Sapphire (Sapphire) crystal – the most hard oxide crystal|Sapphire (Sapphire) crystal – the most hard oxide crystal

sapphire (Sapphire) crystal – the most hard oxide crystal, is the most basic form of alumina (Al2O3) single crystal. It has a series of excellent physical and chemical properties such as strength, high hardness, high temperature resistance, abrasion resistance, corrosion resistance, good light transmission performance, excellent electrical insulation performance and so on. Therefore, it can be widely used in the fields of national defense, scientific research, civil industry and so on.  

lattice structure:

;  

six party system

;  

unit cell parameters:

; &nbspA=4.785Å

;     c=12.991Å

Melting point:  

2045;

;  

density:  

3.98g/cm3

Mohs hardness:  

;

coefficient of thermal expansion:

; &nbsp5.8×

; 10  -6  /K 

specific heat:

; &nbsp0.418W.s/g/k 

;

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Reactor failure phenomena, causes and elimination methods|Reactor failure phenomena, causes and elimination methods

  phenomenon: the kettle cover, the kettle body sealing surface leakage.

;

 

reason: main nut loose; sealing surface damage.

;

 

elimination method: the main nut is tightened; trimming and polishing sealing surface.

;

  phenomenon: leakage of the valve or connection.

;

 

reason: valve pin, valve sealing surface damage, screw loose.

;

 

elimination method: grinding valve needle, valve port or replace the valve, tighten the screws.

   

; phenomenon: mixing abnormal noise.

;

 

: motor magnet absorbing foreign body.

;

 

exclusion method: open the case to clean up the foreign body.

Reaction material — sodium hydroxide (NaOH) characteristics|Reaction material — sodium hydroxide (NaOH) characteristics

sodium hydroxide (NaOH), commonly known as caustic soda, caustic soda, caustic soda, with another name caustic  soda in Hongkong known as caustic soda, room temperature is a white crystal, with strong corrosion resistance. Soluble in water, its water solution is alkaline, can make phenolphthalein red. Sodium hydroxide is a very common alkali, is one of the essential drugs in the chemical laboratory. Sodium hydroxide in the air easy to absorb water vapor seal to save it must be, and to use the rubber stopper. Its solution can be used as a washing liquid.

shape

molten white particles or strips, are often made of small flakes. Easy to absorb moisture and carbon dioxide in the air. 1g soluble in 0.9ml cold water, 0.3ml boiling water, 7.2ml ethanol, 4.2ml methanol, soluble in glycerol. It is soluble in water, alcohol, or a series of hot. Solution is strongly alkaline. Relative density 2.13. Melting point 318. Boiling point 1390. Half lethal dose (mouse, abdominal) 40mg/kg. Corrosive property. The solution has astringent and greasy feeling.

;   storage

sealed dry preservation.

;  

(that is, can not be placed on the open. The air contains water vapor (H2O), carbon dioxide (CO2), and NaOH water vapor easily deliquescence, easy to react with carbon dioxide to generate sodium carbonate (Na2CO3),  

will deteriorate;

chemical equation for 2NaOH+CO2, Na2CO3+H2O,,  

uses

is widely used in sewage treatment agent, basic analytical reagent, preparation of a standard alkali and a small amount of carbon dioxide and water absorbent, acid and salt making. The manufacture of other containing hydroxyl ions reagent; in the paper, printing and dyeing, wastewater treatment, electroplating, chemical drilling has an important purpose; domestic brands: Tianhui licensing, licensing, licensing gold day.

;  

sodium hydroxide is a good catalyst for many organic reactions. One of the most typical is the hydrolysis of esters:   RCOOR’  +  NaOH  RCOONa  +  R’OH   

security measures  

sodium hydroxide

sealed packaging, stored in a cool dry place. And acid, ammonium type, easy (can) fuel storage and transportation.

;  

do not contact with the skin, if the skin (eyes) contact, rinse with flowing water, apply boric acid solution.

;  

if eaten, water gargle, drink milk or egg white (acid harmless food) and require immediate medical attention.

;   treatment method

abandoned sodium hydroxide can not directly into the sewer, you can use acid neutralization, such as hydrochloric acid, sulfuric acid, etc. (chemical equation for   2NaO>