0
comentarios
Proportioning
The key to achieving a strong, durable concrete rests in the careful proportioning and mixing of the ingredients. A mixture that does not have enough paste to fill all the voids between the aggregates will be difficult to place and will produce rough surfaces and porous concrete. A mixture with an excess of cement paste will be easy to place and will produce a smooth surface; however, the resulting concrete is not cost-effective and can more easily crack.
Portland cement's chemistry comes to life in the presence of water. Cement and water form a paste that coats each particle of stone and sand—the aggregates. Through a chemical reaction called hydration, the cement paste hardens and gains strength.
The quality of the paste determines the character of the concrete. The strength of the paste, in turn, depends on the ratio of water to cement. The water-cement ratio is the weight of the mixing water divided by the weight of the cement. High-quality concrete is produced by lowering the water-cement ratio as much as possible without sacrificing the workability of fresh concrete, allowing it to be properly placed, consolidated, and cured.
Portland cement's chemistry comes to life in the presence of water. Cement and water form a paste that coats each particle of stone and sand—the aggregates. Through a chemical reaction called hydration, the cement paste hardens and gains strength.
The quality of the paste determines the character of the concrete. The strength of the paste, in turn, depends on the ratio of water to cement. The water-cement ratio is the weight of the mixing water divided by the weight of the cement. High-quality concrete is produced by lowering the water-cement ratio as much as possible without sacrificing the workability of fresh concrete, allowing it to be properly placed, consolidated, and cured.
Almost any natural water that is drinkable and has no pronounced taste or odor may be used as mixing water for concrete. Excessive impurities in mixing water not only may affect setting time and concrete strength, but can also cause efflorescence, staining, corrosion of reinforcement, volume instability, and reduced durability. Concrete mixture specifications usually set limits on chlorides, sulfates, alkalis, and solids in mixing water unless tests can be performed to determine the effect the impurity has on the final concrete.
Although most drinking water is suitable for mixing concrete, aggregates are chosen carefully. Aggregates comprise 60 to 75 percent of the total volume of concrete. The type and size of aggregate used depends on the thickness and purpose of the final concrete product
Although most drinking water is suitable for mixing concrete, aggregates are chosen carefully. Aggregates comprise 60 to 75 percent of the total volume of concrete. The type and size of aggregate used depends on the thickness and purpose of the final concrete product
Relatively thin building sections call for small coarse aggregate, though aggregates up to six inches in diameter have been used in large dams. A continuous gradation of particle sizes is desirable for efficient use of the paste. In addition, aggregates should be clean and free from any matter that might affect the quality of the concrete.
Hydration Begins
Soon after the aggregates, water, and the cement are combined, the mixture starts to harden. All portland cements are hydraulic cements that set and harden through a chemical reaction with water call hydration. During this reaction, a node forms on the surface of each cement particle. The node grows and expands until it links up with nodes from other cement particles or adheres to adjacent aggregates.
Once the concrete is thoroughly mixed and workable it should be placed in forms before the mixture becomes too stiff.
During placement, the concrete is consolidated to compact it within the forms and to eliminate potential flaws, such as honeycombs and air pockets.
Once the concrete is thoroughly mixed and workable it should be placed in forms before the mixture becomes too stiff.
During placement, the concrete is consolidated to compact it within the forms and to eliminate potential flaws, such as honeycombs and air pockets.
For slabs, concrete is left to stand until the surface moisture film disappears, then a wood or metal handfloat is used to smooth off the concrete. Floating produces a relatively even, but slightly rough, texture that has good slip resistance and is frequently used as a final finish for exterior slabs. If a smooth, hard, dense surface is required, floating is followed by steel troweling.
Ergonomy
Ergonomics comes from the Greek
words for work (ergon) and law (nomos) and can be interpreted as "a study
of the laws of work." However, we generally think of ergonomics in the workplace
as the science of designing work to fit the capabilities of workers, thereby
enhancing worker well being.
