Calcium Carbonate (Chalk Powder) — High Purity, FEMAS Certified

Calcium Carbonate is a fine, off-white powder produced from very high purity Carboniferous limestone — crushed, milled, dried and classified to give a consistent, ultra-fine particle size. With a minimum CaCO₃ content of 98.25% and FEMAS (Feed Material Assurance Scheme) certification, this is a premium grade chalk powder suitable for craft, cosmetic, garden, industrial and animal feed applications.

Best known to crafters as the key ingredient for making your own chalk paint, and to gardeners as a fast-acting alternative to granulated garden lime for correcting soil pH. Equally trusted by smallholders and pet owners as a natural calcium source for animal feeds.

Common Uses

Craft & Hobby Uses

• Chalk paint — the essential ingredient for making your own DIY chalk paint by mixing with emulsion paint and water; gives that classic matt, vintage finish at a fraction of the cost of branded chalk paints
• Gesso & primers — traditional artists’ ingredient for preparing canvas, wood panels and other surfaces before painting with oils or acrylics
• Air-dry clay & modelling compounds — combine with PVA glue and a little water to make smooth, white, fine-textured air-dry clay for sculpting and craft projects
• Paper mâché — adds body, smoothness and a fine finish to paper mâché paste for sculpting and decorative work
• Cold porcelain — base ingredient in homemade cold porcelain clay for fine flower-making and decorative crafts
• Ceramics & pottery — used in clay bodies, glazes and slip casting; acts as a flux and matting agent
• Soap making — adds opacity, hardness, a silky feel and helps reduce soap-on-a-rope softening in cold-process soaps
• Cosmetic formulation — bulking agent in mineral makeup, blushers, tooth powders and bath products
• Putties & fillers — used as a filler in wood fillers, polyester resins, adhesives and homemade plaster repairs
• Casting & sculpting — extends plaster of Paris and improves workability in casting compounds
• Line marking — use dry or mixed with water to mark out sports fields, pitches, garden boundaries and play areas

Animal Feed & Nutrition

• Poultry feed — supports digestion, eggshell formation and shell strength; essential for laying hens to prevent thin or soft-shelled eggs
• Equine (horse) feed — natural calcium source for bone development and overall skeletal health
• Livestock feed — supplied to cattle, sheep, pigs and goats to support growth, milk production and prevent calcium deficiency conditions such as milk fever and displaced abomasum
• Reptile supplements — vital for healthy shell development in tortoises and turtles, and for bone health in lizards, snakes and amphibians
• Pet feed supplement — added to homemade pet diets and raw feeding regimes to support bone, teeth and joint health
• Bird feed — provides essential calcium for caged birds, parrots and breeding flocks
• Smallholder & backyard flock use — popular natural feed additive among hobby keepers of chickens, ducks, geese and quail

Garden & Soil Use

• Soil pH correction — corrects acidic soils, raises pH, increases phosphorus availability and enhances mineralization and nitrification; powdered form acts much faster than granulated garden lime
• Heavy metal soil remediation — used to “tie up” heavy metals in contaminated soils, reducing their uptake by plants
• Plant health — strengthens cell walls, supports new cell development and helps prevent calcium deficiency disorders such as blossom end rot in tomatoes and peppers

Garden Application Rates

Always check your soil pH first — neutral soil is pH 7.0, with anything below being acidic. Best applied in winter for annual crops to take effect before spring planting, or before planting perennial plants, lawns, shrubs, fruit or trees rather than once established (surface application around established plants can take years to take effect).

• General soil improvement: 5-12 kg per 100 m² spread evenly over the area
• Digging into soil before planting: approximately 250 g per m², mixing well into the topsoil
• Potting mix: 250-500 g per 1000 litres of compost

For best results, work the powder into the soil to a depth of a few inches.

Animal Feeding Guidance

Calcium Carbonate should be added to your livestock or pet’s normal feed each day. The exact amount depends on the species, age, size, stage of growth and overall diet. We strongly recommend speaking to a qualified veterinarian or animal nutritionist before adding to your animal’s diet to ensure correct dosage and avoid over-supplementation.

Product Specification

• Grade: High purity ground calcium carbonate, FEMAS certified
• Chemical name: Calcium Carbonate
• Molecular formula: CaCO₃
• CAS number: 1317-65-3
• EINECS number: 215-279-6
• E number: E170
• Calcium as CaCO₃: 98.25% min.
• Calcium as CaO: 55.00% min.
• Moisture content: 0.2% max. (typical 0.05%)
• Loss on ignition (1000°C): 43.60%
• Specific gravity: 2.65 g/cm³
• Bulk density (loose): 1.20 t/m³
• Particle size — d50: 18 µm · d98: 150 µm
• Heavy metals: Lead ≤ 20 ppm · Arsenic ≤ 15 ppm · Cadmium ≤ 2 ppm · Mercury ≤ 0.3 ppm
• Appearance: Fine off-white powder
• Odour: Odourless
• REACH: Limestone is exempt from REACH registration

Storage

Store in dry conditions in a sealed container. Avoid contact with water to maintain free-flowing quality.