DE3032157A1 - METHOD FOR UNLOCKING PHOSPHATE STONE - Google Patents

Description

Patent attorneys.; "... ■ - .. ^::

_, .. "-. ~~ ^ ~ ^ & Wilson Ltd.

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Dr. rer. nat Thomas Bofendt - <S- PW 626

5.i> <: l! F Gr -.hn-StraOe 38 O 8 MOnehen 00 Dr. Be / he

Albright & Wilson Limited Oldbury, Warley, West Midlands, England

Process for opening up phosphate rock

(Addition to P 30 07 131.9)

ORIGINAL INSPECTED

Al.br.ight & Wilson Ltd. PW

Dr.Be/he description

The invention relates to a thermal treatment method, in particular the thermal treatment of phosphate rock.

Rock containing calcium phosphate contains many contaminants, including organic compounds such as humic acid. The organic contaminants can cause excessive foaming when the rock is treated with acid to form calcium sulfate and wet phosphoric acid, and also give rise to the formation of colored decomposition products, ζ.B, phosphoric acid and alkali phosphate salts. It is known to remove the organic substances from phosphoric acid or its salts by treating with activated carbon or using oxidizing salts or by calcining the rock. In calcination, the rock is usually burned in order to convert the organic constituents into carbon dioxide and to leave a calcined rock that is practically free of organic carbon and suitable for being converted into reaction products, temperatures of 750 ° C. or above being useful for this calcination are. The properties of the foam formation can be eliminated by heating at temperatures above 650 ⁰ C for a long time, whereby not necessarily a complete oxidation of the organic .Compounds takes place (see FIG. Chemical Eng. Progress, Volume 58 (1962), pages 91 to 93).

It has been found that by thermal treatment of the rock at lower temperatures than indicated above the organic compounds at least partially and usually can be completely converted into insoluble particulate carbon, which together with the calcium sulfate can be filtered off during the subsequent acidification with the formation of wet phosphoric acid.

•• / 9 130046/0529

303215Z

"" -40-

The invention provides a method for digesting phosphate rock / wherein the phosphate rock, which contains organic compounds, is ^{heated to 380 to 600 °} C. until at least some of the organic compounds are converted to carbon. Preferably, the heated rock containing carbon particles is reacted with a mixture of sulfuric acid and phosphoric acid to form a solid fraction of calcium sulfate and carbon particles and phosphoric acid and the acid is separated from the solid fraction. The phosphate rock is heated to a temperature which is sufficient to convert at least some of the said impurities and preferably the entire amount of these impurities into particulate carbon, but not sufficient to burn all of the carbon to an oxide of carbon, so that the treated rock Contains carbon particles. When the treated rock is reacted with the acid, a mixture is formed which contains phosphoric acid, sulfuric acid, calcium sulphate, usually in the form of gypsum, carbon particles and usually some uncontaminated rock, which mixture can be filtered to produce a wet phosphoric acid without carbon. - leaving behind particles of matter and significantly reduced color, e.g. yellow instead of the deep brown of the acid from untreated rock.

Heating the phosphate rock by the process of the present invention allows the reaction with the acid to proceed in a satisfactory manner, with less or no foaming than when attacking untreated rock, so that the acidification is preferably carried out in the practical absence of antifoam. The reaction with the rock can also be carried out at a faster rate of filtration and the attack on the rock is faster than when the rock is under attack, which has been calcined at 950 ⁰ C. In addition, the heating in the process of the invention reduces or eliminates the need to use activated carbon or oxidizing agents for the acid or its salts,

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to reduce their coloration. Heating to lower Temperature also offers a significant economic Advantage.

The rock is heated to a temperature not exceeding 600 ⁰ C, that is 380-600 ⁰ C, for example 450-600 ⁰ C and in particular 510-590 ° C or 450-550 ⁰ C, for example 460 - heated 540 ⁰ C, wherein temperatures from 380 to 500 ⁰ C, for example 380-480 ⁰ C and in particular 380-440 ⁰ C and 420-480 ⁰ C can be used, but the rate of conversion of the organic matter to carbon is less than at higher temperatures. The rock is usually heated to the specified temperature 0.01-10 hours, e.g. 0.1-10 hours and preferably under 2 hours, e.g. 0.6-2 hours if the procedure is batchwise, or 1 minute -1 Hour, for example 2-40 minutes, if the processes are continuous, which are inversely dependent on the temperature. The time and temperature are chosen so that preferably at least 30%, in particular at least 80%, of the organic compounds are converted into carbon. Particularly useful combinations of 40 minutes to 2 hours at 450-550 ⁰ C for rock from Florida or Zin (Israel) in batchwise digestion or 15 minutes to 2 hours, e.g., B. 1 hour at 450-550 C in the continuous process, while for rock from Morocco (e.g. Khouribga or white rock from Youssoufia) 30 minutes to 2 hours at 380-440 ⁰ C with intermittent digestion or 15 minutes to 2 hours, e.g. 15 minutes to 1 hour at 380-440 ⁰ C are preferred for continuous work. 380 to 44.0 ⁰ C is also rock from Syria, Senegal, Algeria, Jordan preferably for 560 to 590 ⁰ C for black Youssoufia rock is usable. Preferably, when the rock in the range of 460 - is heated 540 ⁰ C, this not from Egypt when heated at 490-510 ⁰ C and not from Russia when heated to 490 - 540 ⁰ C and not from Florida on heating to 49 , 0 - 510 ⁰ C, unless a continuous heat treatment takes place instead of the intermittent work. When the rock 510 - heated 590 ^ C, it is not derived preferably from Utah or Morocco, when 540 - 560 ° C is heated and not from Russia, if at 510-540 ⁰ C is heated and when the heating at 440 - 460 ⁰ C happens, the rock preferably does not come from either Utah or Morocco. With rocks from Egypt, Russia, Florida, Utah and Morocco, these temperatures can be continuous

