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Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
1
Manufacturing Sand
This paper has been presented from an equipment supplier's perspective. It is theintention of this paper to walk you through some fundamentals in the total processof manufacturing sand.
We will take a look at the international scene and the developments that may wellbecome a part of the New Zealand scene.
History
Manufacturing sand used to be that stuff minus 6mm that those crushers produced.We called it crusher dust.
Some of us had to use Rod Mills or Cage Mills to grind or crush surplus materialinto minus 6mm material.
Some of us got to use a Barmac but it was still just minus 6mm. We gave it, we stillgive it names like AP6 or PAP6. It was seen as a necessary evil.
Customer Demands
Now our Portland Cement Concrete and Asphalt Concrete producer customers aredemanding much more from the "by-product".
Did you know that they are measuring
GradationShapeTexture
New Zealand Portland Cement specification is a performance based specification
• The amount of material retained on 4.75mm sieve shall not exceed 5% by mass.
• The voids content of the sand passing the 4.75mm sieve shall not exceed 48%.
• The flow time shall lie within limits set out in Table 3 of the standard.
• The individual flow times obtained do not vary by more than 2s from the averageflow time of 50 samples.
• Sand Equivalent not less than 60.
• Batching plant responsible for acceptable performance.
And their affect on the performance in concrete.
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
2
How do we measure the shape and texture. We measure the flow time through aflow curve
NSZ 3121 – Table 3
This is a New Zealand test which is fast becoming an International Standard.
How does shape affect concrete
Simply put, cubical shape decreases the surface area therefore reducing thecement content required for any given strength of concrete.
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
3
Particle Shape Affects
Flaky and elongated particles create:
• Poor workability.• High water demand.• High cement or bitumen demand.
Cubical aggregates and sand create:
• Excellent workability.• Excellent finishability.• Reduced cement or bitumen demand.• Higher compressive and flexural strengths.
Consistency
The number one requirement from our customer is consistency.
They need:
• Consistency of rock quality – soundness.• Consistency of gradation.• Consistency of shape.• Consistency of texture.
They can then design their mix designs for the various final concrete requirementswith confidence that it will perform as specified.
We need to design a process that produces a consistent product with the abovefour qualities in mind.
Process Plant Design
Let's go through the total process.
Primary Section - Considerations
• Removal of deleterious and plastic materials.
• Ability to manage variations of feed material, yet provide a reasonablyconsistent feed rate to the secondary crushing station.
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
4
The feeder and scalping unit needs to be sized to accommodate the variations inthe raw feed so as to provide the required feed rate to the secondary section.
Secondary Section
The secondary section needs to include devices that allow the crushers to be feedconsistently.
The items we need to consider are:
• Surge pile reclaim systems that avoid segregation.
• Surge bin prior to secondary crusher to have level controls and feed ratecontrols.
• Ability to adjust on-line the setting of the crusher.
• Use of automation that removes the human element and allows on streamadjustments to provide a consistent product.
Secondary crushing is all about reduction but it is important to start the process ofconsistency. Consistency of gradation and shape.
The most universal crusher type used in the secondary section is the cone crusherand the crushing action is a mixture of cleavage, shatter and attrition.
Primary Jaw Crusher
Scalp Material
Fresh Feed
Scalping Screen
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
5
The very best way to ensure the consistency of gradation and shape from a conecrusher is to choke feed the crusher consistently.
Crushing
Mantle
Concav
CSSOSS positionCSS position
Nominal stroke
Eccentricshaft
Pivot pointCrushing zone
Filling density
Bulk density
Cavity density
Concave
OSS positionCSS position
Attrition between particles
Higher cavity density increases interparticular crushing:• correct and constant feed fragmentation• choke feed• selection of parameters
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
6
However the final result from a cone crusher only plant can be a disaster.Complete circuit design including screening is very important.
The circuit in above is a typical circuit where "crusher dust" was produced with noreal thought about the shape of the final product (including the coarse aggregate).
1
t/
GranitRock
202 B13-44-
Load 32
Opening 1002010
10 3
Setting 90
C11
44
st3.7
10
10
4CVB1845-#40 mm/E94#25 mm/E95#6 mm/E82
37
16710
3
5
Stroke 25
GP200
69
coars2.7
Setting 32
16
16
6
Stroke 40
GP30
100
fin1.7
Setting 17
21
21
7FS#23 mm/E89#12 mm/E93#6 mm/E95
21 454
7
8
360/5m
79
235/10m
41
2610/20m
51
150/5m
3
1
10
21
21
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
7
The circuit in above is one that has the best opportunity to product a better shapedcoarse aggregate. All final products produced by tertiary crusher.
Note: i. CSS setting of final fine chamber cone crusher.ii. Surge bin ahead of final cone.
