Calcium carbonate goes into glass batches, feed rations, soil programs, water treatment and growing media, and each of those buyers is purchasing something different under the same name. The chemistry is CaCO3; what decides whether a delivery works in your process is the particle size, the moisture, the trace constituents and the documents that come with it. This guide covers what to specify, how to compare offers and how to qualify a new source.
What are you actually buying?
Most industrial calcium carbonate is ground limestone or marble, which is the mineral calcite. Precipitated calcium carbonate is manufactured rather than mined. Dolomitic limestone carries magnesium carbonate alongside the calcium. Natural oolitic aragonite, which AragoCor supplies, is the same compound as calcite in a different crystal structure, formed as rounded marine grains. The difference between aragonite and calcite shows up in solubility and grain shape; the difference between calcitic and dolomitic material matters wherever magnesium does.
The specification: six things to write down
- Application and grade. Name the process, not just the product. A glass batch, a layer ration and a contactor bed need very different material.
- Chemistry. The calcium basis you buy on — CaCO3, elemental calcium or CaO — and limits on the constituents your process cares about: iron for glass, magnesium for growing media, contaminants for feed.
- Particle size. A sieve distribution with the openings stated, a top size and a fines limit, and whether results are reported as passing or retained.
- Moisture and basis. Whether figures are as received or dry, and the moisture your handling and dosing equipment can accept.
- Documents. The data sheet, safety data sheet, lot certificate of analysis and any listing your market requires.
- Quantity, destination and receiving. Order size, repeat pattern, delivery point and the packaging format your site can unload.
Read the data sheet before the price
A supplier’s data sheet mixes measured results, published ranges and reference values, and they do not carry the same weight: a representative analysis describes a tested sample, not a guaranteed lot. Before comparing two suppliers, put their figures on the same basis and find out which ones will appear on the lot certificate. How to read a calcium carbonate data sheet and COA walks through the statuses and the questions to ask.
AragoCor’s own figures show the pattern. The material is 96.17% CaCO3 and 38.51% elemental calcium, both representative analysis by ASTM C 25. Sizing is published by grade: AG-CAL 0.2–0.5 mm, GL-CAL below 0.1 mm and WT-CAL 1–3 mm, each a published range, with PL-CAL classified to customer specification.
Compare offers on delivered cost per accepted ton
Calcium carbonate is heavy and low in value per ton, so freight often decides the comparison. Ask every supplier to quote the same quantity to the same delivery point, in the same unit (short ton or metric tonne), and to say whether packaging is included in the mass. Then divide each total — material, packaging, freight and any receiving charges — by the tonnage you expect to accept. A lower price at the shipping point can still cost more delivered.
Price is only comparable once the products are. A cheaper material that needs drying, screening or a recipe change carries a cost the invoice does not show.
Qualify the source before you switch
A first sample shows whether the material can work; it does not show that every lot will. Agree what the trial must demonstrate, run it against your current material as the reference, and record the conditions. Then agree which attributes will be controlled on repeat orders, how they will be reported on the certificate of analysis and how a change at the source will be communicated.
Industry guides
What to specify depends on where the material is going. These guides cover the questions each industry’s buyers ask:
- Glass-grade limestone specifications — calcium basis, iron, loss on ignition, moisture and sizing for batch houses.
- Calcite vs. aragonite contactor media — remineralization and pH correction.
- Calcium carbonate equivalent and fineness — comparing agricultural liming materials.
- Feed limestone — calcium, particle size and contaminant limits for feed mills.
- Calcitic vs. dolomitic lime in growing media — calcium, magnesium and reaction speed in substrates.
If your application sits outside AragoCor’s four grades, custom classification to customer specification is offered across 20–325 U.S. mesh, a published range.
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