130CU6 / 0529 ..Z ₁₁

ORIGINAL INSPECTED

Procedures are used. A rock mix can be used.

While with the usual calcining at 650 ⁰ C or above the rock gives off a considerable amount of hydrogen fluoride in any gaseous waste gases that occur from the heating, the heating at the lower temperature according to the invention can give much less fluoride and often practically no fluoride is found in the waste gas, which facilitates the cleaning of the exhaust gas.

The heating treatment can be carried out under substantially anaerobic conditions, with substantially none free oxygen or some other agent capable of oxidizing the organic contaminants is present is. Thus, the rock can be heated from the outside in the absence of air, e.g. in an oven with exclusion of air. Preferably, however, the rock is in the presence of a gas containing molecular oxygen, e.g. air or aerated Combustion gases and in the absence of added organic * see compounds and in the absence of oxidizing agents (in addition to oxygen) heated, which are able to oxidize the organic impurities. Preferably contains the gas has no added chlorine and / or hydrogen chloride. The rock can be heated e.g. by an oxidizing flame in a rotary kiln down to the required temperature. The heating can be carried out with an oxygen deficiency, with respect to the amount needed to convert the organic impurities to carbon, but preferably at least the required amount and in particular an excess is used. Conditions are usually sufficient to produce a heated To give rock that contains carbon particles and practically no acid-soluble organics (as defined below) and often contains practically no other organic compounds ..

The heat treatment is preferably carried out continuously, so that the rock through at least one heated zone of 380 - passes through x 600 ⁰ C, at least a portion of the organic comparison

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13QCU6 / Q5? *

to convert bonds into carbon and to pull off a heated rock containing carbon particles, which is usually allowed to cool.

The heating is usually conducted at 380-600 ⁰ C without the temperature is then raised above 600 ⁰ C. Then the rock temperature is reduced. A rotary kiln is preferably used with simultaneous or countercurrent flow to rock and hot combustion gases, e.g. hot combustion products of a flame, or the rock is mixed with fuel and the fuel burns and the rock is heated when both pass through a calcining furnace. Alternatively, a fluidized bed of rock and hot gases can be used, or a rock layer can be fed continuously under a flame or through an externally heated zone. Ring or tunnel ovens can also be used

the. While the heat treatment can be carried out on a rock with large particles, the rock will preferably have a grain size below 5 mm and is preferably ground first, for example to a size of 0.01-1 mm, for example at least 50 % having a grain size of 0.01-0.5 mm and preferably less than 30% below 0.1 mm.

The rock can contain 0.05-6% by weight , for example 0.05-1.0% by weight or 0.5-6.0 or 1.0-6% by weight of organic material (based on the weight referred to as organic carbon) as well as common contaminants in the rock. The rock can thus 15-45% by weight P ₂ ° 5 ' ^z ' ^{ü '25} ~ ^{40 GGW} - ~ ^{il p} o ° $ ^{and 25} ~ 35% by weight or 30-40% by weight ^; i or in particular _{30-35% by weight P 3} O ₅ and 25'- 55% by weight, for example 45-55 or 50-55% by weight Ca as CaO and 0.01-8% by weight, e.g. 0.05% by weight or 0.5-5% by weight ^Fe 2 ° 3, the total iron and aluminum content being, for example, below 10% by weight, in particular below 4% by weight (expressed as Pe ₃ O ₃ and Al ₃ O ₃ ) and 1.0-7% by weight, ■ for example 1-3.5% by weight or 3.5-7% by weight of carbonate (expressed as CO ₂ ). The invention is particularly applicable to the treatment of apatite as phosphate rock, for example rock which forms brown liquids when digested with 27% hydrochloric acid. Examples of such rocks are those

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von Zin in Isareal and Florida. Other rocks, e.g. from the western states of the United States of America e.g. Idaho or other deposits such as in North Carolina, Tennessee, Tunisia, Jordan and Morocco (e.g. Youssoufia) Algeria, Senegal, Kola, Nauru or Oceania can also be treated. ^{The phosphate ore preferably contains 0.05-0.4} % by weight of organic substances or a weight ratio of organic substances, to P ₂ ° 5 of u '°° l ~ 0' ^{1: 1} V whereby rocks with a low content of organic substances, eg from Zin (Israel), Khouribga (Morocco), El Massa (Jordan), Algeria, Tunisia, Senegal or Oron (Israel) atuininen.

