Retardation ammonium dihydrogen phosphate

The reaction between MgO and ammonium dihydrogen phosphate (ADP) in aqueous solution yields struvite, MgNH4P04. bHjO, and schertelite, Mg(NH4)2(HP04)2.4H2O, as the main reaction products. Both may be regarded as cementing species. Only minor amounts of MgO are consumed during these reactions as it is present in excess. The reaction is exothermic. Sodium tripolyphosphate (STPP) or borax may be added to retard the reaction. The main course of the reactions may be represented thus ... 

Overall, these characteristics demonstrate that ammonium dihydrogen phosphate makes excellent rapid-setting grouts for outdoor applications such as road-repair materials in winter time in cold countries, because cold weather retards the initial setting, release of ammonia does not affect the workers and users in an open atmosphere, and the high strength makes these cements superior to conventional Portland cement. Products based on this material have been marketed commercially. 

Nanassy (6J) also examined the effects of fire retardants on the resulting char. He studied the effects of ammonium dihydrogen phosphate on the thermal diflFusivity, thermal conductivity, and specific heat of treated and untreated Douglas-fir specimens that had been... 

Small amount of impurities sometimes retard dramatically the crystal growth rate. Chromium(III), for example, suppresses the crystal growth of potassium sulfate(i), ammonium dihydrogen phosphate(2) and ammonium sulfate (5), etc. in aqueous solutions. Other metallic ions, iron(III), aluminium(III) are also effective impurities W... 

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