Compare Molybdenum dithiophosphate (MoDTP) Costs Across Treat Rates

A buyer who compares only the quoted price per kilogram will often pick the wrong grade. Molybdenum dithiophosphate (MoDTP) is dosed to hit a molybdenum target in the finished oil, so a lower-priced grade with less metal in it can cost more per tonne of oil. Sorting this out before the RFQ goes out is cheaper than discovering it after the first blend.

This article shows how to convert any MoDTP quote into a cost per tonne of finished oil, which inputs you can treat as confirmed, and where the numbers stop being reliable. The worked figures use assumed inputs, not our price list.

Why the price per kilogram misleads

Three variables decide what a grade really costs you:

• Molybdenum content of the grade. A grade with more Mo needs a lower treat rate to reach the same ppm.
• Target Mo level in the oil. Typical formulation targets are set by the performance you need, not by the additive supplier.
• Price per kilogram. This is the only number most quotes show.

Two grades at the same kilogram price are not equal if their Mo content differs. The same applies to a "cheaper" grade: it only wins if its price drops by more than its Mo content does. The fair comparison metric is cost per kilogram of contained molybdenum, then cost per tonne of finished oil.

Cost per finished oil calculation at different Mo targets and treat rates

Use these three formulas. They work for any grade once you have the Mo percentage from the certificate of analysis.

1. Treat rate (wt%) = target Mo ppm ÷ (Mo wt% in additive × 10,000) × 100
2. Additive per tonne of oil (kg) = treat rate (wt%) × 10
3. Additive cost per tonne of oil = additive kg × price per kg

Worked example. The inputs below are assumptions for illustration: a grade with 8.0% Mo and a price of USD 20 per kg. Replace both with the figures from your actual quote and CoA.

Cost scales linearly with Mo target. Doubling the target from 200 to 400 ppm doubles the MoDTP cost. Performance rarely doubles with it, which is why the target deserves a bench test before you commit.

Same price, different Mo content

Grade B would have to be quoted at 37.5% less to match Grade A on cost. The conclusion holds when both grades deliver the same friction and wear result at the same Mo ppm. It does not hold if a lower-Mo grade carries a different carrier, solvent, or phosphorus and sulfur load that changes performance. In that case, a bench result outranks the cost table.

Confirmed, estimated and unknown cost inputs

Do not mix these categories in an internal cost memo. An estimate presented as a fact is the quickest way to lose credibility with purchasing.

What a higher treat rate buys, and what it does not

Teams usually look at MoDTP when a formulation shows a high friction coefficient, a large wear scar, weak extreme pressure results, PB/PD values below target, or marginal oxidation stability. Raising the Mo level may reduce friction in the SRV test. It will not necessarily fix a PB/PD shortfall, which often depends on the EP chemistry rather than the friction modifier.

• Friction coefficient too high: A step up in Mo target is the logical first test. Run SRV at two or three levels, not one.
• Wear scar too large: MoDTP may help, but check whether your phosphorus and sulfur chemistry is already adequate. Sulfur based EP/AW additives may be the cheaper lever.
• PB/PD failing: Treat this as an EP problem first. Adding more Mo past the point of diminishing return only inflates cost.
• Oxidation weak: Test MoDTP alongside your existing antioxidant. Do not assume the benefit is additive.

MoDTP also brings phosphorus and sulfur into the oil. If your specification caps either element, calculate the contribution at each treat rate before you fix the Mo target. That limit can cap the dose long before cost does.

Common mistakes when comparing MoDTP quotes

• Comparing price per kg without the Mo percentage from the CoA.
• Locking the Mo target from a competitor's datasheet instead of your own SRV and wear data.
• Testing a single treat rate and assuming the trend is linear.
• Ignoring the phosphorus and sulfur limits in the finished oil specification.
• Costing the single component only, when the real choice may be a complete package. Compare against lubricant additive packages on a finished oil basis, since a package may already include friction control.
• Treating freight, duty and exchange rate movement as confirmed costs.

Step by step: build a comparable cost sheet

1. Collect the CoA Mo percentage for each grade you are comparing.
2. Fix a test matrix of three Mo targets, for example 100, 200 and 300 ppm.
3. Calculate treat rate and additive kg per tonne with the formulas above.
4. Blend and run your standard tests: SRV friction, wear scar, PB/PD where relevant, and an oxidation test.
5. Select the lowest Mo target that passes all limits with some margin.
6. Cost that target in the finished oil, adding freight and handling as clearly labeled estimates.
7. Repeat the cost at the next target up, to know what extra margin would cost.

Scenario: a hydraulic or gear oil blender sees SRV friction pass at 200 ppm but marginal at 100 ppm. The cost table shows 200 ppm adds USD 25 per tonne over 100 ppm, under the assumed inputs above. If the oil is sold at a margin that absorbs that figure, 200 ppm is the safer choice. If it is not, the next lever to test is the EP/AW system, for example organic molybdenum friction modifiers in combination with other chemistry, rather than a higher Mo dose alone.

How we support the sourcing step

Luoyang Fangshan Chemical was founded in 2017 and operates under ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 management systems. Our R&D team includes more than 30 PhD and master's degree holders, and functional chemical production capacity exceeds 10,000 tons. We are a professional lubricant additive manufacturer supplying import substitute additive products to global buyers.

Two practical points matter for the cost exercise above. There is no MOQ, so you can run the three-point matrix with small quantities rather than committing to a drum order first. Our stated dispatch time is 3 days for samples and 7 days for bulk orders. If a delivered lot has a product quality problem, we negotiate a return with you.

If the comparison shows that a single component is not the cheapest route, we can also review hydraulic oil additive packages or industrial gear oil additive packages against your target specification.

Buyer checklist before you request a quote

• Target Mo range in ppm, and the test method you will judge it by.
• Base oil type and the other additives already in the formula.
• Phosphorus and sulfur limits in the finished oil.
• Pass/fail values for SRV friction, wear scar, PB/PD and oxidation.
• Monthly volume, so quotes reflect your real usage.

Send your target Mo range, base oil and test limits to our technical sales team, and we will return a sample plan and a cost-per-tonne sheet built on actual CoA values. Request a sample or quote through the contact page on fanschem.com.