Single Super Phosphate Plant

Single Super Phosphate Plant

Single Super phosphate is a chemical Fertilizer which contains Phosphorus as a major plant nutrient. It is relatively very cheap and contains many micro nutrients like Calcium, Magnesium, Iron, Aluminum, Sulphur and Gypsum. The Gypsum works as a SOIL CONDITIONER. The SSP is manufactured by the reaction of finely grounded Rock Phosphate with diluted Sulfuric Acid. The SSP is available in powder and granulated form. The Powder form is called as PSSP and the granulated form is called as GSSP. The PSSP and GSSP are available in two grades. Grade A and grade B. The grading is done on the basis of Water soluble Phosphorous Penta Oxide present in the product. The A grade contains 16% water soluble phosphorous Penta Oxide and the B grade contains 14% W.S. P2O5. The granulated Super phosphate is some what costlier in comparison to PSSP because of the cost of granulation. The GSSP dissolves slowly in the water present in the soil so it is available to the crops for a longer time. The free Phosphoric acid present in the SSP is very useful for alkaline soils. The PSSP & GSSP are white, cream, gray, brown or black in colour and packed in 50 Kg bags.

Single Superphosphate:

The SSP is manufactured by the reaction of finely ground Rock Phosphate and diluted Sulfuric acid. The Rock phosphate is available in Jordan, Egypt, India, China, Israel, Morocco, Syria, Senegal and many other African countries. The Sulfuric Acid is produced by using Sulphur as raw material.

RAW MATERIALS AND THEIR RESOURCES:

The raw materials for manufacturing SSP are as follows:

1. ROCK PHOSPHATE: Rock phosphate is mined in many countries like India, China, Israel, Jordan, Syria, Morocco, Egypt, Malaysia, Indonesia and many African & American countries. The 31% plus grade is suitable for the production.
2. SULPHURIC ACID: The technical grade Sulfuric acid that is 98.5% pure is suitable for the process.
However spent sulfuric acid from other industries like textiles, Detergent and which is a waste, can also be used along with the technical grade sulfuric acid in the plants designed by us.
3. FUEL: To dry GSSP any fuel like Furnace Oil, H.S. Diesel, LDO etc may be used.
4. FILLERS: Gypsum, Sand etc

5. BAGGING MATERIAL: HDPE bags.

PROCESS OF MANUFACTURING:

The Rock phosphate brought from the mines is stored in rock storage shade. This is very important because it is very difficult to ground wet Rock phosphate. If the Rock Phosphate is received wet, first of all it has to be dried with the help of Rock dryer. The rock dryer contains a drum connected with a Hot air generator and cyclone with ID fan & scrubber. The dried Rock is fed to a Ball Mill to grind it to -100 mesh (90%). The ground Rock is stored in the Ground Rock hopper. The Sulfuric acid received from the manufacturer is stored in the Sulfuric acid storage tanks. The special lined tank may be used for the spent acid storage.

The reaction between the raw materials takes place in the mixer. The mixer is a vessel with acid and heat resistant lining. The ground Rock Phosphate is controlled, weighed and fed to the mixer with the help of rotary airlocks, screw conveyors and elevator. The Sulfuric acid is pumped, controlled, measured and fed into the mixer with the help of pumps, pipelines, Rotameter and valves. The mixed material is kneaded for some time and dumped into a Den. The den is a enclosed, acid & heat resistant lined and slow moving conveyor. The materials keep on reacting for about an hour. The mixer and den are connected to an ID Fan through the scrubbers to scrub the emitted gases. The mixed material which was a free flowing slurry in the mixer becomes a semi solid in the den and becomes a cake at the discharge end of the den. At the discharge end of the den the cake is disintegrated by den cutter. The reaction is very fast and exothermic. The reaction rate depends on many parameters but most importantly it depends on the origin of rock Phosphate.

The material is discharged from the den and it is heaped in the green SSP shade with the help of an Electric Overhead Travel Crane. The reaction continues in the heap and it may complete in 5 days to 21 days. This period depends entirely on the origin of Rock Phosphate as the reactivity of the rock is related to its origin. The heaps are regularly monitored and as soon as the material is cured it is shifted for manufacturing either GSSP

The reaction between the rock phosphate and acid is called as acidulation & proceeds with the emission of Fluorine based gases. These gases are scrubbed by the state of the art Ventury scrubbers which have 90 - 95% efficiency, convert the gases into Hydro Fluoro Silicic Acid. and Silica. The Hydro Fluoro Silicic Acid is recycled back into the Mixer. The silica formed is used as a filler in PSSP & GSSP manufacture. So a zero effluent system is used.

Properties of Single Super phosphate:

Nature:

Free flowing powder and Granules

Grayish to brownish white

angle of repose 36O

slight Hygroscopic / Caking at long storage

acidic in nature,

stored in dry place.

Quality Specifications :

Powder SSP(Green super phosphate)

Moisture Contents Max 12%

Free Acidity Max 4%

Water Soluble P2O5 Min 16