Installation Of M92 Alumina Tiles

Alumina ceramics are a special aluminum-oxide ceramic developed specifically for use as a wear resistant surfacing material. Harder than any naturally occurring substance except diamond, almost any surface subjected to sliding abrasive action can be protected with alumina ceramic. For example, it is being used to protect the metal surfaces of chute, bins, and hoppers, vibrating feeder pans, cyclones, centrifuges, conveyors, elbows and other equipment which is subject to severe abrasion.

Alumina ceramics are easily installed by plant maintenance people. They are available in standard brick and tile shapes as well as in special shapes to fit irregular contours.

Fastening the ceramic to metal or other backing material is accomplished by using cements, by mechanical means, or by a combination of cementing and mechanical attachment. The type of installation will determine which of the following methods to use.

Installation options

Application With Cements

Neat Portland cement (Masonry or White)

Neat Portland cement may be used to install ceramic brick in cylindrical shells or in confined areas, such as chute. Installation should be designed to utilize the high compressive values of cement since it adhesive qualities decrease with age. While Portland cement is used only when contamination colour is objectionable. Acid-resistant cement should be used where acids or other materials may weaken Portland cement. Fast-setting cement is desirable.

Epoxy Resin Cements (Megapoxy PM)

Epoxy Resin cement is recommended if lasting adhesive strength is required. Cementing alumina ceramics to a backing surface is similar to any other cementing operation. The epoxy cement selected must withstand maximum operating temperatures expected and must not be affected by any liquids that might be encountered. Special high-temperature heat-cure epoxies capable of withstanding 205°C temperature are now available and should be used if temperatures above 80°C are anticipated.

Silicone Rubber Cements

Several brands of silicone rubber cements are capable of withstanding temperatures up to 315°C, however, these have lower shear strength than epoxy resin cements. For many applications this is not a disadvantage. Silicone rubber cements retain a light resiliency which is an advantage if ceramic is subjected to impact.

Acid-Resistant Cements

Some installations may be exposed to acids that weaken cement bond strength. Cements are available which will withstand acid conditions. Users should follow the manufacturer’s recommendations in selecting the type of acid-resisting cement to employ for a specific application. We will be glad to suggest the names of several makers of special-purpose cements.

Attachment Made by Welding or Bolting

Welding

Under certain conditions it may be desirable to weld the ceramic in place when it is possible that the maximum temperature rating of an adhesive may be exceeded or if the simplicity of welding is preferred. Standard brick in 13mm to 50mm thickness aver. holes with a steel weld able insert. To attach, the insert is plug welded in place. Normal inserts are cold rolled steel, however, stainless steel 304 or 316 may be specially ordered. A ceramic cap is provided to protect the weld.

Bolting

As an alternative to welding the “weldable” brick, it may be bolted using a 6,35mm bolt. If a larger diameter bolt is desired for additional strength, brick with large holes may be specially ordered. Ceramic caps to protect the bolts are provided upon request.

Mechanical Restraints

Fasteners other than bolts or welding may be used. Similarly grooves or slots may be specially ordered for “T” retainers.

Attachment Utilizing prefabricated Panels

For many installations it is possible to pre-fabricate panels made up of alumina ceramic attached to a backing plate of steel or other material. The panels can then be installed as a unit on the surface to be protected. The backing material can be expanded, perforated or solid steel sheet or plate to which stud bolts have been welded to provide for attachment of panel.

Shaping Multotec MP92 Alumina Ceramic ON-THE-JOB

Special shapes of bricks are best made at the time of manufacture. For flexibility in filling in odd corners and narrow spaces, 6mm tiles can be manufactured with grooves arranged in different patterns so that they may be broken manually. However, it may not always be possible to foresee all the specials required. If necessary, field shaping can be done.

For most wear resistant applications, “rough” shapes will normally be satisfactory. These can be made by (a) scoring; (b) chipping; (c) cutting; or (d) heat shock. Although a diamond saw will give the cleanest cut, its cost or unavailability usually lead to using one of the other methods.

Scoring (3mm thick tile)

This method requires a diamond saw or a diamond, ceramic or carbide tool bit - in that order of durability - clamped to a tool holder for ease of handling. Bear down hard and scratch a line where the break is desired. Place the tile on a small steel rod, scratch side up with the scratch in line with the rod. Place a rag over the tile and bear down on both sides to break.

