TECHNOLOGICAL INSTITUTE OF THE PHILIPPINES 363 P.Casal St., Quiapo, Manila
CHEMICAL PROCESS INDUSTRIES
Submitted by: Mayor, Marnel R. CH42FA1
Submitted to: Engr. Crisanta Apostol Professor
February 22, 2013
PHOSPHORIC ACID HISTORY 1770, Phosphoric acid was discovered by K. W. Scheele and J. G. Gahn in bone ash . Scheele later isolated phosphorus from bone ash (1774) and produced phosphoric acid acid by the action of nitric acid on phosphorus (1777). (1777). 1818 Coignet & Cie , founded in Lycon the manufacture of gelatin and glue by treating bone with hydrochloric acid, and became the leading French manufacturer of pure phosphorus and a major manufacturer of matches until the latter became a government monopoly in 1872; thereafter Coignet concentrated on making superphosphates from bonemeal as well as copper phosphate, phosphoric acid and phosphate of soda. soda. 1840 Justus Von Liebig's Liebig's book entitled Organic entitled Organic Chemistry in its Application to Agriculture and Physiology booms the interest in manufacturing phosphoric acid for fertilizers. In this book Liebig stated that the insoluble phosphate present in bones and mineral phosphate, through treatment with sulfuric acid, could be converted to a form that served as a nutrient nutrient to growing plants. John Bennet Lawes was an English entrepreneur and agricultural scientist. He founded an experimental farm at Rothashed, where he developed a superphosphate that would mark the beginnings of the chemical fertilizer industry. In 1832, Lawes had begun to interest himself himself in growing plants . About 1837 he began to experiment on the effects of various manures on plants growing in pots, and a year or two later the experiments were extended to crops in the field. One immediate consequence was that in 1842 he patented a manure formed by treating phosphates with sulphuric acid, and thus initiated initiated the artificial manure industry. In the succeeding year he enlisted the services of Joseph Henry Gilbert, with whom he carried on for more than half a century those experiments in raising crops and feeding animals which have rendered Rothamsted famous in the eyes of scientific agriculturists all over the world. Some 9 years later, Albright and Wilson, Ltd was founded at Oldbury.In the early days, white phosphorus was obtained from bone ash by treating them with hydrochloric acid to produce precipitated phosphates. Then heating the meta phosphate for several days in a sealed crucible, in a retort, and distilling off phosphorus vapour, under water. Huge quantities of coal were needed for heating these retorts.
The production of white phosphorus was improved by using phosphate rock and sulfuric acid instead of bone ash and hydrochloric acid; and by the use of reverberatory furnaces instead of the direct-heated furnaces. White and amorphous phosphorus remained the main product of Albright and Wilson until World War I. In 1899 Albright and Wilson added phosphorus sesquisulfide production. They were the first company to produce phosphorus sesquisulfide commercially: it was fiery and dangerous to make. Two French chemists, , proved that year that it was non-poisonous and could be used to make safety matches. Savene and Cahen Patented the match formula. In 1929 the British Match Corporation, formerly known as Bryant and May, set up a jointly-owned company with Albright and Wilson: The A & W Match Phosphorus Company. It took over ownership of a small part of the Oldbury site concerned with producing amorphous amorphous phosphorus and and phosphorus sesquisulfide. sesquisulfide. In 1955 Albright and Wilson took over the Marchon Chemical Company based in Whitehaven, which produced phosphorus-based detergents by the " wet" process. In 1999, The name "Marchon" ended when the French company, Rhodia, took over Albright and Wilson.
DEFINITION: Phosphoric acid is mineral acid which molecules that can combine themselves in a number of different ways. It is the c ombination of phosphate rock and sulphuric acid. Phosphoric acid is a white solid that melts to form a colorless, viscous liquid. High concentrations of the liquid are corrosive. Phosphoric acid is non-flammable non-flammable and non-toxic. It is a mineral (inorganic) acid having the chemical formula H3PO PO4 4 and having a formula weight of 98 g/mol. The term phosphoric term phosphoric acid can acid can also refer to a chemical or reagent consisting of phosphoric acids, usually orthophosphoric acid.
