E538 CALCIUM FERROCYANIDE

E538 Calcium ferrocyanide, also known as calcium hexacyanoferrate(II), is an inorganic coordination compound containing calcium ions and the ferrocyanide complex, and it is primarily used in very limited, regulated industrial applications (especially historically in salt anticaking systems) because of its ability to reduce clumping in powdered salts and similar materials by interfering with crystal adhesion and moisture-driven aggregation.
E538 Calcium ferrocyanide is chemically related to other ferrocyanides (like E535 and E536), but uses calcium as the balancing cation instead of sodium or potassium.
E538 Calcium ferrocyanide improves salt flow properties and storage stability in certain formulations.

CAS Number: 13821-08-4
Molecular Formula: C6CaFeN6(-2)
Molecular Weight: 252.03
EINECS Number: 237-508-9

Synonyms: CALCIUM FERROCYANIDE, 13821-08-4, dicalcium hexacyanoferrate, calcium hexacyanoferrate(II), UNII-906D36VLZG, INS-538, yellow prussiate of lime, hexacyanoferrate of calcium, EINECS 237-508-9, dicalcium hexacyanoferrate(4-), ferrate(4-) hexacyano dicalcium, E-538, ferrate(4-) hexakis(cyano-kappaC) calcium (1:2), RefChem:122831, yellow prussiate of lime calcium hexacyanoferrate, dicalcium iron hexacyanide, Q1026348, calcium(1:2),(oc-6-11)-ferrate(4-hexakis(cyano-c)-;CALCIUM FERROCYANIDE;dicalcium hexacyanoferrate;Calciumhexacyanoferrat (II);Calcium hexacyanoferrate(II);icalcium,iron(2+),hexacyanide;dicalcium,iron(2 ),hexacyanide

E538 Calcium ferrocyanide consists of a stable iron–cyanide coordination complex where iron is strongly bound to six cyanide ligands, with calcium ions balancing the overall charge, and this structure makes it relatively stable under normal neutral and mildly alkaline conditions, meaning it does not readily release free cyanide ions unless exposed to strong acidic environments.
E538 Calcium ferrocyanides behavior is therefore governed by coordination chemistry rather than free cyanide reactivity.
E538 Calcium ferrocyanide improves chemical stability and controlled industrial behavior.

E538 Calcium ferrocyanide typically appears as a yellowish crystalline solid or powder, and like other ferrocyanides it is water-soluble to some extent but remains stable in dry storage conditions, with low volatility and minimal reactivity under normal handling environments used in food and industrial processing.
It is generally less commonly used than sodium or potassium ferrocyanide in modern applications.
E538 Calcium ferrocyanide improves handling safety and industrial consistency.

E538 Calcium ferrocyanide functions mainly as an anticaking and anti-humidity agent, where it helps prevent fine salt particles from binding together by reducing crystal bridging and moisture absorption effects, particularly in refined salt systems where small particle size increases the risk of clumping during storage and transport.
However, its use is more restricted and less widespread compared with other ferrocyanides.
E538 Calcium ferrocyanide improves product flowability and material handling performance.

E538 Calcium ferrocyanide is best described as a stable iron–cyanide coordination compound used in very limited or regulated anticaking applications, mainly in salt processing, due to its ability to prevent clumping while remaining chemically stable under normal conditions but subject to strict controls due to its cyanide-containing structure.
E538 Calcium ferrocyanide is also relevant in moisture-sensitive mineral processing systems, where it can help maintain the physical separation of fine particulate salts and mineral powders by reducing surface attraction between particles, especially in materials that have been finely milled for industrial use and therefore have a high tendency to compact under pressure during storage or transport.

E538 Calcium ferrocyanides role is mainly physical and structural rather than strongly chemical in everyday conditions.
E538 Calcium ferrocyanide improves powder flow behavior and bulk material handling.

In bulk industrial logistics of salt and mineral products, calcium ferrocyanide can contribute to preventing “bridging” inside silos and storage tanks, where fine particles form stable arches that block discharge flow, a common problem in large-scale handling systems for hygroscopic materials exposed to humidity fluctuations.
This makes it useful in improving operational reliability in storage infrastructure.
E538 Calcium ferrocyanide improves industrial flow continuity and reduces material blockage.

In formulation comparison studies within food additive science, it is sometimes evaluated against sodium and E538 Calcium ferrocyanide to understand how the choice of counter-ion (Ca²⁺ vs Na⁺ vs K⁺) affects performance, cost, solubility behavior, and compatibility with different salt refining technologies.
These comparisons help optimize industrial anticaking strategies.
E538 Calcium ferrocyanide improves additive selection and formulation efficiency.

E538 Calcium ferrocyanide is studied as an example of how different metal cations influence crystal lattice structure in coordination compounds, because calcium ions can create different packing arrangements compared with monovalent ions, affecting solubility, stability, and crystal morphology.
This is important in understanding coordination solid chemistry.
E538 Calcium ferrocyanide improves materials science and crystal engineering knowledge.

