Overview:
This 1916 bulletin from the US Department of Agriculture delves into the potential of hemp hurds, the woody inner portion of the hemp stalk, as a source for paper-making. The publication explores both the agricultural aspects of hemp hurd production, including its availability and handling, and the manufacturing process of transforming hurds into paper.
The bulletin highlights the potential economic benefits of utilizing hemp hurds, which are currently considered a waste product. It emphasizes the increasing use of machine-breaking in hemp production, which creates a more concentrated and readily available supply of hurds. The report also acknowledges the environmental benefits of using hemp hurds over wood pulp, noting the faster regeneration rate and smaller land requirements for hemp production.
Key Findings:
- Hemp hurds are a readily available and underutilized waste product from hemp fiber production.
- Machine-breaking of hemp leads to greater availability of hurds, increasing their potential as a paper-making material.
- Hemp hurds, when treated properly, can produce a paper comparable to standard machine-finish printing paper.
- Hemp hurds offer environmental benefits over traditional wood pulp due to faster regeneration and lower land requirements.
Learning:
- Hemp Hurds as a Paper-Making Material: This bulletin will teach you about the potential of hemp hurds, a waste product from hemp fiber production, as a sustainable and economical source for paper-making.
- Details: Hemp hurds are the woody inner portion of the hemp stalk, separated from the fiber during the breaking process. They can be processed into a pulp that, when combined with other fibers, can be used to manufacture high-quality paper.
- Advantages of Hemp Hurds over Wood Pulp: You will learn about the key advantages of utilizing hemp hurds as a paper-making material.
- Details: Hemp hurds offer several benefits over traditional wood pulp, including faster regeneration rates, lower land requirements, and a more sustainable and environmentally friendly production process.
- Paper-Making Process from Hemp Hurds: This text will outline the process of transforming hemp hurds into paper.
- Details: The paper-making process involves cooking the hurds in a caustic-soda solution, followed by washing, bleaching, and refining. The pulp is then mixed with other fibers, such as sulphite or soda poplar, and processed into a finished sheet of paper.
Historical Context:
This bulletin was written in 1916 during a time of increased demand for paper due to industrialization and the rise of mass media. This demand led to concerns about the sustainability of the wood pulp industry, which was relying heavily on unsustainable logging practices. The search for alternative paper-making materials became a priority, prompting research into the potential of hemp hurds and other plant fibers.
Facts:
- Hemp hurds are the woody inner portion of the hemp stalk. Hemp hurds are essentially the leftover woody material after the fiber is extracted.
- Hemp hurds are currently considered a waste product. They are not utilized for any profitable purpose in the United States, making them a prime candidate for reuse.
- Most hemp in the US is dew retted. This means the stalks are spread on the ground and exposed to the weather, allowing bacteria to break down the pectin and gums.
- Hemp hurds are available only from machine-broken hemp. Hand-breaking methods result in scattered piles of hurds, making them too costly to collect and utilize.
- Machine breaking of hemp is increasing in the US. This trend is driven by the faster and more efficient fiber production that machine brakes provide.
- Machine breaking leads to concentrated piles of hurds. This makes the collection and transportation of hurds more efficient and economical.
- Hemp is a staple agricultural crop in the US. This ensures a steady supply of hurds for paper-making, unlike wood pulp, which is subject to fluctuations due to unsustainable logging practices.
- Hemp can be grown in various regions of the US. This allows for geographic diversification in the production of hemp hurds.
- Hemp hurds need to be baled for efficient transportation and storage. Baling helps reduce the bulk of the hurds, making it more economical to ship.
- Burlap or chipboard can be used to cover bales of hurds. These materials help prevent the hurds from shaking out during transport and storage.
- The cost of baling hurds is relatively low. This makes hemp hurds an economically viable alternative to wood pulp.
- The average yield of hemp fiber is 1,000 pounds per acre. This information is relevant to the overall production of hemp, as it provides context for the amount of hurds that can be expected.
- The weight of hurds is about five times that of the fiber. This helps explain the volume of hurds produced during hemp processing.
- Hemp hurds are composed of a mixture of bast fibers and wood tissue. The bast fiber (the long, strong fibers used for rope and textiles) is a small percentage of the hurds, but can add strength to the resulting paper.
- The physical properties of hemp hurds make them suitable for paper-making. The hurds can be chemically treated to release the cellulose fibers, which can then be formed into paper.
- The pulp produced from hemp hurds is similar to soda poplar pulp. This means it can be used in conjunction with other fibers to create a variety of paper products.
- The hurds need to be sieved to remove sand, dirt, and chaff. This step is crucial for producing high-quality paper.
- The cooking process involves treating the hurds with a caustic-soda solution. This chemical treatment breaks down the lignin and other non-cellulose materials in the hurds, leaving behind the cellulose fibers.
- The cooking process can be controlled to produce different qualities of pulp. This is important for ensuring the final paper product meets the desired specifications.
- Hemp hurds require a longer cooking time than wood pulp. This is due to the harder, more robust nature of the hurds.
Statistics:
- The weight of hurds is about five times that of the fiber. This demonstrates the significant volume of hurds produced as a byproduct of hemp fiber processing.
