, the more moisture and agglomeration of the fertilizer will be. If the weather is dry or the raw materials are dried, the fertilizer will not agglomerate.

Third, the higher the room temperature, the better the dissolution. Generally, the raw materials dissolve in their own crystal water and cause agglomeration. When the temperature is higher, the water evaporates and it is not easy to agglomerate. This temperature is generally above 50°C. We usually need to heat to reach this temperature.

Fourth, the greater the pressure applied to the fertilizer, the easier the contact between the crystals and the crystals, and the easier it is to agglomerate; the lower the applied pressure, the less likely it is to agglomerate.

Fifth, the longer the fertilizer is placed, the easier it is to agglomerate, and the shorter the storage time, the less likely it is to agglomerate.

How to prevent caking?

First, choose raw materials reasonably, that is, choose raw materials that are not easy to agglomerate as our raw materials, such as trace element foliar fertilizers, using iron, copper, manganese, zinc, sulfate, boric acid, and ammonium molybdate as raw materials, and additives Magnesium sulfate is the main material, the main material is relatively dry, and when the air is not too humid, the produced fertilizer will not agglomerate. Fertilizers with humic acid as the main raw material and fertilizers with amino acid as the main raw material are not easy to agglomerate. In addition, choose the material to be as dry as possible.

Second, choose an appropriate production time. Since most parts of China belong to the northern temperate zone, the rainy season is mostly concentrated in June, July, and August, and the higher temperatures are also concentrated at this time. Therefore, fertilizers are produced in spring, late autumn and winter. The chance of agglomeration is lower. This is because the air humidity is low and the temperature is not high, which is not conducive to agglomeration.

Third, add some anti-caking agents, such as talcum powder, humic acid and other powders that are not easy to agglomerate, and they play a role in breaking the bridge. You can also add some special anti-caking,

Fourth, take reasonable packaging to prevent squeezing. The packaging materials are mainly to prevent moisture absorption and ventilation. Preventing excessive squeezing during transportation and storage can also effectively prevent the problem of agglomeration.

Second, the main cause of flatulence

1. Fermentation and decomposition of organic materials to produce carbon dioxide (related to temperature);

2. Hydrolysis of urea (related to temperature);

3. Calcium carbonate filler is added to the packaging bottle;

4. Borax with a small amount of carbonate;

5. Ammonium salt (mixed with alkaline substances or the temperature is too high);

6. Fillers (such as light calcium carbonate, kaolin, etc.);

7. Impurities in raw materials.

Flatulence solution

First, mix the raw materials reasonably, and no chemical reaction can occur between the raw materials and the raw materials.

Second, when choosing fillers, inert fillers such as white carbon black, talcum powder, starch sugars, etc. should be selected as much as possible.

Second, purchase qualified raw materials and packaging (air-permeable packaging / bottles without calcium carbonate).

Fourth, the appropriate pH value of the solution.

Three, precipitation problem

First, raw materials are inherently not easily soluble in water, and blindly increase their share in fertilizers. Such as borax and boric acid at room temperature. The solubility of these materials in water is 30-50 kg per ton of water, and precipitation will occur if there are more. If several fertilizers are dissolved in water at the same time, there is also a quantity requirement, such as Zinc sulfate is easier to dissolve in water, while potassium sulfate is less soluble in water. When the two raw materials are dissolved in water at the same time, potassium sulfate crystals will be formed. The above two kinds of precipitates will be dissolved after adding water.

Second, the material reacts to produce precipitation. Some materials cannot be mixed. After mixing, they will produce precipitation when dissolved in water, such as zinc, copper, iron, and manganese ions. Borax will precipitate when it encounters phosphate. This type of precipitation is insoluble For water, ammonium molybdate encounters phosphate and will also cause precipitation. These materials cannot be mixed together. They not only produce precipitation when mixed together, but also make fertilizers useless.

Third, it is possible to dissolve some fertilizers in a certain proportion, but over a certain amount of force will cause salting out, that is, another substance will precipitate out. For example, amino acids and zinc sulfate are both very soluble in water, but when they are together, zinc sulfate will precipitate the amino acids. The salting-out effects of zinc, copper, iron, and manganese on amino acids and humic acid can produce salting-out. Therefore, the appropriate ratio of these materials should be selected for the matching of these materials.

Fourth, the pH of the solution. Some materials are easily soluble in acidic substances, such as metal salts, but precipitation will occur on the contrary. Some materials are easily soluble in alkaline media, such as humic acids. Will produce precipitation.

Prevent precipitation:

First, choose the right materials to prevent precipitation from mutual reactions. Second, a reasonable ratio to prevent precipitation from salting out and supersaturation.

Third, adjust the pH value of the solution reasonably to prevent precipitation.

Fourth, add appropriate additives to protect the reaction material and prevent precipitation.

Fifth, add a co-solvent to increase the solubility of insoluble substances and prevent precipitation.