The method is particularly suitable for the treatment of rock which contains acid-soluble organic components, as defined below. The term "acid-soluble organic substances" as used in the following means organic compounds which are found in phosphate rock and are of such a nature and occur in such an amount that when the rock is digested with a mixture of 56% by weight sulfuric acid and 20 wt .-% thermal phosphoric acid (the mixture contains enough sulfuric acid to convert the calcium oxide content of the rock to calcium sulfate) a suspension is formed in a liquid that ^{contains 25-30 wt% P} 2 ° 5 and at least 600 ppm (e.g. 600 - 60 000 ppm) contains dissolved organic substances (expressed as total carbon), i.e. in a weight ratio of dissolved organic substances (expressed as total carbon) to P ₂ ° ^{r in the} liquid of at least 0.002: 1, e.g. 0.002 - 0, 2: 1. Alternatively, the liquid content of the dissolved organic substances, expressed as oxidizable carbon, is at least 100 ppm, for example 100-10 000 ppm, ie one weight hts ratio of organic substances to P ₃ O ₅ of 0.0003: 1, for example 0.0003-0.3 ': 1. It is these rocks that produce acids, which contain higher amounts of dissolved organic substances and which are quite expedient by the Heat treatment according to the invention can be improved to produce treated rocks from which acid can be produced which contains minor amounts of organics (e.g. 500 ppm or less total carbon or 50 ppm or less oxidizable carbon).

/ 14 130046/0529

The rocks that can be treated according to the method according to the invention include those in which the rock itself has a low content of organic substances, for example 0.05-0.4 wt% (total carbon). However, these organics are acid soluble as previously defined. Such rocks are obtained, for example, from zin in Isarel, Algeria, Tunisia, Jordan and Senegal. According to another embodiment of the invention, a method for the heat treatment of phosphate rock is thus provided, wherein a phosphate rock, which contains a total of 0.05-0.4% by weight of organic compounds (expressed as carbon) and acid-soluble organic substances, to a temperature of 380-600 ⁰ C is heat-treated in order to convert at least some of the organic compounds into carbon and to form a heated rock which contains carbon particles. The rock preferably contains 30-40% by weight P ₃ O ₅ and 45-55% by weight Ca, expressed as CaO.

It has also been found that when phosphate ^{rocks are heat-treated at 650 °} C., a treated stone is obtained which, when acidified with a mineral acid, produces hydrogen sulfide in different amounts depending on the stone, and that when the stone is heat-treated by the method according to the invention at a lower level Temperature of 380 - 600 C, for example, the amount of unpleasant and poisonous hydrogen sulfide, which is formed during acidification, can be reduced, as well as the iron content of the product acid. It is assumed that this effect of the high temperature is due to the conversion of acid-insoluble iron sulfide, which is present in the rock, at the higher temperature into acid-soluble iron sulfide, which forms hydrogen sulfide and dissolved iron when acidified. The low temperature can also reduce the arsenic content of the product acid compared to rocks calcined at high temperatures.

Thus, in a particular embodiment of the invention, a Process for the production of phosphoric acid created, in which phosphate rock, the organic impurities and in

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Containing acid insoluble wärinelabiles iron sulfide at 380-600 ⁰ C is heated to convert at least a portion of the organic impurities in the carbon, but the heating is not sufficient to the total amount of the insoluble in acid sulfide to be converted into acid-soluble iron sulfide, wherein the heating process results in a treated rock containing carbon particles and acid-insoluble iron sulfide. Preferably, the treated rock is reacted with the mixture of sulfuric acid and phosphoric acid to form a reaction mixture of phosphoric acid, sulfuric acid, calcium sulfate, carbon particles and acid-insoluble heat-labile iron sulfide, after which a solid fraction of the carbon particles and the acid-insoluble iron sulfide and calcium sulfate, usually as Gypsum, from which wet phosphoric acid is separated. The terms "in acid insoluble" and "acid-soluble iron sulfide" mean those iron sulfides' ^{5 G} ew .-% SO ₃ in a wet process phosphoric acid which 28 wt .-% P ₂ ⁰ S ^unc3 ° are unslöslich or soluble. The term "heat-labile" iron sulfide in this specification means iron sulfide in the rock that can be converted from acid-insoluble iron sulfide to acid-soluble iron sulfide when heated. The heat treatment is at 380 ⁰ C - 600 ⁰ C, for example at 380-480 ⁰ C, in particular 400 450 ⁰ C or 450 to 550 ⁰ C and usually insoluble in acid at a temperature below the phase transition temperature in the rock for conversion to acid-soluble iron sulfide carried out. The heating conditions are otherwise as described above and here too the process is preferably carried out continuously.

The method whereby the formation of hydrogen sulfide is avoided can be applied to any phosphate rock like the above-mentioned phosphate ores, but especially those that are heat-labile, insoluble in acid Contain iron sulfide, e.g. in an amount of at least 100 ppm (preferably at least 500 ppm) sulfide (expressed as the weight of sulfur), such as 100-20,000, e.g.

