Process-water residues in fireclay and magnesia refractory production

Conclusions Particle size analyses of process water residues from fireclay and magnesia refractory production enable settlement rates to be established within water cleaning plant.From wet volume tests on residues it is possible to work out sludge volumes and cleaning cycle times for settlement plantl.Residues consisting of grog, magnesite, chromite, magnesite-chromite mixtures, and grog-clay mixtures with seven-tenths grog or over, should be removed mechanically from a horizontal settling tank after 1 day or longer, e.g., with a bucket crane or similar mechanism. A clay residue should be pumped out, but if it stands for 2 days or more it may be dug out.A coagulated residue of clay or a clay-grog mixture with seven tenths clay or more should be pumped out, but a 73 clay-grog mixture can be removed mechanically after settling for 3 days.Coagulated grog, magnesite, or chromite residues can be moved hydraulically for the first day, but if they stand longer they must be moved mechanically. If sludge is to be moved mechanically from a settling tank the clean water over it must be removed first, and appropriate equipment must be allowed for. If a sludge is to be removed hydraulically it must first be stirred up in some way.Translated from Ogneupory, No. 2, pp. 11–16, February, 1969.     

The reactivity of 1,3-butadiene with butadiene-derived popcorn polymer

Adiabatic calorimetry performed on butadiene-derived popcorn polymer samples from industrial facilities has revealed exothermic behavior accompanied by non-condensible gas production, indicative of possible decomposition, at elevated temperatures. In the presence of low concentrations of 1,3-butadiene, reactivity is observed at temperatures of 60-70 degrees C; that is, 20-30 degrees C below those usually seen for butadiene alone. Once the butadiene is consumed, the reaction behavior reverts to that of the popcorn polymer alone. At higher butadiene concentrations, the low temperature reaction persists, eventually merging with typical butadiene behavior. The butadiene reactivity with popcorn polymer is attributed to polymerization reaction at free radical sites in the popcorn polymer. Different popcorn polymer samples exhibit distinct extents of reactivity, presumably depending on the nature and concentration of the free radical sites and the structure of the material. Uninhibited butadiene exposed to 100 psia air, which may act to generate peroxide species, shows a small, additional exotherm around 50-80 degrees C. Contact of butadiene with lauroyl peroxide, providing free radicals upon decomposition, generates an exotherm at temperatures as low as 60 degrees C.