Some people call ergonomics human
factors engineering. Let's look at an analogy with machinery. If a new machine
is installed in a plant, the responsible engineer will read all the
specifications in the manual that comes with the machine, including operating
and maintenance information, before beginning to operate it. But how about
workers? What are their "specs?" Actually, years of ergonomics
research have resulted in a database that can provide "spec sheets"
on performance of joints and other aspects of human anatomy. This type of data
should be used in designing work, so as to protect the investment in human
capital at least as much as is regularly done for investments in equipment.
OSHA states that one third of all
recordable worker injuries each year result from ergonomic hazards. Such
injuries include upper extremity disorders, often associated with lifting and
repetitive motion, which are on the rise every year. OSHA has estimated the
cost of ergonomic injuries to amount to $15 billion per year.
Obviously workplace injuries are
costly to business, in the form of lost time, worker compensation claims,
reduced productivity, and adverse effects on product quality. Whether good
ergonomic practices are mandated by government or not, they should be mandated
by good business sense, because they pay off.
Most of the chemicals produced and used today are beneficial, but some also have the potential to damage human health, the environment, and public toward chemical enterprises. You must be aware of the potential for the accidental misuse of chemicals, as well as their intentional misuse. Chemical safety and security can mitigate these risks.
A new culture of safety and security consciousness, accountability, organization,
and education has developed around the world in the laboratories of the chemical
industry, government, and academe. Chemical laboratories have developed special
procedures and equipment for handling and managing chemicals safely and securely.
The development of a “culture of safety and security” results in laboratories
that are safe and healthy environments in which to teach, learn, and work.
WHAT ARE THE TYPES OF HAZARDS AND RISKS?
- Large-Scale Emergencies and Sensitive Situations
- Security Breach
- Toxic Chemical Exposure
- Flammable, Explosive, and Reactive Chemicals
- Biohazards
- Hazardous Waste
- Physical Dangers
TEN STEPS TO ESTABLISH A SAFETY AND SECURITY
MANAGEMENT SYSTEM
- Create an Institutional Safety and Security Oversight Committee and Appoint a Chemical Safety and Security Officer (CSSO).
- Develop a safety and security policy statement.
- Implement administrative controls.
- Identify and address particularly hazardous situations.
- Evaluate facilities and address weaknesses.
- Establish procedures for chemical management.
- Employ engineering controls and personal protective equipment.
- Plan for emergencies.
- Identify and address barriers to following safety and security best practices.
- Train, communicate, and mentor.
ISO is an independent,
non-governmental international organization with a membership of 165 national standards
bodies. The International Standards provide solutions to global challenges. ISO
will make every effort to be attractive and responsive to the needs of
industry, as well as those of regulators, consumers and other stakeholders.
In particular, the Strategy will
help the organization respond to a future where:
·
Technological, economic, legal, environmental,
social and political challenges will require examination and continual
improvement of the ISO system.
·
Stakeholder engagement and the challenges to
ISO’s intellectual property will continue to be both a key opportunity and risk
for ISO
v Develop high-quality standards through ISO’s global membership.
The organization must both excel
in the core business of developing standards which includes applying good standardization
practices such as those established by the World Trade Organization and ensure
it makes the most of its valuable network of national members.
v Engage stakeholders and partners.
Effective and wide-reaching
stakeholder engagement is essential in order to maintain ISO’s credibility and
the relevance of International Standards. This means ensuring that all ISO members
can successfully drive stakeholder participation in addition to effectively
engaging with global and regional partners. Stakeholders must see their
national members as the pathway to ISO, as organizations that engage them on
important issues with other national stakeholders and connect them to the
global standards debate. ISO needs to clearly show its value to stakeholders.
v People and organization development.
ISO’s most important resource is
its member organizations and their networks of experts. ISO will therefore
invest in building the capacity of all its members, both at the human and the
organizational level, through learning, research and development solutions.
This includes supporting the transfer of knowledge to a younger generation of
experts.
v Use of technology.
