Limestone powder, commonly referred to as stone powder, is a fine, white or off-white material produced by grinding high-quality natural limestone. It primarily consists of calcium carbonate (CaCO3), with a calcium content exceeding 35%, making it one of the most cost-effective and accessible sources of calcium for various applications. When heated at high temperatures, limestone transforms into calcium oxide (CaO), also known as quicklime. This compound can then be mixed with water to form lime milk, which reacts with carbon dioxide to produce precipitated calcium carbonate—a high-purity, fine, and lightweight form of calcium carbonate.
This product typically contains over 95% calcium carbonate, with calcium levels ranging from 34% to 38%, depending on the geological conditions of the original limestone. On a dry matter basis, the composition of limestone powder includes approximately 96.9% ash, 35.89% calcium, 0.03% chlorine, 0.35% iron, 0.027% manganese, and 0.06% magnesium. In addition to being a valuable calcium source, limestone powder is widely used as a filler or carrier in premixes for trace elements in Animal Feed.
Natural limestone can be safely used in feed if the levels of harmful substances like lead, mercury, arsenic, and fluorine remain within acceptable limits. However, some limestones may contain elevated concentrations of toxic elements, making them unsuitable for use in animal nutrition. For feed-grade limestone, the magnesium content should not exceed 0.5%, and heavy metals such as arsenic must be strictly controlled. The appropriate dosage of limestone powder varies depending on the type of livestock and their growth stage. In general, it is included in compound feeds at 0.5% to 2%, while layer hens and breeding chickens may require up to 7% to 7.5%. Excessive use can reduce the digestibility of organic nutrients and may cause kidney damage in young poultry, leading to urate buildup, inflammation, or even kidney stones. In laying hens, too much limestone powder can result in thin, uneven layers on the eggshell, affecting the quality and passage rate of eggs. It is recommended to combine limestone powder with organic calcium sources like shell powder in a 1:1 ratio for better absorption and performance.
The particle size of limestone powder is important for its effectiveness. For pigs, a medium particle size between 26 and 36 mesh is usually preferred, while for birds, 26 to 28 mesh is ideal. Coarser particles are particularly beneficial for laying hens, as they help maintain stable blood calcium levels and support strong eggshell formation, thus reducing breakage. However, very coarse particles may affect the uniformity of feed mixing. Limestone is processed into calcium oxide through high-temperature calcination, and then converted into calcium carbonate via reaction with carbon dioxide, resulting in a product known as precipitated calcium carbonate. According to China's national standards, this product, produced using a dry precipitation method, is characterized by its small, light particles, low impurities, and high calcium carbonate content—typically over 95%, with more than 38% elemental calcium. It is considered a premium calcium supplement in feed formulations.
Animal Feed
Animal Feed,Animal Feed Additives,Offer Feed Additives,Livestock Feed Additives
Animal Feed,Animal Feed Additives,Offer Feed Additives,Livestock Feed Additives
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