Final Cement Powder/Liquid Matching

Question 1

cement powder composition

Answer 1

ZnO =90.2%
MgO=8.2%
SiO =1.4%
Bi2O3 =0.1%

Question 2

cement liquid compostion

Answer 2

H3PO4 =38.2%
H2O =36%
H3PO4 (with Al and Zn) =16.2%
Zn = 7.1%
Al =2.5%

Question 3

powder production?

Answer 3

components heated for 4-8 hrs at 1300 degrees C to fuse them. sintering processs reduced reactivity of powder (important for manipulation). sintered mass is ground, pulverized, and sieved to desired size

Question 4

particle size of powder is important for controlling?

Answer 4

setting rate; smaller particle sizes generally accelerate the set of the cement

Question 5

ZnO in powder does?

Answer 5

unreacted particles form the reinforceing phase of the cement

Question 6

MgO in powder

Answer 6

condenses the ZnO during the sintering process

Question 7

SiO2 in powder

Answer 7

acts as an inactive filler

Question 8

Bi2O3 in powder

Answer 8

imparts smoothness to the newly mixed cement

Question 9

H3PO4 is a ______ acid

Answer 9

free acid in liquid cement

Question 10

H2O in liquid cement

Answer 10

controls ionization of the liquid

Question 11

Al and Zn do what in liquid cement?

Answer 11

act as buffers or partial neutralizing agents to reduce reactivity of the liquid with the powder