630 results about "Absorption column" patented technology

An apparatus and method for absorbing and recovering carbon dioxide from flue gas using ammonia water as an absorbent, including an absorption column and a circulation cooler connected to the absorption column so that a high-temperature absorbent is recovered from the absorption column, cooled to a preset temperature, and then supplied again into the absorption column, in order to dissipate absorptive heat generated when carbon dioxide is absorbed from the flue gas.

The invention discloses a method for recovering and utilizing waste heat from low-temperature flue gas. An air-water heat exchanger (4) is connected in series or in parallel in the flue at the rear of the induced draft fan or booster fan (3) of the existing boiler or kiln (1). The inlet port of the hot side of the air-water heat exchanger is connected with the induced draft fan or booster fan (3), the outlet port of the hot side is connected with the desulfurization absorption tower (8) or the chimney (9), and the inlet port of the cold side is circulated with the heat user The outlet pipe or condensate pipe of the water or boiler softened water system is connected, the cold side outlet is connected with the hot user circulating water supply or the boiler feed water pump, and a waterway is connected between the hot side outlet pipe and the cold side inlet pipe of the air-water heat exchanger A bypass pipe, and a waterway bypass regulating valve (5) is arranged on the pipe; a flue gas bypass pipe between the induced draft fan or booster fan and the desulfurization absorption tower (8), and a flue gas bypass pipe A flue bypass regulating valve (6) is arranged on it. By connecting a gas-water heat exchanger in series or in parallel in the flue behind the induced draft fan of the boiler or kiln, the purpose of saving heat energy can be achieved.

The invention relates to a stripping ammonia-removing method based on flash evaporation and heat pump technologies. The method comprises the following steps of: absorbing steam which is obtained after stripping ammonia removal and rich in ammonia nitrogen with an absorption column, pressurizing the purified steam with a heat pump set for recycling, carrying out flash evaporation on wastewater subjected to ammonia-removing process with a vacuum flash evaporation set composed of a Venturi and a liquid ring vacuum pump, and directly heating for pretreating wastewater with high ammonia nitrogen content. Compared with the traditional process with high ammonia-removing steam consumption and high operation cost, the method disclosed by the invention has prominent effects in energy saving and consumption reducing, and has broad market application prospect and high application potential in the treatment of wastewater containing ammonia nitrogen.

The invention discloses a method of distillation and ester exchange reaction for producing dimethyl carbonate and dihydroxyl alcohols comprising the following steps, counterflow contacting cyclic carbonates absorbent with mixed gas containing alkylene oxide and carbon dioxide in an absorption column, reacting alkylene oxide with carbon dioxide to obtain cyclic carbonate, the cyclic carbonate synthesized liquid entering a rectifying tower, the cyclic carbonate on top of the tower entering an reaction rectifying tower through pipe lines, carrying out ester exchange reaction with menthol at the presence of ester exchange catalyst, obtaining dimethyl carbonate and dibastic alcohol.

A photolytic device for breaking down organic chlorine compounds, such as trichloroethylene and tetrachloroethylene, in a fluid includes a first reaction chamber, a second reaction chamber, and an acid component absorption column. The first reaction chamber and the second reaction chamber are connected in series, and the second reaction chamber and the acid component absorption column are connected in series. The first reaction chamber is a perfect mixing type chamber, and the second reaction chamber is an imperfect mixing type chamber. The first reaction chamber and the second reaction chamber each have an ultraviolet light source capable of emitting light of wavelength 300 nm or less.

This invention discloses a method for separating phosphorus and fluorine of kiln process phosphoric acid by absorption. The method comprises: sending relatively high temperature phosphoric acid after hydration in primary and secondary hydration columns to a circulation tank for cooling, pumping into the hydration columns for circulation, sending gases after primary and secondary absorption to a Venturi absorber for re-absorption, collecting the residual acid mist by a collector, sending the absorbed gas and tail gas after fluorine absorption together to a chemical absorption column, and exhausting the tail gas. Besides, qualified fluosilicic acid can be obtained from the fluorine-containing diluted H3PO4 in the collector. The method utilizes the air with residual heat in the kiln, and has such advantages as no extra energy consumption, high phosphorus and fluorine separation efficiency, high concentration and low fluorine content in obtained H3PO4, and low P2O5 content in obtained fluosilicic acid. The obtained fluosilicic acid has a wide concentration range and a high purity, and is easy to utilize.