- The average yield of hurds per acre is about 2.5 tons. This highlights the potential volume of hurds available for paper-making.
- A bale of hemp hurds weighs approximately one-third less than a bale of hemp fiber. This is important for transportation and storage considerations.
- The annual supply of hemp hurds from machine-broken hemp in the US is estimated at over 7,000 tons. This showcases the potential market for hemp hurds.
- The annual consumption of wood by the paper industry is about 3% of the total forest cut. This demonstrates the significant reliance of the paper industry on wood pulp, highlighting the need for alternative sources.
- The ratio of pulp yield from wood to hemp hurds is approximately 2:1. This suggests that hemp hurds require a greater volume of raw material to produce the same amount of pulp as wood.
- A 25-ton pulp mill requires 15,000 cords of wood annually, but only 25,000 tons of hemp hurds. This demonstrates the greater land requirement for wood production compared to hemp hurds.
- The annual growth of hemp per acre is approximately 10,000 pounds, while that of wood is 0.55 tons per acre. This highlights the faster regeneration rate of hemp compared to trees.
- Hemp hurds require a caustic soda concentration of 107 grams per liter for optimal cooking. This is important for understanding the chemical treatment process.
- The yield of total fiber from hemp hurds is 35% of bone-dry fiber, compared to 47% for wood pulp. This suggests that hemp hurds are less efficient in terms of fiber yield.
- The total washing and beating time for hemp hurds is about three hours. This provides context for the processing time required for the hurds.
- The strength factor of the paper produced from hemp hurds is 0.33, compared to 0.28 for standard machine-finish printing paper. This demonstrates that hemp-hurd paper can achieve a higher strength than standard paper.
- The folding endurance of the hemp-hurd paper is significantly higher than standard paper. This shows that hemp hurds can impart greater durability to the final product.
Terms:
- Retting: The process of removing the gums and pectin from the hemp stalks, allowing for the separation of the fibers. This can be done through dew retting (exposure to the weather) or water retting (immersion in water).
- Breaking: The process of separating the fiber from the woody hurds.
- Scutching: The process of removing the remaining woody material from the fibers.
- Cooking: The chemical treatment of the hurds with a caustic-soda solution to release the cellulose fibers.
- Bleaching: The process of whitening the pulp to meet the desired color standards.
- Furnishing: The process of mixing the pulp with other fibers, loading agents (e.g., clay), and sizing agents to create a balanced furnish.
- Beating: The process of reducing the fibers to the desired length and refining the pulp for better felting.
- Jordan Refining: A process that refines the pulp, reducing the presence of shives and improving the paper’s surface.
- Shives: Small, unrefined pieces of wood that can negatively impact the paper’s quality.
- Dandy Roll: A rotating roll with a patterned surface used on the paper machine to create a textured finish.
Examples:
- Dew Retting: The bulletin describes how hemp is typically dew retted in the US, where stalks are laid out in swaths on the ground and exposed to the weather. This process helps break down the gums and pectin, allowing for easier fiber separation.
- Machine Breaking: The bulletin discusses the advantages of using machine brakes to break the hemp stalks, leading to concentrated piles of hurds that can be efficiently collected and transported. It mentions that machine brakes are becoming increasingly common in the US hemp industry.
- Hand Breaking: The bulletin notes that hand brakes are still prevalent in Kentucky, but the process results in scattered piles of hurds, making them too costly to collect and utilize for paper-making.
- Baling: The bulletin highlights the need for baling hurds for efficient transportation and storage. Bales of hurds require burlap or chipboard covers to prevent the hurds from shaking out during transport and storage.
- Sieving: The bulletin describes the sieving process for removing dirt, sand, and chaff from the hurds before cooking. This step is crucial for producing high-quality paper.
- Cooking: The bulletin explains how the hurds are cooked in a caustic-soda solution to break down the lignin and other non-cellulose materials, leaving behind the cellulose fibers.
- Bleaching: The bulletin discusses the bleaching process, where the brown-colored cooked stock is bleached to a white product, which is desirable for many paper applications.
- Furnishing: The bulletin outlines the furnishing process, where the hurd pulp is mixed with other fibers, loading agents, and sizing agents to create a balanced furnish for the paper.
- Beating: The bulletin highlights the importance of beating, a critical step in reducing the fibers to the desired length and refining the pulp for better felting, which greatly impacts the quality of the final paper.
- Jordan Refining: The bulletin explains how Jordan refining can be used to further refine the pulp, reducing the presence of shives and improving the paper’s surface.
Conclusion:
This 1916 bulletin provides compelling evidence for the viability of hemp hurds as a sustainable and economical alternative to wood pulp for paper-making. The study demonstrates that hemp hurds can be processed to produce high-quality paper, and it highlights the significant environmental benefits of this alternative material. The authors emphasize the increasing availability of hurds due to the adoption of machine-breaking methods, creating a growing market potential for this underutilized resource. While there are challenges to overcome, such as the need for efficient storage and the lower pulp yield compared to wood, the potential benefits of hemp hurds for paper-making warrant further investigation and development.