Separators, Classifiers and Screeners Information Screeners, classifiers, shakers and separators are used for classification of powders or other bulk materials by particle size as well as separation of particles by density, magnetic properties or electrical characteristics. Round and rectangular screeners, magnetic separators, electrostatic separators, rotary sifters, wet or concentrating tables, rake classifiers, classifying hydrocyclones, floatation systems and trommels are included in the...
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Q & A on Separators, Classifiers, and Screeners

We asked our users for their input on Separators, Classifiers, and Screeners. Here are the results of 103 users familiar with Separators, Classifiers, and Screeners.

Who Took Our Poll? | Design Trends | Applications and Use | Features | Buying Advice |

Who Took Our Poll?Top

Design TrendsTop

Q:
What new technologies are influencing separator, classifier and screener design?
15 answers
Answers:
The point of technology that catches us is about efficiency of separation that attends the regional laws of emission to separation, and classifiers and screeners should have parts that must be changed frequently very easily. We tend to look more to the fact that the new equipment must be as close as possible to the others we have installed, to make it easy to maintain spare parts at maintenance department.
~Process Engineer, Balsa Nova, Brazil
The enhanced efficiency, throughput, separating at extreme coarse and slimy sizes are some areas that new technologies are revolving both by evolutionary and revolutionary concepts.
~Belavadi Ravi, Research & Development, Bangalore, INDIA
The movement toward finer and finer powders. Providing more efficient separations; ie, less HP for more production. More critical sizing specs for desired products.
~General Corporate Mgmt, Hanover, MA
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Q:
From your perspective, which companies are creating the most innovative separators, classifiers and screeners?
20 answers
Answers:
Derrick screens, Metso minerals, Bateman-Delkor-Multotec group, MBE-Humbold_Wedag-Sayaji group, FFE, Australian MDL-Gekko, Eriez, Weirminerals, Capex, Ingawenia, Sepor, Derrick, ABB etc
~Belavadi Ravi, Research & Development, Bangalore, INDIA
I cannot remember the names for all, but I definitely can say that for separators ACS (a Portuguese company) is a good name.
~Process Engineer, Balsa Nova, Brazil
Western European companies, like Binder, IFE, Bühler, etc. and American companies.
~Other, Budapest, Hungary
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Applications and UseTop

Q:
What are some of the applications you have used separators, classifiers and screeners for?
22 answers
Answers:
Classifiers is used for de-sliming and closed circuit grinding. Screens are used for amenability of sample to sizing and in closed circuit crushing and grinding operations. The various separators are used to separate the minerals based on their differential properties to obtain pure minerals at minimum misplacement, wastage and cost.
~Belavadi Ravi, Research & Development, Bangalore, INDIA
Coke Milling for Fuel Preparation (a vibrating screen classifier is used after the coke grinder to return particles above 3 mm size to the grinder; then the Pulverizer has a built-in classifier that only lets particles below 200 mesh size to exit it)
~Sebastiano G., Process Engineering Specialist, Panama, Panama
From aggregates at 3/4" separations to metal and glass powders at 10 micron cuts. From oily spices to drilling oil mud. Cosmetics, chemicals, pharmaceuticals, mining, metal powders, aggregates and plastics.
~Bob Grotto, President/Ceo, Mamaroneck, NY
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Q:
Please share with us any “non-standard” applications that separators, classifiers and screeners have been used for.
6 answers
Answers:
Some years ago we used a centrifugal decanter to separate an emulsíon of water, animal fat, hair. We had to be very careful because there were solids that should remain in the liquid phase but at the same time the hair and undesired debris had to be removed. We were testing a Sharples decanter during 1 week. At the end the project didn't fly because of budget problems but the testing and the analysis were very interesting.
~Israel Ortega, Marketing/Sales, Poza Rica / Veracruz, Mexico
Difficult to screen, very fine materials, sticky or tacky products, slurries, dedusting and extra high throughputs.
~Bob Grotto, President/Ceo, Mamaroneck, NY
Removing black specks of material in white soap powder that does not allow such specks in the final product.
~General Corporate Mgmt, Hanover, MA

Q:
Do you know of any disastrous mistakes that occurred due to the incorrect usage of separators, classifiers and screeners?
8 answers
Answers:
Without assuring proper material flow through the separator it is possible to load up the entire machine with material, thereby stopping any production and creating an incredible mess to clean up...especially in large unit such as used in cement production. Preventative maintenance must be performed to prevent wear through of parts and the shell of large separators. At hundreds of tons per hour, it doesn't take long for a leak to create huge cleanups and perhaps plant shutdowns. Also, internal inspections at reasonable intervals can prevent breakdowns and destruction of parts that wear through. Failing to lubricate, especially in high speed separator can cause bearing failure and unexpected shut downs and loss of production.
~General Corporate Mgmt, Hanover, MA
Yes, incorrect use of classifier - ball mill in closed circuit grinding of friable minerals have led to over grinding leading to slimes formation and subsequent extra lost besides reduction in capacity. Assuming the grinding nature of feed is same as that of concentrate has led to reduction in concentrating grinding capacity of iron ore concentrator to 50%. Besides people tend to forget that uniform ore bodies, representative samples, fool proof test reports and assumptions are myths.
~Belavadi Ravi, Research & Development, Bangalore, INDIA
Inefficient separating machinery is disastrous in itself. Consider how much money, time and effort go into making a product, only to have it go into a separator that sends good product back to the recycle instead of into the box, and contaminates the good product with oversize and fine particles. WTF????
~Bob Grotto, President/Ceo, Mamaroneck, NY
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FeaturesTop