The invention provides a novel method for absorption and separation of high-purity chlorogenic acid, comprising an absorption process, an impurity cleaning process and an elution process. The method is characterized in that: after chlorogenic acid stock solution is dynamically absorbed by at least dual tandem absorption column which is filled with macroporous resins until penetration, impurity removal solution is added for impurity removal; and finally eluent is used for elution until no chlorogenic acid flows out, and effluent is collected. The purity of the pure chlorogenic acid solution obtained by the method can reach over 92 percent as shown by HPLC detection, and the concentration can reach between 0.1 and 0.8 milligram per milliliter; and the pure chlorogenic acid solution can be widely applied in the fields such as foodstuff, medicines, cosmetics and so on. Solid, namely dried chlorogenic acid powder, obtained after direct drying of the pure chlorogenic acid solution prepared by the method, does not require reprocessing, can be directly applied, and is convenient for conveying.

To provide a novel technique capable of further reducing the argon purge amount in a process for producing ethylene oxide.A method for producing ethylene oxide, including: a step of supplying an ethylene oxide-containing reaction product gas produced in an ethylene oxidation reaction step in an ethylene oxidation reactor, in which ethylene is subjected to contact gas-phase oxidation using a molecular oxygen-containing gas in the presence of a silver catalyst, to an ethylene oxide absorption column to bring the reaction product gas into contact with an absorption liquid supplied to the ethylene oxide absorption column, supplying an ethylene oxide-containing column bottom liquid of the ethylene oxide absorption column to an ethylene oxide purification system, and purifying ethylene oxide in the ethylene oxide purification system; and a step of supplying at least part of a carbon dioxide gas-containing gas discharged from a column top part of the ethylene oxide absorption column to a carbon dioxide gas absorption column to bring the carbon dioxide gas-containing gas into contact with an absorption liquid, extracting the resulting carbon dioxide gas-rich absorption liquid as a column bottom liquid of the carbon dioxide gas absorption column and supplying the same to an upper part of a carbon dioxide gas stripper column, and stripping a carbon dioxide gas from the carbon dioxide gas-rich absorption liquid and discharging the same from a column top part of the carbon dioxide gas stripper column as an exhaust gas, the concentration of molecular oxygen (O2) in the molecular oxygen-containing gas supplied from outside the system into the system being 99.7% by volume or more.

The invention discloses a combined technology of a catalytic cracking absorbing stabilizing system and C3 intercooling oil absorption, belonging to the technical field of integration of oil refining and ethylene, and providing a method for recovering dry gas by the combination of the absorbing stabilizing system and the C3 intercooling oil absorption. The method eliminates a desorption column of the absorbing stabilizing system, and avoids the constant circulation of a great amount of ethylene, ethane and liquefied gas in desorption gas between absorption and desorption, thus reducing the load of an absorption column and saving the energy consumption of the desorption column; as coarse C3 in a dethanizing column kettle of an ethylene unit is used as an absorbent, raw material is easy to obtain, and the cost is low; the desorption column of an original C3 oil absorption column for absorbing intercooling oil is eliminated, the constant circulation of a great amount of C2 and C3 in the desorption gas between absorption and desorption is avoided, and an expansion engine and an ice chest are adopted for recovering refrigeration capacity, thus saving consumption of the refrigeration capacity and heat capacity; and the regeneration of a C3 absorbing agent, the demethanation and the separation of the ethylene are all conducted in the ethylene unit, thus fully showing the reciprocity of the oil refining and ethylene, and being reasonable in flow.

The invention discloses a method and equipment for producing highly purity carbon tetrafluoride gas; the method includes the steps: the fluorine gas and highly purity active carbon successively experience the chemical synthesis reaction, dedusting, water washing, alkaline washing, gas liquid separation, water removal, rectification, liquefaction and collection. The equipment includes a fluorine gas storage tank, a reaction kettle, a dust catcher, a water scrubber, an alkaline tower, a gas-liquid separator, an absorption column, a rectifying still, a rectifying column and a condenser. The carbon tetrafluoride gas produced with the method and equipment has high purity and the invention has the advantages of simple equipment, easy operation, convenient and safe operation, continuous production and so on.

