Complex Fertilizer

Complex Fertilizers 

Complex fertilizers (also known as compound fertilizers) are made from mixing two or more of macro-nutrient type fertilizers. They may also be further blended with elements that provide some of the less-common plant nutrients (known as secondary or trace nutrients, such as sulfur, calcium and magnesium). Compound fertilizer can be packaged and distributed in liquid or granular form.

         A numbering system is used to define the percentages of the three essential plant nutrients. For example, a 20-20-10 fertilizer would contain 20 percent nitrogen, 20 percent phosphorus and 10 percent potassium. Secondary nutrients and trace elements are typically listed.

1.            Diammonium Phosphate (18-46-0)

2.            Diammonium Phosphate (16-44-0)

3.            Ammonium Phosphate Sulphate (16-20-0)

4.            Ammonium Phosphate Sulphate (20-20-0)

5.            Ammonium Phosphate Sulphate Nitrate (20-20-0)

6.            Ammonium Phosphate Sulphate (18-9-0)

7.            Nitro Phosphate (20-20-0)

8.            Urea Ammonium phosphate (28-28-0)

9.            Urea Ammonium Phosphate (24-24-0)

10.          Urea Ammonium Phosphates (20-20-0)

11.          Mono Ammonium Phosphate (11-52-0)

12.          Nitrophosphate (23-23-0)

13.          Ammonium Nitrate phosphate (23-23-0)

14.          Ammonium Poly Phosphate (10-34-0) Liquid

15.          Ammonium Phosphate (14-28-0)

16.          16:35:0:15 S

17.          Nitrophosphate (24-24-0)

N.P.K. COMPLEX FERTILIZERS

Nitrophosphate with Potash (15-15-15)

1.           N.P.K (10-26-26)

2.           N.P.K.(12-32-16)

3.           N.P.K. (22-22-11)

4.           N.P.K. (14-35-14)

5.           N.P.K. (17-17-17)

6.           N.P.K. (14-28-14)

7.           N.P.K. (19-19-19) 

8.           N.P.K. (17-17-17)

9.           N.P.K. (20-10-10)

10.         N.P.K. (15-15-15)

11.         N.P.K. (16:16:16)

12.         N.P.K. (15:15:15:9 S)

13.         N.P.K. (12:11:18  with MgO)

14.         N.P.K 9:25:25

15.         N.P.K. 14:14:21

16.         N.P.K. 21:6:13

17.         N.P.K. 15:15:15

18.         N.P.K. 15:9:25

100% WATER SOLUBLE COMPLEX FERTILIZERS

                           i.        Potassium Nitrate (13-0-45)

                           ii.       Mono Potassium Phosphate (0-52-34)

                           iii.      Calcium Nitrate

                           iv.       NPK (13-40-13)

                           v.        NPK (18-18-18)

                           vi.       NPK (13-5-26)

                         vii.        NPK (6-12-36)

                       viii.         NPK (20-20-20)

                         ix.         NPK (19-19-19)

                           x.        Potassium Magnesium Sulphate

                         xi.         Mono Ammonium Phosphate (12-61-0)

                       xii.          Urea Phosphate (17:44:0)

Complex fertilizers –manufacturing ammonium phosphates –nitrophosphates and NPK complexes

Complex Fertilizers

               Complex fertilizers is defined as a material containing all three primary nutrients ( N,P and K) and it is also designated as complete complex fertilizers while a fertilizer material containing one or two of the primary nutrient elements (N and P or P and K etc ) are known as incomplete complex fertilizers. They are produced by a process of chemical reaction. Most important complex fertilizers are Nitro phosphates & polyphosphate

based fertilizers etc

Nitro phosphates

         It is a granular fertilizer containing stabilizer which prevents reversion of citrate soluble phosphates to insoluble phosphate. Being granulated it maintains excellent physical condition during storage and handling. Nitrophosphate contains nitrogen and phosphorus in different proportions depending upon the process of manufacture. It also contains easily soluble and readily available N03 N as well as NH4-N. Phosphorus is also present as water soluble as well as citrate soluble forms. All nitrophosphates have less acidic effect on soil compared to other fertilizers.

Ammonium Phosphate

         Ammonium phosphate is an incomplete complex fertilizer and both monoammonium and diammonium phosphates are manufactured by the combination of ammonia with H3PO4 and also by treating with rock phosphate with H2SO 4 and (NH4 )2SO4 as follows:

NH3+H3PO4 = NH4H2PO4 (Mono-ammonium phosphate)

2 NH3+ H3PO4= (NH4)2H2PO4 (Diammonium phosphate)

Ca3PO4) 2 + (NH4)2SO4 + 2H2SO 4 = 3 CaSO4 + 2NH4H2PO4 (Rock phosphate).