BASIC CHEMISTRY: Phosphoric acid applied in certain reactions involving other materials produces certain products. Phosphoric acid when combined with a base (neutralization reaction) will react violently and produce water, salt and heat (heat of neutralization). Phosphoric acid in contact with common metals reacts to produce flammable and potentially explosive hydrogen gas. About 10 million tons of phosphoric acid, H3PO4, is produced in this country each year. Most of the acid (about 80%) is used in the production of agricultural fertilizers, fertilizers, with the remainder being used for detergent additives (about 10%), cleaners, insecticide production, and cattle feed additives. The commercial method of preparation is the addition of sulfuric acid to phosphate rock.
H2SO4(l ) + Ca3(PO4)2(s ) + 6 H 2O(l O(l ) →
2 H3PO4(s ) + 3 CaSO4 x 2H2O(s O(s )
Pure anhydrous phosphoric acid is a white solid which melts at 42.350C to form a viscous liquid. In aqueous solution, phosphoric acid behaves as a triprotic acid, having three ionisable hydrogen atoms.
PROPERTIES OF PHOSPHORIC ACID Molecular formula: formula: H3PO4 Density (g/cm3): 1.885g/mL 2.030g/mL (crystal at 25oC)
(liquid);
1.685g/mL
Boiling point / oC: 158oC (decomp) Viscosity: 2.4-9.4 cP (85% aq. soln.); 147 cP (100%) Melting point: 42.35oC (anhydrous) Solubility in water: 5.48g/L vapor density: 3.4 vapor pressure: 2.2 mm Hg (20oC) color: white
(85%
solution);
TYPES OF PHOSPHORIC ACID •
FOOD GRADE PHOSPHORIC ACID •
Food grade phosphoric acid is used as a sour agent to lower pH and to impart a tart, acid taste in cheese manufacture, cold beverages. Besides, in the vintage industry, it is used to keep nutrition and prevent bacteria breeding.
FOOD ADDITIVE PHOSPHORIC ACID QUALITY INDEX
Items
Index
Color
20
The mass fraction of phosphoric acid %
85.0
The mass fraction of arsenic (As)/(%)
0.0001
The mass fraction of fluoride (F)/(%)
0.0010
The mass fraction of heavy metal (Pb)/(%)
0.0010
The mass fraction of chloride (Cl)/%
0.0005
The mass fraction of sulphate (SO4)/%
0.005
The mass fraction of readily rea dily oxidizable substance (H3PO3)/(%)
0.012
TECHNICAL GRADE PHOSPHORIC ACID Technical grade phosphoric acid is highly viscous, transparent colorless or light yellow liquid. It may be used to produce variety of phosphates, electrolyte treatment liquids or chemical treatment liquids, refractory mortar with phosphoric acid. It is also used as a catalyst, drying agent and cleaner. In coating industry it is used as a rust-proof coating for metals. TECHNICAL GRADE PHOSPHORIC ACID QUALITY INDEX
Items of sulphuric chloride Analysis acid
Iron
Arsenic
Heavy Color metal
0.003
0.002
0.0001
0.001
20
0.0005
0.003
0.002
0.0001
0.001
20
85%
0.0005
0.005
0.002
0.005
0.001
30
4
topquality phosphori c acid
75%
0.0005
0.005
0.002
0.005
0.001
30
5
qualified phosphori c acid
85%
0.0005
0.01
0.005
0.01
0.05
40
6
qualified phosphori c acid
75%
0.0005
0.01
0.005
0.01
0.05
40
No.
GRADE
1
super phosphori c acid
85%
0.0005
2
super phosphori c acid
75%
3
topquality phosphori c acid
USES: MEDICAL FIELD: Phosphoric acid is used in the manufacture of glycerin sodium phosphate, iron phosphate. At the same time, as an etching solution, phosphoric acid is to use to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. Phosphoric acid is also used in many teeth whiteners to eliminate plaque that may be on the teeth before application. FOOD AND DRINKS Phosphoric acid (additive E338) is used to acidify foods and beverages such as various colas because of its sour intensity. Phosphoric acid is used directly in soft drinks, jams and jellies as an acidity controlling agent, to maintain clarity, for flavor enhancement and to increase the preservative effect. It is also utilized in sugar refining and pet foods. IN THE INDUSTRIAL FIELD Phosphoric acid is an important commodity. It is safer and less potent than muriatic acid, will effectively clean a broad range of surfaces, including concrete and other types of masonry. Otherwise, pure liquid phosphoric acid is used as the electrolyte e lectrolyte in phosphoric acid fuel cells. IN DETERGENT INDUSTRY Phosphoric acid is used to make phosphorus-based builders. Furthermore, phosphoric acid is also used to manufacture aluminum phosphate catalysts and can be used to extend the life of catalysts by reducing coking. AGRICULTURE Fertilizer and mineral supplements are areas of direct application of phosphoric acid. In fertilizers, purified phosphoric acid is used for spray and houseplant fertilizers because of its higher purity and lack of solids. IN THE FIELD OF FLAME RETARDANT Phosphoric acid is the material of red phosphorus, boron phosphate, ammonium phosphate and ammonium polyphosphate, halogenphosphorus, amino ammonium phosphate and so on.
