Walnut Shell

The properties of the walnut shell are outstanding. This substance is of high hardness and wear resistance. Walnut shell also has a high chemical composition for solubility in both acidic and alkaline solutions, in line with specialization processes. On the other hand, walnut shells exhibit strong adsorption and cutting properties of 27-50% adsorption ability, which is ideal for filtration systems. Moreover, the product has a low operation cost and is easily manageable, giving walnut shell a cost-effective character for many industries. These characteristics make the substance applicable in a wide range of industrial sectors. The following article is dedicated to going further into the fantastic world of walnut shells, what these nuts are used for, and the properties that allow this usage.

Prior to our insightful article about walnut shells, it seems helpful to bring up the name of a reliable walnut shell provider in the international market. JAM Group Co. is a prominent walnut shell manufacturer offering this substance in various mesh sizes and grades. Products from this company suit every application, from oil well drilling to cosmetics. As a powerful walnut shells supplier, JAM Group presents its products to every customer no matter where they are. So, you can rely on this company and enjoy a smooth purchase followed by effortless transportation. Click on About Us to learn more.


What is Walnut Shell?

Walnut shells are derived from the hardy outer encasement of walnuts. So, they have a unique mix of cellulose, hemicellulose, and lignin added to traces of their protein and minerals. They are durable and tough in nature; hence, they are used in abrasive applications. Also, the porous structure can easily be filled and held with liquids; materials of this type serve for filtration and adsorption perfectly. The great thing about walnut shells is that they are biodegradable; that is, by the action of nature, they can easily be decomposed and become something good for the soil. It rather gives a green alternative to synthetic. The physical properties, such as the specific gravity of 1.2 to 1.4 and the hardness of 1.5 MOH scales, make walnut shells applicable in various industrial sectors.

Walnut shell is safe and aggressive, pointing to its use in applications that replace hazardous substances, which may, for instance, pose the dangers of silicosis. On close examination of the structure, the walnut shell has many layers, from the green outer shell to the hard woody layer and the brown shell containing the nutritive seed. Each of them has specific benefits that go way beyond the strict scope of their mere nutritional value to the different industries. For example, shell powder, since it does not have volatile solvents, serves as an eco-friendly alternative to sustainable traditional abrasives such as sand to avoid the issue of exposure to silica.


Different Grades of Walnut Shell

Walnut shells can be sorted into different groups based on specific physical characteristics. These categories are defined by:

  • Appearance: This relates to the overall look of the walnut shell, including its texture and the presence of any foreign materials.
  • Mesh Size: Mesh size determines the granularity of the walnut shell powder, which affects its abrasive quality and suitability for certain applications.
  • Color: The color of the walnut shell varies, influencing its uses across the industry.

In the following discussions, we will introduce the various grades of walnut shells and explore how each characteristic influences its application in industrial settings.

Corin Grade of Walnut Shell

This grade has its specificity in mesh size, given as between sizes ranging from 4-12, 6-10, and 8-12. The process of classification is thus referred to as coarse or fine, depending on the walnut shell particle to make them be used with a variety of uses. For example, size 4-12 mesh is coarse and meant for aggressive scrubbing and cleaning, while 8-12 mesh is rather finer in nature and finds its application in delicate polishing. The medium size would, therefore, be 6 to 10 mesh, which balances the needed abrasiveness but has enough tenderness for many more kinds of surfaces.

Medium Grade of Walnut Shell

The walnut shell medium grade—mesh sizes between 10-20, 12-20, and 14-30— is another type of this material with specific abrasiveness to be applied in particular contexts. It has fine particles that provide effective cleaning and polishing capabilities without the harshness accompanying larger material. Therefore, it is most effective for finishes that combine thorough cleanliness with maintaining the integrity of the surface being treated. For instance, mesh sizes 10-20 and 12-20 would best serve soft metals, fiberglass, and plastics when aggressive abrasives might cause damage. On the other hand, the 14-30 mesh size is slightly coarser; it, therefore, makes a more potent abrasive capable of resisting greater strength in scratching.