E538 Calcium ferrocyanide is included in studies examining how ferrocyanide complexes behave when bound to different metal ions in soil and water systems, particularly how calcium-containing systems may influence precipitation and mobility compared with sodium- or potassium-based ferrocyanides.
These studies support environmental regulation and risk modeling.
E538 Calcium ferrocyanide improves environmental safety evaluation.

E538 Calcium ferrocyanide may appear in older salt-processing methods, although it has largely been replaced by more efficient sodium and potassium ferrocyanides due to better solubility control, easier dosing, and more consistent performance in modern industrial salt refining systems.
This reflects its reduced but historically relevant industrial role.
E538 Calcium ferrocyanide improves understanding of industrial evolution.

In industrial quality assurance testing, ferrocyanide compounds including E538 Calcium ferrocyanide may be analyzed as part of regulatory compliance checks to ensure correct additive levels in salt products, even when they are not the primary anticaking agent used.
This is part of modern food safety monitoring systems.
E538 Calcium ferrocyanide improves regulatory compliance and product safety assurance.

E538 Calcium ferrocyanide is studied alongside other ferrocyanides to confirm that the stability of the ferrocyanide complex remains largely consistent regardless of the counter-ion, reinforcing the understanding that the toxicity profile is governed mainly by complex stability rather than the associated metal ion.
This supports chemical safety evaluation frameworks.
E538 Calcium ferrocyanide improves toxicological understanding of coordination compounds.

LogP: -0.250 (est)
FDA UNII: 906D36VLZG
EPA Substance Registry System: Ferrate(4-), hexakis(cyano-.kappa.C)-, calcium (1:2), (OC-6-11)- (13821-08-4)

E538 Calcium ferrocyanide is used in specialized salt and mineral processing systems, where it helps maintain free-flowing properties in finely divided salt products that are prone to absorbing moisture and forming hard agglomerates during storage, packaging, or long-distance transportation, especially in humid environments where even small amounts of moisture can significantly affect product quality.
Its effectiveness is similar to other ferrocyanides but less commonly applied in modern industrial formulations.
E538 Calcium ferrocyanide improves bulk material handling and storage stability.

In industrial salt refining processes, E538 Calcium ferrocyanide may be used to support flow consistency in vacuum-dried or finely milled salt products, where extremely small particle size increases surface contact and makes clumping more likely due to electrostatic and moisture-driven interactions between crystals.
E538 Calcium ferrocyanide helps maintain consistent physical properties in processed salts.
This improves industrial salt quality and process efficiency.

E538 Calcium ferrocyanide is sometimes studied alongside sodium and potassium ferrocyanides to evaluate differences in anticaking efficiency, solubility behavior, and performance under varying humidity conditions, helping manufacturers decide which ferrocyanide salt is most suitable for specific environmental or processing requirements.
This is mainly relevant in industrial research and product optimization.
E538 Calcium ferrocyanide improves formulation development and material selection.

E538 Calcium ferrocyanide is used as part of broader studies on iron–cyanide complexes, where scientists examine how different metal counter-ions (such as Ca²⁺, Na⁺, or K⁺) influence crystal structure, solubility, and stability of ferrocyanide systems.
These studies help understand solid-state chemistry and lattice interactions.
E538 Calcium ferrocyanide improves scientific understanding of coordination compounds.

E538 Calcium ferrocyanide is included in research models assessing the stability and breakdown behavior of ferrocyanide compounds in soil and water systems, particularly under different pH conditions, since calcium-based salts may behave differently in precipitation and solubility compared to sodium or potassium analogs.
This supports environmental risk assessment and regulatory evaluation.
E538 Calcium ferrocyanide improves chemical safety analysis and environmental monitoring.

In historical industrial salt treatment, E538 Calcium ferrocyanide was sometimes used in earlier anticaking formulations before sodium and potassium versions became more dominant due to better solubility and handling properties, making it less common in modern food-grade applications today.
This reflects its reduced role in current food additive systems.
E538 Calcium ferrocyanide improves understanding of industrial development history.

In industrial packaging design considerations, its use (where permitted) influences how salt is stored and packaged, since maintaining free-flowing powder reduces mechanical stress on packaging equipment and improves consistency in automated filling systems used in large-scale production plants.
This is important for efficiency in automated manufacturing lines.

E538 Calcium ferrocyanide improves packaging performance and production efficiency.
E538 Calcium ferrocyanide is a specialized and less commonly used ferrocyanide salt primarily relevant in anticaking systems, material handling, and coordination chemistry research because of its ability to influence powder flow behavior, crystal interactions, and structural properties of salt-based materials while remaining chemically stable under normal industrial conditions but tightly regulated due to its cyanide-containing coordination structure.

Uses Of E538 Calcium ferrocyanide:
E538 Calcium ferrocyanide is mainly used as a limited anticaking agent and industrial flow-control additive because of its ability to reduce clumping in fine salt particles by preventing moisture-induced crystal adhesion.
In salt processing, it is used to keep refined salt free-flowing during storage and packaging.
This improves product handling and usability.

