Rice Husk (Hull)
Rice is regarded as main food of Thai people for a long time. Beside domestic consumption, rice is a major agricultural product that extremely high exportation value. In rice manufacturing, rice husk is the by-product from paddy grinding. So far, rice husk has been successfully used as fuel in many industrial factories and used as biomass fuel in electricity generating  because of its low humidity and simple operation.
Rice husk is one of the most widely available agricultural wastes in many rice producing countries around the world. Rice husk is the outermost layer of protection encasing a rice grain. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material or fuel. It is yellowish in colour and has a convex shape.
Rice husk a major by- product of the rice milling industry, is one of the most commonly available lignocellulosic materials that can be converted to different types of fuels and chemical feedstocks through a variety of thermo chemical conversion processes.
Composition of Rice Husk
Rice husk contains 75-90 % organic matter such as cellulose, lignin etc. and rest mineral components such as silica, alkalis and trace elements. Rice husk is unusually high in ash compared to other biomass fuels in the range 10-20%. The ash is 87-97% silica, highly porous and light- weight, with a very high external surface area. Presence of high amount of silica makes it a valuable material for use in industrial application. Other constituents of Rice Husk Ash (RHA), such as K2O, Al2O3, CaO, MgO, Na2O, Fe2O3 are available in less than 1 %. Rice husk having bulk density of 96-160kg/m3, oxygen 31-37%, nitrogen 0.23- 0.32%, sulphur 0.04-0.08%.
Properties of Rice Hull
Rice hulls are unique within nature. Rice Husk (hull) has all the properties one could expect of some of the best insulating materials and, its true potential is emerging. Rice husk do not flame or smoulder very easily; are highly resistant to moisture penetration and fungal decomposition; do not transfer heat very well; are not odorous; do not emit gases; are not corrosive with respect to metals such as aluminium, copper or steel.
Rice hulls are very tough and abrasive, consisting of two interlocking halves. These halves encapsulate the tiny space vacated by the milled grain and, in proximity to a myriad of other hulls, they form a thermal barrier that compares well with that of other excellent insulating materials.
The high percentage of opaline silica within rice hulls is most unusual in comparison with other plant materials. Some scientific evaluations have concluded that, during the combustion of rice hulls, the silica ash may form a ‘cocoon’ that prevents oxygen from reaching the carbon inside. Another school of thought among scientists is that, because silica and carbon may be partially bonded at the molecular level, silicone carbide is formed during high-temperature combustion and that the presence of this heat-resisting compound impedes the easy combustion of rice hulls.
Rice hulls (also called ‘rice husks’) are flame-retarding and self-extinguishing. A lighted match thrown onto a pile of rice hulls will, in general, cause it to burn and smoulder without producing a high flame. Production of a flame will require a flammable starter to ignite the pile.
In general, all organic materials absorb or release moisture until they come into equilibrium with the relative humidity of the surrounding air. The high presence of silica on the outer surface of rice hulls impedes the atmospheric transfer of moisture into the hull. Also the presence of a small percentage of a bio-polyester in the rice hull in combination with a wax produced by the rice plant forms a highly impermeable barrier to moisture and heat. The high concentration of opaline silica on the outer surface of the rice hull also strengthens and makes the outer shell hard. However, due to lignin within the rice hull, this hardness is tempered with flexibility and elasticity. The rice hull is hard and yet elastic, so it resists settling and compression far better than some materials.
Use & Applications of Rice Husk
Rice husk used for different applications depending upon their physical and chemical properties like ash content, silica content etc. In power plants, rice husk is directly used as a good fuel. It is also used as a raw material for making some compounds like silica and silicon compounds. Rice husk have various application in different industries and domestic fields.
(a) As an Industrial Fuel
For processing paddy and generation of process steam, rice husk used as a fuel. Heat energy is produced by combustion and gasification. In small sector process industries, rice husk used as a fuel in low capacity boilers. For producing 1MWH (million watt hour) electricity, 1 tonne of rice husk is required. It is also used as alternative fuel for household energy.
