Determine whether the quality of quicklime is qualified

Judging whether the quality of quicklime is qualified can be done from the following aspects:

1、 Appearance inspection

1. Color: Qualified quicklime is usually white or off white in color. If the color turns yellow, black, or has other abnormal colors, it may be due to impurities or insufficient calcination.

2. Block size: Quicklime generally exists in block form. Qualified quicklime blocks should have a relatively uniform size and should not have lumps that are too large or too small. If there is a significant difference in the size of the blocks, it may affect the effectiveness of use.

3. Hardness: Gently press the quicklime block with your hand. Qualified quicklime blocks should have a certain hardness and be not easily broken. If the quicklime blocks are easily broken, it may be caused by excessive calcination or improper storage.

2、 Chemical composition analysis

1. Calcium oxide content: Calcium oxide is the main component of quicklime, and its content directly determines the quality of quicklime. Generally speaking, qualified quicklime should have a calcium oxide content of over 90%. The content of calcium oxide can be accurately determined through chemical analysis methods such as titration, atomic absorption spectroscopy, etc.

2. Magnesium oxide content: Magnesium oxide is an impurity component in quicklime, and its high content can affect the quality of quicklime. The magnesium oxide content in qualified quicklime should be below 5%. The content of magnesium oxide can also be determined by chemical analysis methods.

3. Other impurity content: In addition to magnesium oxide, quicklime may also contain small amounts of impurities such as silicon, aluminum, and iron. The content of these impurities should also be controlled within a certain range to ensure the quality of quicklime. The content of other impurities can be determined by chemical analysis methods or X-ray fluorescence spectroscopy.

3、 Activity testing

1. Definition: The activity of quicklime refers to the rate and degree of reaction between quicklime and water. The higher the activity, the faster the reaction between quicklime and water, the more calcium hydroxide is generated, and the better the quality.

2. Detection method: Hydrochloric acid titration is usually used to detect the activity of quicklime. Mix a certain amount of quicklime sample with water, then titrate with hydrochloric acid standard solution, and calculate the activity of quicklime based on the amount of hydrochloric acid consumed. The qualified activity of quicklime is generally above 300ml/4N HCl.

4、 Determination of digestion time

1. Definition: Digestion time refers to the time required for complete digestion of quicklime mixed with water. The shorter the digestion time, the better the quality of quicklime.

2. Testing method: Mix a certain amount of quicklime sample with water and observe its digestion process. You can use a stopwatch to record the time from mixing to complete digestion. The qualified lime digestion time is generally within 5-10 minutes.

5、 Packaging and Storage

1. Packaging: Qualified quicklime should be packaged with sealed and moisture-proof packaging materials to prevent it from absorbing moisture and carbon dioxide from the air and deteriorating. The packaging should indicate the product name, specifications, production date, manufacturer, and other information.

2. Storage: Lime should be stored in a dry and ventilated warehouse, away from sources of fire and flammable materials. During storage, attention should be paid to moisture and rain prevention, and contact with substances that react with quicklime should be avoided. If the packaging of quicklime is damaged or the storage conditions are improper, it may affect its quality.