The invention discloses a production device, particularly a production device for sodium bisulfide continuous absorption reaction, and belongs to the technical field of chemical engineering production equipment. The invention provides the production device for the sodium bisulfide continuous absorption reaction, which is low in power consumption and production cost and easy in control of product quality. The production device comprises an absorption tower, an absorption column bottoms pump and a sodium bisulfide production solution storage tank, a process tail gas output interface is arranged at the top of the absorption tower, a process absorption liquid input interface is arranged at the upper part of the absorption tower, a hydrogen sulfide gas input interface is arranged at the lower part of the absorption tower, an input end of the absorption column bottoms pump is connected with the bottom of the absorption tower, and an output end of the absorption column bottoms pup is connected with the process absorption liquid input interface and the sodium hydrosulfide production solution storage tank respectively.

The invention relates to a process of extracting flavone from lotus leaf, which comprises following steps: deposition-extraction-ultra-filtering-micro porous absorption resin column: condensing and dealcoholizing to remove water insoluble foreign matter through depostion, extracting with ligarine to remove fat soluble foreign matter, ultra-filtering to remove water soluble micro-molecular foreign matter, using macroporous absorption column to absorb chromocor selectively, washing and collecting different types of high-purity chromocor. The invention is characterized in that it removes water insoluble foreign matter through deposition, and removes fat soluble foreign matter through extraction with benzinum purificatum, and eliminates water soluble macromolecular foreign matter through ultra filtering membrane, after the processes, the foreign matter is effectively removed from upper column and reduces influence to resin absorption, the absorption performance to chromocor is greatly improved, the absorption volume is increased from 83mg / ml to 200 mg / ml. It is suitable for mass production.

A microorganism desulfurizing and sulfur recycling method. A gas material flow containing hydrogen sulfide is fed into an absorption column and then is subjected to chemical absorption with an alkali solution sprayed from the top of the column in a counter-contact manner, wherein treated purified gas is discharged out from the top of the absorption column. A back-washing apparatus is arranged in the absorption column to wash the sulfur attached to a filling material. A rich solution, in which the hydrogen sulfide is dissolved, is fed into a rich solution tank from the bottom of the absorption column and then is fed into a bio-reactor for aeration, so that a carrier, on which desulfurization bacteria is immobilized, is fluidized and the sulfide in the absorption solution is biologically oxidized to generate elementary sulfur. The regenerated solution containing the sulfur then is fed into a settling tank through an overflow weir of the bio-reactor and a supernatant liquid is fed into a barren solution tank. The supernatant liquid then is fed back to the absorption column for being recycled through a barren solution pump. Sulfur slurry in the bottom layer is discharged through the bottom of the settling tank and then is subjected to solid-liquid separation in a centrifugal machine to obtain biological sulfur. A separated filtrate is fed back to the bio-reactor for being recycled. The bio-desulfurization technology is green and environment-friendly, is energy-saving and emission-reducing and can recycle resources, and has social, economical and environmental benefits.

The invention discloses a mining machinery shock absorbing base, which includes a box body, a shock absorbing column is fixedly connected to the center of the bottom of the inner wall of the box, and a shell is fixedly connected to both sides of the bottom of the inner wall of the box. The side of the housing away from the shock-absorbing column is fixedly connected to the box, and the inside of the housing is longitudinally slidably connected with a baffle, and the top and bottom of the side of the baffle away from the shock-absorbing column are fixedly connected with a shock-absorbing spring. The end of the damping spring away from the baffle is fixedly connected with the casing. The present invention is provided with a box body, a support plate, a groove, a support rod, a first through hole, a fixed plate, a fixed rod, a bracket, a shock-absorbing column, a connecting rod, a housing, a second through-hole, a baffle plate and a shock-absorbing spring It solves the problem of poor shock absorption effect of existing mining machinery. The shock absorption base of mining machinery has the advantages of good shock absorption effect, which is convenient for users to use and improves the practicability of mining machinery. It is worth promoting .

A method for producing acrylic acid by using an acrylic acid-containing solution of high concentration without azeotropic distillation is provided. This method of producing acrylic acid comprises introducing an acrylic acid-containing gas obtained by catalytic gas phase oxidation reaction into an absorption column and supplying the acrylic acid-containing solution to crystallization step thereby separating the solution into acrylic acid and residual mother liquid, and distilling at least part of the residual mother liquid and circulating the distillate obtained by the distillation to the absorption column.