         The resulting solution contains both nitrogen and phosphorus. The liquid is turned into a granular product in the granulator. The granular product is dried and screened. Product that is too small or too large is recycled to the granulator. In India, different types of nitrophosphates are manufactured with different chemical reactions and mixing process by different fertilizer company. They marketed the complex fertilizers as their different grades and commercial names. Most important grades of nitrophosphate is 20: 20 : 0 and it means that nitrophosphate contains 20 percent nitrogen. 20 per cent phosphorus and no potassium. Besides these there are various other commercially produced complex fertilizers suphala of different grades e.g. 15: 15 : 15: 20: 20 : 20 etc.

Polyphosphate based fertilizers

         Ammonium polyphosphate. potassium polyphosphate. zincated poly phosphates etc. are the most popular complex fertilizers that have been recently developed. Ammonium polyphosphate. It is a complex fertilizer. Although it contains N and P but it contains chiefly phosphorus because polyphosphate is a compound derived from the condensation of two or more phosphoric acids.

         Ammonium polyphosphates may be granular and liquid. Different grades of polyphosphates are marketed like 15-62-0; 12-53-0, 15-60-0; etc. as solid or granular and 10-54-0, 11-37-0as liquid. In addition to these there are Sulphated and Zincated ammonium polyphosphates which are also available in the market to supply secondary and micronutrient to the plant along with nitrogen and phosphorus. So the polyphosphate based different micronutrient fertilizers which acts as slow-release micronutrient are going to be developed recently. Zincated polyphosphates can also be manufactured with the rock-phosphate containing Zn and polyphosphates and that is also soluble in water and available to plants. A potassium polyphosphate solution of grade 0-26-26 was produced and this was made by reacting superphosphoric acid and potassium hydroxide and contained a mixture of ortho-pyro-and higher polyphosphates. Solid potassium polyphosphates of grades 0-42-42 to 0-47-47 are also available.

When polyphosphatic fertilizers are applied to soils, these are hydrolysed step by step either chemically or biologically to form orthosphosphate.

         Diammonium phosphate(DAP) (chemical formula (NH4)2HPO4)It is one of a series of water-soluble ammonium phosphate salts. which can be produced when ammonia reacts with phosphoric acid. DAP is used as a fertilizer and a fire retardant. When applied as plant food, it temporarily increases the soil pH (more basic), but over a long term the treated ground becomes more acidic than before upon nitrification of the ammonium. It is incompatible with alkaline chemicals because its ammonium ion is more likely to convert to ammonia in a high-pH environment.

Product containing diammonium phosphate as essential ingredient with small amount of mono ammonium phosphate. Total nitrogen: x (18-21)%P2O5 soluble in neutral ammonium citrate and water: y (45-53)%

Manufacture of mono, di-ammonium and nitro-phosphate.

Mono and Di-ammonium Phosphate:

Mono Ammonium Phosphate is manufactured by slowly neutralizing orthophosphoric acid with ammonia gas as shown in the following equation:

                                             NH3 + H3PO4 → (NH4)H2PO4    

         A considerable amount of heat is generated in this reaction. Consequently the liquid mono ammonium phosphate is thickened. When this is cooled, the mono ammonium phosphate crystallizes out. The mother liquor is drained and the crystals are dried and bagged.

Di-ammonium phosphate is produced, when an excess of ammonium gas is passed through orthophosphoric acid in order to maintain the pH of the slurry at 5.8 to 6.0 as shown below:

                                          2NH3 + H3PO4 = (NH4)2HPO4

         Both mono and di-ammonium phosphate are soluble in water. Mono ammonium phosphate is a light grey material. Di-ammonium phosphate is a dark brown material. They absorb a little moisture from the atmosphere and are acidic fertilisers.

         The acidity caused by the application of every 100 pounds of mono ammonium phosphate can be neutralized by adding about 55 pounds of powdered limestone to the soil. The acidity caused by adding every 100 pounds of Di-ammonium phosphate can be neutralized by adding about 77 pounds of powdered limestone to the soil.

         Mono and Di-ammonium phosphate can be used in alkaline and calcareous soils. Mono Ammonium Phosphate contain 11.0 per cent N and 48.0 per cent P2O5 Di-ammonium Phosphate contains 21.0 per cent N and 54.0 per cent P2O5.

Manufacture of Nitro-Phosphate:

This is manufactured by treating apatite with a mixture of nitric and sulphuric acids.

They react together as shown below:

            [Ca3(PO4)2]CaF2 + 12HNO

Liquid ammonia is then added to the slurry and then react together as shown below:

         Nitro-phosphate is a granulated fertiliser containing a stabilizer which prevents the reversion of citrate soluble phosphate to insoluble tricalcium phosphate. It contains nitrogen and phosphorus in various proportions. If it is necessary, potassium salts are also added to it. Three types of nitro phosphates (Trade Name SUPHALA) 20:20:2, 18:18:9 and 15:15:15 are manufactured.

Usually about one-third of the phosphate contained in these is water soluble and the rest of the two thirds is citrate soluble. The water soluble phosphate is readily available and hence useful in the early stages of crop growth, while the citrate soluble phosphate helps the crop to grow and attain maturity. Nitro phosphate contains ammoniacal and nitrate nitrogen.