(b) Preparation of Activated Carbon
Rice husk contain large amount of cellulose and lignin contents, due to this it used as a raw material for preparation of activated carbon. Activated carbon are effective adsorbents due to their complex microporous structure.
Precipitated Silica from Rice Husk Ash
Precipitated silica, a form of synthetic amorphous silicon dioxide, is derived from quartz sand, a crystalline form of silicon dioxide. It is an amorphous form of silica; the word amorphous denotes a lack or crystal structure, as defined by x-ray diffraction. Early interest in amorphous silica was purely academic.
Amorphous silica can be broadly divided into three categories. Vitreous silica or glass made by fusing quartz, Silica made indicating either amorphous or crystalline silica with high speed neutrons & Micro amorphous silica. Micro amorphous silica includes sols, gels powders & porous glasses, all of which are composed of ultimate particles or structural units less than 1/um in diameter.
Amorphous silica is precipitated from super saturated solution obtained by concentrating an under saturated solution a hot saturated solution, or generating Si(OH)4 of silica ester SiH4, SiS2, SiCl4 or Si.
Precipitated Silica soluble silicate solutions are of fine controlled particle size & porous in nature. Precipitated silica powders have a more open structure with higher volume than dried pulverized gels. The physical & chemical properties or precipitated silica vary according to the manufacturing process. Ultimate & aggregate particle size in silica’s precipitated from solution can be varied by reinforcement & control of suspension pH, temperature & salt content. The particle size in gynogenic silica’s is controlled by combustion conditions. The surface area as determined by nitrogen adsorption is a function of particle size.
The physical properties of precipitated silica can be manipulated during the manufacturing process to deliver products with a wide range of performance-enhancing features engineered for many different end-use applications.
1. Nature: Amorphous powder
2. Appearance: White fluffy powder
3. Purity: > 98 %
4. Surface Area: 50 - 200 m2/gm
5. Bulk density: 120 – 200 g/liter
6. Loss on Iginition: 3.0 – 6.0 %
7. pH of 5 % slurry: 6.3 ± 0.5
8. Heat loss: 4.0 – 7.0 %
PHYSICO - CHEMICAL CHARACTERISTICS OF PRECIPITATED SILICA
1. pH Value
The pH value of precipitated silica is generally in neutral range. It is determined electrometrically with a glass electrode and pH meter.
2. Drying Loss
There is very small amount of physically bonded water content in precipitated silica. The major part of this water content is removed by drying in drying cabinet at 105ºC for 2 hours.
3. Ignition Loss
Precipitated silica contains chemically bonded water in the form silanol groups is also removed after 2 hours of ignition time at 1000oC. The ignition loss is determined with the substance that has previously been dried for 2 hours at 105oC.
4. DBP Absorption
The DBP absorption is a numerical value used to indicate absorptive capacity of filler. Owing to the automatic measurement process, however, this method can be carried out more accurately than the determination of the oil absorption. The DBP absorption capacity is influenced by other parameters, such as the particle size.
5. SiO2 Content
Silicon dioxide content is determined gravimetrically by fuming off with hydrofluoric acid. The sulphate and chloride contents are determined by potentiometric titration.
6. SIEVE Residue
SIEVE residue is determined by using Mocker apparatus. In this process the silica suspension is washed through the sieve with 4 bar water pressure. 45 micron sieves (325 mesh) is used for this process. The sieve is then dried and sieves residue is weighed.
7. Tamped Density
The tamped density is calculated from the initial weight of the sample and the resulting volume, reported in g/l. It is used for the purpose of calculating weight of product in powder form.
Uses & Applications
Rubber Grade Precipitated Silica
Precipitated silica is used as filler for paper & rubber as a carrier & diluents for agricultural chemicals, as an anti caking agent, to control viscosity & thickness and as a cleansing agent in toothpastes & in cosmetics.
Precipitated silica also finds its applications as anti caking agents in food industry & as thermal insulators. Precipitated silica is perhaps the best not black filler and reinforcing agent used in rubber industry especially for the production of silicon rubber.
