Quick Drying Silica Sol Colloidal Silica for Surface Layer of Precision Casting

• Customization: Available
• CAS No.: 7631-86-9
• Formula: Nsio2nh2o
• Model NO.: KJN830
• EINECS: 201-173-7
• Classification: Silicon Dioxide
• Grade Standard: Industrial Grade
• Kind: Alkaline Oxide
• Quality: First Class
• Type: Adsorbent
• Colors: Milky White
• Transport Package: Standard Packing
• Specification: 250 kg/d
• Trademark: KEHAN
• Origin: Shandong China
• HS Code: 382410
• Production Capacity: 70000ton/Year

Product Description

KJN Quick Drying Series Silica sol


PRODOUCT PARAMETER

NO.	Series	Type	technical parameter						Stable period (M)
			SiO2%	Density (25ºC,g/cm3)	Na2O%	pH (25ºC)	viscosity (25ºC,mpa.s)	Average particle size(nm)
1	Quick Drying Series silica sol	KJN-830	26~30	1.17~1.20	≤0.5	9.5~10.5	≤9	7~10	6M
2		KJN-1430	28~30	1.18~1.20	≤0.5	9.5~10.5	≤9	10~15	6M
3		KJN-1430-D1	30~32	1.20~1.22	≤0.3	8.5~10	≤15	10~15	6M
Note: Technical parameters can be adjusted and manufactured according to customers'needs.

 

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 Product Features
The quick-drying silica sol is obtained by polymer-modifying the surface of the silica sol, so that the casting shell mold can establish the wet strength in advance, shortening the drying time of the casting shell mold, thereby improving the casting production efficiency.
Since the solvent used in the silica sol is water, the dry gelation hardening time of the silica sol shell is related to the degree of stability damage and the rate of water loss. Therefore, the gelation hardening mechanism of the quick-drying silica sol shell is as follows:
First, when the slurry is prepared, the quartz powder or the mullite powder impacts the space network structure of the high molecular molecule, the adsorption of the polymer molecules from the particles, the adsorption layer of the fast-drying silica sol is destroyed, and the colloidal reaction occurs. Produces a very strong gel and moisture. which is:
mSiO2·nH2O→mSiO2·(n-1)H2O+H2O
Second, the desorbed polymer molecules are re-joined together to form a thin layer of high polymer film with cohesiveness. In addition, controlling the humidity and wind speed of the environment, the quick-drying silica sol shell and the silica sol shell also form a humidity gradient with a high inside and outside, and the water accelerates and evaporates, and the gelation hardening time is shortened.
Conditions for use of quick-drying silica sol:
1. This product does not need to change the shell making process during the use process. The requirements for the selection of precision casting powder, coating ratio, temperature and humidity of the shell workshop are similar to those of ordinary silica sol.
 2. Under the same process conditions as ordinary silica sol, the interlaminar drying time is about half of that of ordinary silica sol.
 3. The shell has high wet strength, can withstand low humidity and large wind, and has certain anti-dissolution and anti-cracking ability.

Product application field
This series of products is suitable for precision castings that require high precision and fast drying speed in precision casting.