calcium chloride

Calcium chloride identity

Record the identity claim, supporting evidence and unresolved alternatives without treating appearance as proof.

1. What evidence identifies the material as CaCl2 rather than another calcium salt or another chloride salt? definition
2. Which supplier records or analytical results support that identification for this material? provenance

Material boundary

Record whether other constituents represent water, incidental impurities or intentional formulation ingredients.

1. Which constituents besides calcium chloride and water are present, and which were intentionally added? definition
2. Does the agent's decision concern calcium chloride itself or a blend that needs a neighbouring formulation model? boundary

Hydrate assignment

Record the claimed hydration state and the evidence supporting its applicability to the current material.

1. Is the solid designated anhydrous, a specified hydrate or an unresolved mixture of phases? definition
2. What measurements support the hydration assignment, and can they distinguish hydration water from additional moisture? measurement

Usable calcium chloride quantity

Record CaCl2 content with units, reporting basis, uncertainty and measurement conditions.

1. What is the measured calcium chloride content, and is it reported as anhydrous equivalent, hydrate content or another explicitly defined basis? measurement
2. What supplied mass or solution volume delivers the target amount, using the verified assay and any necessary density at the relevant temperature? action

Moisture exposure assessment

Record exposure history and evidence of moisture-related change without inferring a precise assay from appearance.

1. When was the material opened or transferred, and what humidity or liquid-water exposure is documented? provenance
2. What changes in mass, water content, flowability or visible wetness have been observed since the last accepted assessment? measurement

Current phase condition

Record clarity, undissolved material or crystallisation together with concentration and temperature.

1. At what temperature and measured concentration is the material clear, crystalline or a solid-liquid mixture? measurement
2. What evidence distinguishes calcium chloride crystallisation or incomplete dissolution from insoluble contamination before the material is used? action

Grade claim support

Record the exact grade claim, governing specification and available lot-level evidence.

1. Which specification and version define the claimed grade, and what certificate links that claim to this lot? provenance
2. Which impurity, insoluble-matter and assay results are available, with methods and detection limits? measurement

Intended-use decision

Record acceptance criteria and the resulting suitability decision for the specified application.

1. What calcium chloride content, form, impurity limits and documentation does the intended application require? boundary
2. Does this lot meet every required criterion, or must it be restricted, retested or rejected? action

Controlled dissolution and dilution

Record a preparation procedure that accounts for heat release and specifies how the final solution is accepted.

1. Which documented procedure specifies addition order, addition rate, mixing and temperature limits for this starting material and batch size? action
2. How will the final concentration be verified after the solution reaches the procedure's specified measurement temperature? measurement

Supported handling envelope

Record permitted contact materials and handling conditions with evidence applicable to the actual material.

1. Which safety data and compatibility references apply to this calcium chloride form, concentration, temperature and contacted equipment? provenance
2. What containment, moisture protection, exposure controls and spill-response actions do those references require? action

Kinds and varieties

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Anhydrous CaCl₂ (pellets, prills or powder, typically ≥94% as CaCl₂)
• Calcium chloride dihydrate (CaCl₂·2H₂O)
• Calcium chloride hexahydrate (CaCl₂·6H₂O)
• Flake technical solid (typically about 77-80% as CaCl₂, mixed hydrate)
• Liquid calcium chloride brine (typically 28-42% w/w)
• Food-grade calcium chloride (E509 / INS 509 / FCC)
• De-icing and dust-control grade (ASTM D98 Type S solid or Type L liquid)
• Pharmaceutical / parenteral grade (USP calcium chloride, including 10% injection)

1. Which of these kinds and varieties hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Identifiers and schemes

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• CAS Registry Number - 10043-52-4 - Anhydrous calcium chloride; the usual parent CAS.
• CAS Registry Number - 10035-04-8 - Calcium chloride dihydrate.
• CAS Registry Number - 7774-34-7 - Calcium chloride hexahydrate.
• EC / EINECS - 233-140-8 - EC number for calcium chloride (anhydrous parent).
• PubChem CID - 24854 - Compound record for CaCl₂.
• Wikidata - Q208451 - Wikidata item for calcium chloride.
• InChIKey - UXVMQQNJUSDDNG-UHFFFAOYSA-N - Standard InChIKey of anhydrous CaCl₂.
• E number / INS - E509 / INS 509 - Food-additive code (firming agent, sequestrant, stabilizer).
• HS / CN - 2827.20 - Harmonized System heading for calcium chloride.
• ATC - A12AA07 - Calcium chloride as a mineral supplement / injectable calcium salt.

1. Which of these identifiers and schemes hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Standards and regulation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• ASTM D98 Standard Specification for Calcium Chloride (ASTM International) - Type S solid and Type L liquid for ice control, dust control and related uses.
• 21 CFR 184.1193 Calcium chloride (U.S. FDA) - GRAS food-additive listing.
• Commission Regulation (EU) No 231/2012, specification for E 509 calcium chloride (European Commission), under Regulation (EC) No 1333/2008.
• Food Chemicals Codex (FCC) monograph for calcium chloride (U.S. Pharmacopeial Convention) - food-grade identity and purity.
• USP-NF Calcium Chloride and Calcium Chloride Injection monographs (U.S. Pharmacopeial Convention) - pharmaceutical identity, assay and parenteral quality.
• REACH registration, EC 233-140-8 (ECHA) - EU chemical safety and classification of the substance.
• GHS/CLP classification as typically published on ECHA and supplier SDS (commonly skin/eye irritant; some suppliers classify serious eye damage) - labelling and workplace handling.
• Codex Alimentarius INS 509 (FAO/WHO Codex) - international food-additive numbering aligned with E509.

