Key points
Industrial mixers serve an essential role in modern industry, preparing materials for downstream production equipment, creating homogeneous blends of disparate components, de-dusting powders, and giving bulk solids producers more control over the materials and products they work with.
While not all mixing operations require testing, the diverse landscape of industrial mixer roles, combined with the endless matrix of potential starting materials and end product qualities, means testing can often be the difference between an efficient and reliable production line, and one rife with unexpected shutdowns, excessive maintenance costs, and profit-draining inefficiencies.
The following information covers how producers utilising pin mixers and pugmill mixers (also known as paddle mixers or pug mills) can take advantage of testing facilities such as the FEECO Innovation Centre to engineer a high-performance mixing process, optimise an existing process, or design a custom mixer.
*Note: All testing facilities differ in both their testing capabilities, and the data they can gather. The following information is based on testing in the FEECO Innovation Centre and may be specific to FEECO testing methods and capabilities.
The Many Roles of Industrial Mixing Testing
Although testing is not always necessary, it can be a critical step in avoiding some potential pitfalls in both new and existing operations. In many cases, the cost of not testing can be far more expensive than the initial testing itself, when what seems like a simple operation quickly results in frequent process upsets, a struggle to reach rated capacity, an inability to produce product to spec, or otherwise.
In a broad sense, producers can utilise testing to confirm feasibility of an intended process, establish proof of product, and illustrate proof of process – all key steps on the path to successful commercialisation, no matter what the end goal. On a more granular level, this can translate to meeting a range of objectives in both new and existing mixing lines.
Developing a New Industrial Mixing Process
In developing a new mixing process or engineering a custom mixer, producers can use testing to:
- Establish a working familiarity of the material and its response to mixing
- Develop small samples for field testing
- Establish basic operating parameters
- Gather data for scale-up
- Determine the most appropriate mixer type
- Identify the need for pretreatment of feedstock
- Refine process parameters to reach desired product quality
- Fine-tune process conditions to optimise for efficiency
- Establish data necessary for commercial equipment design
- Predict expected wear points or trouble spots to address through mixer design
Enhancing an Existing Industrial Mixing Process
The value of testing goes beyond developing a new process or designing a mixer tailored to its intended application; its value also extends to optimising an existing process or mixer. For those looking to improve their current mixing line, testing can serve as a way to:
- Evaluate different binders, process additives, or equipment modifications
- Reveal potential process improvements and inefficiencies
- Improve product quality
Pigment agglomerates produced in a pin mixer during testing in the FEECO Innovation Centre
Testing also offers the opportunity to improve or optimise various qualities of the material exiting the mixer; by adjusting process variables and equipment configuration during the testing process, producers can hone-in on reaching specific target parameters such as:
- Flowability
- Uniformity
- Particle size distribution
- Bulk density
- Moisture content
Testing can also be used to evaluate the potential addition of a mixer to an existing production line.
How the Industrial Mixing Testing Process Works
The testing process can vary considerably depending on the specific objectives of a project and the capabilities of the chosen facility. The most important aspect of testing, however, is that testing is based on a representative sample of the intended feedstock so the results are accurate and can be relied upon for process scale-up.
In most cases, the qualities of the starting feedstock, combined with the desired qualities of the end product, will determine the type of mixer most suitable for the job. Pin mixers are ideal for producing small, dense agglomerates or seed pellets, as well as de-dusting fine powders such as carbon black. Their use of a high rotational speed means they generally do not bode well with abrasive materials unless measures are taken to protect the pins.
Batch pin mixer used for testing
Glass batch after conditioning in a pin mixer
In contrast, pugmill mixers offer an excellent option for conditioning abrasive materials, processing sludges, and producing rough agglomerates.
Ore dust conditioned in a pugmill mixer (paddle mixer)
When mixer selection is unclear, producers can begin by evaluating how the material responds to each type of mixer in order to identify the best fit.
