Fiber, Filler and Fines

Fiber

In the way of paper manufacture even is pulp or recycle paper used fiber. fiber or fibre are the slender, thread-like cellulose structures that forms the main part of tree trunk and from separated and suitably treated, cohere to form a sheet of paper.

Softwood Fiber

Internal Structure

Fiber

study about fiber is closely related to the filler in papers and a variety of terms associated with the word. Below are some words related to fiber

• Fiber cut            -----> A fiber cut is a short, straight cut located on the edge of the web, caused   by a fiber embedded in the web of paper
• Fiber Coarseness -----> weight/unit lenght of fiber
• Fiber debris        -----> Pieces of material which has been separated from the main body of the fiber
• Fiber flock         -----> fiber that have agglomerated as a result of poor formation
• Fiber orientation-----> Refers to the alignment of the fibers in the sheet
• Fiberboard        -----> Board made from defibrated wood chips, used as a building board
• Fibrillation        -----> A structural change occurring in the wall of chemical fiber during beating
• Fibrils              -----> String-like element that are loosened from the paper fiber during the beating process.They aid in the bonding processes when the paper is being manufactured
• Fiber axis Ratio   -----> Ratio of fiber width to fiber thickness

Filler

Filler reduce strength properties of paper. Most of filler are cheaper than fibers and so filler are added to reduce the overall cost of paper.

Any inorganic substance added to the pulp during manufacturing of paper.  Filler are also used to improve optical and other print-ability related properties. Filler improve opacity and brightness.  

Test	Increased	Decreased
Brightness	+	-
Bursting Strength	-	-
Caliper	-	+
Dimensional Stability	+	-
Folding Endurance	-	+
Ink absorbency (Uncoated paper)	Gets more uniform	Gets less uniform
Internal Bond Strength	-	+
Opacity	+	-
Picking Resistance	-	+
Rattle	-	+
Smoothness	+	-
Stiffness	-	+
Tearing Resistance	-	+
Tensile Strength	-	+

Fines

Small particles fiber defined arbitrarily by classification. 

Retention

The amount of filler or other material which remain in the finished paper expressed as a percentage that added to the furnish before sheet formation. Retention can occur by various mechanisms. The simplest of these is mechanical sieving by the forming fabric. Once a fiber mat begins to form, the mat itself usually can act as a much more effective and finer sieve than the forming fabric. But even then, particles less than about 10 micrometers in size are not effectively retained by sieving. Rather, retention of fine particles requires the action of colloidal forces, including polymeric bridging or a charged patch mechanism. Retention aid chemicals can be effective either by attaching fine particles to fiber fines or fibers or by agglomerating them so that they can be sieved more effectively.

Retention Aid

Chemical additives, especially high molecular weight copolymers of acrylamide, designed to increase the retention efficiency of fine materials during paper formation.

First Pass Retention

First-pass retention gives a practical indication of the efficiency by which fine materials are retained in a web of paper as it is being formed. First-pass retention values can be calculated from just two consistency measurements, the headbox consistency, and the white water consistency. There is a very wide diversity of first-pass retention on different paper machines, from less than 50% to almost 100%. The key rules that papermakers follow are that (a) first-pass retention should have a steady value, and (b) that value should be high enough to avoid operational problems or an excessively two-sided sheet. Some operational problems that can be caused by low values of first-pass retention.

How to check silo overflow to calculate the fiber loss

First you have to prepare some data for: 

How to check silo overflow to calculate the fiber loss
The data need to be taken:
1. level (%)
2. flow rate in ml / (1 / 1000) seconds on the conversion to liters / sec
3. data consistency (%)
4. Data ash content (%)
The data above is required to calculate the fiber loss (kg / day), ash loss / day

Supporting data for the parameters that need to be made is
1. pH
2 temperature (oC)

CHECK	25-26 Feb 11
	pagi	siang
Level (%)	94,5	94,5
flow rate (Liter/sec)	2.70	0.97
consistency (%)	0,25	0,27
ash (%)	34.13	36.00
	583	226
fiber loss(Kg/day)	384	145
ash loss(Kg/day)	199	81
pH	7.04	6.98
Temp	44	44

calculation

a. Calculate the fiber loss (kg / day)

Fiber loss = (Flow Rate x 60 x 1440 x% consistency) - ash loss

b. Calculate ash loss (kg / day)

Ash's loss = (Flow Rate x 60 x 1440 x% consistency) x ash content (%)