Cutting-edge technology, shifting
demographics, changing social behaviours and new collaborative work practices
are creating new demands and possibilities for all organizations. It also challenges traditional notions of how
we consume and use information; of pub- lishing and copyright. The impacts of
these changes are particularly profound for global, information-based
businesses such as ISO.
v Communication.
The value and impact of International Standards
must be recognized by decision makers in both the public and private sector, as
well as by all stakeholders and the general public. The ISO member network,
supported by ISO’s Central Secretariat, is key to fulfilling this aspiration.
Beyond their role as national standards bodies, ISO members “ are ” ISO in
their country and are the driving force for communicating with the various
groups interested in, and affected by, standards.
Petroleum Processing
The term petroleum comes from the Latin stems petra, “rock,” and oleum, “oil.” It
is used to describe a broad range of hydrocarbons that are found as gases, liquids,
or solids beneath the surface of the earth.
The two most common forms are natural
gas and crude oil.
Natural gas: Natural gas which is a mixture of lightweight alkanes, accumulates in
porous rocks. A typical sample of natural gas when it is collected at its source contains
about 80% methane (CH4
), 7% ethane (C2
H6
), 6% propane (C3
H8
), 4% butane and
isobutane (C4
H10), and 3% pentanes (C5
H12). The C3
, C4
, and C5
hydrocarbons are
removed before the gas is sold.
The commercial natural gas delivered to the customer
is therefore primarily a mixture of methane and ethane. The propane and butanes
removed from natural gas are usually liquefied under pressure and sold as liquefied
petroleum gases (LPG).
Crude oil is a composite mixture of hydrocarbons (50-95% by weight) occurring
naturally. The first step in refining crude oil involves separating the oil into different
hydrocarbon fractions by distillation. Each fraction is a complex mixture.
For example,
more than 500 different hydrocarbons can be found in the gasoline fraction.
Petroleum is found in many parts of the world which include the Middle East, southern
United States, Mexico, Nigeria and the former Soviet Union.
Chemical Processes
Every industrial process is designed to produce a desired product from a variety of
starting raw materials using energy through a succession of treatment steps integrated
in a rational fashion. The treatments steps are either physical or chemical in nature.
Energy is an input to or output in chemical processes.
The layout of a chemical process indicates areas where:
- raw materials are pre-treated
- conversion takes place
- separation of products from by-products is carried out
- refining/purification of products takes place
- entry and exit points of services such as cooling water and steam
Units that make up a chemical process
A chemical process consists of a combination of chemical reactions such as synthesis,
calcination, ion exchange, electrolysis, oxidation, hydration and operations based on
physical phenomena such as evaporation, crystallization, distillation and extraction.
A chemical process is therefore any single processing unit or a combination of processing
units used for the conversion of raw materials through any combination of
chemical and physical treatment changes into finished products.
Unit processes
Unit processes are the chemical transformations or conversions that are performed
in a process.
In Table 1.1, examples of some unit processes are given:
Unit Operations
There are many types of chemical processes that make up the global chemical industry.
However, each may be broken down into a series of steps called unit operations.
These are the physical treatment steps, which are required to:
- put the raw materials in a form in which they can be reacted chemically
- put the product in a form which is suitable for the market In Table1.2, some common unit operations are given.
It is the arrangement or sequencing of various unit operations coupled with unit
processes and together with material inputs, which give each process its individual
character. The individual operations have common techniques and are based on the
same scientific principles.
For example, in many processes, solids and fluids must
be moved; heat or other forms of energy may be transferred from one substance to
another; drying, size reduction, distillation and evaporation are performed.
By studying systematically these unit operations, which cut across industry and
process lines, the treatment of all processes is unified and simplified.
Classification of Industries
Industry is a general term that refers to all economic activities that deal with production of goods and services. Goods and services are key words when you talk of industry. We then expect industry to include the following sectors:
- Manufacturing
- Agriculture
- Energy
- Transport
- Communication
- Education
- Tourism
- Building and construction
- Trade
- Finance
- etc
Classification of the Manufacturing Industry
The manufacturing industry is the area of focus in the study of this module. Manufacturing
produces manufactured goods. This makes it distinct from other sectors like
agriculture which also produce goods. In manufacturing, materials are transformed
into other more valuable materials.