IN COSMETICS/ASPHALT INDUSTRY Phosphoric acid is widely used in cosmetics, dehydrating agent, asphalt and bitumen additive, analysis and so on. CHEMICAL INDUSTRY Phosphoric acid is used to manufacture phosphate salts and as a catalyst to speed up the setting action of some resins. INDUSTRIALMAINTENANCE Phosphoric acid assists in applications requiring the descaling of boilers and heat exchanger tubes. METAL INDUSTRY Finishing Phosphoric acid is used in metal cleaning and chemical polishing applications. Phosphoric acid is used as a rust converter. When the solution in liquid or gel form is placed directly on rusted areas of steel, steel tools or steel surfaces, the rust is converted from the red oxide to a black ferric phosphate. This is common when pickling steel. After the rust has been converted to black ferric phosphate it can easily be scrubbed off. REFRACTORIES Phosphoric acid proved to be a strong bonding agent for alumina, carbon, magnesia, and zirconia refractories. SANITIZING Phosphoric acid is an important component of some CIP cleaners that are utilized for cleaning hard and sometimes impossible to reach places.
PRODUCTION OF PHOSPHORIC ACID THERMAL PROCESS This very pure phosphoric acid is obtained by burning elemental phosphorus to produce phosphorus pentoxide and dissolving the product in dilute phosphoric acid. This produces a very pure phosphoric acid, since most impurities present in the rock have been removed when extracting phosphorus from the rock in a furnace. The end result is foodgrade, thermal phosphoric acid; however, for critical applications, additional processing to remove arsenic compounds may be needed.
WET PROCESS Wet process phosphoric acid is prepared by adding sulfuric acid to , typically found in nature as apatite DIHYDRATE PROCESS ADVANTAGES There is no phosphate rock quality quality limitation limitation Operating temperatures are low Start-up and shut-down are easy Wet rock can be used (saving drying costs) DIS ADVANTAGES Relatively weak product acid (26-32% P2O5) High energy consumption in the acid concentration stage 4-6% P2O5 losses, most of them co-crystallised with the calcium sulphate HEMIHYDRATE (HH) PROCESS Operating conditions are selected in this process so that the calcium sulphate is precipitated in the hemihydrate form. It is possible to produce 40-52% P2O5 acid directly, with consequent valuable savings in energy requirements.
ADVANTAGES Capital savings Purer acid Lower rock grinding requirements DIS ADVANTAGES Filtration rate Phosphate losses Scaling Filter cake impurity Corrosion RECRYSTALLISATION PROCESSES The best P2O5 recovery efficiencies that generally can be expected in the single-stage dihydrate and hemihydrate processes considered so far are 9496% and 90-94% respectively. The P 2O5 losses are retained in the filter cake and this can create problems with disposal or use of the by-product gypsum. Some of this loss of P 2O5 passes into solution and can be recovered when the calcium sulphate is finally separated, if the calcium sulphate is made to recrystallize to its other hydrate. This not only raises the overall efficiency of the process but also gives a much cleaner calcium sulphate. HEMIDIHYDRATE (HDH) PROCESS ADVANTAGES Produces strong acid directly (40-52% P2O5). Produces purer acid (low SO4, Al, F). Limited post- precipitation. Uses coarse rock. Low sulphuric acid consumption. High P2O5 efficiency (98.5%). Produces a purer gypsum.
DIS ADVANTAGES Two-stage filtration, filtration, lower utilisation. utilisation. Limited number of rocks processed industrially. Care required in design and shut-down. High recrystallization volume. High capital cost.
DIHEMIHYDRATE PROCESS ADVANTAGES Flexible as to rock source. Proven process. Produces a pure hemihydrate. High P2O5 efficiency (98%). Higher acid strength (32-36% P2O5). Lower sulphuric acid consumption. Gypsum may be used directly for plasterboard, plaster plaster or as a cement retarder, after the addition of lime and natural rehydration in a storage pile. DIS ADVANTAGES Two stage filtration, lower utilisation. utilisation. High capital cost. Requires steam for conversion. Requires 35% acid storage and evaporators. Rock slurry feed unacceptable.