Depending on the process goals and what data has already been established, testing typically begins by simply running the material through a batch mixer to gauge its response and confirm or deny any initial assumptions. In some cases, for example, testing may reveal the need for pretreatment of the material, such as size reduction, screening, or pre-drying.
Process experts continue to work with feedstock and process parameters until they identify the conditions necessary to consistently produce the desired results with a high level of certainty. Once this basic process criteria has been established, testing can move to running the process on a continuous pilot scale to gather the data necessary for scale-up.
During this time, data on feed rates, particle size distribution, binder use, effect of liquid addition, horsepower usage, and more are firmed up to establish the conditions necessary to produce the product to desired specifications on a continuous basis.
It’s important to note that even if specific material characteristics are not sought, such as when preparing wastes for landfill deposition, testing offers a way to optimise mixer design for reliable, consistent, and efficient processing.
This process continues with optimisation of factors such as pin/paddle wear, process stability, etc., to yield a high-performance, efficient process.
Information Gathered Through Testing
The testing process provides an opportunity to gather a wide range of process and material data:
- Mixer configuration (spray port locations, feed location, drive assembly requirements, customisations, materials of construction, etc.)
- Pin/Paddle placement
- Mixer shaft speed
- Feed rate
- Retention time
- Feedstock requirements
- Potential trouble spots
In the Innovation Centre, this data serves as the basis for designing and building a commercial-scale mixer expertly tailored to its application.
Questions Answered Through Testing
Producers can also get answers to several questions through the testing process:
New Processes
- Which mixer type will best suit my process and product goals?
- Will my mixer require any customisations for optimal performance?
- How will my material respond to mixing?
- How will the mixer need to be designed to meet my process and product goals?
Existing Processes
- Can I improve the efficiency of my mixing process?
- Can I improve the quality of my product?
- What steps do I need to take to improve my process or product?
- Could the addition of a mixer to my existing line provide benefits?
Why Consider an External Industrial Mixing Testing Facility?
While in-house R&D programs are an option for test work, a dedicated testing facility can offer a few key benefits that can make an external testing facility the better choice.
A Faster Path
An external testing facility can provide a lifeline for producers to expedite the path to commercialisation while minimising early investment costs by lending outside expertise to the process, so development can move more efficiently and expediently.
Low Risk
In settings where producers are looking to improve an existing process, an external facility allows them to avoid making unnecessary modifications to the existing line or putting production schedules at risk; the use of an external facility allows the testing process to happen independently of any existing operations.
Process Integration
The facility may also offer testing for the processes surrounding the mixer as well, such as drying, pelletising, and more. This is beneficial when testing a continuous granulation or pelletising line complete with additional agglomeration equipment, drying, screening, and a recycle circuit.
High Confidence
When working with an OEM testing facility, the data gathered through testing provides the OEM with the information necessary to engineer an effective, efficient mixer with a high level of confidence. In some cases, this may even allow for the OEM to issue a process guarantee with the mixer, so buyers can be confident that their mixer will suit their needs exactly.
Concluding Remarks
Testing facilities can be a valuable tool in the development of both new and existing mixing processes, establishing baseline process data and optimising process parameters for maximum efficiency and minimum downtime.
Testing can illustrate proof of process, as well as answer a number of questions, gather critical process data, and provide the information needed to design a mixer uniquely tailored to its application.
An external testing facility, such as the FEECO Innovation Centre, has the benefit of bringing in outside expertise, comprehensive testing, development, and analytical capabilities, and when optimising an existing process, eliminating the risk associated with testing in a live production environment.
Carrie Carlson is a Technical Writer who has been with FEECO for over a decade. She works closely with engineers and process experts to turn complex ideas into easy-to-understand literature.
Chris Kozicki is a Process Sales Engineer specialising in agitation agglomeration and has been with FEECO for over 30 years. Chris is an active member of the agglomeration community and former president of the Institute for Briquetting and Agglomeration (IBA).
