Enhancement of the Dewetability Characteristics of Fine Silica Particles

Ramazan ASMATULU

Makale detayları

Enhancement of the Dewetability Characteristics of Fine Silica Particles

Yazarlar:

Ramazan ASMATULU

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Engineering and Environmental Sciences 2002 Vol.26 Issue 6, pp.513-520

Belge Tipi:

Makale

Yayın Tarihi:

5/2002

Belge Dili:

Türkçe

Document ID (Org No.):

2000745159

Sıklık:

Üç Yıllık

eISSN:

1303-6157

pISSN:

1300-0160

Özet:

 

The dewatering of fine particles is the most difficult part of fine  particle processing in preparation plants.  The difficulty is due to  the fact that fine particles have a higher specific surface area  than coarse particles.  For this reason, the currently used dewatering  techniques (i.e., vacuum, pressure and centrifugal filters) cannot  produce a desired moisture content of a filter cake that can be  directly used in markets; therefore, most filter cakes are fed to  thermal dryers.  Thermal drying is costly, and creates  environmental pollution where the operation is located.    In the present study, dewatering tests were conducted on fine size  silica (SiO2) powder in a vacuum filter using different  chemicals.  These include electrolytes, dodecylamine and a  hydrophobizing agent.  The test results showed that the electrolytes  neutralized the particle surface charge in an aqueous medium and  coagulated the suspension, which should assist moisture reduction of  the particles.  The dodecylamine made the particle surface slightly  hydrophobic at pH 9.5 in order to adsorb the hydrophobizing agent on  the fine silica surfaces.  Afterwards, the particle surface became  super hydrophobic; for example, the contact angle of the silica powder was  improved from 44° to 89°, which was determined  using  the newly developed thin layer wicking method.  As a result, the  moisture content of the filter cake was decreased from 26.3% to 7.4%  at 1.5 cm cake thickness and 85 kPa vacuum pressure.  It was,  therefore, concluded that changing the surface properties of the  silica particles helped lower the dewatering cost of the fine  particles and environmental concerns in plants.

 

The dewatering of fine particles is the most difficult part of fine  particle processing in preparation plants.  The difficulty is due to  the fact that fine particles have a higher specific surface area  than coarse particles.  For this reason, the currently used dewatering  techniques (i.e., vacuum, pressure and centrifugal filters) cannot  produce a desired moisture content of a filter cake that can be  directly used in markets; therefore, most filter cakes are fed to  thermal dryers.  Thermal drying is costly, and creates  environmental pollution where the operation is located.    In the present study, dewatering tests were conducted on fine size  silica (SiO2) powder in a vacuum filter using different  chemicals.  These include electrolytes, dodecylamine and a  hydrophobizing agent.  The test results showed that the electrolytes  neutralized the particle surface charge in an aqueous medium and  coagulated the suspension, which should assist moisture reduction of  the particles.  The dodecylamine made the particle surface slightly  hydrophobic at pH 9.5 in order to adsorb the hydrophobizing agent on  the fine silica surfaces.  Afterwards, the particle surface became  super hydrophobic; for example, the contact angle of the silica powder was  improved from 44° to 89°, which was determined  using  the newly developed thin layer wicking method.  As a result, the  moisture content of the filter cake was decreased from 26.3% to 7.4%  at 1.5 cm cake thickness and 85 kPa vacuum pressure.  It was,  therefore, concluded that changing the surface properties of the  silica particles helped lower the dewatering cost of the fine  particles and environmental concerns in plants.

Makale detayları

Enhancement of the Dewetability Characteristics of Fine Silica Particles

Yazarlar: Ramazan ASMATULU

Yayıncı: TUBITAK

Dergi: Turkish Journal of Engineering and Environmental Sciences 2002 Vol.26 Issue 6, pp.513-520

Belge Tipi: Makale

Yayın Tarihi: 5/2002

Belge Dili: Türkçe

Document ID (Org No.): 2000745159

Sıklık: Üç Yıllık

eISSN: 1303-6157

pISSN: 1300-0160

Sayı

Yazarlar:

Ramazan ASMATULU

Yayıncı:

TUBITAK

Dergi:

Turkish Journal of Engineering and Environmental Sciences 2002 Vol.26 Issue 6, pp.513-520

Belge Tipi:

Makale

Yayın Tarihi:

5/2002

Belge Dili:

Türkçe

Document ID (Org No.):

2000745159

Sıklık:

Üç Yıllık

eISSN:

1303-6157

pISSN:

1300-0160