Cooling treatment

Phenylhydrazine may be prepared by reducing phenyldiazonium chloride solution with excess of warm sodium sulphite solution, followed by acidification with hydrochloric acid, when the hydrochloride crystallises out on cooling. Treatment of the latter with excess of sodium hydroxide solution liberates the free base. The reaction is believed to proceed through the following stages —... 

In the fast cooling method, two different samples were heated and cooled very rapidly. The first was B2 (same composition in powder lamination method) the second was B4, obtained from B2 by sintering in an A1N BN powder bed. The surface of B2 was ground until 70% P-SiAlON was obtained before fast cooling treatment. Then, the specimens were inserted in a furnace with high-speed cooling. They were heated to 1600°C at a rate of 15°C/min and cooled rapidly by immediate removal from the furnace. 

A still further purification of the rhodium is effected 3 by fusing the metal obtained in the preceding manner to dull redness with metallic zinc, whereby the compound RhZn2 is formed, with considerable heat evolution, a portion of the zinc being volatilised. On cooling, treatment of the mass with concentrated hydrochloric acid effects the solution of the excess of zinc, the insoluble crystalline alloy remaining unaffected. 

The needles shown in Fig. 10-3a were subjected to this heat-cool treatment resulting in the large three-dimensional crystals shown in Fig. 10-3b. Success in growing seed crystals both prepares seed for larger batches and establishes that this compound will actuaUy grow. It is then necessary to determine if it will grow at a practical rate in the actual reactive crystallization system. 

Make-up propylene, in a purity higher than 90 per cent volume and with a propane content lower than 4.5 per cent volume, is first vaporized by heat exchange with the hot effluents issuing from subsequent cooling treatment Steam and air are then added to it so that the final mixture contains an average of 4 to 5 per cent volume of propylene, 30 to 40 per cent volume water, and 55 to 65 per cent volume air. It is then raised to the requisite temperature by countercurrent contact with the effluent coming from the first step of the reaction. 

Irrigated Treatment Drought-Heated Treatment Drought Treatment Drought-Cooled Treatment //I Drought-Cooled Treatment 2 Drought-Cooled Treatment 3... 

Hj-the enthalpy of incoming air flow after cooling treatment... 

Rochas (1982) obtained the sol-gel transition diagram of the potassium salt of K-carrageenan using polarimetry and ionic conductivity during heating and cooling treatments. The diagram shows the relationship between the total ionic concentration and the inverse of the... 

Solution treatment conditions depend on subsequent product application. When cold formabil-ity is required, the material should be solution treated just above the p transus (785 °C, or 1450 °F). Tb obtain a better combination of strength and ductility after aging, the material should be solution treated at 735 °C (1350 °F) for 0.5 to 1 h. Water quenching is preferable as a cooling treatment after solution treating. 

During the subsequent cooling treatment a similar hysteresis is observed as in the recrystallized case. Below 740K the atomic mohity is essentially reduced and the changes of resistivity freeze at about 700K. 

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