Coarse Grade of Walnut Shell

The coarse grade of walnut shell, with its mesh sizes ranging from 60-35, 60-40, 100-40, 100-60, to 200-60, is customized for applications that demand a refined touch. This grade’s finer particles are adept at gentle polishing and cleaning, making it ideal for surfaces that need an accurate approach. The variety within this grade, from the lower end of 60-35 and 60-40 to the finer 100-40, 100-60, and especially the 200-60 mesh sizes, allows for a broad spectrum of uses. These finer meshes are perfect for delicate tasks, such as cleaning sensitive equipment or polishing soft metals, where preserving the surface quality is paramount.


Walnut Shell Production Process

The production process of walnut shells is critical, as it directly influences the material’s chemical and physical characteristics, determining its applications and grade. This process ensures that the final product meets specific requirements for various industrial uses. The stages of this process, from the initial collection and sorting of walnut shells to their crushing, grinding, and sieving into different mesh sizes, are carefully managed to produce the desired quality. The following paragraphs will closely examine the manufacturing phases of walnut shell powder and its details.

Material Choice

Material choice stands at the outset of walnut shell production. During this initial stage, human senses play a crucial role in evaluating the quality of walnut shells. The appearance of each shell is scrutinized to ensure the color is consistent with what is typically expected, devoid of any unusual odors that might indicate decay or contamination. Additionally, it is crucial to inspect for the absence of small holes that could suggest infestation by worms, a sign of compromised integrity. Alongside these visual and olfactory checks, measuring the moisture content of the walnut shells is essential. This step ascertains that the shells have the optimal level of dryness required for processing, which prevents mold growth and ensures the shells are in the best condition for the subsequent stages of production.


Following the initial selection, storage is the next critical phase in walnut shell production. This stage necessitates that the chosen walnut shells are stored in conditions that ensure their quality is maintained. Before storing, a thorough safety inspection of the warehouse is conducted to confirm its security, waterproofing, and absence of dampness. It’s also vital to check that doors and windows are intact, guaranteeing the facility is sturdy, moisture-proof, well-insulated, ventilated, and airtight. 

After sterilization, prompt ventilation is necessary to minimize the impact of any adverse environmental conditions on the walnut shell raw materials. Storage personnel are tasked with regularly monitoring the storage environment, paying close attention to temperature, relative humidity, and air circulation within the warehouse to prevent mold development on the walnut shells. 


In this stage, the raw materials undergo a secondary selection phase. This crucial step involves thoroughly reassessing the walnut shells stored in the warehouse. The aim here is to ensure that every piece of raw material meets the required standards established in the initial selection phase. Walnut shells that do not meet these specific criteria for firmness and quality are systematically removed. This process guarantees that only the best quality shells, free from defects and inconsistencies, advance to the subsequent stages of production.


After selecting the finest walnut shells, the next stage in their production is the cleaning process. It involves the use of water that complies with the standard of the production process (in this method, GB5749-2008 drinking water sanitary standard). It ensures that the cleaning medium is of the highest purity and safety. The objective during this phase is to efficiently remove any residual dirt, dust, or foreign materials adhering to the shells while minimizing the soaking time to prevent the absorption of excessive moisture by the shells. 

Oven Drying

Following the previous step, the production progresses to oven drying. After ensuring the shells are adequately drained of excess water, they are placed in an oven where the temperature is carefully regulated between 60°C and 80°C. This precise temperature control is vital for effectively removing moisture without damaging the integrity of the shells. The drying process continues until the moisture content of the walnut shells falls below 8%, a critical threshold that guarantees the shells are adequately dried for further processing or application.


Walnut shells must undergo another step, called freezing. This stage involves subjecting the shells to cryogenic temperatures between -50°C and -60°C. The cooling period is carefully timed to last between 60 to 90 minutes, ensuring the shells reach their brittle point. This critical step is designed to alter the physical properties of the walnut shells, making them more susceptible to fragmentation into finer particles in subsequent processing stages. The shells’ structural integrity is modified to facilitate their breakdown by reducing the temperature to this specific range. It enhances their usability in various applications.


