Mono Magnesium Phosphate powder: MgH4(PO4)2 ∙ 2H2O

Description: Dry, water soluble, Mono-Magnesium Phosphate for use in Fast Setting Cements, Investment casting, Gunning Mixes, and Fertilizers

Ref-Bond MP2 QD (MP2 QD) is used in refractory applications as well as specialty cementing. This material has been used commercially for decades in dental and cement applications. Typically Mono Magnesium Phosphate was dried driving off physical water and leaving the chemically bound water. Drying MP2 drives up the cost and makes it very hygroscopic. It was found that a more stable material could be produced by not driving off the physical water. This brought down the cost so that it could be considered for bulk refractory applications.

Typical Chemistry:

  • MgO: 15.5%
  • P2O5: 55%
  • LOI: 25%

Typical Uses:

  • Fast Setting Cements
  • Investment casting
  • Gunning Mixes
  • Fertilizers

Effect of Additives on the Properties of Magnesium Phosphate based cements

By George Gower, P.E.

The effects of various additives on the Magnesium Phosphate Cement (MgPC) system are investigated. Magnesium Phosphate cement is comprised of Mono Magnesium Phosphate and a source of MgO (Fused or Dead Burned). This is a rapid reaction requiring additives to slow the setting of the Cement. In addition, additives may be used to vary strength and flow characteristics. Utilizing a standard test mix the effect of additives on set time, flow, and strength are studied.

(Presented at the Fiftieth Symposium on Refractories sponsored by The St. Louis Section and Refractory Ceramics Division of the American Ceramic Society March 26, 2014)

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Phun with Mono Magnesium Phosphate

By George Gower, P.E.


Ref-Bond MP2 (MP2) is a family of products which are used in refractories where a source of dry P2O5 is required.

MP2 can be used to form cement with the addition of alkali. Other uses for MP2 include gunning, dry mortars and technical cements. One of the early uses for MMP is in the area of dental investment casting. Cement produced with MP2 bonds readily to itself and other material such as steel. Table 5 shows the chemistries for Ref-Bond MP2 products. RMCI produces this material in large batches which are then homogenized to maintain consistency from lot to lot. MP2 is an excellent source of P2O5where a liquid phosphate is inconvenient to use.

(Presented at the Forty Fifth Symposium on Refractories sponsored by The St. Louis Section and Refractory Ceramics Division of the American Ceramic Society March 25, 2009)

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Properties of Magnesium-Phosphate-Bonded Refractory Castables

George D. Gower, P.E., and Irving W. Gower, P.E

Phosphate-bonded products have been used for many years in dental prosthetics and cements, in highway repair, and for refractory applications. While phosphates have been used in the creation of refractory mortars and plastics, they have not been used extensively in refractory castables. A magnesium-phosphate castable has been developed utilizing a closely-graded, sintered mullite aggregate with a magnesium phosphate/magnesium oxide/aluminum oxide binder. A magnesium phosphate castable’s advantageous properties include a fast (yet retardable) set, and strength that increases when the product is fired to mid-range temperatures (approx. 1500° F) and, in general, over time.

( Published in Refractories Applications and news, Volume 11, Number 5  September/October 2006)

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