47results about "Condensed phosphoric acids" patented technology

The invention relates to a process for producing a unique phosphation reagent and to a simple, single-stage process utilizing is reagent to produce alkyl phosphate esters having high monoalkyl phosphate content in combination with low dialkyl phosphate, trialkyl phosphate, phosphoric acid and residual alcohol.

A method for using phosphoric oxide to concentrate diluted phosphoric acid to prepare polyphosphoric acid, including following steps: mixing yellow phosphorus and air with the proportion of 1kg yellow phosphorus to 6.3-6.6 m3, burning, absorbing the obtained P2O5 by diluted acid; applying the obtained phosphoric acid into a phosphoric acid groove; then using acid pump to send into a condenser to remove the heat; then sending the phosphoric acid into a hydration tower to circularly spray and absorb P2O5 to increase the concentrated phosphoric acid; cycling without stop to obtain the phosphoric acid having 82%-84% P2O5. The recovery coefficient of phosphorus is more than 98%. The obtained product reaches the standard of the food-level phosphoric acid. This invention may greatly reduce the cost of package and distribution of the phosphoric acid production enterprise via using the wet-method phosphoric acid or hot-method phosphoric acid of the concentrated content of the phosphoric acid anhydride of less than 100% obtained by yellow phosphorus burning. This invention does not need to consume the extra energy, and can fully use the burning heat and the hydration heat of the yellow phosphorus; the generated steam can be recycled. So this invention has the advantages of saving energy and greatly reducing the production cost of the polyphosphoric acid, with remarkable social and economic benefits.

The invention discloses a hot-process phosphoric acid production device with low-temperature heat energy recovery. The device comprises a combustion tower, a first-level absorption tower, a tube-shell boiler, a second-level absorption tower, a Venturi, a mesh mist eliminator and an induced draft fan, wherein the temperature of polyphosphoric acid in the first-level absorption tower is 150-200 DEG C. According to the hot-process phosphoric acid production device, the heat energy of polyphosphoric acid is converted into low-pressure steam for recovery by the tube-shell boiler; and the manufacturing cost of the low-temperature heat energy recovery device is low, 10-30% of the heat energy of the combustion heat of yellow phosphorus can be recycled, the water resource consumption and environmental pollution are reduced, and the device conforms to the production technology requirements of high efficiency, energy conservation, environmental protection and cleanness.

The invention discloses a manufacturing method of polyphosphoric acid, which comprises the following steps: 500g of wet phosphoric acid purification acid or thermal phosphoric acid of which the quality percentage concentration is 75-85percent is taken to be added into a vacuum distillation unit, the temperature rises to 160-300 DEG C in a speed of 5 DEG C/min, and the vacuum distillation unit is decompressed and distilled for 1-2h under the conditions that the vacuity is 0.0-0.085Mpa and the stirring speed is 100-300rpm; the phosphoric acid after water elimination is placed into a polymerization reactor which can control reaction temperature and is provided with an electric agitator, the quantity of the added phosphorus pentoxide is 41.4-49.2percent of raw material acid quantity and peroxide is 0.0032-0.0007percent of the raw material acid quantity under the conditions that the temperature is 80-150 DEG C and the stirring speed is 200-500rpm, and the polymerization is performed for 3-6h; when the reaction is over, the temperature of products is reduced to the normal temperature to obtain the polyphosphoric acid. The manufacturing method has the advantages of simple technics, easy industrialization, low cost, good quality, moderate operating conditions, low investment, cleaning and no pollution.

The invention discloses a phosphoric acid production device by employing a hot method, and belongs to the technical field of energy-saving technologies of phosphoric acid production by employing a hot method. The device comprises a combustion tower, an absorption tower, a dynamic wave demister, a gas-liquid separator and an induced draft fan, wherein the combustion tower is communicated with the inlet in the top of the absorption tower; the absorption tower is connected with the dynamic wave demister; the dynamic wave demister is communicated with the induced draft fan through the gas-liquid separator; meanwhile, the absorption tower is connected with a heat exchanger through an absorption tower circulating pump; the heat exchanger is communicated with the absorption tower to form a loop through a pipeline; and the dynamic wave demister and a demister circulating pump form a loop through a pipeline. According to the device, the resistance of the system is reduced, the dosage of circulating acid and circulating water is lowered, the installed capacity of the system is greatly lowered, energy conservation and consumption reduction are achieved, the production capacity of the system is improved, and the device has the characteristics of low investment cost, small floor area, low power consumption, low production cost, and low coal resource and water resource consumption.

