Calcium chloride (CaCl₂) is an inorganic compound with strong hygroscopicity, high solubility, and excellent chemical stability. Among its various specifications, Calcium Chloride 96% (anhydrous) is widely used in industry, agriculture, medicine, and other fields due to its balanced purity and cost-effectiveness. This article will focus on how to achieve the 96% content of anhydrous calcium chloride and its main application scenarios, combining professional production technology and practical application cases to provide a comprehensive introduction.
How to Achieve 96% Content of Anhydrous Calcium Chloride?
The core of preparing anhydrous calcium chloride with 96% content lies in two key links: precision purification to remove impurities and deep dehydration to remove free water. Only by strictly controlling each step of the process can the main content of CaCl₂ reach and stabilize at 96%, while ensuring that the total amount of impurities is controlled within 4%. The specific process is as follows:
1. Raw Material Selection and Pretreatment
High-quality raw materials are the foundation for ensuring product purity. The main raw materials for industrial production of anhydrous calcium chloride are limestone (CaCO₃ ≥ 95%) and industrial hydrochloric acid (concentration 31%). First, the limestone is crushed into small particles and added to the dissolution tank, and then mixed with industrial hydrochloric acid in a ratio of 2.2:1 for a metathesis reaction to generate a crude calcium chloride solution with a concentration of 300–350 g/L. The gas generated during the reaction is sent to a spray tower for harmless treatment to avoid environmental pollution.
2. Precision Purification to Remove Impurities
The crude calcium chloride solution contains a variety of impurities, such as magnesium ions (Mg²⁺), iron ions (Fe³⁺), sulfate ions (SO₄²⁻), and insoluble substances, which need to be removed step by step to ensure the purity of the final product:
- Removal of sulfate ions: Add barium chloride to the crude solution, so that sulfate ions form barium sulfate precipitation, which is then filtered and removed to avoid affecting the purity of calcium chloride.
- Removal of metal impurities: Heat the solution to 70–75℃, add lime milk to adjust the pH value. When the pH is 4.0–4.5, iron ions form ferric hydroxide (Fe(OH)₃) precipitation; when the pH is adjusted to 10.5–11.5, magnesium ions form magnesium hydroxide (Mg(OH)₂) precipitation. After standing and clarification, filter to remove these precipitates.
- Fine adjustment of purity: Introduce carbon dioxide or air into the filtered solution to adjust the pH to 7.5–8.5, so that the excess calcium ions in the solution form calcium carbonate precipitation, which is filtered again to avoid introducing new anions and ensure the stability of the main content.
- Advanced purification (optional for high-stability products): For products that require higher stability, selective ion membrane electrodialysis technology is used to further remove trace impurities. This technology can reduce the content of Mg²⁺ from about 2.5% to less than 0.05%, and the removal rate of sulfate ions is more than 99.5%, making the main content of calcium chloride more stable at 96% or above.
3. Deep Dehydration to Obtain Anhydrous Products
The purified calcium chloride solution still contains a large amount of free water, which needs to be deeply dehydrated to obtain anhydrous calcium chloride. There are two main industrial dehydration methods:
- Spray drying dehydration: The purified neutral calcium chloride solution is sprayed into fine mist through a sprayer, and contacted with hot air at 300–450℃ in countercurrent. The water in the mist is quickly evaporated, and the solid powder obtained is anhydrous calcium chloride. This method has the advantages of fast drying speed and uniform product particle size, which is suitable for large-scale industrial production.
- Dehydration of dihydrate calcium chloride: First, the purified solution is evaporated and crystallized to obtain dihydrate calcium chloride (CaCl₂·2H₂O), and then heated to 200–300℃ (the key temperature is not lower than 260℃) for continuous drying and dehydration. The dihydrate calcium chloride loses crystal water and is converted into white porous anhydrous calcium chloride. This method is suitable for small and medium-sized production and can effectively control the moisture content of the product.
4. Quality Inspection and Control
After the production is completed, strict quality inspection is carried out to ensure that the content of CaCl₂ reaches ≥96%. The main inspection indicators include: main content of calcium chloride (detected by complexometric titration or argentometric titration), water insoluble matter, metal ion content (Mg²⁺, Fe³⁺, etc.), and moisture content. Only products that meet the standards can leave the factory. At the same time, during the storage and transportation process, sealed packaging is adopted to avoid moisture absorption and reduce the content of calcium chloride due to water absorption.