Chipping

Using a mason’s standard 350 gram brick hammer is the quickest and cheapest tool for “rough” shaping. Mastering the procedure requires a little practice following the ideas shown in these sketches. Repeated sharp blows along a line, holding the hammer for a “loose” swing all produce large chips. Start working about 6,35mm from the edge and continue until rough shape desired is being reached. Then switch to a “tighter” swing the complete hammer and forearm moving as a unit, and lowering the angle of the handle to accomplish the finish chipping. CAUTION - chips produced are very sharp and proper safety pre-cautions should be exercised. Chipping is most feasible on thick alumina ceramic.

Cutting

A lab or mason’s saw, such as a Clipper Saw, with a diamond blade of about 10 grit and 100 concentrations, operating at high speed, will cut alumina ceramic. A coolant must be used on the blade, following the instructions of the blade and saw manufacturers. Since alumina is similar in hardness to sapphire and tungsten carbide, these types of blades will not usually be economical. Sawing is most feasible on thin alumina ceramic.

Heat Shock

This method utilizes equipment normally found in most work ships, and although more time consuming than chipping, will produce better parts. The basic idea is to concentrate an intense heat along the desired break line and cause the differential thermal expansion or heat shock, to fracture the ceramic.

An oxy-acetylene unit is required, since a butane flame is not hot enough.

Put ceramic flat on bench, and lay two 6.35 thick pieces of steel on tile, leaving a 3mm slot at desired break line.
One of the following tips is recommended for best flame size: Linde No. 15,
Smiths No. MW108 or Oxweld No. 20. A hole size about equal to a No. 52 drill is good.

Feather flame for a 9.25mm to 12.7mm long hot zone and apply tip of this bright
blue cone to the tile surface.
Play torch back and forth in slot - faster on thin tile - keeping at least 6.35mm from any edge of
tile. Swelling will cause tile to spall.
No mechanical pressure is required to break the tile. The action is purely thermal.

Warning: use appropriate protective equipment. Protect face with clear plastic hood and
button shirt at collar in case the tile does split.

Nibbling

Another approach to shaping thin (up to 6,35mm thick) alumina tile is by nibbling. This can be done effectively using a pair of mechanic long handle pliers. The tile is gripped in one hand and the pliers are held in the other (If the ceramic tile is too small to be held in the hand conveniently, it may be held with a regular pair of pliers while it is being shaped). A small (2mm or less) bite of ceramic is taken with the tip of the jaws. The top jaw of the pliers should be angled approximately 20° to 40° from the top of the tile. Experience will show what angle works best for each person. This creates a point-loaded stress on the ceramic and it will chip, often leaving the chip held in the jaws of the pliers. A little practice will let you chip off a uniform straight line or even circular cut-outs and square corners.

Caution: These chips are very sharp, including those still held by the pliers. Be careful! Use gloves and safety glasses.

Selection of Blades for Cutting Alumina Tiles

Saw Blade diameter: As specified by saw manufacturer,
(Typical 225 - 250mm diameter)

Saw Blade width: 2,3mm

Diamond grit size: 100 - Variable

Diamond concentration: 75 – Variable.

Bond: Brass

Blade speed: As specified by blade manufacturer, (typical)
850 RPM or Tip Speed of 2,225 FPM)

Coolant: Water is suggested

Blade dressing: Dress as necessary using abrasive stone.
(Typical silicon carbide, pumice abrasion stick or
refractory brick).

Attaching Alumina Ceramic by Bolting

Under certain conditions it is desirable to bolt the ceramic in place in addition to or instead of cementing. One such situation is an application that will - or just might - exceed the maximum temperature rating of the adhesive especially if the ceramic is so located that it could slip or drop off. Another situation is one that is in motion so that reciprocating or rotating forces are present. When bolting is required the ceramic must be ordered with bolt holes. It is not feasible to add the holes in the field. Standard weldable brick may be fastened with a 6mm bolt.

After the ceramic and mounting surface is clean, check layout of ceramic to
insure proper fit, allowing for thin cement joints, and then transfer punch the hole
locations.
For 6mm bolt, drill 8mm clearance holes for bolts (or tap 6mm holes if projections
on the back side of mounting surface CANNOT be tolerated).