The invention discloses a process for selectively producing phosphorus pentoxide. By using yellow phosphorus as a basic material and sulfuric acid as a drying agent, the phosphorus pentoxide is prepared by combustion in a phosphorus combusting furnace, phosphorus pentoxide smoke prepared by combustion of the yellow phosphorus is introduced into a multistage sedimentation system after being cooled through a cooling system, and sent to a material collecting bin after being further cooled by the multistage sedimentation system to prepare phosphorus pentoxide powder, and a tail gas is exhausted after being purified; or the phosphorus pentoxide smoke prepared by combustion of the yellow phosphorus combustion is sequentially introduced into a polyphosphoric acid absorbing tower and a phosphoric acid absorbing tower for being absorbed after being cooled by the cooling system so that polyphosphoric acid and phosphoric acid are respectively obtained, and the tail gas is exhausted after being absorbed through a foam absorbing tower, an ammonia absorbing tower and a fiber demister. According to the process, equipment is capable of reasonably optimizing a structure of production equipment; the purity of the produced phosphorus pentoxide reaches above 99.5 percent, and the phosphorus pentoxide can be largely produced.

The invention relates to the field of phosphorus chemical industry, in particular to a preparation method for polyphosphoric acid. The method for preparing polyphosphoric acid includes: letting dilute phosphoric acid enter a heater through a heat exchange tube acid inlet to be heated to 185DEG C-230DEG C, then discharging the dilute phosphoric acid out of the heater from a heat exchange tube acid outlet, and making the dilute phosphoric acid enter a separator to undergo flash concentration, keeping the vacuum degree in the separator ranging from -500 to -700mmHg, discharging the concentrated acid liquor out of the separator through an acid outlet tube at the lower end of the separator, and leading the concentrated acid liquor into a concentrated acid tank through a concentrated acid tank acid inlet to undergo cooling and storage. The heat exchange tube is coiled in an S shape in the heater, from the heat exchange tube acid inlet to the heat exchange tube acid outlet, the heat exchange tube tilts downward at an angle of 1-3 degrees. The preparation method for polyphosphoric acid provided by the invention has a simple process, can prepare high concentration polyphosphoric acid from dilute phosphoric acid by one-step polymerization. By taking dilute phosphoric acid as the raw material, the acid liquor cannot adhere to the heat exchange tube wall, thus avoiding blocking of the heat exchange tube. Further, the prepared polyphosphoric acid product has uniformly distributed components.

The invention belongs to the technical field of phosphoric acid production in the inorganic chemical industry, and relates to a novel production method and equipment for producing polyphosphoric acid with wet process phosphoric acid. According to the method, a reverberatory furnace is mainly adopted innovatively, the equipment such as a burner nozzle, a polyphosphoric acid tank, a low polyphosphoric acid circulating pump, a fume extractor, a filler washing tower and a plurality of control valves is additionally arranged, and the wet process phosphoric acid is used as a raw material for concentrated polymerization production of the polyphosphoric acid. The reaction equipment is reliable and stable, and easy and convenient to operate and control, and solves the problem that scales easily deposit on tubes of a tubular heat exchanger in single-stage or multi-stage evaporation of the wet process phosphoric acid and are stubborn at home and abroad at present. Temperature control is moderate, and the phenomenon that a large number of acid particles are carried away due to local overheating and excessively high temperatures is avoided. No vacuum mode is required, and energy is saved. Two-stage product output is adopted, thereby facilitating the improvement on the production efficiency. Tail gas is recycled by a cleaning solution which then is used as a raw material, the product yield is increased, exhaust emission is reduced, and the environmental protection is facilitated.

The invention provides a process for preparing polyphosphoric acid by utilizing wet-process phosphate purified acid. The process comprises the following steps: (1), adding the wet-process phosphate purified acid into a reaction kettle, heating the wet-process phosphate purified acid to 85 to 95 DEG C while stirring, and then stirring at a constant temperature; (2), directly heating phosphorus pentoxide to 575 to 590 DEG C and ensuring that the phosphorus pentoxide is melted; regulating stirring speed in the reaction kettle to 700 to 900r/min, subsequently, centrifugally atomizing the melted phosphorus pentoxide into phosphorus pentoxide fog droplets with the thickness of 30 to 50 micrometers, and then spraying the phosphorus pentoxide fog droplets into the wet-process phosphate purified acid in the reaction kettle; continuously stirring for 100 to 150 minutes after the spraying is ended to ensure that a reactant becomes transparent liquid; stopping stirring to obtain the polyphosphoricacid. The process disclosed by the invention has the advantages of simple steps, short production time and low production cost; moreover, the prepared polyphosphoric acid can reach the food-grade requirement.