The distinguishing feature of the growth of precipitated silica industry in India is that it has classifiably flourished in the small-scale sector. Readily available new materials low capital investment & high rates of return offer a distinct advantage to the small-scale manufacturers to venture into this field.
2. Chappals: Precipitated silica is used in shoe soles for its resistance to wear and to tearing, its non-scuffing characteristics and to obtain compounds with light color or even transparent materials. Provides superior durability and resilience and improved modulus. Acts as white reinforcer facilitating manufacturing of colored end products.
Because Precipitated Silica is white it allows the formulator to produce either colored or translucent nonmarking soles. Precipitated Silica provides superior durability and resilience while improving compound stiffness for all types of rubber soled footwear.
3. Conveyor Belt & Transmission belt: Precipitated Silica is used to improve the tear strength due to its small particle size and complex aggregate structure. It imparts the highest degree of reinforcement to elastomer compounds. Precipitated Silica is used to prevent from cracking and cut growth of Conveyor Belts and power transmission belts.
• Provides higher tensile strength.
• Provides longer life and durability.
• Imparts abrasion resistance.
• Improves tear resistance.
4. PVC Sheets: Precipitated Silica is used to improve pigment dispersion and acts as a parting agent and as an absorbent to improve the flow and imparts a dry feel to the compound.
• Improves tear resistance.
• Acts as reinforcing agent.
• Provides higher tensile strength.
• Provides longer life and durability.
Cement from Rice Husk Ash
Cement is the basic ingredient of construction and the most widely used construction material. It is a very critical ingredient, because only cement has the ability of enhancing viscosity of concrete which in returns provides the better locking of sand and gravels together in a concrete mix.
Cements are materials that exhibit characteristic properties of setting and hardening when mixed to a paste with water. This makes them join rigid masses into coherent structures. It is powdery bonding material having adhesive and cohesive properties.
Chemically it is a finely ground mixture of calcium silicates and aluminates which set to a hard mass when treated with water. These are called as Hydraulic Cements (Portland Cement) and those setting in air are Non Hydraulic cements (Ordinary Lime).
Varieties of Cement
There are some varieties in cement that always find good demand in the market. To know their characteristics and in which area they are most required, it will be better to take a look at some of the details given below.
• Portland Blast Furnace slag cement (PBFSC): The rate of hydration heat is found lower in this cement type in comparison to PPC. It is most useful in massive construction projects, for example - dams.
• Sulphate Resisting Portland Cement: This cement is beneficial in the areas where concrete has an exposure to seacoast or sea water or soil or ground water. Under any such instances, the concrete is vulnerable to sulphates attack in large amounts and can cause damage to the structure. Hence, by using this cement one can reduce the impact of damage to the structure.
• Rapid Hardening Portland Cement: The texture of this cement type is quite similar to that of OPC. But, it is bit more fine than OPC and possesses immense compressible strength, which makes casting work easy.
• Ordinary Portland Cement (OPC): Also referred to as grey cement or OPC, it is of much use in ordinary concrete construction. In the production of this type of cement in India, Iron (Fe2O3), Magnesium (MgO), Silica (SiO2), Alumina (AL2O3), and Sulphur trioxide (SO3) components are used.
• Portland Pozolona Cement (PPC): As it prevents cracks, it is useful in the casting work of huge volumes of concrete. The rate of hydration heat is lower in this cement type. Fly ash, coal waste or burnt clay is used in the production of this category of cement. It can be availed at low cost in comparison to OPC.
• Oil Well Cement: Made of iron, coke, limestone and iron scrap, Oil Well Cement is used in constructing or fixing oil wells. This is applied on both the off-shore and on-shore of the wells.
• Clinker Cement: Produced at the temperature of about 1400 to1450 degree Celsius, linker cement is needed in the construction work of complexes, houses and bridges. The ingredients for this cement comprise iron, quartz, clay, limestone and bauxite.
• White cement: It is a kind of Ordinary Portland Cement. The ingredients of this cement are inclusive of clinker, fuel oil and iron oxide. The content of iron oxide is maintained below 0.4% to secure whiteness. White cement is largely used to increase the aesthetic value of a construction. It is preferred for tiles and flooring works.