As each ceramic is cemented in place, insert flat head bolt with soft, compress- ible washer through ceramic and mounting surface and install lock washer and nut. (If tapped hole is used install long headless screw from back while cementing and then run screw up through the ceramic to clean the tapped threads. Finally, install bolt with washer through ceramic and screw into mounting surfaces).
Tighten to maximum of 5,42Nm (Newton metres).
Do not use excessive cement as it will only provide a weaker bond. The proper amount will be that sufficient to provide a good seat for the ceramic. Cement should be of type that does not shrink as it sets, as there should be no need to re-tighten bolts after cement has set. (Both the soft washer and cement are used to distribute pressure on the ceramic, avoiding stress concentration at a single point.)
If a high temperature application does not permit the use of bedding cement, or if easy removal of the brick is desired, use a compressible gasketing material to “bed” the ceramic. Caution that the coefficient of expansion for most epoxies is half that of plain steel.

Attaching Alumina Ceramic by welding's

Multotec MP92 weldable ceramic brick is used for ease of installation and for high temperature applications. By using weldable ceramic, a wear resistant ceramic surface can be easily applied to any weldable surface. Each brick is provided with a pre-installed, force-fit steel welding insert (see Fig. 1). The force-fit insert will remain in place during handling regardless of the position of the brick. This MP92 feature is particularly helpful for overhead installations.

All weldable MP92 bricks are furnished with inserts in place
Caps included with all bricks

Multotec MP92 weldable brick is available in numerous standard sizes in 13mm, 15mm and 50mm thickness. Brick up to 100mm x 150mm have a single welding hole, while larger brick sizes have two holes with two welding inserts.

Welding Techniques

The normal insert is cold rolled steel which can be plug welded using conventional procedures. For corrosion resistant applications stainless steel type 304 or 316 inserts are available. Plug weld to fasten the bottom edge of the insert to the backing plate (see Fig. 3). Do not fill the insert more than 1/3 full or thermal shock (cracking) may result. Do not splatter the weld as it may interfere with the fit of the protection cap. Verify that you have a good weld.

Wire Welding (MIG Progress)

Use a mild steel wire (typically of approximately 1.14mm diameter. Set the machine at about 200 volts and 200 amps for a smooth sputtering arc. Gas flow should be low, about .22 - 28 cubic metres per hour.

“Sticks” or Manual Welding

Multotec provides a ceramic cap (plug) to cover the weld insert. Normally the same cement or adhesive used as a bedding material can be used to hold the cap in place. The standard cap is a “loose” fit “Dee” shape to facilitate installation with the high viscosity silicone rubber adhesive. You may order a “tight” fit circular cap for special applications such as direct impingement.

Installation Procedure

Recommended Bedding Material: Always use a bedding material with weldable brick.

The use of a silicone adhesive bedding material may be advantageous when installing Multotec MP92, 1) by securing the ceramic in place while welding; and 2) increasing impact resistance. Silicone rubber adhesive is ideally suited for this application due to it’s higher than normal viscosity. A small 6.35mm diameter bead on the brick underside and between each edge is all that is normally required. (See Fig. 2)


6.35mm bead on brick underside Figure 2: Multotec MP92 brick Bedding material	Backing plate F Figure 3:Multotec MP92 Cross section

6.35mm bead on brick underside Backing plate F
Figure 2: Multotec MP92 brick Figure 3: Multotec MP92
Bedding material Cross section

Optional Bedding Materials:

For applications above 205°C but below 315°C Multotec MM500HT may be used. Above this temperature the use of cement such as MM400 is suggested.
For application where a more rigid base is desired and temperatures are low, the use of an epoxy resin adhesive may be used.

When installing, leave area near the hole clear of cement or adhesive to facilitate welding operation.

Silicone Adhesives

Silicone adhesives are specially formulated material for weldable brick or as an adhesive where epoxy is not suitable. They can also be used to bond, seal, gasket, repair, weather proof and insulate.

Important considerations:

Easy to use, single component
Room temperature cure
High resistance and moisture
High resistance to aging
Stays flexible and remains functional in temperatures as low as 24°C below zero
Can withstand temperatures as high as 315°C for extended periods.
Higher “tack” - strength - helps hold tile in place during installation.
Available in 315gr disposable tubes.

Typical properties: the following table lists the typical physical properties that can be expected from a 2mm thick film cured seven (7) days at room temperature 23°C and 50% relative humidity.

Specific Gravity: 1.05
Functional Temperature Range: 70°C to 315°C
Tensile strength: 28.1 kg/cm²
Tear strength:: 2,81 kg/cm²
Elongation, %: 600

(These values listed above are typical values).

