Primary material sources Notes — AQA Design and Technology 8552

Identify the primary sources of materials and explain the main processes involved in converting them into workable forms.
Describe how cellulose fibres are derived from wood and grasses and converted into paper and board.
Explain the seasoning, conversion, and creation processes of natural and manufactured timbers.
Understand the extraction and refining processes required for metal-based materials.
Describe the processes of refining crude oil, fractional distillation, and cracking to produce polymers.
Explain how raw materials are obtained from animal, chemical, and vegetable sources, and processed and spun into textile-based materials.

From natural resources to usable materials

A factory rarely starts with a tree, a lump of ore or crude oil. These primary sources must first be processed into materials that manufacturers can work with. The resulting stock forms include timber planks, metal sheets, polymer granules and rolls of fabric.

The useful connection is source → processing → workable material. Processing may separate useful fibres, remove unwanted substances, reduce moisture or change molecules chemically. Understanding this journey also helps designers recognise the resources and energy needed before manufacture even begins.

Paper and board: separating and joining plant fibres

Paper and board are made from cellulose fibres, found in the cell walls of plants. Trees are a major source, but grasses and bamboo can also supply cellulose. Used paper can provide recovered fibres rather than relying entirely on newly harvested plants.

For wood-based paper, trees are felled, branches and bark are removed, and the wood is chipped. The chips are broken down by pulping, for example by cooking them with chemicals, to release the fibres. The result is pulp: a wet mixture containing separated fibres.

The pulp is cleaned and may be bleached when a white material is wanted. Bleaching is not essential for every paper or board; unbleached pulp retains a brownish colour. The wet pulp is spread into a continuous layer, then pressed and dried using rollers. As water is removed, the fibres form a connected sheet.

The sheet can be supplied in rolls or cut to size. Thickness and further processing determine the resulting paper or board. For example, corrugated card has a fluted paper layer between flat layers, rather than simply being one very thick sheet. Recycled paper follows a related route: it is re-pulped and formed into new sheets.

Natural timber: conversion and seasoning

Timber comes from trees, including both hardwood and softwood species. After felling and removing branches and bark, the log is sawn into usable sections. This is conversion. Plain sawing and quarter sawing are different ways of arranging cuts through the log to produce planks and boards.

Freshly cut timber contains moisture. Seasoning reduces this moisture before the timber is used. It helps limit later changes in size and shape as the wood dries, reducing problems such as shrinkage and warping.

In air seasoning, boards are stacked with spaces between them so air can circulate. They are sheltered from rain while moisture gradually leaves the wood. In kiln seasoning, timber is dried in a chamber with controlled conditions. This allows drying to be managed more quickly and consistently.

The seasoned timber can then be planed and cut to its final dimensions. Planing removes thin layers to produce flatter, smoother surfaces. The resulting stock forms include planks, boards, sections and dowels.

Manufactured timber: rebuilding wood into boards

Manufactured timber is made by bonding wood material together. It is not simply a solid plank cut from a tree. This allows wood layers or smaller pieces to be converted into useful sheets.

Plywood is made from thin layers of timber called veneers. These are glued together with the grain direction of neighbouring layers usually at right angles. The crossed arrangement helps produce a strong, rigid board.

Chipboard is made from wood chips and particles mixed with adhesive, compressed and formed into sheets. This provides a route for using smaller pieces of wood and some timber-processing waste.

These routes differ from seasoning: seasoning removes moisture, whereas making a manufactured board joins wood material into a new structure.

Metals: extraction followed by refining

Most primary metal production begins with ore mined from the ground. The useful metal is often present as a compound mixed with other rock material, rather than as a ready-to-use piece of pure metal.

Extraction obtains the metal from its ore. The method depends on the metal. Smelting uses high temperatures and chemical reactions to obtain certain metals; it is more than simply melting the rock. Unwanted material must be separated from the useful metal.

Aluminium follows a different route. Its ore, bauxite, is refined to produce alumina, or aluminium oxide. Aluminium is then extracted from alumina by electrolysis, using an electric current.

Extracted metal may still contain impurities. Refining removes unwanted substances so that the metal is suitable for its intended use. The metal can then be cast into blocks called ingots and further worked into sheets, bars, rods or tubes. Extraction, refining and shaping therefore have different jobs: obtaining the metal, improving its purity and producing a usable form.

Polymers: separating, breaking and joining molecules

Many common synthetic polymers begin with crude oil, extracted from underground by drilling. Crude oil is a mixture of hydrocarbons, so it must be processed before suitable starting materials for polymers can be obtained.

During refining, fractional distillation separates crude oil into fractions with different boiling ranges. The oil is heated, and substances condense at different temperatures. This separates the mixture; it does not turn the oil directly into plastic.

Cracking breaks some large hydrocarbon molecules into smaller ones. Some of these smaller molecules can act as monomers, the building blocks of polymers. During polymerisation, many monomers join chemically to form long molecular chains.

The polymer is then prepared in a workable form, often pellets or granules. Manufacturers can process these into products or other stock forms such as sheets, films and rods. The key sequence is therefore crude oil → separated fractions → suitable smaller molecules → polymer → workable form.

