All Categories
History
This section provides an overview for apha (hazen unit color numbers) as well as their applications and principles. Also, please take a look at the list of 0 apha (hazen unit color number) manufacturers and their company rankings.
Table of Contents
Categories Related to APHA (Hazen Unit Color Numbers)
APHA color, also known as the Hazen scale, is a measure of color intensity in liquid chemical products at room temperature, or in chemically produced products that become molten when heated. This scale is widely applicable to solvents, petroleum products, plasticizers, and chemical raw materials.
The APHA color scale assigns a value of 1 to a solution containing 1 milligram of platinum in the form of hexachloroplatinate ions and 2 milligrams of cobalt chloride (II) hexahydrate per liter. Originating from the American Public Health Association, this scale was initially developed for wastewater color measurement but now extends to broader industrial applications. It's often referred to as the “yellowing index,” evaluating the quality of liquid substances from transparent to slightly yellow.
APHA color is utilized for assessing the coloration of liquid chemical products at room temperature and those that melt when heated. It's a critical quality control tool in various industries to ensure consistency in product appearance.
APHA color measurement involves visually comparing a sample's color with that of standardized Hazen color comparison solutions. These solutions are prepared from a standard stock solution (Hazen color number 500), which is created by dissolving specific amounts of hexachloroplatinic acid potassium and cobalt chloride (II) hexahydrate in a hydrochloric acid solution. The Hazen color number is determined based on the proportion of the standard stock solution in the prepared liquid.
For measurement, liquid samples are placed in comparison tubes and visually compared against standard color tubes, using white light. Solid samples are melted and compared similarly. The Hazen color number is identified by the closest match to the standard color solutions. These solutions, when stored properly, remain stable for up to a year, ensuring reliable measurements over time.
While traditional APHA color measurement relies on visual assessment, variations among individuals can impact accuracy. To overcome this, spectrophotometers are used for more precise measurements. These devices analyze the light absorbance of the sample, providing quantifiable color information.
Spectrophotometers designed for APHA color measurements come with pre-registered calibration curves, enabling color number determination without standard comparison solutions. Although transitioning from visual to spectrophotometric methods might raise concerns about continuity, registering calibration curves from previous measurements can address this issue, maintaining consistent and accurate color assessments.
*Including some distributors, etc.
Sort by Features
Number of Employees
Newly Established Company
Company with a History