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1300A6 / 0529

^ _:. . ORlGtNALlNSPECTED

500 - -DOOO or 2000 - 100,000 ppm - 5000 ppm ocfer at least 200 ppm Mefcülsulf Ad (as Ge weight Fe ^) as 200 40000 1000 VDE. The divided anviäraaalabü.en acid-insoluble sulfide from the unheated rock is obtained from the maximum content of the hydrochloric acid-soluble sulfide found in rocks that have been heated ^{to any temperature in the range of 100-1000 ° C.} Such rocks are for example those of Zin, Youssoufia, Senegal, Christmas Island and especially Florida, the preferred heating temperature at 450 from the latter ore - 550 ⁰ C, further from rocks from Tennessee, N.Carolina, Idaho and other western states of the United States of America, which can be treated in a similar way.

According to a further embodiment of the invention A heated phosphate rock is created that contains carbon particles and acid-insoluble heat-labile iron sulfide contains, wherein at least 70 wt .-%, for example at least 80 wt .-%, in particular 80-98 wt .-% or at least 90 wt .-% of the Rock is insoluble in acid, and the remainder, if any, is soluble in acid. Preferably the rock contains at least 500 ppm, e.g. 500-5,000 ppm, of this acid-insoluble, heat-labile iron sulfide (expressed than sulfur).

The heat-treated rock, which is carbon particles contains (regardless of whether it contains iron sulfides) separates with at least one member of the phosphoric acid group and sulfuric acids are reacted to make a calcium phosphate fertilizer to build. The reaction with phosphoric acid results in a fertilizer called triple superphosphate becomes, while the reaction with sulfuric acid gives a superphosphate fertilizer, the calcium dihydrogen phosphate and contains calcium sulfate. Preferably the amount of acid is at least 80%, e.g. 80-120% of that amount is required to react with the calcium in the rock to form calcium dihydrogen phosphate when the acid Phosphoric acid, or only of that amount that is required, is a mixture of calcium dihydrogen phosphate and Calcium sulfate (and virtually no free phosphoric acid) too

13QQU / Q529

:: ORIGINAL INSPECTED

form when the acid is sulfuric acid. The rock was preferably ^{heated to 460-540 0} C and does not come from Morocco or Utah, if the heating was carried out to 380 to 440 ⁰ C or 560-600 ⁰ C or if the rock was reacted with sulfuric acid or a mixture of sulfuric acid and phosphoric acid , or if the rock has been heated as part of a continuous operation. According to one embodiment, the rock containing carbon particles is reacted with phosphoric acid or sulfuric acid, but not a mixture of these two acids. The calcium phosphate fertilizer can be mixed with ammonium nitrate or phosphate in solution or in solid form and optionally also with potassium chloride to form a compound fertilizer after mixing or granulating.

The heat-treated rock can also be reacted with a mineral acid containing hydrochloric acid, nitric acid or sulfuric acids to produce a mixture of a calcium salt of these acids, phosphoric acid and carbon particles, a solid fraction containing these particles being separated from the mixture. Preferably, the rock is 380 - heated 590 ⁰ C, particularly when the acid alone is hydrochloric acid and the rock not preferably from Florida or Morocco submitted, if the heating at 380 - was 590 ⁰ C, or if not the heating as part of a continuous procedure, took place. The rock is preferably treated with an oil volume equivalent to at least 90% of the calcium content of the rock in order to convert the phosphate values in the rock into phosphoric acid. Although hydrochloric acid can be used as the attack acid, it is preferable to use an acid which contains or consists of nitric acid or sulfuric acid, because then the separated solid fraction also contains calcium nitrate or sulfate, whereby the calcium content that remains after separation in the Fluid is decreased.

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13QCU6 / 0529

ORIGINAL INSPECTED

In the conversion of the heat-treated rock to wet phosphoric acid, regardless of whether or not it contains a significant amount of iron sulfide, the rock is treated with sulfuric acid and phosphoric acid to produce the aforesaid reaction mixture, which contains a liquid and a solid fraction, in which a major part of the solid fraction consists of calcium sulphate and a smaller amount of carbon particles (and optionally iron sulphide) and there is usually some unaffected rock. The amount of sulfuric acid is usually such that at least 90% by weight, e.g. at least 95% by weight of the phosphate values in the rock are converted to wet phosphoric acid or that the amount is equivalent to at least 90% by weight of the calcium oxide content of the rock, preferably 95 - 105 '£. The reaction of the treated rock with the mixture of phosphoric acid and sulfuric acid can be carried out at a low temperature and using a low concentration of sulfuric acid so that gypsum is formed, or at a high temperature, e.g. above 90 ^° C and with a high concentration of sulfuric acid, so that calcium sulfate hemihydrate or anhydrite is formed. The rock is expediently mixed with sulfuric acid and weak recycled phosphoric acid and a recycled suspension of calcium sulfate in wet phosphoric acid in order to form the suspension of calcium sulfate, some of which is recycled and the remainder, for example by filtration, and the filter cake of calcium sulfate (with carbon particles and possibly iron sulfide) is washed with water to give a filtrate of weak phosphoric acid which is recycled to the stage at which the rock is to be attacked. The crude wet phosphoric acid produced after treatment with mineral acid and separation of the solids can be used as such, especially when calcium sulfate is separated, or can be further treated, often after a concentration, e.g. 40-60% P ₃ O ₅ the acid from attack with a mixture of sulfuric acid and phosphoric acid.