A method of decomposing any phosphate ore with hydrochloric acid and sulfuric acid to produce polyphosphoric acid is provided. The method includes: decomposing the phosphate ore with the hydrochloric acid to produce calcium chlorophosphate, decomposing the calcium chlorophosphate with the sulfuric acid by utilization of a hemihydrate-dihydrate method or a dihydrate method to produce phosphoric acid with a high concentration, desulfurizing, concentrating and polymerizing to obtain industrial polyphosphoric acid. Another method includes purifying the calcium chlorophosphate, decomposing with the sulfuric acid by utilization of a hemihydrate-dihydrate method or a dihydrate method, producing the phosphoric acid with a high concentration, desulfurizing, concentrating and polymerizing to obtain low-arsenic polyphosphoric acid. Calcium chlorophosphate mother liquor is salted out to obtain chloride through feeding HCl, and is returned to the e phosphate ore decomposing step. Rare earth, iodine, uranium, and other useful elements in the phosphate ore is enriched and extracted. The chloride and silicon slag are prepared into a high-activity silicon fertilizer by intermediate-temperature calcination. A byproduct HCl gas is fed into calcium chlorophosphate mother liquor of the next cycle to salt out the chloride, thus forming a closed cycle process. Water is added into phosphogypsum, pulped, and washed to obtain high-quality gypsum.

The invention relates to a method for synthesizing polyphosphoric acid by taking wet-process purified phosphoric acid and phosphoric acid anhydride as raw materials, belonging to the technical field of phosphorous chemical industry. The method is characterized by comprising the following steps: placing phosphorus pentoxide into a three-neck flask at one time, slowly adding the wet-process purified phosphoric acid, continuously stirring to ensure that the phosphorus pentoxide is dissolved as much as possible, and setting the temperature and the rotating speed of a heat-collection type constant temperature heating magnetic stirrer so as to sufficiently mix materials; and after the materials are uniformly mixed, heating to a reset temperature, adding a dispersant, and carrying out polymerization reaction at constant temperature for 2-6 hours to obtain the colorless flowing transparent polyphosphoric acid of which the mass concentration of the phosphoric acid 114-120 percent. The method disclosed by the invention has the advantages that the production energy consumption of the polyphosphoric acid is greatly reduced as the wet-process purified acid is used as a raw material; the method is safe and simple to operate and has good generalization practicability.

The invention relates to a novel phosphoric acid and polyphosphoric acid production technological method which is characterized by comprising the following two steps: combustion absorption and purification and arsenic removal; a directly connected spray gun of a phosphorus supply pump is changed to a plate-and-frame press filter by adopting the traditional production technological one-step method combustion absorption and hydration one-step method, different products adopt different structures and materials, a material 316L stainless steel jacket is adopted, an air stirrer is arranged, replacement is not needed, long-term operation can be ensured, and a transmission device for stirring is not needed; and by adopting the principle of being high in technical content, low in production cost, fewer in three wastes and easy in treatment, the invention provides a two-step technological method of combustion-hydration three-level absorption acid mist capturing and production of polyphosphoric acid.

The invention provides an arsenic-removing filtering method for high-concentration polyphosphoric acid, which includes: using industrial polyphosphoric acid as the raw material, adding water-soluble phosphorus pentasulfide emulsion used as arsenic-removing agent to enable arsenic contained in the polyphosphoric acid to form sulfide precipitate under the acidic condition, and purifying and refining the polyphosphoric acid by means of filtering, aerating and the like to produce low-arsenic polyphosphoric acid. By the low-arsenic polyphosphoric acid production method that filter cakes are formed on filter media from the dilute polyphosphoric acid containing arsenic residue first, and then the polyphosphoric acid with added arsenic-removing agent is filtered, the technical problem of filtering in the low-arsenic polyphosphoric acid preparation process is solved, and low-arsenic polyphosphoric acid production can be industrialized. Further, the arsenic-removing filtering method for high-concentration polyphosphoric acid is low in operating cost and simple in operating process, and low-arsenic polyphosphoric acid products, which cannot be obtained by conventional methods and are 105%-118% in concentration, namely percentage composition of P2O5 ranges from 76.1% to 85.5%, and arsenic content is no more than 10ppm, can be obtained by the arsenic-removing filtering method.