This invention provides a method for removing tar, naphthalene, ammonia, hydrogen sulfide, organic sulfur, HCN and benzene from coal gas in one apparatus at the same time, characterizing: simultaneously absorb more than 50 impurities that are harmful to chemical production such as tar, naphthalene, ammonia, hydrogen sulfide, organic sulfur, HCN and benzene by the various, multi-layer adsorbents filled inside the absorption column. desorb the 50 more impurities from the absorbents by heated carrier gas, and obtain different kind and relatively enriched impurities according to different carrier gas temperature and desorbing time, such as naphthalene rich didymium, sulfur rich didymium, and rich didymium of benzene and homology thereof. The different kind and relatively enriched impurities can be directly sent to the recovering system of coke-oven plant for recovering and reusing and producing chemical products with high added value.

The invention relates to equipment for preparing a molecular sieve, which comprises a tubular reactor, a gas-solid separator and an absorption column, wherein the tubular reactor comprises a first feeding hole, a discharging hole and a tube body, the first feeding hole and the discharging hole are respectively positioned at two end parts of the tube body, the tubular reactor is communicated with the gas-solid separator through the discharging hole, the upper part of the gas-solid separator is communicated with the absorption column, and the position where the gas-solid separator is connected with the discharging hole is lower than that where the gas-solid separator is connected with the absorption column. The equipment for preparing the molecular sieve, provided by the invention, can realize the continuous operation of the contact reaction of the molecular sieve and SiCl4, and can control the contact time of the molecular sieve and the SiCl4 through controlling the length of the tubular reactor and the flow speed of the carrier gas, thereby being capable of enabling the contact reaction of the molecular sieve with the SiCl4 to be fully carried out in the tubular reactor.

A method is disclosed which produces acrylic acid in a high yield as maintaining the conditions for purifying acrylic acid in constant ranges and preventing the acrylic acid from polymerization. By using a reactor which has first reaction zone and second reaction zone formed of different reaction tubes, propylene concentration adjusting in the range of 7–15 vol. % and water concentration adjusting in the range of 0–10 vol. % are introduced thereto thereby obtaining an acrylic acid-containing gas. Then the gas is introduced to an acrylic acid absorption column to adjust water concentration in the range of 1–45 wt. %, thereby preventing from polymerization.

This invention relates to a absorption approach of 3 - cyan pyridine, mainly solve the problem that while using circulating water solution to assimilate 3 - cyan pyridine in anciently literature, not involved with theoretical plate number of absorption column, weight proportion of liquid and air, as well as 3 - cyan pyridine easily hydrolyzing. This invention adopts two tandem circulation absorption columns. Control the concentration of 3 - cyan pyridine in first absorption column bottom at 3 to 10 percent of weight, the liquid temperature while circulating to overhead is 5 to 50 deg, theoretical plate number of absorption column is 2 to 20 pieces, weight proportion of liquid and air is 2 to 15. The weight ratio between liquid circulating to second absorption column overhead and circulating to first absorption column overhead is 0.25 to 0.8.

The invention relates to equipment for preparing a catalytic cracking catalyst, which comprises a tubular reactor, a gas-solid separator, an absorption column, a beating machine and a nodulizer, wherein the tubular reactor comprises a first feeding hole, a discharging hole and a tube body, and the first feeding hole and the discharging hole are respectively positioned at two end parts of the tubebody; the tubular reactor is communicated with the gas-solid separator through the discharging opening, the upper part and the lower part of the gas-solid separator are respectively communicated withthe absorption column and the beating machine, the position where the gas-solid separator is connected with the discharging hole is lower than that where the gas-solid separator is connected with theabsorption column, and the nodulizer is used for receiving materials from the beating machine. The equipment for preparing the catalytic cracking catalyst, provided by the invention, can realize continuous operation of the contact reaction of the molecular sieve and SiCl4, and can control the contact time of the molecular sieve and the SiCl4 through controlling the length of the tubular reactor and the flow speed of the carrier gas, thereby being capable of enabling the contact reaction of the molecular sieve with the SiCl4 to be fully carried out in the tubular reactor.

Provided is an absorption column for body fluid purification by which the saturated adsorption amount of a substance to be adsorbed can be increased or the time required for reaching the saturated adsorption can be shortened, and therefore, the column capacity can be considerably reduced and the treatment time can be considerably shortened. The adsorption column having functional groups 6 specifically binding to a substance to be adsorbed including at least low density lipoprotein, immobilized on the surface of a porous support 5. The porous support 5 has double-pore structure comprising: a skeleton 7 made of a silica gel or silica glass having a three-dimensional network structure; through-pores 8 of an average diameter measured by the mercury intrusion method of 1 μm or more but less than 4 μm and having a three-dimensional network structure, which are formed in the voids of the skeleton; and micropores 9 having an average diameter measured by the mercury intrusion method larger than the grain diameter of the substance to be adsorbed, which are dispersedly formed on the surface of the skeleton.

