Comparing liquid ferric chloride quotes on delivered cost per kilogram of iron

Purchasing teams tend to receive a price per tonne of solution. Operators need to know the cost of meeting a treated-water target. Calculate cost per kilogram of iron first, then run a comparison on the same raw water.

Identify what the percentage measures

Ask the supplier to distinguish FeCl₃, total iron as Fe and ferric iron as Fe, and to identify the mass or volume basis. NHMRC gives an example in which a 42% ferric chloride solution contains about 14.5% iron. Entering 42% in the iron field would understate cost per kilogram of iron. If the COA reports both total and ferrous iron, agree which measure will be used.Read NHMRC’s ferric chloride guidance

Compare both delivered quotes on the same basis

For a metric tonne of commercial solution, kilograms of iron equal 1,000 times the iron mass fraction. Divide the delivered price per tonne by those kilograms. Include the same taxes, freight and packaging charges in both quotes.

• Solution A. At an illustrative delivered price of CNY 1,000/t and 14.5% iron, one tonne contains 145 kg of iron. The cost is approximately CNY 6.90 per kilogram of iron.
• Solution B. At an illustrative delivered price of CNY 900/t and 12.0% iron, one tonne contains 120 kg of iron. The cost is CNY 7.50 per kilogram of iron.

These hypothetical prices illustrate the calculation. Solution B costs less per tonne of solution but more per kilogram of iron. For a price per litre, use the lot’s density at the agreed temperature to convert to a mass basis first.

Use the same raw water for the treatment trial

Collect a representative raw-water sample and record turbidity, temperature, pH and alkalinity. Apply the same mixing, settling and sampling conditions to each candidate. Record how much commercial product reaches the target and check residual iron, sludge or downstream filtration as appropriate.

Multiply the dose in kg of commercial solution per m³ of raw water by the price in CNY/kg of solution to obtain chemical cost in CNY/m³. Compare only trials that meet the same treated-water target. The plant should verify the result under its operating procedures before scaling the laboratory dose.

Three records for the purchasing handover

1. Two quotations for the same delivery point and cost basis, showing net weight, freight and returnable packaging costs.
2. A sample-specific analysis report identifying the assay, method and lot number.
3. The common-water jar test record, with the target, observation time and product dose needed to meet it.

Worksheets and related materials

Download the editable trial or purchasing worksheet (TXT)

View ferric chloride specifications and purchasing information　Water treatment: coagulation and flocculation