Curing characteristics - silicone adhesive cures due to the presence of humidity in the air. Depending on temperature and humidity tack free time for Silicone Adhesive is between 10 and 30 minutes. Cure rates can be quickened by increasing temperature to 65° - 120°C. Optimum physical properties are obtained after full cure - 7 days at room temperature at 50% relative humidity.

Silicone Adhesive

When installing large flat bricks, use a bead approximately 6mm wide, about 13mm from edges. A silicone room temperature cure will only cure for about 20mm from the edge. Wider areas will not cure as the adhesive seals itself at the edges and does not permit the moisture to react with the inner adhesive.

Attaching Alumina Ceramic to Metal Using Epoxy Resin Cement

The cementing of alumina ceramic to a metallic backing surface in many ways is similar to any other cementing operation, plus a few additional details that will ensure the best possible bond. Epoxy resin cement is recommended if a lasting adhesive strength is required. Check operating conditions, especially maximum temperature and solvents before selection of epoxy adhesive.

Carefully follow instructions for the selected adhesive.

Surface preparation

Heavy coatings of grease or oil should be cleansed with lacquer thinner, acetone, or similar solvent. Clean the surface to be lined of all grease, oil, rust, scale and water by grit or sandblasting. The surface may be ground or wire brushed if unable to sandblast. If compressed air is used to clean surface, be sure air has an adequate oil filter to prevent coating surface with an oil skim.

Clean ceramic of all dirt or loose calcine (ceramic sand on surface). Excessive calcine can be removed by rubbing two ceramic pieces together. Lay out the brick in place to insure proper fit before starting to bond. Allow enough space between the tiles for adhesive joints. Stagger joints in direction of material flow.

Rubber gloves should be worn while mixing and applying epoxy adhesives. Use in a well ventilated area.

Within the temperature limits given for the selected epoxy the curing time can be reduced by either heating the adhesive (in the sun, placing containers in a hot water bath etc.) or gently heating the metal surface with a torch.

Mixing

The mixing ratio of the adhesive should be carefully followed. Scoop out required portions of resin and hardener onto a mortar board or any other clean mixing surface. Mix the two ingredients until a uniform colour is attained. Before applying, scrape down to the mixing surface and fold the mixture over on itself several times to insure thorough blending.

Application

Apply adhesive to a thickness of approximately 1mm on the area to be lined. “Wet” the total surface with the adhesive. Apply only to an area which will be covered by brick within the working time of the adhesive. Next groove the adhesive using a corrugated trowel.

Place brick on the coated surface about 10mm away from the desired location. Exert heavy downward pressure on the tile and slide it into position. This will insure good contact between the two surfaces. Be careful not to trap pockets of air between the brick and base. Wipe off the excess adhesive that has squeezed out from the joints between the brick before it starts to harden. Do not clean the ceramic until adhesive has been cured. Thicker adhesive joints may be used if necessary due to loose fit of brick, and it does not affect wear resistance of the application. The strongest epoxy joint is usually 0,5mm to 1mm thick.

Clean Up

Tools may be kept clean by vigorous washing in hot soapy water before the adhesive hardens or by using a recommended solvent. When using epoxy adhesives, maintain proper VENTILATION in the immediate area.

CAUTION: Avoid contact of epoxy adhesives with skin - rubber or plastic gloves are helpful. Any material on the skin should be removed immediately with soap and water. Do NOT use solvents. Should epoxy adhesives get into the eyes, flush immediately with running water and contact a Doctor. Clothes soiled by epoxy adhesives should be laundered before they are worn again.

Radial Brick

Radial Brick are made pie-shaped for use in locations where concentric courses are required. The brick are made from standard 100 x 150mm Multotec SA90 blanks and are available in all standard thickness.

The drawing above shows a target-shaped area lined with Radial Brick. The brick at left illustrates the pie shaped that is unique to a radial brick design. The dimensions of the brick are calculated to ensure close fit between courses. The uniformity of brick also contributes to tight joints.

By adding side angles to the radial brick, it becomes a simple matter to line a conical surface, as shown in this sketch. Examples of conical linings would be a cyclone or a conical hopper. Linings of this type require some engineering to ensure best fit.