1. Which of these standards and regulation hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Real-world use

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Road and pavement de-icing and anti-icing as flake, pellet or 28-42% brine, used because the CaCl₂-water eutectic is far colder than that of NaCl.
• Dust suppression on unpaved roads and construction sites: hygroscopic brine keeps fines damp.
• Concrete set accelerator in cold weather (chloride-bearing admixture); limited or banned in prestressed/reinforced concrete because of rebar corrosion.
• Industrial and laboratory desiccant (anhydrous or drying tubes) and brine for refrigeration and heat-transfer loops.
• Oil- and gas-well completion and workover fluids (dense CaCl₂ brine for density and shale inhibition).
• Food: firming agent and electrolyte (pickles, canned vegetables, cheese, sports drinks); coagulant for tofu in place of or with nigari/gypsum; labelled E509 in the EU.
• Water and wastewater: pH/alkalinity adjustment adjunct and source of hardness ions; not a primary coagulant in the alum/iron sense.
• Medicine: 10% calcium chloride injection for acute hypocalcaemia, calcium-channel-blocker overdose and some cardiac arrest protocols - more elemental calcium than gluconate, but vesicant on extravasation.

1. Which of these real-world use hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Typical measurements

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Assay as CaCl₂ (solid product) - 77-80 (flake Type S) to 94-100 (anhydrous pellets/reagent) - % w/w
• Solution concentration (commercial liquid) - 28-42 - % w/w CaCl₂
• Density of ~32% brine (near 15-20 °C) - 1.31-1.32 - g/mL
• Melting point (anhydrous) - 772-775 - °C
• Solubility in water at ~20 °C - about 74-75 - g CaCl₂ / 100 g water
• CaCl₂-H₂O eutectic temperature - about −50 to −52 - °C
• pH of dilute (around 5%) aqueous solution - 8-10 - pH
• Solid bulk density (flake vs pellet, as shipped) - about 0.8-1.2 - g/cm³ (bulk)

1. Which of these typical measurements hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Failure modes and hazards

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Deliquescence and caking in humid storage; anhydrous material pulls water until it becomes a brine, ruining dry handling and packaging.
• Exothermic dissolution: adding water to bulk solid (or vice versa in poorly designed mixers) can boil, splash hot brine and cause thermal burns.
• Skin and eye irritation; concentrated solutions and dust can cause serious eye injury; 10% injection is a vesicant (extravasation necrosis).
• Wet CaCl₂ is corrosive to steel, aluminium and vehicle metals; chloride also drives pitting of reinforcing steel in concrete.
• Runoff phytotoxicity and freshwater salinization: roadside vegetation burn, soil structure damage, and elevated Cl⁻ in receiving waters.
• Hypercalcaemia and cardiac arrhythmia if parenteral calcium chloride is overdosed or pushed too fast.
• Mis-grade substitution: industrial de-icer used in food, or CaCl₂ used where a non-chloride accelerator was specified.

1. Which of these failure modes and hazards hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Regional variation

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• United States and Canada: municipal liquid brine (often specified to ASTM D98 Type L, commonly ~32%) is a standard anti-icer; food use is GRAS under 21 CFR 184.1193 and FCC.
• European Union: food use is as E509 with purity in Regulation 231/2012; several states restrict or discourage chloride de-icers near watercourses and vegetation, sometimes preferring acetate/formate blends.
• East Asia: food-grade CaCl₂ is a recognised tofu coagulant alongside magnesium chloride nigari and gypsum; labelling follows local food-additive lists rather than E-numbers.
• Naming in trade: English "calcium chloride" / "liquid calcium"; French "chlorure de calcium"; Russian "хлористый кальций"; food packs in the EU show E509.

1. Which of these regional variation hold for the sense of calcium chloride this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Reported by the breadth pass; each item needs checking against its source before it becomes normative.

• Sodium chloride (NaCl) - NaCl is far less hygroscopic and its ice-melting eutectic is only about −21 °C versus about −51 °C for CaCl₂; confirm Ca²⁺ by flame (brick-red) or oxalate precipitation, or assay Ca vs Na.
• Magnesium chloride (MgCl₂, often hexahydrate) - Same de-icer/dust-control niche and similar brines; separate by Ca vs Mg (AAS/ICP, or EDTA titration with masking) and by hydrate water (MgCl₂·6H₂O is the usual solid).
• Calcium hypochlorite (Ca(OCl)₂) - A chlorinating oxidizer, not a chloride salt for de-icing; available-chlorine / starch-iodide test is positive, and it is classified as an oxidizer (typical CAS 7778-54-3).
• Calcium carbonate (CaCO₃) - Sparingly soluble, not deliquescent; fizzes with acid (CO₂) and leaves little dissolved Ca²⁺ in water, whereas CaCl₂ dissolves freely without gas.
• Calcium hydroxide (hydrated lime) - Saturated solutions are strongly alkaline (pH ~12.4) versus mildly alkaline dilute CaCl₂ (pH ~8-10); lime is only slightly soluble and is not a chloride source.
• Calcium gluconate (injectable) - Same clinical calcium indication but less elemental calcium per millilitre and much less vesicant; label, anion assay and osmolarity separate the two ampoules - they are not interchangeable millilitre-for-millilitre.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of calcium chloride this model covers, and on what evidence? provenance