The invention relates to a kind of purification method of tungsten hexafluoride gas. First, put impure tungsten hexafluoride gas in the storage tank of crude product into the bottom of absorption column where there are multihole spherical filling of sodium fluoride or potassium fluoride, remove the most impurity of hydrogen fluoride under temperature of 10-80 degree C,put it into rectifying column through pipe and fluidify it, stop entering tungsten hexafluoride gas after fluidifing it for 5kg-50kg, put helium gas of high purity into bottom of tungsten hexafluoride liquid and keep it boiling under temperature between 3 degree C and 20 degree C,the vaporized gas enter rectification column and rises, it gradually gets into condensation and circumfluence during the process of rising ,continues to rectify it to remove impurity, check it with gas chromatography, when concentration of impurity of gas discharged from tower top whose boiling point is higher than that of tungsten hexafluoride gas reduce to the request index, stop entering helium gas of high purity, and when helium gas's index reaches the request, collect tungsten hexafluoride gas of high purity into storage tank of quality product.

The invention discloses a method of deeply purifying heavy metal micro-polluted water body through resin-based nano hydrated ferric oxide, which pertains to the technical field of water environmental treatment. The steps are: nano hydrated ferric oxide granules are supported on cation exchange resin so as to generate the resin-based nano hydrated ferric oxide materials; the water micro-polluted by the heavy metal passes through an absorption column which is filled with the resin-based nano hydrated ferric oxide or the heavy metal micro-polluted water and the resin-based nano hydrated ferric oxide are mixed in a container and then are vibrated before being centrifugally dried; the absorbed resin-based nano hydrated ferric oxide can be desorbed by acid fluid such as HC1or HNO3 solution etc. or can be desorbed and regenerated by EDTA solution. When a great number of cations such as Na<+>, k<+>, Ca<2+>, Mg<2+>, etc. exist in the polluted water, the invention still can reduce and lead the effluent heavy metal concentration to meet safety control standard; when a great number of competitive cations coexist in the heavy metal micro-polluted water, the effluent heavy metal concentration can be reduced to meet the safety control standard with very large treatment capacity.

There is provided an exhaust gas treatment system including a CO2 recovery unit with further enhanced energy efficiency. An exhaust gas treatment system (1) of the present invention includes: a CO2 recovery unit (10) including a CO2 absorption column (11), an absorbing solution regeneration column (16), and a reboiler (21); and an exhaust gas heat exchanger (5) provided on a gas upstream side of the CO2 recovery unit (10). Heat exchange is performed between process condensate discharged from the CO2 absorption column (11) and steam condensate discharged from the reboiler (21) in a heat exchanger (22). The heated process condensate is fed to the absorbing solution regeneration column (16). Heat exchange is performed between the cooled steam condensate and exhaust gas in the exhaust gas heat exchanger (5) so that the steam condensate is heated while the exhaust gas is cooled.

An apparatus and method for absorbing and recovering carbon dioxide from flue gas using ammonia water as an absorbent, including an absorption column and a circulation cooler connected to the absorption column so that a high-temperature absorbent is recovered from the absorption column, cooled to a preset temperature, and then supplied again into the absorption column, in order to dissipate absorptive heat generated when carbon dioxide is absorbed from the flue gas.

The invention relates to a device and a method for preparing high-purity silane through disproportionation reactive distillation of trichlorosilane. The method comprises a disproportionation reactive distillation process (A), a silicon tetrachloride absorption process (B), a fixed bed absorption process (C) and a product filling process (D). The method comprises the steps that: two-step disproportionation reaction is adopted, and the distillation separation action of a reactive distillation column is utilized to finally obtain a mixed gas of silane and dichlorosilane on a column top to be used as non-condensable gas of a condenser to be extracted, and a silicon tetrachloride product is obtained at a column bottom after reaction formation; a gaseous product which is recovered through a disproportionation reactive distillation column enters into a silicon tetrachloride absorption column, wherein the main ingredient of an absorbed gas is silane, an absorption liquid is filled into a silicon tetrachloride desorption column, the desorbed dichlorosilane is recovered on the column top, and the desorption liquid of the column reflows back to the silicon tetrachloride absorption tower; the absorbed gas is filled into a fixed bed to absorb so as to obtain a high-purity silane product; and the silane product is filled into a buffer tank under the pressurization condition. Technological equipment is simple, and the obtained silane product has high purity.