Uses of Cement
1. It is used in mortar for plastering, masonry work, pointing, etc.
2. It is used for making joints for drains and pipes.
3. It is used for water tightness of structure.
4. It is used in concrete for laying floors, roofs and constructing lintels, beams, stairs, pillars etc.
5. It is used where hard surface is required for the protection of exposed surfaces of structures against the destructive agents of the weather and certain organic or inorganic chemicals.
6. It is used for precast pipes manufacturing, piles, fencing posts etc.
7. It is used in the construction of important engineering structures such as bridges, culverts, dams, tunnels, light houses etc.
8. It is used in the preparation of foundations, water tight floors, footpaths etc.
9. It is employed for the construction of wells, water tanks, tennis courts, lamp posts, telephone cabins, roads etc.
Following are some of the major names in the Indian cement industry:
Ethanol from Rice Husk
Ethanol (ethyl alcohol, grain alcohol) is a clear, colorless liquid with a characteristic, agreeable odor. In dilute aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions it has a burning taste. Ethanol, CH3CH2OH, is an alcohol, a group of chemical compounds whose molecules contain a hydroxyl group, –OH, bonded to a carbon atom. Ethanol is a clear, colorless alcohol made from the sugars found in grains, such as corn, sorghum, and barley, as well as potato skins, rice, sugar cane, sugar beets, and yard clippings. Ethanol is a renewable fuel because it is made from plants. There are several ways to make ethanol using these sources. Sugar cane and sugar beets are the most common ingredients used to make ethanol in other parts of the world. Since alcohol is created by fermenting sugar, sugar crops are the easiest ingredients to convert into alcohol. It is
Uses of Ethanol
the principal type of alcohol found in alcoholic beverages, produced by the fermentation of sugars by yeasts. It is a neurotoxic psychoactive drug and one of the oldest recreational drugs used by humans. It can cause alcohol intoxication when consumed in sufficient quantity. Ethanol is used as a solvent, an antiseptic, a fuel and the active fluid in modern (post-mercury) thermometers. It is a volatile, flammable, colorless liquid with a strong chemical odor.
Ethanol is Used
• in the manufacture of alcoholic drinks, e.g. Vodka, etc.,
• as a widely used solvent for paint, varnish and drugs,
• in the manufacture of ethanal, (i.e. acetaldehyde), and ethanoic acid, (i.e. acetic acid),
• as a fuel (e.g. in Gasahol),
• as the fluid in thermometers, and
• in preserving biological specimens.
Chemical Properties of Ethanol
Ethanol is a monohydric primary alcohol. It melts at - 117.3°C and boils at 78.5°C. It is miscible (i.e., mixes without separation) with water in all proportions and is separated from water only with difficulty; ethanol that is completely free of water is called absolute ethanol. Ethanol forms a constant-boiling mixture, or azeotrope, with water that contains 95% ethanol and 5% water and that boils at 78.15°C; since the boiling point of this binary azeotrope is below that of pure ethanol, absolute ethanol cannot be obtained by simple distillation. However, if benzene is added to 95% ethanol, a ternary azeotrope of benzene, ethanol, and water, with boiling point 64.9°C, can form; since the proportion of water to ethanol in this azeotrope is greater than that in 95% ethanol, the water can be removed from 95% ethanol by adding benzene and distilling off this azeotrope. Because small amounts of benzene may remain, absolute ethanol prepared by this process is poisonous.
Ethanol burns in air with a blue flame, forming carbon dioxide and water. It reacts with active metals to form the metal ethoxide and hydrogen, e.g., with sodium it forms sodium ethoxide. It reacts with certain acids to form esters, e.g., with acetic acid it forms ethyl acetate. It can be oxidized to form acetic acid and acetaldehyde. It can be dehydrated to form diethyl ether or, at higher temperatures, ethylene.
Grades of Ethanol
Ethanol is available in a range of purities that result from its production or, in the case of denatured alcohol, are introduced intentionally.
Pure ethanol and alcoholic beverages are heavily taxed as psychoactive drugs, but ethanol has many uses that do not involve consumption by humans.