Requires final re-hydration of hemihydrate to gypsum. Normally, requires rock grinding. Care required in design and shut-down. Requires sophisticated materials of construction.
POTENTIAL HEALTH EFFECTS INHALATION: Inhalation is not an expected hazard unless misted or heated to high temperatures. Mist or vapor inhalation can cause irritation to the nose, throat, and upper respiratory tract. Severe exposures can lead to a chemical pneumonitis. INGESTION: Corrosive. May cause sore throat, abdominal pain, nausea, and severe burns of the mouth, throat, and stomach. Severe exposures can lead to shock, circulatory collapse, and death. SKIN CONTACT: Corrosive. May cause redness, pain, and severe skin burns. func tion may be more susceptible to the effects of the substance.
EYE CONTACT: Corrosive. May cause redness, pain, blurred vision, eye burns, and permanent eye damage. Chronic Exposure: No information found. Aggravation of Pre-existing Conditions:
Persons with pre-existing skin disorders or eye problems, or impaired respiratory FIRST AID MEASURES Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Call a physician immediately. Ingestion: If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give anything by mouth to an unconscious person. Get medical attention immediately. Skin Contact: Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Call a physician, immediately. Wash clothing before reuse. Eye Contact: Immediately flush eyes with gentle but large stream of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Call a physician immediately. FIRE FIGHTING MEASURES Fire: Not considered to be a fire hazard. Contact with most metals causes formation of flammable and explosive hydrogen gas. Explosion: Not considered to be an explosion hazard. Fire Extinguishing Media: Use any means suitable for extinguishing surrounding fire. Water spray may be used to keep fire exposed containers cool. If water is used, use in abundance to control heat and acid build-up.
Special Information: In the event of a fire, wear full protective clothing and NIOSH-approved selfcontained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode. ACCIDENTAL RELEASE MEASURES Ventilate area of leak or spill. Wear appropriate personal protective equipment. Isolate hazard area. Keep unnecessary and unprotected personnel from entering. Contain and recover liquid when possible. Neutralize with alkaline material (soda ash, lime), then absorb with an inert material (e. g., vermiculite, dry sand, earth), and place in a chemical waste container. Do not use combustible materials, such as saw dust. Do not flush to sewer! HANDLING AND STORAGE Keep in a tightly closed container. Protect from physical damage. Store in a cool, dry, ventilated area away from sources of heat, moisture, incompatibilities, and direct sunlight. Corrosive to mild steel. Store in rubber lined or 316 stainless steel designed for phosphoric acid. Do not wash out container and use it for other purposes. When diluting, the acid should always be added slowly to water and in small amounts. Never use hot water and never add water to the acid. Water added to acid can cause uncontrolled boiling and splashing. Protect from freezing. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product. STABILITY AND REACTIVITY Stability: Stable under ordinary conditions of use and storage. Substance can supercool without crystallizing. Hazardous Decomposition Products: Phosphorus oxides may form when heated to decomposition.
Hazardous Polymerization: Will not occur. Incompatibilities: Liberates explosive hydrogen gas when reacting with chlorides and stainless steel. Can react violently with sodium tetrahydroborate. Exothermic reactions with aldehydes, amines, amides, alcohols and glycols, azocompounds, carbamates, esters, caustics, phenols and cresols, ketones, organophosphates, epoxides, explosives, combustible materials, unsaturated halides, and organic peroxides. phosphoric acid forms flammable gases with sulfides, mercaptans, cyanides and aldehydes. It also forms toxic fumes with cyanides, sulfide, fluorides, organic peroxides, and halogenated organics. Mixtures with nitromethane are explosive. Conditions to Avoid: Incompatibles.
ECOLOGICAL INFORMATION Environmental Fate: When released into the soil, this material may leach into groundwater. When released to water, acidity may be readily reduced by natural water hardness minerals. The phosphate, however, may persist indefinitely. Environmental Toxicity: No information found. DISPOSAL CONSIDERATIONS Whatever cannot be saved for recovery or recycling should be handled as hazardous waste and sent to a RCRA approved incinerator or disposed in a RCRA approved waste facility. Processing, use or contamination of this product may change the waste management options. State and local disposal regulations may differ from federal disposal regulations. Dispose of container and unused contents in accordance with federal, state and local requirements.