Designing With Multotec Alumina Ceramics

Engineering designers today are faced with an extensive choice of available materials to utilize in their quest for an improved product or process. Some of these materials have been developed by new technologies, others have been with us for centuries but in either case the successful application of the material is often doomed from the start because of insufficient knowledge and poor design application.

Ceramics are no exception to this. It is a frequent mistake to attempt to replace a troublesome component with an identical ceramic item. Designers often forget that the shapes of most components have been based on the way in which the chosen material can be fabricated, usually by casting, moulding or machining or whatever method is convenient and economic and this is so often related to the quantity required. For example, metal components produced in small batches by turning and milling take on a completely different cross section when produced in large quantities by casting; sections become thinner and stiffening ribs are introduced.

When a ceramic material is to be used in an engineering application it is essential to consider the properties of the ceramic itself and the ways in which it can be fabricated. The term “ceramic” applies to a very wide range of materials from porcelain and steatite right through to silicone nitride and silicon carbide, but for the purpose of illustration we shall confine ourselves to the more widely used “alumina” or aluminum oxide.

Design Procedures

In most cases a re-design or re-think of the application would be beneficial in ensuring a reasonable change of success and in doing this the following considerations are necessary:

What is the basic function of the component and what properties are we trying to improve, i.e. resistance to chemical attack, wear resistance, extended use at elevated temperature, etc.?
Are we looking for an improvement in performance or merely a saving in cost?
Ignore the present shape of the component and outline in engineering terms what it has to do.
Produce an outline design utilising the good properties of ceramic and minimising the poor ones. Detail what factors are essential and which can be varied.
State quantity requirements both immediate and future. These have a significant influence on the chosen method of manufacture. If possible, state a target unit price.
Above all, seek advice from a ceramic manufacturer as early as possible in the design program.

Method of Manufacture

The overall process and individual fabrication method obviously has a direct influence on what can or can’t be made. Alumina ceramics are manufactured by first ball milling or fluid energy milling raw aluminum oxide to a fine particle size. The materials are then debased by the addition of clays to make the body plastic and easy to form, and fluxes to drop the firing temperature. The resultant slip is then spray dried to give a free flowing powder. Control of the particle size is critical to the final quality of the product and is the primary agent in influencing firing shrinkage and dimensional control.

Subsequent production methods and limitations associated with them are:

Extrusion - The powder is re-mixed with various organic binders and controlled moisture content and extruded through a nozzle of the required cross section. The general manufacturing tolerance is ± 0.2mm or ± 2% whichever is the greater.

Limitations: symmetrical cross sections are preferable, thin wall tubes where wall thickness are less than 1/10 of the diameter should be avoided - sharp corners rounded off.

Dry pressing - Powder containing suitable binders is fed into a tool cavity and compacted, with vertical pressure only, into the required shape. This process is well suited for mass production and automatic presses with multi-impression tooling can produce hundreds of components per minute. Close tolerance control on dimensions can be maintained by this method, ± 1% is now normal by monitoring pressed weights and densities and in extreme cases ± ½% has been achieved.

Limitations: long thin articles; thin plates where length to thickness ratio exceeds 25:1; cavities or counter bores greater than 1/3 of total component depth should be avoided; avoid deep small diameter holes and feather edged components.

Isostatic pressing - powder is placed in a rubber mould or sack, sometimes with a central mandrel, immersed in a pressure vessel of liquid and the pressure increased to compact the article. This is obviously a slower method of production than dry pressing but is ideal for producing large blanks of material within uniform “green” density. The technique has been utilised to the full extent in the production of spark plug bodies because of the ability to produce long thin articles with a complete bore form.

Limitations: Very few except for the need to carry out a forming operation on the outside of the blank after pressing but even this has been automated on spark plug production.

Injection moulding - as with plastic moulding this is a process which permits intricate machining. The ceramic powder is hot-mixed with thermoplastic resins and plastisers then cooled and granulated. These granules are then fed into injection machines with the thermoplastic completely filling the interslices between the ceramic crystals. The injected material behaves as an incompressible liquid producing a consistent unfired density. The removal of excess thermoplastic is essential before firing.

Limitations: Generally confined to small components of a few hundred grams in weight - limiting factors tend to be thick wall sections giving rise to voids.

Tape casting - this process was prompted by the problems experienced in the dry pressing of thin plates whose lateral dimensions/thickness ratio exceeded 25:1. In tape casting the ceramic powder is blended into an organic binder/carrier and the resultant slurry cast onto glass or metal trays under a doctor blade. After evaporation of the carrier the pliable tape can be stored for subsequent blanking operations of desired shapes.