The crude wet phosphoric acid, which after treatment of the heat-treated '* Rock with the mineral acid and separation of the solid fraction with or without concentration can be obtained with

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ORIGINAL INSPECTED

: -f $ 0321S7

treated with a water-immiscible organic solvent to form an organic phase and an aqueous phase, the acid being isolated from at least one of these phases. The heat treatment according to the invention lowers the production of emulsions in it. Stage and increases the rate of separation of the phases compared to that obtained if there is no heat treatment of the rock. 590 ⁰ C heated when the acid alone iüt hydrochloric acid and the organic phase contains dissolved phosphoric acid - if the rock has not been continuously heated as above, the rock was in this case preferably to 380 for sale. The solvent may be one in which phosphoric acid is not substantially soluble or which is incapable of extracting phosphoric acid from an aqueous phosphoric acid of the given concentration so that the solvent extracts impurities and leaves most of the phosphoric acid in the aqueous phase. The impurities can simply be impurities in the acid that can be removed, e.g. iron, or can be valuable in themselves, as is the case with uranium. Examples of solvents to remove iron from the acid, usually without concentration, are long chain amines, alcohols, ethers, esters and ketones from dilute phosphoric acid. Examples of solvents for removing uranium from the acid, usually without concentration, are trialky! Phosphine oxides, e.g. trioctylphosphine oxide, Dlalkylphosphate, e.g. di (2-ethylhexyl) phosphate or in particular mixtures thereof or alternatively monoalkyl pyrophosphates, such as mouoctyl pyrophosphate and / or dialkyl pyrophosphates or alternatively mono ( alkylphenyl) phosphates and / or di (alkylphenyl) phosphates, in particular mixtures thereof, such as from mono- and di-octylphenyl / phosphoric acid, in each case each alkyl contains 6-12 carbon atoms.

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130046/0529

. "._ ORIGINAL INSPECTED ..,,.

When using phosphine oxide and / or the diester As an extraction agent, the uranium in the acid must be up to

hexavalent state, which is why the in Iron present in the acid is inevitably also oxidized. Application of the thermal process of the invention often reduces the iron content of the acid compared to that obtained from a calcined at high temperature Rock is preserved and thus less oxidizing agent can be needed to oxidize the uranium. A product containing uranium can be recovered from the organic phase, e.g. by Re-extcEfction in aqueous Acid and, if necessary, conversion to uranium oxide.

The water-immiscible organic solvent can be one, which is preferably phosphoric acid
extracted and leaves the majority of the impurities in the aqueous phase of the raffinate, which is separated from the organic phase which contains purified phosphoric acid, after which phosphoric acid is recovered from the organic phase as phosphoric acid or phosphate salt, e.g. by contacting with water or an aqueous phase and if necessary heating. Examples of suitable solvents are alcohols, ethers, organic esters and ketones _# of which aolcho with 4 to 9 Kolilünutollatoaien

Tövorzugt sixiarz.3. Butanoi, amyl alcohols, isopropyl

ether and methyl isobutyl ketone.

Other esters such as Trialky! Phosphate, e.g. tributyl phosphate

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BATH ORIGINAL

can also be used. This solvent extraction process is very useful if hydrochloric acid or nitric acid is used as the mineral acid for attacking the rock, since this process separates the phosphoric acid from the calcium salts of the crude reaction mixture. The phosphate values in the extract can be determined by evaporation or, preferably, contacting the extract with water and / or a base. The solvents with a higher carbon content are usually used with such acids after concentration to, for example, 50-60% P ₂ ^ c.

The wet phosphoric acid, which remains after the solid fraction has been separated from carbon particles, especially if it contains calcium nitrate or sulfate, can also be concentrated with odörohn.e to, for example, 40-60% ^ρ o ° 5 ^m '"" ^{t less} a nitrogen-containing compound containing ammonia, treated in order to obtain at least one ammonium phosphate salt, for example mono and / or diammonium phosphate, for fertilization purposes. Often the ammonia is mixed with ammonium nitrate or nitric acid is added first or used as attack acid and the use of the heat-treated rock according to the invention allows less nitrate to be used than if untreated rock had been used, because the latter and thus also the one obtained from it Acid contains organic compounds and these react with the nitrate.

The wet phosphoric acid, which remains after the solid fraction has been separated from carbon particles, and especially if this fraction also contains calcium sulfate, can also be treated with an alkali in order to obtain at least one phosphate salt, which is derived from solids such as heavy metal hydroxides and phosphates are also formed, is separated. The alkali can be a hydroxide, carbonate or bicarbonate of sodium or potassium. The reaction of base and acid can be carried out up to an atomic ratio of metal: P of 1: 1/2: 1 or 3: 1 or preferably 1.67: 1, the latter ratio for a subsequent heat treatment to form alkali metal lipoles ^ phosphates are used. The procedure

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for heat treatment of rock allows the amount of oxidizer to reduce and, if necessary, to eliminate, which is required for the acid or the phosphate brine and thus to decolorize the tripolaphosphate.

Especially when the attack acid is hydrochloric acid, but also in the case of sulfuric acid and nitric acid, the wet phosphoric acid can after separation from the solid fraction then with one or more than one, e.g. two to four servings of an alkaline earth metal base, e.g. a hydroxide or Carbonate of calcium or magnesium can be treated to produce a number of fractions of alkaline earth metal hydrogen phosphate, e.g. of calcium, which is suitable as animal feed that can be separated from the mother liquor, which contains calcium chloride or nitrate or water, depending on the attack acid. The invention is accomplished by the following Examples explained in more detail.