We define manufacturing industry as follows:
Manufacturing industry is a compartment of industry or economy which is
concerned with the production or making of goods out of raw materials by means
of a system of organized labour.
Manufacturing industry can be classified into two major categories namely, heavy
and light industry.
- Capital-intensive industries are classified as heavy while labour intensive industries are classified as light industries.
- Light industries are easier to relocate than heavy industries and require less capital investment to build. Using the above classification criteria, examples of heavy industries include those that produce industrial machinery, vehicles and basic chemicals.
Manufacturing sub-sectors
Because the raw materials and the actual products manufactured are so varied,
different skills and technologies are needed in manufacturing. Manufacturing is
therefore divided into sub-sectors which typically deal with category of goods such
as the following:
- Food, beverages and tobacco
- Textiles, wearing apparel, leather goods
- Paper products, printing and publishing
- Chemical, petroleum, rubber and plastic products
- Non-metallic mineral products other than petroleum products
- Basic metal products, machines and equipment.
- Let us now focus on the chemical, petroleum, rubber and plastic products subsector. We shall generally call it the chemical industry.
Our Environment
Plastics are environmentally friendly
A carbon footprint is the sum of all greenhouse gases given off to the
atmosphere during the processes of extraction and refining of a material,
production, transport, use and recycling. Comparisons show that the sum of
greenhouse gases released in manufacturing plastic solutions is smaller than
in manufacturing other traditional materials.
A comparison of materials
In the framework of a in-depth study,
pipes in a length of one metre and
made of various materials were
compared. The results showed that
a plastic pipe has a carbon footprint
which is up to five times lower than
that of a comparable steel pipe.
Lightweight all-plastic solutions
Plastics score particularly well because of their low weight, which pays off especially in the areas of transport and processing. All-plastic solutions from GF Piping Systems are lighter in weight than other piping systems made of conventional materials and this has a positive effect on the carbon footprint.
Lower energy costs
Energy costs can be reduced with
targeted layout planning and
optimal pressure dimensioning
allowing lower pump capacity
requirements. Using plastic
components contributes to a steady
flow rate as well as a stable energy
requirement. Pre-insulated plastic
pipes further reduce energy
requirements and have a positive
impact on the carbon footprint.
What are the challenges for the chemical industry
today?
The chemical industry is undergoing huge changes worldwide. As we have
seen above, one concerns the emergence of Middle Eastern countries and China,
India and Brazil as manufacturers of chemicals on a mammoth scale, for their
own consumption and also for export worldwide.
Companies in these countries are also investing in plant in the US and Europe whilst US and European companies are investing in plant in these large emerging countries, making the industry as a whole totally international in the way it conducts business.
The challenge for companies in the US and Europe is to cut their costs while ensuring that they conform to the best practice in protecting the environment. This concern about the environment is discussed in the separate units on individual chemicals.
Companies in these countries are also investing in plant in the US and Europe whilst US and European companies are investing in plant in these large emerging countries, making the industry as a whole totally international in the way it conducts business.
The challenge for companies in the US and Europe is to cut their costs while ensuring that they conform to the best practice in protecting the environment. This concern about the environment is discussed in the separate units on individual chemicals.
A new revolution beckons. As oil and natural gas become ever scarcer and
more expensive, chemists are searching for new feedstocks to supplement or even
replace oil and natural gas. And they are rediscovering the virtues of coal
(still in huge supply, even though it is a fossil fuel that cannot be replaced)
and biomass.
Thus we are coming full circle. In the late 19th and the first part of
the 20th centuries, the organic chemical industry was based largely on coal and
biomass. Coal was heated strongly in the absence of air to form coal gas (a
mixture of hydrogen, methane and carbon monoxide).
