Hydrated Lime Manufacturing Process

Lime is the high-temperature product of the calcination of limestone. Although limestone deposits are found in every state, only a small portion is pure enough for industrial lime manufacturing. To be classified as limestone, the rock must contain at least 50 percent calcium carbonate.

The controlled slaking of quicklime with water gives us white dry powder then the released heat of reaction is captured & the extra slaking water is evaporated. The chemical formula of our pure hydrated lime is Ca(OH)2. It is extensively used in various industrial and chemical applications. The hydrated lime powder manufactured by us is considered to be the best chemical reagent and so it is widely used in various specialty chemical applications. Here we take a look at the main production process of hydrated lime.

The heart of a lime plant is the kiln. The prevalent type of kiln is the rotary kiln, accounting for about 90 percent of all lime production in the United States. This kiln is a long, cylindrical, slightly inclined, refractory-lined furnace, through which the limestone and hot combustion gases pass countercurrently. Coal,oil, and natural gas may all be fired in rotary kilns. Product coolers and kiln feed preheaters of various types are commonly used to recover heat from the hot lime product and hot exhaust gases, respectively.

Lime is manufactured in various kinds of kilns by one of the following reactions:

CaCO + heat → CO2 + CaO (high calcium lime)

CaCO3 + MgCO3 + heat → 2CO2+ CaO + MgO (dolomitic lime)

The resulting lime is reacted (slaked) with water to form hydrated lime. The basic processes in the production of lime are:

  1. quarrying raw limestone;
  2. preparing limestone for the kilns by crushing and sizing;
  3. calcining limestone;
  4. processing the lime further by hydrating;
  5. miscellaneous transfer, storage, and handling operations.

In addition,the lime making process consists of the burning of calcium or magnesium carbonates to liberate carbon dioxide and to obtain the derived oxide. The calcium oxide product from the kiln is generally crushed, milled and/or screened before being conveyed to silo storage. From the silo, the burned lime is either delivered to the end user for use in the form of quicklime, or transferred to a hydrating plant where it is reacted with water to produce slaked lime.

A flow chart for a hydrated lime manufacturing process:

 hydrated lime manufacturing process