Textiles: obtaining fibres and making yarn

Textile fibres have animal, vegetable or chemical sources. Wool comes from sheep, cotton from cotton plants, and synthetic fibres such as polyester and nylon are made from chemicals commonly derived from crude oil.

For natural fibres such as wool and cotton, the raw material is collected, sorted and cleaned. The fibres are prepared and aligned, then spun into yarn. In this form of spinning, fibres are drawn together and twisted so they hold as a continuous thread. Yarn can then be woven or knitted into fabric.

Synthetic fibres follow a different initial route. A suitable polymer is produced and forced through tiny holes to form fine, continuous strands called filaments. These are solidified and prepared for textile manufacture. Here, fibre spinning means forming the strands, rather than only twisting short natural fibres together.

Regenerated fibres connect natural and chemical sources. For example, viscose starts with cellulose from wood pulp, but chemical processing converts it into a material that can be formed into filaments. A plant origin therefore does not necessarily mean that the fibre is used without substantial processing.

Assessing the whole material journey

A life cycle assessment, or LCA, considers environmental impacts throughout a product's life. Its basic stages are obtaining raw materials, manufacture, use and end-of-life treatment. Transport between stages also contributes to the overall impact.

To carry out a basic assessment, identify the stages and gather relevant information: the resources, energy and water used; emissions and waste produced; how long the product is used; and whether it is reused, recycled or discarded. Compare products that perform the same job, rather than judging only their material names.

For example, comparing paper and plastic shopping bags means considering trees or crude oil, their conversion into bag materials, manufacture, repeated use and eventual disposal. A conclusion can change if one bag is reused many times or if another is recycled. There is no reliable overall judgement from the raw material alone.

Recycling returns waste material to a usable form. Paper can be re-pulped, and suitable metals can be remelted and formed again. Recycling can reduce demand for new raw materials, but collection, sorting, transport and reprocessing still use resources and energy.

Some LCA information, such as water consumption or waste mass, can be measured. Other impacts, such as habitat damage, are harder to compare with a single number. A sound judgement considers the whole life cycle, recognises trade-offs and explains the assumptions behind the conclusion.

Sources and conversion routes

Paper and board: wood or grasses → cellulose pulp → cleaning and optional bleaching → sheet forming, pressing and drying. Recycled paper can be re-pulped.
Natural timber: trees → felling and debarking → sawing into sections → seasoning → planing and final sizing.
Metals: mined ore → extraction → refining → casting and working into stock forms.
Polymers: crude oil → fractional distillation → cracking → polymerisation → granules or other workable forms.
Textiles: animal, vegetable or chemical sources → fibre preparation or formation → yarn → woven or knitted fabric.

Essential distinctions

Conversion cuts logs into usable sections; seasoning reduces moisture. Seasoning may use air or a controlled kiln.
Plywood: bonded veneers with neighbouring grain directions at right angles. Chipboard: wood particles bonded and compressed into sheets.
Extraction obtains metal from ore; refining removes impurities. Aluminium: bauxite → alumina → electrolysis.
Fractional distillation separates a mixture; cracking breaks large molecules; polymerisation joins monomers.
Wool: animal source. Cotton: vegetable source. Polyester and nylon: synthetic chemical sources. Viscose: chemically processed cellulose.

Life cycle assessment

Consider raw materials → manufacture → use → end of life, including transport.

Compare resource, energy and water use, emissions, waste, lifespan and recycling. Recycling reduces some demand for new resources but still requires processing. Justify conclusions across the whole life cycle, not one favourable stage.

Link each material to its original source, then describe the conversion stages in order. A stock form such as a sheet is not a primary source.

For timber, distinguish conversion into planks from seasoning to reduce moisture content.

Do not describe every metal as being extracted by smelting: aluminium is extracted using electrolysis.

Distinguish fractional distillation, cracking and polymerisation: they separate, break down and join molecules respectively.

In a life cycle comparison, consider all stages and justify your conclusion using the information given. Being recyclable does not mean a product has no environmental impact.

The original natural resource from which a material is obtained, such as trees, metal ore or crude oil.

A standard shape or size of material supplied for manufacture, such as a plank, sheet, rod or roll.

A substance in plant cell walls whose fibres can be separated and used to make paper and board.

A wet mixture containing separated fibres, used in making paper and board.

The cutting of a tree trunk or log into usable timber sections, such as planks and boards.

Controlled drying of timber to reduce its moisture content before use.

A board made by bonding wood layers, particles or fibres together, rather than cutting a solid board directly from a log.

A naturally occurring rock containing enough metal or metal compound for extraction to be worthwhile.

The removal of impurities from a material to make it suitable for use.

Separation of a mixture such as crude oil into fractions using differences in boiling point.

The breaking of large hydrocarbon molecules into smaller molecules, including some used to make polymers.

The chemical joining of small molecules called monomers to form long-chain molecules called polymers.

A continuous thread made from fibres, used to make fabrics by processes such as weaving or knitting.

An assessment of environmental impacts across a product's life, from obtaining raw materials through manufacture and use to disposal or recycling.