Limitation: thickness in excess of 1.25mm.

Components produced by any one of the five processes outlined are frequently subjected to further machining operations to achieve the final desired shape prior to firing or sintering. These operations are quite normal turning, milling or drilling methods.

During the sintering operation a general shrinkage of 15-20% takes place and it is the problem of predicting this shrinkage that brings about the need for a general manufacturing tolerance of ± 0.2mm or ± 2% whichever is greater.

Post-firing machining operations are carried out by diamond grinding and tolerances of ± 0,01mm can be held consistently. It is worth noting, however, that the desirable hardness quality of alumina ceramic becomes a drawback in that diamond grinding is a costly operation and can quite easily increase a component price tenfold. Designers should therefore pay very careful attention to the costs associated with quoting unnecessarily tight tolerances.

General Considerations

Physical dimensions - apart from the specialist manufacture of long thermocouple tunes the maximum dimensions that can be manufactured are measured in mm rather than metres. Thin walled tubes of 750 x 750mm long have been manufactured but difficulty would be experienced in firing a solid mass 200mm³.

Brittleness - critical strain in ceramic is 0.1 per cent when fracture occurs usually by surface crack propagation. This lack of ductility prevents the ceramic from accommodating stress concentrations with consequent poor impact resistance. Design should, therefore, eliminate these stress concentrations by avoiding sharp corners and adding a radius of chamfer to edges. Soft PTFE or nylon bushes can be used to relieve a concentration.

Mechanical strength - alumina ceramics have ten times the strength in compression that they have in tension therefore designs should be based on using the compressive strength where possible, as in the manufacture of aerial insulators.

Thermal shock - this is an arbitrary criterion determined by a balance of mechanical strength, thermal expansion, thermal conductivity and geometry of the component. Although alumina can withstand temperatures of up to 1700°C depending on the grade, it is limited in its capability to withstand sudden changes in temperature.

Versatility

The authors company has produced many thousands of different shapes in alumina ceramics. They are in use in the nuclear, aircraft, plastics, textiles, steel, paint, electrical and electronic, wire, food and refractory industries.

Alumina ceramic can be specially formulated for specific applications. Thus a certain composition can be made acid resisting whilst a different formula is used for ceramic tool tips. There are in commercial existence perhaps 40 - 50 compositions.

List of Some Typical Materials Handled

Alumina, Asbestos,Wood chips, Bark, Bauxite, Borax, Cement, clinker, Clay, Coal -crushed and pulverized, Coke, Copper Ore, Dolomite, Feldspar, Glass Cullet, Grain, Iron Ore, Lead, Zinc Ore, Limestone, Perlite, Phosphate, Quartz, Sand, Sinter, Sulphur,Taconite, Talcum

Typical Coal Preparation System Applications of Multotec MP92

Component recommendation

COMPONENT	RECOMMENDATION
Crusher by Pass Chute	100 x 150 x 25mm Multotec MP92 brick, epoxy bottom and sides.
Raw Coal Belt	13mm thick 100 x 150mm Multotec MP92 brick, welded on skirt board liners, 25mm or 50mm thick epoxies on panels in transfer sections.
Raw Coal Silo Distributor Chutes	25mm thick 100 x 150mm Multotec MP92 brick epoxy.
Vibrating Feeders	Light Duty - 6mm thick 100 x 100mm Multotec MP92 tile. Heavy Duty - 13mm thick 100 x 150mm Multotec MP92 brick welded.
Diverter & Diverter Gate	25 or 50mm thick 100mm Multotec MP92 epoxy.
Surge Bins	25mm thick 100 x 150mm Multotec MP92 epoxy.
Screens	25mm thick 100 x 150mm Multotec MP92 epoxy in feed and overflow chutes.
Cyclones	Solid ceramic - total cone or apex valve vortex finder 13mm special shapes in fines system, 25mm special shapes in oversize and sand systems epoxy.
Dewatering Centrifuge	13mm special tiles on screw flute edges welded.
Feed Pipes	Special shape inlet port and epoxy. Also housing 6mm tiles, 6mm or 13mm thick tiles in elbows and transition areas epoxy.
Refuse System	25mm thick 100 x 150mm brick in chutes and deflectors epoxy.

