Decrepitation

One of the problems with early hydride systems was decrepitation of the alloy. Each time the metal hydride storage tank was recharged the particles would break down and eventually the particles became so small that they began to pass through the 5-p.m sintered metal filter which kept the hydride inside the tank. Addition of 0.5% manganese, which caused the decrepitation process to cease once the particles reached a size of about 10 p.m, solved this problem. 

Some limestones, more often the coarse crystalline types, can never be calcined successfully. Such stone tends to decrepitate during preheating or calcination into fine particles that interfere with this pyrochemical reaction. The adaptabiflty of a stone for calcination can only be ascertained with surety by empirical methods. Possibly the greatest influence on lime quaflty is the size gradation of limestone. Narrow gradations, such as... 

Size Reauction Three major size-reduction mechanisms occur in the fluidized bed. These are attrition, impact, and thermal decrepitation. 

Thermal decrepitation occurs frequently when crystals are rearranged because of transition from one form to another or when new compounds are formed (i.e., calcination of limestone). Sometimes the strains in cases such as this are sufficient to reduce the particle to the basic ciystal size. 

Abknisterung, /. decrepitation, abkochecht, a. fast to boiling, abkochen, v.t. boil, decoct boil off reboil. 

Dekorations-farbe, /. decorative color, -lack, m. decorative varnish, dekorieren, v.t. decorate, dekrepitieren, v.i. decrepitate. 

Zerknallstoss, m. shock of explosion, zerknicken, v.t. crack (esp. by bending), zerknistem, v.i. decrepitate, zerknittem, zerknuUen, v.t. crumple, rumple corrugate. 

Occurrence of pyrrhotite, arsenopyrite and high iron content of sphalerite indicate low fs,2 and /02 conditions. Decrepitation temperatures of fluid inclusions in quartz from Sn-Cu-As stage are 403-322°C (Enjoji and Takenouchi, 1976). 

Main ore minerals are few. They are cinnabar, metacinnabar, stibnite and pyrite. Gangue minerals are quartz and calcite. Fluid inclusion decrepitation temperatures... 

Mellor, 1956, Vol. 2, Suppl. 1, 613 Decomposes with decrepitation above 60°C. See related metal perchlorates... 

H-H interaction due to the lattice expansion becomes important and the hydride phase (P phase) nucleates and grows. The hydrogen concentration in the hydride phase is often found to be H M = 1. The volume expansion between the coexisting a- and P-phases corresponds in many cases to 10-20% ofthe metal lattice. Therefore, at the phase boundary high stress is built up and often leads to decrepitation of brittle host metals such as intermetaiiic compounds. The final hydride is a powder with a typical particle size of 10-100 pm (Figure 5.24). 

There are a number of engineering properties relating to practical applications of hydrides hysteresis, reversible capacity, decrepitation, activation, reaction kinetics, impurity tolerances, chemical stability, heat transfer, safety, cost and... 

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