Examples 1-3 and Comparative Examples A-D

Phosphate rock from Zin, Israel is used, which had the following analysis: 32.0 '■ & P ₂ O ₅ ; 6.0 ΐ CO ₃ ; 2, OS SO ₃ ; 1.5% SiO ₃ ; 4.0% F; 51% Ca (as CaO); 0.2% Mg; 0.3% al (as Al ₃ O ₃ ); 0.2% Fe (as Fe ₀ O-); 0.9% Na (as Na ₉ O); 0.2% oxidizable organic material (expressed as air, C).

The particle size distribution was such that 6.5% over 0.5 mm, 27.3% between 0.25 and 0.5 mm, 38.9% between 0.15 and 0.25 mm and 27.3 % under - 0.15 mm particle size.

A layer of the rock was placed in an oven for 1 hour in the presence of air at a temperature given below

ORIGINAL

heated. The treated rock was tested after cooling. The rock that ^{had been treated at 400-700 °} C. was dark and showed the presence of carbon particles.

To assess the effect of heating on removing the organic matter from the rock, the rock was used (heat-treated or untreated) in quantities of 100 g each gradually added to a rock of concentrated hydrochloric acid (205 g 35%) and water (75 g). The temperature the mixture was kept at 40-45 ° C. and the mixture was then heated to the boiling point for 1 hour. The extent of the Foaming as the rock and acid react was noted. The reaction mixture was filtered hot to Carbon particles, unreacted rock and calcium salts to remove and then allowed to cool to room temperature and filtered again, taking crude phosphoric acid was obtained. The color of the crude acid was noted and the following results were obtained.

130CK6 / 0529

Table I.

example Heating Rock acid Foam temperature C product, colour coloring A (comparison) sandy deep brown strong B (comparison) 200 π Il η 1 400 black (pale) deep yellow 2 450 black (medium) medium yellow 3 500 black pale green C (comparison) 700 Gray η little D (comparison) 900 green π π

Examples 4-8 and Comparative Example D.

In the same way as in Examples 1-3, phosphate rock from Zin, Israel of the same analysis and particle size was found at different temperatures for different periods of time. The treated rock was reacted with hydrochloric acid as before and treated in separate experiments with a mixture of sulfuric acid and phosphoric acid and the color of the liquid noted, as well as the content of organic substances and P ₂ Oe of the liquid recorded. The mixture of sulfuric acid and phosphoric acid contained 200 g of 20% P ₂ O ₅ from thermal phosphoric acid and so much 56% sulfuric acid that a combination with 98 % of the calcium content of the phosphate rock used was possible, the amount being such that 40 e P ₂ ⁰ C were included. The indicated amount rock stirring with 200 g of phosphoric acid at 6O ⁰ C was added / mixed. When the foaming subsided, the sulfuric acid was added and the mixture was ^{stirred for 2 hours at 70 °} C., a suspension of gypsum in phosphoric acid being obtained. The suspension was filtered hot and the filter cake was washed 3 times with 50 ciir cold tap water. All filtrates were combined and a product acid was obtained which was analyzed for PpOc, total carbon and oxidizable carbon content. Before and after heating, the rock was also analyzed for fluorine. The results are given in Table II. The rock made of tin before the heat treatment contained acid-insoluble iron sulfide in an amount of 250 ppm (in terms of sulfur).

30046/0529

Examples 9-1β, Comparative Examples E-J

In the same way as in Examples 4-8, the same procedures were carried out for heating phosphate rock and reacting the rock with hydrochloric acid or the mixture of sulfuric acid and phosphoric acid with rocks other than tin. Details of the rock analyzes and the results obtained are given in Tables III to V. In each case, the heat treatment was carried out for one hour, unless otherwise stated. When the unheated Moroccan rock was digested with the mixture of sulfuric acid and phosphoric acid, the liquid contained (after filtering) 27.8% by weight P ₂ Oc, 100-200 ppm total carbon and 15-20 ppm oxidizable carbon.

Examples 17-19

The rock of tin according to Example 4 was continuously heat-treated in a curved rotary calciner, in to which the rock was slowly fed against a stream of air and burned gas. The dwell time took 20-30 minutes. The temperatures of the fed The gas, the solids where they left the furnace, and the outflowing gas were measured. The heat-treated rock was collected and mixed with the mixture of sulfuric acid and phosphoric acid according to Example 4 treated. The insoluble parts (containing gypsum and carbon particles) were filtered off and the color of the product acid was noted. The following results were obtained.

example exiting Temperature ⁰ C Gas leak Color of Solid Product acid 430 Gas inlet 510 210 17th 520 800 200 orange yellow 18th 880 very pale green 19th 890 η η

Table II

example Rock warmth
treatment Time
(Min) t 15th % F in
rock HCl acidification H ₂ SO _{4 an}
souring E. Temp. ⁰ C 60 3.8 Color of the foams
Product
acid Color of
Product acid 4th uncalciniei 15th - strong red-strong
Brown reddish brown 400 30th 3.8 - slightly red
light brown 6th 400 60 - yellow something yellow 7th 500 3.9 - pale yellow 8th 500 3.8 yellow-green little - 500 pale green little very pale green

