Rotary foundry sand dryer-efficient drying for sand

What is foundry sand?

Foundry sand is mainly used in the foundry industry, it is made by mixing various materials such as base sand, clay, coal powder, water, and silica sand in a specific ratio. To ensure the sand molds and cores have sufficient strength and do not deform or break during transportation, molding, and pouring of molten metal, a sand binder is typically added during the casting process to bind the loose sand grains together. Foundry sand has advantages such as high strength, refractoriness, permeability, and plasticity, is particularly suitable for manufacturing casting molds.

Why does foundry sand need to be dried?

If the moisture in foundry sand is too high, it will cause problems such as porosity and sand flushing, and reduce the permeability and strength of the molding sand. Therefore, it must be dried. The advantages of drying foundry sand mainly as follows:

1. Improve breathability: High moisture content will fill the gaps between sand particles, affecting gas discharge. Drying can remove water between sand particles and improve breathability.

2. Improve casting quality: High moisture content reduces the strength of the molding sand. Drying sand can maintain its strength and permeability, improving casting accuracy and surface smoothness.

3. Prevent surface defects: Too high moisture in sand can cause porosity on the surface of castings. When pouring molten metal, the high temperature causes the moisture to evaporate rapidly, leading to defects such as porosity on the surface of the casting. Drying foundry sand can effectively prevent this situation from occurring.

The moisture content requirement for foundry sand is generally between 0.5% and 1.5%. If it the moisture contect is too high, it will reduce the strength of the mold and the quality of the casting, so drying is necessary.

Advantages of using rotary dryer for foundry sand

At present, rotary dryer is the most common equipment used for drying foundry sand, and it has the following advantages:

1. Foundry sand itself has certain wear and corrosion properties. The lining and lifting plate of the rotary dryer can be made of high wear resistant steel, which has a wear resistance 3-4 times higher than ordinary carbon steel, and the equipment service life more than 10 years.

2. Foundry sand has strict requirements for moisture content. Rotary dryers can sense the moisture content of the sand and intelligently adjust the drying temperature and airflow to stably reduce the moisture content of the foundry sand to 0.5-1%, meeting the moisture requirements of the foundry industry.

3. The rotary foundry sand dryer adopts a multi-stage structure and optimized layout of lifting plates, with a thermal efficiency of up to 80% and low total power, saving 40% energy.

4. Fuels available include coal, diesel, natural gas, and biomass. Rotary foundry sand dryer can stably dry foundry sand, quartz sand, resin sand, and powdered recycled sand below 40mm, with wider adaptability.

5. Adopting three-drum structure, the footprint of the dryer is reduced by 40% compared to a single drum dryer, and the civil engineering investment is reduced by 50%.

Case study of Vietnam foundry sand dryer

Vietnam customer purchased a set of foundry sand rotary dryer from our company in 2024. The customer operates a local automotive parts foundry, but due to high humidity during the rainy season and high moisture content in the sand, the quality of the castings is unstable and therefore needs to be dried. After multiple communications with the customer, Zhengzhou Jiutian has developed a 20 t/h triple pass foundry sand drying plan based on the customer's actual production situation. After drying, the sand's moisture content was 0.8%, greatly improving the quality of the castings. Currently, the equipment has been running stably for over a year, and customer feedback indicates excellent performance in all aspects.

Conclusion

The moisture content of foundry sand has a great impact on the quality of castings, and rotary dryers have multiple advantages and mature technology for drying foundry sand. If you are interested in foundry sand drying process, please feel free to contact us. We are a professional manufacturer of rotary drying machines with many successful sand drying cases, and can make customized solutions for you.