A liquid (coal tar) was formed as a by-product which contained many useful organic chemicals, including benzene, and the solid residue was coke, an impure form of carbon. Coke was the source of what we now call synthesis gas. Steam was passed over it at high temperatures to yield carbon monoxide and hydrogen. Another source of organic chemicals was biomass.
For example, the source of many C2 chemicals was ethanol, produced by fermentation of biomass. C3 and C4 chemicals such as propanone and butanol were also produced on a large scale by fermentation of biomass.
A liquid (coal tar) was formed as a by-product which contained many useful organic chemicals, including benzene, and the solid residue was coke, an impure form of carbon. Coke was the source of what we now call synthesis gas. Steam was passed over it at high temperatures to yield carbon monoxide and hydrogen. Another source of organic chemicals was biomass.
For example, the source of many C2 chemicals was ethanol, produced by fermentation of biomass. C3 and C4 chemicals such as propanone and butanol were also produced on a large scale by fermentation of biomass.
Since then, from the 1940s onwards, the industry has found better and
better ways of using the products from the refining of oil to produce not only
all the chemicals mentioned above but many more. An example is the growth of
the petrochemical industry, with the array of new polymers, detergents, and
myriad of sophisticated chemicals produced at low cost.
Perhaps therefore the greatest challenge lies in finding ways to reduce
our dependence on non-renewable resources. Thus, as oil and natural gas
supplies dwindle, we must find ways to use the older technologies based on
biomass to produce chemicals in as an environmentally acceptable way as
possible, in terms of energy expended and effluents produced. For example, some
ethene and a range of polymers, as well as very large quantities of ethanol,
are now being produced from biomass.
Another challenge is reduce our dependence on non-renewable resources to
produce energy. The easiest way to do this is to find ways to run our chemical
plants at lower temperatures with the aid of catalysts or using alternative
routes. This has already begun in earnest and over the last 20 years, as noted
in the last section, the consumption of energy per unit of product has been
falling at an average of about 6% in the EU and about 2.5% in the US per year.
In consequence, the emission of carbon dioxide has fallen per unit of product
by 68% and 40% over the same time scale.
The new technologies based on nanomaterials will also be to the forefront in future advances in the chemical
industry and it will be important to ensure that the production of these
revolutionary materials is safe and of economic benefit.
The chemical industry has many challenges in the 21st century which must
be overcome in order to remain at the heart of every major country. It is only
through this that the industry can help society to maintain and improve its
standard of living and do so in a sustainable way.
Much of the data used in
this unit is derived from published work by CEFIC (Conseil Européen des Fédérations de l'Industrie
Chimique, The European Chemical Industry Council) and the American Chemical Council.
The chemical
industry: how safe and how environmentally regulated?
Safety must be at the top of the chemical industry’s agenda and for good
reason. Many of its products are potentially hazardous at some stage during
their manufacture and transport. These chemicals may be solids, liquids or
gases, flammable, explosive, corrosive and/or toxic.
Manufacturing processes
frequently involve high temperatures, high pressures, and reactions which can
be dangerous unless carefully controlled. Because of this the industry operates
within the safety limits demanded by national and international legislation.
Risks and injuries
In spite of dealing with hazardous operations, the chemical industry
actually has a lower number of accidents than industry as a whole. Between 1995
and 2005, across the whole of European manufacture of all types, there were
over 4 injuries for every 1000 employees, twice that sustained in the chemical
industry.
US data, recorded as days lost due to accidents, show an even starker
difference; the number of days lost in major companies in the chemical industry
through accidents is 4 times less than in manufacturing generally.
Environmental regulations
There are serious concerns about the potential impact of certain
manufactured chemicals on living organisms, including ourselves, and on the
natural environment. These concerns include air, land and sea pollution, global
warming and climate change, ozone depletion of the upper atmosphere and acid
rain.
