The results show that when the cooling rate is 0.05—0.055 ℃/min,the crystallization time is 460—500 min,the final temperature is 58—62 ℃,and the sweating temperature is 82—83 ℃,the nitrochlorobenzene that contains PNCB 89.310/0 is separated optimally;
The yield of sodium metasilicate pentahydrate is approximately 40% under the optimum conditions,the crystallization solution concentration is 7.8～8.4mol/L,the molar ratio of Na 2O to SiO 2 is 1.60～1.70,the crystallization time is 2～6h,and the final crystallization temperature is 25～45℃.
The urea peroxide(UP) was made up of 30%H_2O_2 and urea,the effect of the mole ratio of H_2O_2 to urea,reaction temperature,reaction time,crystallization time,drying temperature and time on the content of H_2O_2 were studied.
the best extracting and crystallizing technology was extracting and crystallizing pressure was 15Mpa,extracting and crystallizing temperature was 45℃,extracting and crystallizing time was 1.0h,entrainer was methanol.
The optimum operating conditions for the two kinds of typical material composition were found out by synthesizing all operation conditions: w(p-NCB)=89.31%,w(m-NCB)=10.69%,cooling rate 0.049 1 ℃/min,crystallizing time 480 min,final temperature 60 ℃;
The study shows that craft conditions:dissolvable temperature is 80～90 ℃,density is 1.37～(1.39 g/cm~(3),)hot fitering temperature≥75 ℃,cooling and crystallizing time 8 h,stirred speed is 50～60 r/min,cold filtering temperature is 18 ℃. Drying temperature is 45 ℃.
The key points for the production of sodium percarbonate are as following:To increase properly the reaction and crystalline temperature,add high-effective stabilizer,select suitable preparation ratio of raw materials,and control the amount of salting out agent and reaction and crystalline time,so that the yield of the product can be increased,the quality of the product improved,the scale of production expanded and the manufacture cost decreased.
By experiment and calculation, the optimum technical conditions for the reaction are as follows: the molar ratio of nitric acid to potassium chloride is 1.5∶1, the time of reaction is 20 minutes, the time of crystallization is 4 hours, the size of potassium chloride is through 160 mesh sieve, the temperature of the reaction is 30 ℃, the concentration of nitric acid is 25 % .
Research on crystallization of hydrate trichloroacetaldehyde was reported. To a mixture of equal molars of trichloroacetaldehyde and water, chloroform was added at temperature of 40℃～50℃, and modifier HS was added at the beginning of crystallization. This shortened the time of crystallization and drying 50%, and yield and purity of product 84% and 99.5%, respectively.
At 468.3 K the half crystallization time (t1/2) of samples freeze-dried from a solution of 1×10-4 g/mL was about 36 s, which was merely one tenth of that of the bulk sample.
The isothermal crystallization time had little effect on the melting temperatures.
The shortening of the melting-crystallization time and phase-transition memory of irradiated samples, which persist for several recrystallization cycles, is found and interpreted theoretically.
It is found that the feed polymer with a wider molecular weight distribution (P-1) is characterized by lower values of the half-crystallization time as compared to the polymer with a narrower molecular weight distribution (P-2).
It was shown that the crystallization time decreases and the eutectic grain scale changes under a field.
This process, labeled MILC-MA, not only lowers the temperature but also reduces the time of crystallization.
The results show that a small change of free energy can significantly increase the crystallization rate, thus the induction time of crystallization decreases rapidly as the shear rate increases.
The time of crystallization of the Massif is 30.3 m.y.
2600 Ma ages date the time of crystallization of igneous garnet in late granitic intrusions.
In West Rhodope, the co-magmatic zircon cores of the amphibolitized eclogite yielded a lower intercept 206Pb/238U age of 245.6±3.9?Ma, which is interpreted as the time of crystallization of the gabbroic protolith.