To relieve the tax burden on these uses, most jurisdictions waive the tax when an agent has been added to the ethanol to render it unfit to drink. These include bittering agents such as denatonium benzoate and toxins such as methanol, naphtha, and pyridine. Products of this kind are called denatured alcohol.
Absolute or anhydrous alcohol refers to ethanol with a low water content. There are various grades with maximum water contents ranging from 1% to a few parts per million (ppm) levels. Azeotropic distillation is used to remove water, it will contain trace amounts of the material separation agent (e.g. benzene). Absolute alcohol is not intended for human consumption.
Absolute ethanol is used as a solvent for laboratory and industrial applications, where water will react with other chemicals, and as fuel alcohol. Spectroscopic ethanol is an absolute ethanol with a low absorbance in ultraviolet and visible light, fit for use as a solvent in ultraviolet-visible spectroscopy.
Pure ethanol is classed as 200 proof in the U.S., equivalent to 175 degrees proof in the UK system.
Oxalic Acid from Rice Husk
Oxalic acid is an organic compound with the formula C2H2O4. It is a colorless crystalline solid that forms a colorless solution in water. It is a widely occurring natural product of animals, plants and other organisms. The occurence and the distribution of oxalate vary enormously among organisms. For instance, in plants the highest oxalate concentrations commonly occur in the leaves and the lowest in roots. The oxalic powder is then mixed with water to turn into a solution of oxalic acid. At high doses, oxalic acid is very dangerous, but at moderate doses it is safe for various useful functions. Oxalic acid is commercially available as the dehydrate containing 28.5% water. Anhydrous acid is shombic, hypyramedical, odourless and white in colour. De-hydrate is a monoclinic prism, particle size varying from fine powder to coarse granules which are also colourless, melting point 187ºC of anhydrous form and 101.5ºC of dehydrate form.
The effects of oxalic acid in the human body, when ingested in foods, flow from its ability to combine chemically with certain metals commonly found in and important to the human body, such as magnesium and calcium. When oxalic acid combines with such metals, the result is, in chemical terms, a “salt” (table salt is just one specimen of the general class of salts); those oxalic-acid+metal salts are called oxalates.
Of the four general technologies that have been employed for the commercial synthesis of oxalic acid, ie, alkali fusion of cellulose, nitric acid oxidation of carbohydrates, by-product formation during carbohydrate or sugar fermentation, and synthesis from sodium formate, only oxidation by nitric acid currently is used.
The manufacture of oxalic acid by nitric acid oxidation includes, in addition to carbohydrates, glycols, eg., ethylene and propylene glycols and acetaldehyde.
Oxalic acid in its pure form is very dangerous. It is toxic and corrosive and should be carefully handled. When mixing the powdered acid with water, always wear latex gloves to protect your skin. You should also use protective glasses and a dust mask to avoid eye irritation and to prevent the noxious fumes from getting into your lungs. Always mix oxalic acid in an area that is well-ventilated—preferably outdoors. In case of accidental swallowing, never induce vomiting; instead, contact your physician or your local poison control center immediately.
Uses of Oxalic Acid
Oxalic acid can be used as a bleaching agent for both wood and stone. Wood, when exposed to the elements, can turn gray. When oxalic acid is applied on an old and graying wood floor, it brings back the wood floor’s natural white color. Actually, this acid is often used when preparing to stain old wood floors. It is also used by furniture manufacturers to lighten heavily stained areas of wood furniture in preparation for refinishing.
2. Removing Stains
Oxalic acid effectively removes ink, food stains, and many other types of stains. It is a gentle stain remover that eats the stain but leaves the base surfaces, such as wood, intact. You can use oxalic acid to remove most stains found on stone, brick, linoleum, wood, and vinyl surfaces. However, do not use oxalic acid if your flooring is sealed as it will eat through the finishing.
Although you can also use oxalic acid to remove stains from fabrics such as linen and cotton, it will take a lot of time, so it is better to have your fabrics dry cleaned instead.
Particle Board from Rice Husk
Rice husk particleboard is one such material which is being considered as a potential substitute for wood and wood-based board products.