Q:
What would your design or feature "wish list" be for this product?
14 answers
Answers:
I have always thought that a centrifugal decanter with double concentric drum should deliver dryer solids; if you can solve the problems involved with the bearings and a double screw conveyor driven by the same motor, the discharges of the liquid and solids.
~Israel Ortega, Marketing/Sales, Poza Rica / Veracruz, Mexico
High frequency wet screens, packed column jigs, pulsated jigs, spirals of varying contour to fit the granulometry and heavy-light mineral content ratios, HGMS, selective dispersion and flocculation of slimes followed by flotation-HGMS.
~Belavadi Ravi, Research & Development, Bangalore, INDIA
That they come already with a practical solution to remove the rejected part from screeners, the idea of inspection doors should be more evaluated and more natural for separations on air-solid system.
~Process Engineer, Balsa Nova, Brazil
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Buying AdviceTop

Q:
Do you have any advice for people relative to buying or using separators, classifiers and screeners?
9 answers
Answers:
Be sure to check out the moisture content as it can make a BIG difference in results. Too much moisture = bad separations. The same for humidity which is often overlooked at point of installation. Be sure the feed to the separator in an even and constant flow for a consistent product.
~General Corporate Mgmt, Hanover, MA
Factors in equipment selection: 1) type of material and characteristics (bulk density, hardness, particle size, abrasiveness, flow characteristics, moisture), 2) feed rate range (min/normal/max), 3) screening to be done wet or dry, 4) capital and o&m costs, 5) guarantees.
~Sebastiano G., Process Engineering Specialist, Panama, Panama
To be very careful of the process conditions. Some products can behave in a completely different way under high pressure conditions arised of the high g´s force of the centrifugal separator.
~Israel Ortega, Marketing/Sales, Poza Rica / Veracruz, Mexico
Please try this technology before settling for the existing, old fashioned screeners that have made mediocre results "good enough".
~Bob Grotto, President/Ceo, Mamaroneck, NY
Yes we ask them to get their material characterized and tested in lab / pilot mode and get data from firms already using them.
~Belavadi Ravi, Research & Development, Bangalore, INDIA
Make sure it's sized correctly and have lab tests run on YOUR specific material you are going to separate, classify or screen.
~Engineering, Process/Production, Louisville, MS
Do not buy a too little machine! Count on max. a 75-80% capacity load.
~Torben B. Madsen, Process Engineer, Helsinge, Denmark
Look for maximum efficiency separators.
~Ashok Rajasekar, Engineering, Process/Production, Chennai, India
Be realistic on production.
~Agus H, Process Engineer, Barcelona, Spain

Q:
Is there any advice you want to share with users to help them avoid common errors in selection or usage of separators, classifiers and screeners?
9 answers
Answers:
First look at the type of industrial applications (i.e. food, pharmaceutical, mining) of a studied equipment to see if its manufacturer is strong in the same industry application as the one required for the project; and if the manufacturer has experience handling similar materials as given for the application. If the material is atypical, then pilot testing could also be required.
~Sebastiano G., Process Engineering Specialist, Panama, Panama
Test house, manufacturer and industry is a TEAM where together everyone achieves more. Lost time and trust cannot be regained. There is no shortcut. Each process is unique and copying may not solve problems but may create some. The common errors always lie in different objectives of test house [operator], manufacturer and industry.
~Belavadi Ravi, Research & Development, Bangalore, INDIA
Look for the separators that operate at slow speed to minimize the breakage of material and wear on separator parts. Be sure the manufacturer has the experience and provides the advice and support you need to keep in production if the feed stock changes or other problems affect your separation.
~General Corporate Mgmt, Hanover, MA
The output capacity is very different of the hydraulic capacity of the high speed separator. In some applications output capacity can be the 50% of the hydr. cap. but the process requires longer retention times inside the separator to achieve the separation.
~Israel Ortega, Marketing/Sales, Poza Rica / Veracruz, Mexico
Yes - do not use the mesh system, do size your material and analyze the results. The system is vague and easily manipulated to "fool" customers into thinking they are getting efficient screening when they are not.
~Bob Grotto, President/Ceo, Mamaroneck, NY
Screening and crushing technology has improved in only the last few years. A screen is a screen is no longer the case, the industry has specialized.
~Agus H, Process Engineer, Barcelona, Spain
Run tests at the manuf. factories lab in advance with the real product, and let them give you a keen offer with guarantees on the yield.
~Torben B. Madsen, Process Engineer, Helsinge, Denmark
For products with a acid pH, always check the performance of the sieve material in the screener.
~Process Engineer, Balsa Nova, Brazil
Don't go too small, make sure you figure in peak flows so as not to flood the system.
~Engineering, Process/Production, Louisville, MS


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