The chemical industry has a world-wide initiative entitled Responsible
Care. It began in Canada in 1984 and is practiced now in over 60 countries. It
commits national chemical industry associations and companies to:
Continuously improve the environmental, health, safety and security
knowledge and performance of our technologies, processes and products over their
life cycles so as to avoid harm to people and the environmentUse resources
efficiently and minimise wasteReport openly on performance, achievements and
short comings Listen, engage and work with people to understand and address their
concerns and expectationsCooperate with governments and organisations in the
development and implementation of effective regulations and standards, and to
meet or go beyond themProvide help and advice to foster the responsible
management of chemicals by all those who manage and use them along the product
chain.
In the US, chemical companies spend over $ 12 billion a year on
environmental, health and safety programs. This has, for example, has led to
the reduction of hazardous releases to the air, land and water by over 70
percent over the last 40 years.
Another environmental measure concerns the use
of energy. In the 20 years from 1990, the chemical industry in the US saved
energy at the average rate of 2.1% and in Europe at more than 4%. This also
reduces the emissions of carbon dioxide into the atmosphere, at a rate of
nearly 2.5% and 6% per annum in the US and EU, respectively.
Regulations are in force in every major country. In Europe, they are
enforced through REACH (Registration, Evaluation Authorisation and restriction
of Chemicals). They are fundamentally changing the way chemicals are made, sold
and used, by providing a single standardised framework for the safe management
of chemicals.
REACH places the responsibility on both manufacturers and
importers to ensure that all chemicals produced in quantities greater than one
tonne a year do not adversely affect human health or the environment. The
industry provides comprehensive documented information for all qualifying
chemicals and related substances, enabling users of the chemicals to ensure
that adequate controls are in place.
Chemicals which are produced in amounts of
1000 tonnes or more per year must have been registered by December 2010 and
those greater than 1 tonne must be registered by June 2018.
Only a small proportion of chemical wastes are toxic or hazardous. Most
of these, together with materials which resist natural breakdown, are
incinerated at high temperature. Whenever possible, the waste itself provides
the fuel for this process. The gases produced are thoroughly cleaned and
‘scrubbed’ before release into the atmosphere, leaving only ash for disposal.
Examples of how by-products are dealt with are seen throughout the units on
this web site.
What does the chemical industry produce?
The products of the chemical industry can be divided into three
categories:
- Basic chemicals
- Speciality
chemicals
- Consumer
chemicals
Several other categorisations are used but this one is simple and
helpful in the context of this web site. Outputs range widely, with basic
chemicals produced in huge quantities (millions of tonnes) and some speciality
chemicals produced in modest kilogramme quantities but with very high value.
As explained in the unit on Chemical Reactors, the choice of reactor is often goverened by the amount of chemical that is to be produced.
As explained in the unit on Chemical Reactors, the choice of reactor is often goverened by the amount of chemical that is to be produced.
The value of sales per category for both Europe and the US are broadly
similar, as shown in:
Europe
|
US
|
|||
Basic chemicals
|
62
|
61
|
||
Polymers
|
24
|
18
|
||
Petrochemicals
|
24
|
25
|
||
Basic Inorganics
|
14
|
18
|
||
Speciality
chemicals
|
25
|
24
|
||
Consumer chemicals
|
13
|
14
|
||
Table 1: Products from the chemical industry in 2011 by category (%).
Facts and Figures 2011, CEFIC; 2011 Guide to the Business of Chemistry, American Chemistry Council.
Facts and Figures 2011, CEFIC; 2011 Guide to the Business of Chemistry, American Chemistry Council.
Basic chemicals
Basic chemicals are divided into
- chemicals derived from oil, known as
petrochemicals
- polymers
- basic inorganics
The term ‘petrochemical’ can be misleading as the same chemicals are
increasingly being derived from sources other than oil, such as coal and
biomass. An example is methanol, commonly produced from oil and natural gas in
the US and Europe but from coal in China.
Another is poly(ethene), derived from oil and gas in the US and Europe but increasingly from biomass in Brazil. Other examples are described in the units on this web site.
Another is poly(ethene), derived from oil and gas in the US and Europe but increasingly from biomass in Brazil. Other examples are described in the units on this web site.
