National Academies Press: OpenBook

Water Chemicals Codex (1982)

Chapter: Calcium Oxide (Lime, Quicklime)

« Previous: Calcium Hypochlorite
Suggested Citation:"Calcium Oxide (Lime, Quicklime)." Institute of Medicine and National Research Council. 1982. Water Chemicals Codex. Washington, DC: The National Academies Press. doi: 10.17226/159.
×
Page 20
Suggested Citation:"Calcium Oxide (Lime, Quicklime)." Institute of Medicine and National Research Council. 1982. Water Chemicals Codex. Washington, DC: The National Academies Press. doi: 10.17226/159.
×
Page 21
Suggested Citation:"Calcium Oxide (Lime, Quicklime)." Institute of Medicine and National Research Council. 1982. Water Chemicals Codex. Washington, DC: The National Academies Press. doi: 10.17226/159.
×
Page 22

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

20 Name: CALCIUM OXIDE (LIME, QUICKLIME) CAS No.: 1305-78-8 Chemical Formula CaO — Description: NAS/CWTC 007-82 Formula Weight: 56.0 Hard, white or grayish-white porous pebble or powder, odorless, and quick slaking. Solubility in water: 1 g/840 ml at 25°C, 1 g/1,740 ml at 100°C. Soluble in glycerin, but insoluble in alcohol. Used primarily as a softening agent and for pH adjust- ments. Purity Requirements: The RMIC values are based on a maximum dosage of 500 mg of calcium oxide/liter of water and are to be compared to impurity concentrations obtained by using sample proce- dures described in this monograph. If the actual dosage is other than 500 mg/liter, the user is cautioned to consult Table 2 for appropriate RMIC values. Impurity Arsenic Cadmium Chromium Fluoride Lead Selenium Silver RMIC mg Impurity/kg Calcium Oxide 10 2 10 * 10 10 *A RMIC has not been established for fluoride. All producers of calcium oxide must analyze and state the concentration of fluoride in the calcium oxide produced.

21 Bulk Sample Collection: Sample in accordance with Standard for Lime, AWWA B202-77, American Water Works Association, Denver, Colorado (1977), except store final 2-lb sample in moistureproof glass. Analytical Sample Preparation: Crush about half of the 2-lb sample so that it passes a No. 6 U.S. standard sieve, preferably using a nonmetallic crusher or a glass mortar and pestle. Mix crushed sample thoroughly and place in an airtight moistureproof glass container. Take a 50-g portion of the crushed sample and pulverize using a nonmetallic pulverizer or a glass mortar and pestle until sample passes a No. 100 U.S. standard sieve. Mix pulverized sample thoroughly and place in an airtight moistureproof glass container. Initial Slaking: Pipette 4 ml of deionized distilled water in a 150-ml beaker. Place on a hot plate at a low heat and bring water to approximately 60°C. Place stirring rod in beaker and add 1 g pulverized calcium oxide slowly while stirring. If necessary, remove beaker from hot plate momentarily to control spattering. Mix slurry thoroughly to include all the pulverized lime. When a smooth paste is obtained, remove beaker from hot plate and slowly add 50 ml of 80°C deionized distilled water while stirring. Cool to room temperature. Filter through GF/C filter under vacuum into a 150-ml beaker. Using a 25-ml burette, add 1+4 HNO3 until the pH remains between 1.8 and 2.0 for 5 minutes. Transfer quantitatively into a 1,000-ml volumetric flask and dilute to volume with nitric acid dilution solution. Analytical Sample PreParation--Fluoride: Weigh 10 g of sample (to the nearest milligram) into a 400-ml beaker. Rehydrate the lime by slowly and care- fully adding up to 250 ml of deionized water. Place 400 ml of deionized distilled water into a 1-liter side-arm distilling flask. Carefully add 200 ml of concentrated sulfuric acid. Swirl until contents are homogeneous

22 (essential for safety during distillation). Add 25-35 glass boiling beads. Begin heating, slowly at first, until the temperature of the flask contents reaches 180°C. Discard the distillate. Cool the acid mixture. Quantita- tively transfer the lime suspension (carefully) to the distilling flask until all the slurry has been transferred along with 300 + 5 ml of water (i.e., sample contained in 300 ml of water). If there is reason to suspect presence of chlorides in sample, add 5 mg of silver sulfate for every milligram of chloride. Distill until flask tempera- ture again reaches 180°C. Determine fluoride in the distillate. Sample Analyses: The analyses are to be performed on the calcium oxide solution in accordance with: Standard Methods for the Examination of Water and Waste- water, 15th Edition, American Public Health Association, Washington, D.C. (1981). Arsenic Cadmium Chromium Fluoride Lead Selenium Silver 304 304 304 413B 304 304 304

Next: Carbon, Activated, Granular »
Water Chemicals Codex Get This Book
×
Buy Paperback | $45.00
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF
  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!