Rice is a major food crop in many regions of the world. Due to global demand, rice production is expected to grow from year to year. Rice husk (RH) is the outer covering of the rice grain and is obtained during the milling process. RH constitutes 20% of the total rice produced. As a renewable material, the use of RH can eliminate waste disposal and support environmental protection.
Rice husk is unusually high in ash, which is 92 to 95% silica, highly porous and lightweight, with a very high external surface area. Its absorbent and insulating properties are useful to many industrial applications, such as acting as a strengthening agent in building materials.
Various types of board can be produced from rice husk. These by-products include particleboards, insulation boards and ceiling boards.
Advantages of Particleboard
• Easy to clean and maintain
• Consistent quality
• Adherence to international standards
• Economical board sizes resulting in minimal wastage
• Excellent acoustic properties
• High bending strength
• Excellent machinability
• Saves both time and labour
• The widest spectrum of applications
• Free from warpage and peeling of laminates
Uses & Applications
Particle board has many advantages over the wood. The property of this board can be controlled.
It has got better acoustic properties and hence better sound absorption. It does not support combustion, thus it is safe to use as it is fine safety measure.
It is insect and termite resistant.
It is water resistant.
Rice Husk Briquettes
Briquettes have been in place for a long time as a cheap source of fuel for many applications. Growing environmental concerns have prompted people to look for alternate solutions for heating and ambiance fires that result in minimal environmental pollution. The economic aspects of alternate fuels to replace traditional fuels are also significant. Traditionally, petroleum-based fuels had taken precedence and this trend will probably continue for some time, especially where large industrial applications are concerned.
Fuel is defined as natural or artificial organic substance used as source of energy and raw material for industries. All kinds of fuel as regards their state of aggregation are divided into solid, liquid and gaseous and as regards their origin into natural and artificial fuels. Solid fuels for which bound or compressed rice husk (Briquettes) belong to group under the natural fuel origin. Briquetting is defined as the compaction of loose combustible material for fuel making purpose. The products obtained from the process of briquetting are known as briquettes. Briquetting is a technology, which uses either a dry or a wet process to compress solid waste (rice husk) into different shapes. With briquetting of rice husk a new fuel source is found which will help in reducing wild dumping of rice husk in the rice.
Generally, compared with sawdust, agro-residues have poor flow characteristics and have a higher potash content and higher ash content. But rice husk is proved to have a good flowability, lower moisture content which makes it an exceptional agro-waste. Moreover, rice husk has a high ash sintering temperature since the ash after combustion contains fewer alkaline minerals. Due to these advantages rice husks become an excellent choice as raw materials for fuel briquettes, although its calorific value is less than other biomass materials such as wood.
Rice Husk Pellet (RHP)
Rice husk pellets are made by compacting rice husk, which is obtained as a by-product of rice growing. It has similar characteristics to wood pellets but is more environmentally friendly, as the raw material is a waste product.
Why Make Rice Husk Pellets?
• Rice husk is difficult to ignite and it does not burn easily with open flame unless air is blown through the husk. It is highly resistant to moisture penetration and fungal decomposition.
• Handling of rice husk is difficult because it is bulky and dusty.
• Rice husk has low bulk density of only 70-110 kg/m³, while the bulk density of rice husk pellets is 180kg/m³.
• Rice husk requires large volumes for storage and transport, which makes transport over long distances un-economical.
Property of Rice Husk Pellet
Rice husk pellet is round and pelleted form of rice husk with high density, customized size and stable calorific value. Compared with rice husk of low-density and unusual shape, rice husk pellet is easier to store and transport due to a has higher calorific value & less ash content, which is beneficial to the environment at the same time.
As the new kind of bio-energy, rice husk pellet can be used in heating, living stoves, hot water boilers, industrial boilers, biomass power plant and so on to replace firewood, coal, fuel oil, liquefied petroleum gas. Especially in European areas, pellets are mainly for civil heating and domestic energy.