Basic chemicals, produced in large quantities, are mainly sold within
the chemical industry and to other industries before becoming products for the
general consumer. For example, ethanoic acid is sold on to make esters, much of
which in turn is sold to make paints and at that point sold to the consumer.
Huge quantities of ethene are transported as a gas by pipeline around Europe
and sold to companies making poly(ethene) and other polymers. These are then
sold on to manufacturers of plastic components before being bought by the
actual consumer.
Petrochemicals and polymers
The production of chemicals from petroleum (and increasingly from coal
and biomass) has seen many technological changes and the development of very
large production sites throughout the world.
The hydrocarbons in crude oil and gas, which are mainly straight chain alkanes, are first separated using their differences in boiling point, as is described in the unit Distillation. They are then converted to hydrocarbons that are more useful to the chemical industry, such as branched chain alkanes, alkenes and aromatic hydrocarbons.
These processes are described in the unit, Cracking and related refinery processes.
The hydrocarbons in crude oil and gas, which are mainly straight chain alkanes, are first separated using their differences in boiling point, as is described in the unit Distillation. They are then converted to hydrocarbons that are more useful to the chemical industry, such as branched chain alkanes, alkenes and aromatic hydrocarbons.
These processes are described in the unit, Cracking and related refinery processes.
In turn, these hydrocarbons are converted into a very wide range of
basic chemicals which are immediately useful (petrol, ethanol, ethane-1,2-diol)
or are subjected to further reactions to produce a useful end product (for
example, phenol to make resins and ammonia to make fertilizers). Many examples
are found in the group of units on this site devoted to Basic chemicals.
The main use for petrochemicals is in the manufacture of a wide range of
polymers. Due to their importance of these they are given their own section of
units, Polymers.
Basic inorganics
These are relatively low cost chemicals used throughout manufacturing
and agriculture. They are produced in very large amounts, some in millions of
tonnes a year, and include chlorine, sodium hydroxide, sulfuric and nitric
acids and chemicals for fertilizers.
As with petrochemicals, many emerging countries are now able to produce them more cheaply than companies based in the US and Europe. This has led to tough competition and producers of these chemicals worldwide work continuously to reduce costs while meeting ever more stringent environmental and safety standards.
As with petrochemicals, many emerging countries are now able to produce them more cheaply than companies based in the US and Europe. This has led to tough competition and producers of these chemicals worldwide work continuously to reduce costs while meeting ever more stringent environmental and safety standards.
The units on basic inorganics can be found within the Basic chemicals section of the site.
Speciality
chemicals
This category covers a wide variety of chemicals for crop protection, pains and inks, colorants (dyes and pigments). It also includes chemicals used by industries
as diverse as textiles, paper and engineering. There has been a tendency
in the US and Europe to focus on this sector rather than the basic chemicals
discussed above because it is thought that, with active research and
development (R & D), speciality chemicals deliver better and more stable
profitability.
New products are being created to meet both customer needs and new environmental regulations. An everyday example is household paints which have evolved from being organic solvent-based to being water-based. Another is the latest ink developed for ink-jet printers.
New products are being created to meet both customer needs and new environmental regulations. An everyday example is household paints which have evolved from being organic solvent-based to being water-based. Another is the latest ink developed for ink-jet printers.
Units on selected speciality chemicals can be found within the Materials and Applications section of this site.
Consumer chemicals
Consumer chemicals are sold directly to the public. They include,
for example, detergents, soaps and other toiletries. The search for more
effective and environmentally safe detergents has increased over the last 20
years, particularly in finding surfactants that are capable of cleaning
anything from sensitive skin to large industrial plants.
Parallel to this, much work has been done in producing a wider range of synthetic chemicals for toiletries, cosmetics and fragrances.
Parallel to this, much work has been done in producing a wider range of synthetic chemicals for toiletries, cosmetics and fragrances.
Units on selected consumer chemicals can be found within the Materials and Applications section.
Suscribirse a:
Entradas (Atom)