Main Applications of Calcium Chloride 96% (Anhydrous)：
Calcium Chloride 96% (anhydrous) has a wide range of applications due to its strong hygroscopicity, low freezing point, and excellent chemical properties. It involves many fields such as industry, agriculture, medicine, and environmental protection, and has become an indispensable chemical product in production and life. The specific applications are as follows:
1. Industrial Desiccant and Dehydrating Agent
Due to its strong hygroscopicity, Calcium Chloride 96% is an excellent industrial desiccant, which can be used to dry various gases (such as nitrogen, oxygen, hydrogen, hydrochloric acid gas, sulfur dioxide, etc.) to remove trace moisture in the gas and ensure the purity of the gas. At the same time, it can also be used as a dehydrating agent in organic synthesis, such as dehydrating alcohols, esters, ethers, and acrylic resins, to improve the reaction efficiency and product quality. It is widely used in chemical, pharmaceutical, and electronic industries.
2. Road Snow Melting and Deicing Agent
Calcium Chloride 96% can significantly reduce the freezing point of water (the minimum freezing point of its aqueous solution can reach -55℃), which is much more effective than sodium chloride at low temperatures. It is widely used as a snow melting and deicing agent for roads, bridges, airport runways, and parking lots in cold areas. It can quickly melt snow and ice, prevent road freezing, and improve traffic safety. At the same time, it has less corrosion to roads and vehicles than other deicing agents, and has little impact on plants and soil.
3. Construction Antifreeze and Early Strength Agent
In winter construction, Calcium Chloride 96% can be added to concrete and mortar as an antifreeze and early strength agent. It can accelerate the hydration reaction of cement, shorten the setting time of concrete, improve the early strength of concrete, and enhance the frost resistance of mortar, ensuring that the construction quality is not affected by low temperatures. It should be noted that it cannot be used in reinforced concrete, because chloride ions will cause corrosion of steel bars.
4. Refrigeration Coolant
The aqueous solution of Calcium Chloride 96% has good thermal conductivity and low freezing point, which is an ideal coolant for refrigeration systems. It is widely used in refrigerators, freezers, ice-making equipment, and industrial cooling systems (such as chemical reaction cooling, equipment cooling, etc.). It can effectively transfer heat and maintain the low-temperature environment required by the system, with stable performance and low cost.
5. Petroleum Drilling Auxiliary
In the petroleum drilling industry, Calcium Chloride 96% is used as a weighting agent for drilling fluid (mud). It can increase the density of drilling fluid, balance the formation pressure, prevent well blowout accidents, and at the same time, it can improve the viscosity and shear force of drilling fluid, protect the well wall, and avoid well collapse. It is an important auxiliary agent in oil and gas exploration and development.
6. Biochemical and Pharmaceutical Fields
In the biochemical field, Calcium Chloride 96% (biochemical grade) is suitable for insect cell culture and plant cell culture. It can be used to prepare competent Escherichia coli and transform plasmid DNA or high-molecular-weight genomic DNA of eukaryotic cells. It can also be used to stabilize enzymes and promote protein crystallization. In the pharmaceutical field, it can be used as a calcium supplement, and also as an auxiliary agent in the preparation of drugs to adjust the pH value and stability of the drug solution.
7. Agriculture and Aquaculture
In agriculture, Calcium Chloride 96% can be used as a calcium supplement for crops, which can improve the calcium content of crops, prevent calcium deficiency diseases (such as blossom-end rot of tomatoes), and improve crop yield and quality. In aquaculture, adding it to water can increase water hardness, provide calcium ions needed for aquatic organisms (such as shellfish, crustaceans) to form shells, and at the same time adjust the pH value of water to create a suitable living environment for aquatic organisms.
8. Other Applications
In addition to the above fields, Calcium Chloride 96% also has many other uses: it can be used as a dust suppressant for roads and construction sites, which can suppress dust by absorbing moisture in the air and keeping the surface of the road moist; it can be used as a flame retardant for textiles, which can improve the flame retardancy of textiles and reduce the risk of combustion; it can be used as a precipitant in the production of chrome pigments to improve the purity and color of pigments; it can also be used in food processing as a firming agent for canned vegetables, tofu, and other products to enhance product texture.
In conclusion, the production of Calcium Chloride 96% (anhydrous) requires strict control of raw material quality, precision purification, and deep dehydration, and each process link is closely linked to ensure that the product content reaches 96% and meets the application requirements of various fields. With its excellent performance, Calcium Chloride 96% has become an important chemical product in industrial production and daily life, playing an irreplaceable role in snow melting and deicing, drying and dehydration, construction, petroleum drilling, and other fields. With the continuous development of industry, its application fields will be further expanded, and its market demand will also maintain a stable growth trend. Please visit our website www.toptionchem.com for more information. If you have any requirement, please do not hesitate to contact us.
Post time: Apr-01-2026