Advantages of Pelletizing Rice Husk into Pellet
As a source of alternative energy over the usual non-renewable fossil fuels, rice husk pellets have been gaining a lot of interest all over the world. Now rice husks are collected and transported from various rice mills to rice husking process plant for rice husk pellets production for the following advantages of rice husk pellets.
a. Good to Environment
Rice husk pellets as a biomass fuel will ease the environment pressures caused by fossil fuel combustion. Comparing with the burning of rice husk, the burning of rice husk pellets is much more clean. The ash content is around 15 to 16 % when burning directly which will be largely decreased to 6 to 7 % when it is burned in pellet form.
Sodium Silicate from Rice Husk
Sodium silicate, usually known as “water glass” or “liquid glass”, is well-known due to wide commercial and industrial application. It is mostly composed of oxygen-silicon polymer backbone lodging water in molecular matrix pores. Sodium silicate products are manufactured as solids or thick liquids, depending on proposed use. Sodium silicate is a versatile, inorganic chemical made by combining various ratios of sand and soda ash (sodium carbonate) at high temperature. Its earliest application was in the soap industry, where it was largely used as fillers. It has also some detergent action of its own. These are extensively used in industry in the manufacture of paper, as adhesives in the manufacture of the fibre containers and laminated wall board, in the textile industry and for numerous other purposes.
The soluble silicates in their different forms: amorphous glass, granular solids or liquid solutions, represent one of the most commonly used chemical products.
Sodium Silicate Physical and Chemical Properties …
• Sodium silicate: 37% Wt.% (28% silica + 9% sodium oxide)*
• Chemical formula: Na2O. SiO2
• Water: 63% Wt%
• Appearance: Thick liquid.
• Color: It is colour less and in liquid state, it gives a whitish sky blue shade.
• Odor: Odorless or musty odor.
• pH: Approximately 11.3
• Specific gravity: 1.39 g/cm3 (20°C), 41° Be, 11.62 lbs/gal
• Solubility in water: Miscible.
As the world is turning into a more sustainable society, it has become imperative for both policy makers and the public in general to clamour for new solutions to handling of packaging as its environmental impact outweigh the beneficial effect. Nowadays packaging is pervasive and essential. It is an essential link between the product makers and their customers. It surrounds, enhances and protects the goods we buy, from processing and manufacturing through handling and storage to the final consumer. Without packaging, materials handling would be a messy, inefficient and costly exercise, and modern consumer marketing would be virtually impossible. Packaging technologists must bring to their professional duties a wide-ranging background drawn from a multitude of disciplines. Efficient packaging is a necessity for almost every type of product whether it is mined, grown, hunted, extracted or manufactured.
Properly designed packaging is the main way of ensuring safe delivery to the final user in good condition at an economical cost. All the skill, quality and reliability built into the product during development and production will be wasted, unless care is taken to see that it reaches the user in the correct condition.
Types of Packaging Materials
Whether you are in food business, technology industry or clothes manufacturing, packaging is important. It safeguards the product from all kinds of damage, which may otherwise make the product or item useless.
This is the most common packaging material and, at the same time, one of the most difficult to dispose of. The factors common to all plastics are that they are light, strong cheap to manufacture. It is for these reasons that they are used so much, as an alternative to cardboard glass packaging materials.
Almost 10% of our rubbish consists of different types of plastic. They are a problem in landfills as they are bulky, they contaminate degrade slowly.
Separated the rest of the waste, they can must be upgraded for the good of everyone.
Appropriate for packaging foods (canned foods). For drinks, such as soft drinks beers, aluminium is often used.
Tin plate is a solid, heavy steel covered with tin to protect it against rust. It is used to package canned foods. It can be separated by magnets should be recycled in all cases.
Aluminium is attractive, light strong at the same time, but requires a lot of raw materials energy to make it. For this reason it must be recycled. The majority of cans of soft drinks, lids, aluminium foil, etc. are made aluminium.
A light, strong air-tight packaging material. Ideal for transporting storage. Its complex composition makes it difficult to reycle. It is becoming the main packaging material used for basic foodstuffs.
Complex packaging material, made up of several layers of plastic, paper aluminium. It is also difficult to recycle. It is used mainly to keep drinks such as milk, juice, etc.