Calcium superphosphate
[CAS# 10031-30-8]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Phosphides, metal phosphoric acid, metaphosphoric acid, hypophosphorous acid and pyrophosphate
• Name: Calcium superphosphate
• Synonyms: Calcium superphosphate
• Molecular Formula: CaP₂H₆O₉
• Molecular Weight: 252.07
• CAS Registry Number: 10031-30-8
• EC Number: 600-059-8
• SMILES: O.OP(=O)(O)[O-].OP(=O)(O)[O-].[Ca+2]

Properties

• Melting point: 200 °C

Safety Data

• Hazard Symbols: GHS05;GHS07 Warning
• Risk Statements: H315-H318-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P305+P354+P338-P317-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319

Discovery and Applications

Calcium superphosphate, commonly referred to as superphosphate, was discovered by Sir John Bennet Lawes in the 1840s. Lawes, an English entrepreneur and agricultural scientist, was exploring ways to enhance crop yields. He discovered that treating phosphate rock with sulfuric acid produced a more soluble form of phosphate, which could be easily absorbed by plants. This compound, calcium superphosphate, represented a significant advancement over traditional bone meal and raw phosphate rock. Lawes' innovation led to the development of the first chemical fertilizer and the establishment of the commercial fertilizer industry, revolutionizing agricultural practices and boosting food production globally.

Calcium superphosphate remains a vital component in the agricultural industry. It is primarily used as a phosphorus fertilizer, crucial for the development of plant roots, flowers, and fruits. Its high solubility allows for the rapid release of phosphorus, which is essential for the energy transfer within plants, promoting photosynthesis, and stimulating root development. Farmers use it in various forms, including single superphosphate (SSP) and triple superphosphate (TSP), depending on the phosphorus requirements of the crops and soil conditions. This application has significantly contributed to increased agricultural productivity and food security worldwide.

Beyond providing phosphorus, calcium superphosphate acts as a soil conditioner. It supplies calcium and sulfur, which are secondary nutrients needed for balanced plant nutrition. The calcium helps improve soil structure, enhancing aeration and water infiltration, which benefits root development and overall plant health. Sulfur, on the other hand, plays a critical role in amino acid synthesis and protein formation. By amending the soil with calcium superphosphate, farmers can correct nutrient deficiencies and enhance soil fertility.

Although primarily known for its agricultural use, calcium superphosphate finds limited applications in various industrial processes. It is used in the production of detergents, where the phosphorus content serves as a builder that enhances the cleaning efficiency of detergents by softening water. Additionally, it is employed in the manufacturing of certain chemicals and as a feed additive in the animal husbandry industry, providing essential nutrients to livestock.

With increasing attention on sustainable agriculture, calcium superphosphate plays a role in mitigating the environmental impact of farming. Its use in controlled-release formulations and precision agriculture techniques helps minimize nutrient runoff into water bodies, reducing the risk of eutrophication. Advances in the formulation of superphosphate fertilizers aim to enhance their efficiency and minimize their ecological footprint, supporting more sustainable farming practices.

References

2010. Mercury in some chemical fertilizers and the effect of calcium superphosphate on mercury uptake by corn seedlings (Zea mays L.). Journal of Environmental Sciences, 22(8).
DOI: 10.1016/s1001-0742(09)60236-9

2021. Decreased Methane Emissions Associated with Methanogenic and Methanotrophic Communities in a Pig Manure Windrow Composting System under Calcium Superphosphate Amendment. International Journal of Environmental Research and Public Health, 18(12).
DOI: 10.3390/ijerph18126244

2023. The effect of calcium superphosphate addition in different stages on the nitrogen fixation and ammonification during chicken manure composting. Bioresource Technology, 375.
DOI: 10.1016/j.biortech.2023.128731