The analysis of the acidification filtrate with H ^ PO ^ / K ^ SO ^ resulted in comparative example 27.9% PoOc, 1280 ppm total C and 650 ppm oxidizable C, in example 8 29.9% ***

PpOc, 370 ppm total C and no oxidizable carbon. <^

Table III Phosphate rock analyzes

Rock acid Morocco Jordan Florida Leap (Khourigba) % P ₂ O ₅ 31.5 33.9 31.3 % CaO 51.2 52.8 45.1 % Na ₂ O 0.7 0.57 0.6 % MgO 0.8 0.29 0.75 % Al ₂ O ₃ 0.40 0.28 1.8 % Fe ₂ O ₃ 0.21 0.09 2.4 % SiO ₂ 2.4 2.37 5.9 % SO ₃ 2.1 1.37 3.3 % co ₂ 6.4 4.46 3.6 96 F 4.0 3.88 3.8 % Cl 0.03 0.06 0.005 % organic matter (as C) 0.18 0.30 1.56 % Weight loss after heating 1.1 1.2 0.8

Particle aaaLvse (wt. -%)

open meshes
width (mesh
brit, standard) Morocco Jordan Florida over 1.2 mm (+ 14) 63 _ 0.5mm - 1.2mm
(+ 30) 10 38 35 0.25mm - 0.5mm
(+ 60) 7th 24 39 0.15mm - 0.25mm
(+ 100) 15th 27 23 less than 0.15 mm
(- 100) 5
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Table IV

σ tr »κ?

Hydrochloric acid digestion of Morocco
Acid color Phosphate rock example Jordan
Acid color Jordan
Foam Heat treatment
Temperature C example deep yellow Morocco
Foam G pale yellow some untreated E. deep yellow strong 11 pale yellow
■ mi + · - 400 9 middle UlJ. U
Greenish cast yellow 12th π little 500 10 yellow moderate 900 F. negate
permeable

Similar foaming occurred when rock was treated with Η ^ ΡΟ ^ / Η SO. according to Example 4.

Table V

Florida rocks

example Wäraäoehandlui ag HCl acidification Foam H SO ^ / ILPO ^ acidification Foam H Temp. ⁰ C Time (h) Acid color strong Acid color - 13th uncalcined dark reddish
Brown - - little 14th 400 1 - middle light brown yellow little 15th 500 1 orange-brown little very pale
brown yellow - 16 500 2 pale yellow little - - J 600 1 yellow-green no - little 900 1 orange-yellow very pale green,
almost colorless

Examples 20-22 and Comparative Examples K-N

Phosphate rock from Florida, the analysis of which is given above, was heated to various temperatures for one hour and then the heated rock was reacted with the mixture of sulfuric acid and phosphoric acid according to Example 4. A solid was obtained from calcium sulfate, carbon particles and iron sulfide, which was separated from the reaction mixture, leaving a product acid. The treated rock was treated with 14 wt% hydrochloric acid and analyzed for iron and sulfide.
The following results were obtained.

Example Temperature ⁰ C analysis
Sulfide, ppm rock
% soluble Fe Comparison
example not heated 70 0.57 20th 400 110 0.73 21st 500 220 0.76 22nd 600 980 0.94 Comparison
example L 650 2180 1.12 Comparison
example M 750 3360 1.35 Comparison
example N 900 110 1.36

130Q46 / 0S29

Example 23 and Comparative Example P

The acids of Example 8 (one-hour heat treatment of rock at 500 ⁰ C) and Comparative Example E (not calcined rock) were incubated at 35 ° C in a weight ratio of 3: 2 separately mixed with separate solutions of 0.5 m di (ethylhexyl 2-) phosphoric acid and 0.15m trxoctylphosphine oxide in petroleum ether of boiling point 100 120 C and the phases were allowed to separate. The phases separated immediately with the acid from Example 8 into an aqueous acidic phase and an organic phase, which was separated off and whose uranium content was isolated therefrom by treatment with aqueous phosphoric acid containing iron (II) ions (Example 23). With the acid from Comparative Example E, mixing the acid with the petroleum ether solutions gave an emulsion which cleared after 5 minutes and gave the organic and aqueous phases (Comparative Example P).

Examples 24 to 26

Rock with analysis values as given in example 38 was ^{heat-treated for one hour at 500 °} C. in accordance with example 1. Wet phosphoric acids were produced from this rock and also from rock that had not been heat-treated by reacting it with mixtures of sulfuric acid and phosphoric acid (according to Example 4) and separating a solid fraction of gypsum, carbon particles and unaffected rock. In a similar manner, wet phosphoric acids were prepared from rocks that had analyzes according to Examples 1 and 27. Wet phosphoric acids according to Examples 42 to 44 from heat-treated rock were also investigated. Each acid was concentrated and oxidized by boiling while air was passed through to reduce the ferrous ion content. Each of the six acids, which contained P ₃ O ₅ in the range of 24-29%, was mixed with a solution of 0.5m di (2-ethylhexyl) phosphoric acid and 0.15m trioctylphosphine oxide in petroleum ether at 35 ° C. in the volume ratio, while stirring (Kp 100-120 ⁰ C) mixed. After stirring for 5 minutes, the units were allowed to settle. Within 40 seconds each of the acids separated

- 3Γ-

which is produced as wet phosphoric acid from heat-treated rock into an organic phase containing uranium and an aqueous acid phase. In contrast, each of the Mixtures of acids from rock that have not been heat treated are significant Amounts of residues at the interface and an interface emulsion, which took 10 to 30 minutes to break up before an organic phase could be obtained, which contained uranium, in addition to an aqueous acid phase. In each case, both phases were separated and uranium from the organic Phase isolated by extraction with aqueous phosphoric acid containing iron (II) ions.