After the freezing stage, the walnut shells are promptly transferred to the pulverizing stage. This critical step involves rapidly grinding the brittle, frozen shells for 20 to 30 minutes using a device typically employed for milling medicinal herbs. This specialized pulverizer is adept at breaking down the shells into fine powder, achieving the desired consistency and particle size for various applications.


Following the pulverizing stage, the walnut shell production process advances to screening. This procedure is essential for achieving a specific particle size, with the target being the production of 300-mesh walnut shell ultra-fine powder. However, the target may vary based on various factors, such as your intended grade. The sieving process ensures that only particles of the desired fineness pass through, resulting in a product of uniform consistency.


After processing the walnut shell ultra micro powder, the manufacturing is finished with the packing phase. At this point, the powder is accurately measured and packaged, with the net content of each package meeting the required regulations of the company that produces the product.

Walnut Shell Applications

Walnut shells, thanks to their unique set of properties, find applications across various industrial sectors. Their high hardness and wear resistance, along with excellent pressure resistance, make them an ideal choice for abrasive materials used in cleaning and polishing. Furthermore, walnut shells dissolve easily in acid and alkali solutions, enhancing their versatility in chemical processes. Their strong adsorption and dirt-cutting capabilities, with an adsorption rate of 27-50%, make them essential in filtration and purification systems. In the following sections, we will have a close look at the specific uses of walnut shells in different industrial contexts and highlight their contribution to enhancing efficiency and sustainability.

In the Drilling Industry

Walnut shells play a crucial role in three different sectors of the drilling industry:

  • Lost Circulation Material: Tackling the challenge of lost circulation, walnut shells serve as an effective solution. When drilling fluid escapes into the formation, it can disrupt operations and elevate costs. By integrating crushed or ground walnut shells into the drilling mud, these particles act as a sealant for gaps and fissures, effectively preventing the loss of valuable fluids.
  • Oil Spill Absorbent: Walnut shells contribute significantly to environmental protection efforts within the drilling sector, particularly in managing oil spills. Their porous nature allows them to absorb oil efficiently, several times their weight, thus mitigating the environmental impact. Spreading crushed walnut shells over spilled oil facilitates the absorption process. It creates clusters that are easy to collect and dispose of.
  • Drilling Fluid Additive: Beyond their use as lost circulation material, walnut shells enhance the drilling process as an additive in drilling fluids. Their abrasive qualities benefit the cleanliness and efficiency of the drill bit. This accelerates the drilling process and extends the life of the drill bit.
  • Weighting Agent: Though not traditionally used as weighting agents in the same capacity as materials like barite, walnut shells can be used in some contexts to control the density of drilling fluids. By aiding in the maintenance and efficiency of drilling operations, they can support the overall management of well pressures and stability. 

In Energy and Fuel Generation

Walnut shells are regarded as eco-friendly resources. They find application in two notable areas:

  • Biomass Energy: Utilizing walnut shells for biomass energy production is significant. These shells, when combusted, release heat energy capable of being transformed into electricity. This process positions walnut shell biofuels as a sustainable alternative to conventional fossil fuels, aligning with global efforts to lower carbon emissions and tackle the challenges of climate change.
  • Biochar Production: Another innovative use of walnut shells is in the creation of biochar, a form of charcoal designed to enrich soil. Applying biochar derived from walnut shells to the soil boosts its fertility. This enhancement is achieved through improved retention of nutrients and water, increased microbial activity, and carbon sequestration. 