In industrial salt systems, it helps maintain flowability in bulk storage and transport conditions.
E538 Calcium ferrocyanide improves manufacturing efficiency.
In specialized formulations, it is used in small regulated amounts where ferrocyanide anticaking agents are required.

E538 Calcium ferrocyanide improves product stability in controlled applications.
In research and comparative studies, it is used to evaluate performance differences among ferrocyanide salts.
This improves formulation optimization.

In coordination chemistry studies, it is used as a model compound for iron–cyanide complexes.
E538 Calcium ferrocyanide improves chemical research and understanding.
E538 (calcium ferrocyanide) is mainly used as a limited anticaking and flow-control agent in salt and powdered mineral systems because it helps prevent fine particles from sticking together by reducing moisture-driven crystal adhesion and improving the free-flowing behavior of dry materials.

In salt processing, it is used to prevent clumping in finely ground salt during storage and packaging.
E538 Calcium ferrocyanide improves product usability and handling.
In industrial bulk salt handling, it helps maintain smooth flow in silos, transport systems, and packaging lines.

E538 Calcium ferrocyanide improves manufacturing efficiency and reduces blockages.
In specialized mineral and powder formulations, it is used in small regulated amounts to improve flow properties of hygroscopic materials.
This improves storage stability and material performance.

In comparative additive studies, it is used to evaluate performance differences between ferrocyanide anticaking agents.
E538 Calcium ferrocyanide improves formulation optimization and industrial selection.
In coordination chemistry research, it is used as a model compound for iron–cyanide complexes with calcium counter-ions.

This improves scientific understanding of crystal structure and stability.
E538 (calcium ferrocyanide) is also used in specialized salt granulation systems, where it helps maintain consistent particle size distribution during processing by reducing the tendency of very fine salt crystals to fuse or agglomerate when they are dried and cooled after crystallization, especially in industrial vacuum evaporation systems.

E538 Calcium ferrocyanide is important because finely processed salt is more sensitive to humidity and mechanical pressure during storage.
This improves product uniformity and industrial processing stability.

E538 Calcium ferrocyanide can indirectly improve performance by keeping salt powders free-flowing, which reduces interruptions in filling machines, minimizes blockages in dosing systems, and ensures accurate weight-based packaging in high-speed production lines.
Even small improvements in flow behavior can significantly affect industrial efficiency at scale.
E538 Calcium ferrocyanide improves automation reliability and packaging accuracy.

In humidity-controlled storage engineering, it contributes to maintaining consistent discharge from storage hoppers, especially in facilities where salt is stored in bulk for long periods under varying environmental conditions, reducing the need for mechanical vibration or additional drying steps.
This helps simplify storage infrastructure design.
This improves logistical efficiency and storage system performance.

In formulation science and additive compatibility testing, E538 is studied to understand how calcium-based counter-ions influence ferrocyanide behavior compared with sodium and potassium versions, especially in terms of solubility, crystal lattice formation, and interaction with sodium chloride matrices in salt systems.
These comparisons are important for optimizing anticaking performance under different climatic conditions.
This improves additive design and material optimization.

E538 Calcium ferrocyanide was more commonly used in earlier formulations before being largely replaced by sodium and potassium ferrocyanides due to better solubility control and easier dosing accuracy in modern manufacturing systems.
Its use today is much more limited and application-specific.
E538 Calcium ferrocyanide improves understanding of historical industrial chemistry development.

E538 Calcium ferrocyanide (when present in blends) may be analyzed alongside other ferrocyanides to ensure compliance with strict additive limits in food-grade salt products and to verify that total ferrocyanide content remains within legally permitted thresholds.
This is part of modern food safety control systems.
E538 Calcium ferrocyanide improves consumer safety assurance and regulatory compliance.

Safety Profile Of E538 Calcium ferrocyanide:
E538 Calcium ferrocyanide is considered a low-to-moderate hazard compound under normal regulated conditions, because the ferrocyanide complex is stable and does not release free cyanide ions in neutral or mildly alkaline environments typical of industrial use.
The main hazard arises under strongly acidic conditions, where decomposition may release hydrogen cyanide gas, which is highly toxic; however, this risk is not expected under normal storage or food processing conditions due to strict pH control.
E538 Calcium ferrocyanide makes acidity control essential for safety.

Inhalation of dust may cause mild respiratory irritation, especially in industrial environments where fine particles may become airborne during handling.
E538 Calcium ferrocyanide requires standard dust control measures.
Skin and eye contact may cause mild irritation, but it is not corrosive under normal exposure conditions.

Rinsing with water is usually sufficient.
It must be stored away from strong acids to prevent decomposition risk.
E538 Calcium ferrocyanide improves safe storage practices.

From an environmental perspective, it should not be released in large quantities, because cyanide-containing complexes may pose risks under certain breakdown conditions, even though ferrocyanides are significantly less toxic than free cyanide compounds.
E538 Calcium ferrocyanide requires proper waste handling and environmental control.
E538 Calcium ferrocyanide is a stable anticaking agent with low toxicity under normal conditions, with primary hazards related to acid exposure, mild irritation, and environmental management requirements, making it suitable only for controlled and regulated industrial use.