Our customer service department answers many questions regarding our lime products for all the industries we serve. The questions range from lime applications and use to storage, shipping and handling. As a resource to our customers and website viewers, the listing below represents the most frequently asked questions.
Can I store the lime outside?
No, quicklime products are very hydroscopic and can react with the moisture in the air. Quicklime products should be stored in silos or at a minimum under roof.
What is the shelf life of lime products in a storage tank?
Quicklime products should be stored in silos or at a minimum under roof. Shelf life depends on the amount of exposure to air and the elements. Products stored in moisture proof silos can last several months or more if air infiltration can be kept to a minimum.
How many types of lime are there? I am confused by terms like “agricultural lime”, “quicklime”, slaked lime, hydrated lime. Are these all the same?
There are several types of products that are referred to as “lime.” Most lime is the natural chemical oxide (CaO), which is commonly referred to as lime, quicklime or burned lime. The name quicklime comes from an old meaning of “quick” as in alive or lively, since quicklime reacts vigorously with water. The name burned lime is used because quicklime is produced by burning limestone quarried or mined from the earth. Quicklime resembles white pebbles and is usually produced in sizes ranging from 1-3/4 inch to 1/8 inch.Agricultural lime is usually ground limestone, which is the natural chemical calcium carbonate (CaCO3). Another type of quicklime is dolomitic lime, which contains about 40% magnesium oxide (MgO) in addition to calcium oxide. Slaked lime, hydrated lime and hydrate refer to products formed from reaction of quicklime with water. Quicklime reacts with water to form calcium hydroxide [Ca(OH)2]. Slaked lime is a fluid mixture of calcium hydroxide and water formed by mixing 1 part of quicklime with about 4 parts of water. Users of lime usually produce this mixture themselves in equipment called lime slakers. Slaked lime resembles a milk shake and is sometimes called “milk of lime.” Hydrated lime or hydrate is a dry powder of calcium hydroxide formed by mixing 1 part of quicklime with ½ part of water. Hydrated lime is produced at lime manufacturing plants and shipped to users in bags or in bulk trucks. Hydrated lime resembles talcum powder.
What precautions should I take in handling quicklime or hydrated lime?
Quicklime and hydrated lime are both reactive natural chemicals, and like any chemical have (MSDS) Material Safety Data Sheets that should be referred to prior to use. An MSDS sheet for quicklime and hydrated lime can be obtained in our products listing.
What test methods are available to determine quality of lime and lime-based products?
The two most widely used test methods are from the American Society of Testing and Materials (ASTM) and the American Water Works Association (AWWA). The ASTM Annual Book of Standards Volume 04.01 Cement; Lime; Gypsum is available for purchase from ASTM at www.astm.org. Methods for chemical analysis of lime and lime products are found in method C 25. Physical methods are found in method C 110. The AWWA standard B202-93: Quicklime and Hydrated Lime is available for purchase from AWWA at www.awwa.org
What are some of the typical impurities found in limestone and lime products?
Impurities in limestone are a function of the geology of the ore body. They consist of elements within the limestone matrix and other non-limestone materials (“inerts”) that may have been mined along with the limestone. Some common ranges of impurities in typical limestones are:
Can I purchase lime already in slurry form to avoid having to purchase, operate, and maintain slaking and slurry making equipment?
Ready made lime slurry products (Milk of Lime) are available from Carmeuse under the product name “Aquacal” from certain production locations. We would be pleased to hear from you regarding your Aquacal requirements.
Should I use quicklime, hydrated lime or Milk of Lime?
This will depend on factors like whether you already have good reliable storage and handling equipment, the quantity of lime you require, and the amount of labor available to manage the process.Milk of lime is delivered as a ready-made slurry requiring only a slurry storage system. No storage silos or slaking equipment is needed. This product has the highest direct cost, but no costs associated with silo storage and slaking. After that hydrated lime then quicklime reduce in overall product cost, but increase in handling costs.
Where can I find information on physical and chemical properties of lime, bulk handling and storage of lime in bins and silos, solutions to common lime handling and flow problems, and descriptions of lime slaking equipment and lime slurry feeding systems?
An excellent guide to solutions on lime handling, storage, and usage is the booklet Lime: Handling, Application, and Storage, available from Carmeuse Lime & Stone. To purchase a copy of the guide go to the publication library available at the The National Lime Association website www.lime.org
