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Manufacturers in the brick, ceramic and glass industries have to deal with notoriously difficult challenges in material size reduction. What makes glass and ceramics tough, durable products presents difficulties during the preparation of raw materials. Recycling process scrap and end-of-life disposal are important in considering the size reduction requirements.
The basics of size reduction are simple. Size reduction is simply putting energy into material to make large pieces smaller. Hundreds of machines-ranging from simple to complex-exist to accomplish this objective in many industries and for many materials. A variety of machinery choices are available simply because one size does not fit all. Selecting the best type of equipment for your process will affect plant profitability.
Evaluating Size Reduction NeedsFive basic questions should be asked to begin an evaluation of a size reduction process. If you begin your project by defining these variables, you will be off to a good start:
- What is the material to be crushed?
- What is the size range of the feed to the crushing machine?
- What is the desired production rate (Kg/HR, TPH, PPH)?
- What is the moisture range of the raw material?
- What is the size range desired of the material after crushing?
Machine TypesCompanies that offer a limited size reduction product range (i.e., only one or two types) will logically be more limited in the solutions they can provide. The temptation exists to offer sub- optimal solutions by stretching to meet size reduction processing objectives.
For example, maximum feed size can limit machinery selection and applicability. Most machines are limited by the largest feed accepted. A larger machine or a different machine style altogether may have to be selected to accommodate bigger pieces in the raw material feed stream vs. the tonnage determining the machine style needed.
Reduction ratios vary by machinery type, so this can be another area where a manufacturer can be led astray. For instance, if a glass recycler wants to crush to an intermediate fine product, machines can be selected with reduction ratios of:
- 2:1-roll crusher, jaw crusher
- 10:1-vertical shaft impactors
- 20:1-cage mills, hammermills
- 200:1-ball mills
The choice of size reduction equipment impacts more than just particle size. Other factors affected by the size reduction process may not be as obvious, but they can have significance. For instance, additional factors can include:
- Ability to use one machine vs. two or three
- Operating costs vs. acquisition cost tradeoffs
- Particle shape and the effect on product quality
- Particle shape and the effect on operating costs
- Total energy required for a system
Testing and Toll CrushingThe best size reduction equipment companies operate test plants. Each year, these facilities help quantify the unique size reductions that customers need. Some North American companies have continuously operated test facilities for over 80 years and continue to test for over 100 customers a year. This service will always be in demand due to unique customer requirements.
Testing provides data on a core material processing step-size reduction-and helps to quantify the cost of ownership for the equipment. For a nominal testing fee, producers can tap into the size reduction equipment manufacturer’s knowledge base.
Testing produces information on the following:
- Pre-processing and post-crushing particle size distribution
- Power consumption per unit processed (e.g., KW/MT)
- Wear cost estimate due to metal replacement parts
- Machinery selection confirmation
Toll crushing can allow a relationship to develop between companies before the end user invests capital in buying equipment. In the proper circumstances, toll crushing can be a valuable, worthwhile service.
After-the-Sale ServicePlant personnel with size reduction equipment should ask themselves: “When did I last see someone from the crusher manufacturer?” If you don’t know or can answer “never” to this question, how good is your size reduction business partner?
Factory-trained service and parts sales personnel are part of the value proposition for your equipment selection process. Staying engaged with the crusher manufacturer will help maintain profitability by having professional advice available to keep the crushing systems running in good order. In addition, as machine designs and features are introduced, knowing the original equipment manufacturer helps plant process and maintenance stakeholders evaluate new features that can improve output, lower operating costs, or improve product quality.
Application ExampleBrick plant grinding rooms prepare clays, shales and scrap brick for blending and, ultimately, thermal processing in kilns to produce residential- and commercial-grade brick. Historically, grinding was achieved in three size reduction machines.
New features were introduced by a company that solved several problems that are pervasive in ceramic raw material preparation:
- High-moisture raw materials
- High-plasticity materials
- Large feed size
- Need for a consistent particle size distribution after crushing
- Improved particle shape properties
- Ability to eliminate two crushing machines and related material handling equipment from the process, thereby lowering cost of ownership
- Consistent output production rates with varying moisture of incoming raw material
- Consistent output particle size
- Reduction in extruder power consumption due to improved particle shape
- Increase in extruder die life due to improved particle shape
- Significant reduction in direct costs due to wear parts
- Reduction in maintenance and repair costs
Industry CommitmentIs your size reduction equipment manufacturer dabbling in your industry or are they committed to your industry? Well-maintained crushers should be expected to last 20-30 years. A healthy business partner will belong to and be active in your industry trade association, develop products and features to help solve industry problems, maintain a current website on their products and services, and exhibit at industry trade shows.
Taking a step back when evaluating your choices in size reduction and consideration of these points may help guide you in the best direction objectively. You will want your partner to be there when you need them.
ConclusionDon’t ignore the importance size reduction has on profitability and product quality. Take time to objectively evaluate the systems, equipment, and personnel needed to crush, screen, convey, and store your raw materials. You may be surprised at the improvement opportunities that exist in your plant.
For more information, contact Stedman at 129 Franklin St., Aurora, IN 47001; call (800) 262-5401 or (812) 926-0038; fax (812) 926-3482; email email@example.com; or visit www.stedman-machine.com..