1
t/h
GraniteRock 600mm
3552 B13-44-2V
Load 57 %
Opening 65 mm355219
1373
Setting 100 mm
C110
79 %
std3.5
219
219
4CVB1845-3P#40 mm/E95 %#25 mm/E90 %#6 mm/E87 %
355
2204458
33
5
Stroke 32 mm
GP200S
74 %
coarse2.8
Setting 32 mm
220
220
6
Stroke 32 mm
GP300
100 %
medium fine2.1
Setting 17 mm
203
203
7FS 303#23 mm/E93 %#12 mm/E89 %#6 mm/E89 %
481 15915087
85
8
24 %0/5mm
859
24 %5/10mm
8710
42 %10/20mm
15011
9 %0/5mm
33
12
10 m3
203
203
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
8
However in our opinion the very best circuit will include a four stage. A Barmaccircuit above provides the very best opportunity to product coarse aggregate andsand of the very best quality – consistently.
Note: i. Use of surge bins and we recommend automation to include levelcontrols at each stage.
1
t/h
Granite600mm coarse
164
2 B13-44-2V
Load 28 %
Opening 65 mm164119
45 3
Setting 100 mm
C110
44 %std3.6
119
119
4
Stroke 25 mm
GP300S
62 %
coarse2.5
Setting 35 mm
203
203
5B280T#45 mm/E91 %#5 mm/E77 %
203
39141
23
7
14 %0/5mm
23
9 DS303#23 mm/E87 %#11 mm/E90 %#6 mm/E94 %
175
345232
57
12
32 %10/20mm
52
13
Stroke 32 mm
GP300
100 %
fine1.7
Setting 17 mm
175
175
14
10 m3
175
175
15TS302#10 mm/E100 %#5.5 mm/E91 %
89
123
65
16
15 %5/10mm
24
17
Cascade: 0 %
Barmac B6100
89 %DTR rotor
Tip speed: 55 m/s
1.4
89
89
18
10 m3
89
89
19
40 %0/5mm
65
Copyright Metso Minerals. All rights reserved.
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
9
Most importantly throughout the process we need to consider screening and withoutadequate screening capacity for control of cut sizes the quality of the aggregate andsand will be difficult.
It will be very difficult to control size, gradation and cleanliness of the aggregate.Without that basic control it will be impossible to control the quality and mostimportantly the consistency of the sand produced.
Things to consider when selecting a screen
• Screen size – adequate screen area for proposed production requirement.• Screen media for control and consistency of cut sizes.• Ability for dry screens to remain clean during wet weather.• Washing ability of screen or alternative washing system
Cleanliness From A Screen
• Do not skimp on the amount of water used, consider the feed arrangement.• Take attention with the design of spray bars with respect to number of decks.• Think about water carry over into product.
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
10
Cleanliness From A Screw
• Less water.• More wear.• Additional mechanical device and materials handling.
Final Design Criteria – Sand Specification
Before we finalise any circuit design in respect to how we handle the sand afterscreening is the Sand Product Specification.
Do we need to remove any of the minus 0.75mm material produced.
As we have seen many of the specifications do limit the percent of 0.075mmmaterial permitted.
If we need to modify the tail of the sand we will consider the following:
• Sand Screws
• Dewatering Screens
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
11
• Hydrocyclones
• Dry Classification – more about this following.
• Dewatering Wheel
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
12
Managing The Dirty Water
These days we have the increasing need to "manage" the dirty water. Be it from asand screw, dewatering screen, dewatering wheel or hydrocyclone.
We need to consider total water demand and the need to recycle water.
We need to consider the environmental issues.
We need to consider the way we handle the sludge.
There are many ways the sludge can be managed and today we see a combinationof the following used:
• Settling Ponds• Cyclones• Clarifiers
We do see more and more movement towards clarifiers and filters, or belt presstype processes.
The Lamella Clarifier being one type that provides a manageable sludge withreduced footprint, chemical and labour costs.
Lamella Clarifier
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
13
New Innovations – A Complete Dry Process
Our partners in Japan, Kemco, have developed a complete dry process – theKemco Dry Sand Making System.
They have some 40 units operating at an average total cost of around NZ$1.5million a piece.
They claim that in the market today they can put a business case forward that willsee the capital cost of the plant amortised over five years.
DustVibration
Filler tank
Rotary valve
BM7
Air screen
Water adding mixer
Diffusion
BM7 System
Blower
Prodt
Filler
Manufacturing Sand PaperInstitute of Quarrying Conference 2005
Presented by Ian Rodger – Metso Minerals (NZ) Ltd
14
Summary
As a supplier we ask you to consider the following:
• Please allow us to assist in the design of your circuit so you have consistency offeed to all stages of the process.
• Please consider automation of the process control to minimise variation of feedcondition to each process.
• Please consider the whole process from A to Z crushing, screening, watersupply/volume and treatment of waste water as a total process.
Final Statement
Quality is the elimination of variation.
Your customers want manufactured sand that is consistent in gradation, shape andtexture. Let your suppliers assist in circuit design that ensure consistency.
Ian RodgerGeneral ManagerMetso Minerals (New Zealand) Ltd
Tel: 07 881 9085e-mail: ian.rodger@metso.com
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