How is calcium hydroxide produced

Calcium hydroxide,as an important inorganic compound,has indispensable applications in many fields such as construction,environmental protection,chemical industry,agriculture,etc.Calcium hydroxide is produced using a calcium hydroxide production line,a complete production line that converts raw materials into high-quality calcium hydroxide products through a series of process flows and advanced equipment.

The main raw material for the production of calcium hydroxide is limestone,which directly affects the quality of the product.Excellent limestone should have a high content of calcium carbonate,usually requiring a calcium carbonate content of over 90%.At the same time,the content of impurities such as silica,alumina,iron oxide,etc.should be controlled,as these impurities may affect the activity,purity,and whiteness of calcium hydroxide.

The selected limestone needs to be crushed and screened.Firstly,a jaw crusher is used to crush large limestone into smaller particles,typically ranging from 100-300mm in size.Then,the crushed limestone is sieved through a vibrating screen to remove particles that do not meet the particle size requirements,ensuring that the limestone entering the next process has uniform particle size and meets the calcination requirements.The suitable particle size range is usually between 50-150mm.
Calcination is a key process in the production of calcium hydroxide,and commonly used equipment includes vertical kilns and rotary kilns.Vertical kiln is a traditional calcination equipment with a simple structure and low investment cost,but relatively low thermal efficiency and limited production capacity,suitable for small-scale production.Rotary kilns have the advantages of high production capacity,high thermal efficiency,and uniform product quality.They can control the calcination process and are the primary equipment for large-scale production of calcium hydroxide.

The quicklime from the lime kiln enters the digester for digestion reaction.Common digestive systems include trough digesters and rotary digesters.The trough digester has a simple structure and easy operation,but the digestion time is relatively long and the digestion effect is not very uniform;Rotary digesters have the advantages of fast digestion speed and even digestion,which can better control the reaction process and improve product quality.

In the digester,an appropriate amount of water is added to the quicklime,which undergoes a violent exothermic reaction with water to produce calcium hydroxide.The amount of water added is one of the important factors affecting the quality of the product.Generally,the mass ratio of quicklime to water is 1:3-1:5.If there is insufficient water addition,the quicklime cannot be completely digested,and there will be a large amount of quicklime residue in the product,which will affect the purity and activity of the product;If too much water is added,it will cause the calcium hydroxide slurry to become too dilute,increasing the subsequent dehydration cost.
Due to the digestion reaction releasing a large amount of heat,the reaction temperature increases.Excessive temperature can affect the crystallization process of calcium hydroxide,resulting in coarse product particles and reduced activity.Therefore,appropriate cooling measures need to be taken during the digestion process,such as using jacket cooling or external circulation cooling,to control the reaction temperature at 60-80℃.At the same time,it is necessary to control the digestion time,which is generally 15-30 minutes,to ensure that the quicklime is fully digested.
The crushed calcium hydroxide powder is packaged by an automatic packaging machine,usually using plastic woven bags or paper bags.The packaging specifications are determined according to customer needs,and common ones include 25kg/bag,50kg/bag,etc.During the packaging process,it is important to ensure that the packaging is tightly sealed,

The production process of calcium hydroxide involves high temperature,high pressure,and strong alkaline substances,which pose certain safety risks.Therefore,it is necessary to equip production personnel with necessary personal protective equipment,such as safety goggles,protective gloves,protective clothing,etc.At the same time,clear safety warning signs should be set up on the production site,and safety training for production personnel should be strengthened to enhance safety awareness and ensure the safe operation of the production process.

A complete calcium hydroxide production line converts limestone into high-quality calcium hydroxide products through a series of processes including raw material preparation,limestone calcination,quicklime digestion,product post-treatment,and environmental and safety measures.With the continuous advancement of technology and the increasing demand for environmental protection,the calcium hydroxide production line is also constantly optimized and upgraded to improve production efficiency,product quality,and environmental protection level.