The invention relates to a method for measuring density of slurry in a desulfurization absorption tower, which comprises the following steps: firstly selecting a low-pressure side pressure sampling point and a high-pressure side pressure sampling point in the vertical direction of an absorption tower body, then leading out sampling pipe sections from the high-pressure side pressure sampling point and the low-pressure side pressure sampling point respectively, next connecting a high-pressure side capillary tube and a low-pressure side capillary tube of a double-flange diaphragm differential pressure transmitter to a sampling pipe section respectively, and finally calculating a density value by a measured value delta P of the double-flange diaphragm differential pressure transmitter according to a formula rho1=(delta P + rho2 gh) / (gh), wherein in the formula, rho1 is the density of the slurry in the absorption tower, rho2 is the density of the filling liquid in the capillary tube, g is gravitational acceleration, and h is the altitude difference between the high-pressure side pressure sampling point and the low-pressure side pressure sampling point. The method can measure more conveniently and accurately, needs no complex operation or measures, can simply maintain corresponding used measuring equipment and devices with low cost, and ensure stable and reliable running of the measuring equipment and the devices.

The present invention belongs to the field of chemical industry and environment protection technology, and is especially process and apparatus for eliminating SO2 from fume with waste coking ammonia water in iron and steel and coal chemical enterprise. The process of eliminating SO2 from fume uses low concentration ammonia water from coking production as the ammonia source of the absorbent and has Fe+3 or S2O3-2 ion added in the oxidation process before ammonium sulfate is recovered. The apparatus consists of a high-level ammonia water tank, an absorption column, an absorbing liquid circulating pump, a catalyst solution tank, an absorbing liquid conveying pump, a blower, a fume cooling and mother liquid concentrating tower, a salt oxidizing tower, an ammonium sulfate mother liquid circulating tank, a star valve, an ammonium sulfate output filtering pump, a filter and an ammonium sulfate circulating pump.

The invention discloses a system for treating heavy metal wastewater. The system comprises an aeration pond, a neutralization pond, a flocculation pond, a thickening pond, a mechanical filtering tank, an absorption column, and functional wetland which are connected sequentially, and also comprises a ferric salt feeding system and a sludge backflow system. The concentration of Fe<3+> in wastewateris improved by aerating and feeding ferric salt, and the concentration of lead, arsenic and cadmium in a solution is reduced by using a Fe<3+> co-precipitation effect, and an adsorption effect of active iron hydroxide; by backflow of sludge, the feeding amount of lime is reduced by 5 to 10 percent, and the water treatment capacity is improved by 1 to 3 times; a high-flux large-aperture resin loaded with ferric hydroxide is used as adsorbent which has a strong effect of adsorbing the lead, arsenic and cadmium in wastewater, and effluent meets the requirement of V-grade water body of 'environmental quality standard of surface water' (GB3838-2002); and the functional wetland fully exerts the adsorption effect of filler on heavy meal, and an enrichment effect of plant, and the effluent reaches the requirement of III-grade water body.

The process disclosed herein involves the high temperature processing of phosphate ore in a solid state using a ported rotary kiln. Prior to insertion into the kiln, the ore is pulverized and beneficiated to remove excessive quantities of unwanted materials such as clay, silica, iron, sodium, potassium, and alumina. The calcium oxide to silica ratio of the beneficiated is then adjusted to within a specific acceptable range, a carbon source containing sulfur such as petroleum coke is added and the resulting feed material is pelletized using a binding agent if necessary. The pelletized feed material is then dried, preheated, and fed into a ported rotary kiln. At the elevated temperature maintained in the reducing kiln, tricalcium phosphate undergoes a reduction reaction to produce phosphorus gas and carbon monoxide. Atmospheric air is injected into the rotating kiln chamber, which facilitates the oxidation of phosphorus gas to phosphorus pentoxide and the oxidation of carbon monoxide to carbon dioxide. The reducing kiln exhaust gas stream containing the phosphorus pentoxide and carbon dioxide gas components is processed in an absorption column in which the phosphorus pentoxide is hydrolyzed by water to phosphoric acid. The phosphoric acid is then recovered and concentrated to a commercial grade strength. The slag residue serves as a raw material for cement manufacture.