Uses of Multotec MP92

The Uses of Ceramic Tiles in the Wash Plant

Ceramic tiles have been used extensively as liners in chutes, spouts, collection boxes and launders in the wash plant. The use of this ceramic material is found in the heavy media cyclone circuit, the tromp section, the de-sliming circuit and the magnetite circuit.

The H.M. cyclone circuit is the most complete ceramic lined circuit in the wash plant. The following areas are lined with ceramic tiles:

All the H.M. cyclone underflow and overflow boxes
Feed spouts to each screen
The discharge launders (except the reject screen)
The centrifuge feed chutes and by-pass chutes
Top and bottom tandem sieve bend discharge chutes

The following have been recently ordered by not yet installed:

Tandem sieve bend collection boxes
Tandem sieve bend feed spouts and launders

The material passing through these chutes are mainly 3/8” x 28 mesh clean coal rejects, either in slurry form or with about 35% moisture.

The use of ceramic tiles in the tromp section is found mainly in the slide chutes for raw, coal, clean coal and rejects. The tromp reject chute is also lined with ceramic tiles. The material passing through these chutes is mainly 6” raw coal and 6” x 3/8” clean coal and rejects.

The launders for the deslime screen overflows are all lined with ceramic tiles. Some ceramic lined feed chutes to the deslime screens have recently been ordered and are to be installed soon. The material treated in this circuit is 3/8” raw coal.

The rapid magnetic separator discharge chutes are lined with ceramic tile. The collection box on top of the over dense tank is also lined. These chutes and collection box have been recently installed. The material handled in this circuit is mainly 90% - 95%, 325 mesh magnetite slurries.

Application Schematics

KEY	COMPONENT	RECOMMENDATION
1	Dump Hopper	Impact plate = 25mm or 50 x 100 x 150mm plain
2	Dust Collector System	Lined elbows - 6mm 25 x 100mm plain
3	Reciprocating Plate Feeder	Impact plate = 25mm or 50 x 100 x 150mm weldable
4	Vibrating Grizzly	Bottom section 25 x 100 x 150mm weldable
5	Pan Feeder	Bottom and side walls 25 x 100 x 150mm weldable
6	Transfer Point	Impact panels & skirt boards 25 x 100 x 150mm weldable
7	Transfer Point	Side panels 25 x 100 x 150mm weldable
8	Crusher Feed Chute	Wear panels 25 x 100 x 150mm plain
9	Stockpile Transfer Point	Tripper chute/skirt board 50 x 100 x 150mm plain
10	Stockpile Chute	Bottom chute/skirt board 50 x 100 x 150mm plain
11	Scrubber	Feed chute 6mm to 13 x 100 x 150mm plain
12	Ball Mill	Feed chute 6mm to 13 x 100 x 150mm plain
13	Cyclone	Apex valve, vortex finder, liner
14	3-Way distributor	Sidewalls & deflectors 13 x 100 x 150mm plain
15	SD Mag Separator	Drums 6mm curved tiles
16	10 Way Distributor	Sidewalls & deflectors 13 x 100 x 150mm plain
17	4 Way Distributor	Sidewalls & deflectors 13 x 100 x 150mm plain
18	Cyclone	Apex valve, vortex finder, liner
19	TD Mag Separator	Drums - 6mm curved tile
20	Dryer	Feed spout - 13 x 100 x 150mm plain
21	Dryer	Dump spout - 13 x 100 x 150mm plain
22	Stockpile Transfer Points	Tripper chute 13 x 100 x 150mm plain

Typical Multotec MP92 Applications

Air Conveying System Liners, Bins, Bunkers, Hoppers, Blast: Furnaces - skip cars, weigh hoppers, receiving hoppers, Conveyor skirts, conveyor transfer points, Chemical Reactors, Chokes and Reducers, Chutes, Slides, Classifiers, Cyclone Dust Collectors, Ducts, Fans – Housings, Feeders, Tables, Vibrating, Grinding Mills, Feed and Discharge Chutes, Gas Scrubbers, Grizzlies, Grates, Wear Bars, Mixers, Blenders, and Mullers.

General Material Handling Equipment
Orifices, Spouts, and Slide Valves, Rock Boxes, Plows, Scrapers, Screw Conveyors - flights and troughs, Liquids and Solids Separators, Skid Rails, Guides, Throats and Elbows, Troughs and Launders, Slurry Pipes, Vibrating Chutes, Vibrating Feeder Pans, Cyclone Units.