In The Cosmetics Industry

Walnut shells are used in the cosmetics industry, too. Their applications include:

  • Exfoliants: Walnut shells, recognized for their mild abrasive texture, function in exfoliating skincare formulations. They play a crucial role in sloughing off dead skin cells and other surface impurities, facilitating the revelation of more radiant and smoother skin beneath. Opting for walnut shells as exfoliants reflects an environmental consciousness, as they serve as an eco-friendly substitute for synthetic microbeads.
  • Posinganers: Beyond skincare, walnut shells are also used in oral hygiene products. Finely ground walnut shells are incorporated into toothpastes and dental cleansers as a natural abrasive. This inclusion aids in the effective removal of plaque and surface stains from teeth, ensuring a clean, polished look without jeopardizing the enamel’s integrity.

In Agricultural Applications

Within the agricultural sector, walnut shells are leveraged for their natural benefits in two primary applications:

  • Soil Amendment: Incorporating walnut shells into the soil is an effective natural amendment. Their biodegradable properties positively impact soil health by enhancing its structure, which, in turn, aids in better water retention and increased nutrient availability to plants. Moreover, walnut shells are an excellent mulching material that helps suppress weed growth and maintain consistent soil temperature.
  • Livestock Bedding: In animal husbandry, ground walnut shells are valued for their role as livestock bedding. Their notable absorption capabilities make them ideal for managing moisture and controlling odors within animal enclosures. This results in a cleaner, healthier living space for livestock.

In Filtration and Adsorption Applications

Walnut shells also find application in filtration and adsorption, benefiting two critical areas:

  • Water Treatment: Water treatment facilities utilize the natural porous structure of walnut shells to purify water. This method is highly effective in extracting oil, heavy metals, and various pollutants from water sources, ensuring clean, safe water for both consumption and industrial applications. 
  • Air Filtration: Beyond their use in water purification, walnut shells are also crucial to air filtration systems. Their capacity to adsorb air pollutants makes them an effective solution for enhancing indoor air quality and addressing broader environmental concerns related to air pollution.

As an Abrasive Substance

Walnut shells are regarded as an abrasive substance, too. They find their place in various industrial applications due to their natural, eco-friendly properties:

  • Blast Cleaning: Walnut shells are natural, effective blast-cleaning abrasives. This method utilizes the medium to strip away paint, rust, and other surface contaminants without harming the material beneath.
  • Metal Polishing and Deburring: The inherent hardness and durability of walnut shells make them perfect for the tasks of polishing and deburring metal surfaces. Whether through tumbling or vibratory finishing processes, walnut shells help smooth out rough edges and achieve a mirror-like finish on metal components.


About JAM Group’s Walnut Shell

JAM Group Co. is a reputable player in the global market, dedicated to manufacturing, supplying, and exporting walnut shells customized for various industrial needs. Recognizing the diverse applications of walnut shells, from abrasive blasting at drill sites to oil well drilling, this company produces various grades of walnut shells with different mesh sizes. Each grade is engineered to meet specific application requirements, ensuring that the shells are coarse enough for effective cleaning without risking damage to delicate materials like fiberglass, wood, or plastic.

Further enhancing their appeal to a wide range of industries, this reputable walnut shells provider goes above and beyond by offering these high-quality walnut shells in an assortment of packaging options. This ensures that the products’ grades are maintained from the point of manufacture to delivery, regardless of the destination. Along with robust transportation capabilities, JAM Group Co. guarantees timely and reliable delivery to customers worldwide. To find out about our company, its products, and its offerings, please have a look at About Us.



Walnut shells serve different industries, from chemical enterprises to production, emphasizing the exceptional qualities and sense of reason in transforming from raw material to a complete product. It starts with careful selection that ensures only the best quality. These, in turn, are cleaned, dried, and ground, each stage tuned to provide different grades appropriate to the use to which it will be put. Therefore, grades vary from coarse particles, ideal for abrasive applications such as blast cleaning, to fine powders. Consequently, all sizes of particle grades are applied for cosmetic scrubs and dental products. The hardness makes them good for metal polishing and deburring, and the environmental benefit is clear in such applications—water treatment to soil amendment. This wide area of application shows the adaptability and effectiveness that make it continue as a popular resource in various sectors.