ASTM D4517用无焰原子吸收光谱法测量高纯度水中低量硅总量的标准试验方法

ASTM D4517 Standard Test Method for Low-Level Total Silica in High-Purity Water by Flameless Atomic Absorption Spectroscopy
ASTM D4517用无焰原子吸收光谱法测量高纯度水中低量硅总量的标准试验方法

Control of silica in boiler feedwater and boiler water is necessary to minimize the formation of scale-forming silicates that decrease heat transfer in the boiler. Volatilization and carryover of silica with the steam may cause hard, glassy siliceous deposits to form on turbine blades that reduce turbine efficiency.

Colloidal silica that is not removed by boiler water pretreatment processes may be solubilized in the boiler and thus contribute to the dissolved silica concentration in the boiler. Both dissolved and total silica are of interest.

1. Scope
1.1 This test method covers the determination of total silica in water.

1.2 This test method is applicable in the range from 25 to 250 μg/L of silica as SiO2. Higher concentrations may be determined by decreasing the aliquot volume (see Note 6). Concentration range should not be extended by dilution.

1.3 This test method determines total silica, and does not distinguish between soluble and insoluble forms.

1.4 This test method was tested on reagent water only. It is the user's responsibility to assure the validity of the test method for waters of other matrices.

1.5 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents (purchase separately)
ASTM Standards
ASTM D859 Test Method for Silica in Water
ASTM D1066 Practice for Sampling Steam
ASTM D1129 Terminology Relating to Water
ASTM D1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits
ASTM D1193 Specification for Reagent Water
ASTM D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
ASTM D3370 Practices for Sampling Water from Closed Conduits
ASTM D3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
ASTM D4453 Practice for Handling of Ultra-Pure Water Samples
ASTM D5810 Guide for Spiking into Aqueous Samples
ASTM D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis

Index Terms
atomic spectroscopy; boiler water; graphite furnace; high-purity water; silica; Colloidal dispersions; High-purity water; Inorganic compounds--water; Silica content; Spectroscopy--atomic absorption;

更多防火阻燃测试认证，请咨询中国防火网
电话：400-666-7290
网址：www.firete.com
邮箱：info@firete.com

...

 来源：防火网　发布时间：11/4/2013 点击次数：2001