Calcium phosphate dibasic dihydrate CAS 7789-77-7

1. What is Calcium phosphate dibasic dihydrate ?

The fundamental difference between DCPD and all previous sodium-based phosphates is that it is a calcium salt, carrying the most abundant mineral elements required by organisms—calcium and phosphorus. This inherent identity determines that its main role is not as a "functional aid" (chelation, buffering, bulking), but as a nutritional supplement and material structure.

2. Uses of dibasic dihydrate

2.1 Feed-grade DCPD—the world's most widely used inorganic mineral feed additive

This is the largest application of DCPD in terms of volume. Millions of tons of feed-grade dicalcium phosphate are added to livestock and aquatic feeds globally each year.

Why do animal feeds need extra calcium and phosphorus supplements?

While plant-based feed ingredients (corn, soybean meal, wheat bran) contain phosphorus, 60%–80% of this phosphorus exists in the form of phytic acid phosphorus. Monogastric animals (pigs, chickens, ducks, etc.) lack phytase, an enzyme that breaks down phytic acid, and therefore cannot utilize this portion of phosphorus. Without supplementation with inorganic phosphorus, these animals may experience the following:

Rickets/Osteopathy

Young animals often exhibit skeletal deformities, swollen joints, and difficulty walking.

Growth retardation

Phosphorus is an essential element for ATP (the core molecule of energy metabolism), and phosphorus deficiency directly leads to a sharp decline in feed conversion rate.

Laying hen problem

Thinner eggshells, soaring breakage rate, and decreased egg production – an eggshell contains about 2g of calcium, requiring hens to obtain a stable supply of calcium and phosphorus from their feed.

Reproductive disorders

Irregular estrus in female animals and decreased conception rate.

Typical addition amount

Laying hen feed

● 1% ~ 2% (Calcium demand is extremely high during peak periods)

Broiler feed

● 0.5% ~ 1.5%

pig feed

● 0.5% ~ 1.2% (higher for piglets, lower for fattening pigs)

Dairy cow concentrate supplement

● 1% ~ 2%

Fish and shrimp feed

● 1% ~ 3% (Aquatic animals have a higher requirement for calcium and phosphorus, and their absorption from water is limited)

In actual feed formulations, DCPD is usually used in combination with limestone (calcium carbonate, a pure calcium source) – DCPD provides calcium and phosphorus, while limestone supplements pure calcium, and the two are adjusted to achieve the target calcium-to-phosphorus ratio.

2.2 Plastics Industry – Auxiliary Components of PVC Heat Stabilizers

Polyvinyl chloride (PVC) needs to be heated to 160-200°C during processing (extrusion, injection molding, calendering). At this temperature, the PVC molecular chains will lose HCl, triggering a chain degradation reaction that leads to product discoloration (from white to yellow to black) and a decrease in mechanical properties.

Heat stabilizers are additives that prevent this process. Traditionally, lead salts were the most effective heat stabilizers for PVC, but they are being phased out globally due to environmental and toxicity concerns. Calcium-zinc composite stabilizers are one of the mainstream alternatives, while DCPD plays the role of an auxiliary stabilizer and filler in this system.

Absorbing HCl

● DCPD can react with the released HCl, thus delaying autocatalytic degradation;

lubricating

● The plate-like crystal structure of DCPD generates a certain internal lubrication effect during processing;

Fill enhancement

● To improve the rigidity and dimensional stability of the product;

Cost optimization

● Compared to pure calcium-zinc stabilizers, the introduction of DCPD reduces formulation costs.

DCPD is a common formulation component in rigid and semi-rigid PVC products such as wire and cable sheaths, pipes and fittings, and profile doors and windows.

2.3 Other industrial uses

fertilizer

● DCPD can be used as a slow-release phosphate fertilizer, which slowly releases phosphate in acidic soils, and its release is more sustained and uniform than that of superphosphate.

ceramics and glass

● : Introduced into ceramic glaze formulations as a phosphorus source to improve glaze gloss and chemical stability; calcium and phosphorus are introduced into bioactive glass;

Analytical reagents

● Used as a buffer and calcium-phosphorus standard in chemical analysis laboratories;

Polishing agent

● Utilizing the mild abrasive properties of DCPD, it is used for ultra-fine polishing of precision metals and optical components.

3.Summarize

Calcium phosphate dibasic dihydrate is the most unique member of the phosphate family—it is insoluble in water and does not participate in chemical "operations," but its coverage is broader than any sodium-based phosphate:

From plastic pipes to bone implants—the same CaHPO₄·2H₂O, with varying purities and particle sizes, plays entirely different roles in completely different industries. Understanding this "multi-purpose" characteristic is key to understanding the value of the inorganic phosphate industry.