Examples 27 to 38 and Comparative Examples Q-U

In these examples, the following rocks were used with the specified analytical values are used. Florida II rock came from a different pit than Florida rock, that was used in Examples 13-16.

Florida II Youssoufia
(black)
dried
at 150 ^° C
1/2 hour Youssoufia
(White) Senegal % p ₂ o ₅ 30.9 29.9 31.0 35.8 % CaO 46.0 49.8 51.0 50.1 % SO ₃ 1.4 2.0 1.2 0.33 % co ₂ 4.3 6.7 6.1 1.7 % SiO ₂ 3.4 4.1 % F 3.7 3.9 4.1 3.9 % Cl 0.001 0.024 100 ppm % Na ₂ O 0.7 0.63 0.85 0.18 % MgO 0.7 0.61 0.29 500 ppm % Al ₂ O ₃ 0.9 0.32 0.17 Q, 53 % K ₂ O 0.2 0.028 <0.1 % Fe ₂ O ₃ * 0.15 0.13 1.1 more organic
Carbon% C 0.5 1.3 0.15 1.08

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ORiGfNAL INSPECTED

In each of the following examples, the rock was heated as follows. The rock was heated as a layer in a quartz tray in a muffle furnace that was vented to the atmosphere and heated at a fixed temperature for one hour. The treated rock was then mixed with the sulfuric acid and phosphoric acid from Example 4 and treated separately with 14 wt .-% hydrochloric acid, according to Examples 20-22, and also with 70% phosphoric acid with subsequent separation of the insoluble solids containing carbon particles.

Florida II phosphate

example Temperature ⁰ C Acid-labile, acid-soluble
Sulfide, ppm iron,% Fe - 0.67 - 0.11 - - Acid staining after
HCl treatment
of the rock Q untreated 8th 260 0.95 160 0.12 - - dark brown 27 500 230 220 1.10 - - lemon green 28 600 1030 120 1.31 220 0.11 lemon green R. 750 3280 - , ssouf ia-phosphate, 215 - lemon green YOU - 220 0.12 black S. untreated 0.11 Senegal phosphate dark brown 29 400 0.11 lemon green 30th 500 0.11 lemon green 31 600 lemon green 32 580 Youssoufia phosphate, lemon green White T untreated blue green 33 400 lemon green 34 450 lemon green 35 500 lemon green 36 550 lemon green 37 600 lemon green U untreated Brown 38 500 lemon green

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1300U / 0529

Examples 39 to 41

In these examples, the Florida phosphate used in the Examples 13-16 had been used in Example 39, while for Example 40 the Florida II phosphate from Examples 27 and 28 and in Example 41 Morocco phosphate according to Examples 9 and 10 were used.

In Example 39, the Florida phosphate of Examples 13 to 16 was ^{heated to 550 °} C. in air in an oven for one hour, a gray rock containing carbon particles being obtained. This was treated with the mixture of sulfuric acid and phosphoric acid according to Example 4 and a solid fraction of gypsum and carbon particles was separated off. What was left behind was wet phosphoric acid of a light green color compared to the dark brown color from rock that had not been heat-treated.

In Example 40, the Florida-II-phosphate was 27 and 28 17 nw of Example continuously in accordance with the examples to 19? T heat-treated at a fixed discharge temperature of 500 ⁰ C and temperatures at the inlet and used for fluidizing gas vaa 79O ⁰ C tew . ^ 0 °, with an average residence time of 20 to 30 minutes. The heated rock was treated with the mixture of sulfuric acid and phosphoric acid according to Example 4 and insoluble constituents from gypsum and carbon particles were separated, leaving a wet phosphoric acid of light green color compared to the dark brown color of the acid from non-heat-treated rock.

In Example 41, the Moroccan rocks were continuously according to Examples 17 to 19 wärmeJoehandelt, wherein the discharge temperature of the solids was 390 ⁰ C, and the input · Temperature 760 ⁰ C and the fluidising gas temperature 130 ⁰ C was with an average residence time of 20 to 30 minutes . _t The heat-treated rocks containing carbon particles, treated with the mixture of sulfuric acid and phosphoric acid according to Example 4 and wet process phosphoric acid separated from the insolubles. The acid was medium yellow in color compared to the strong yellow color of an acid from non-heat treated rock.

130CU6 / 0529 ^'37

ORIGINAL INSPECTED

^ 8 303215?

Example 42

Phosphate rock of an analysis according to Example 1 was continuously treated with heat according to Example 19 and the heat-treated rock was continuously converted into wet phosphoric acid with a mixture of sulfuric acid and phosphoric acid in the presence of a slurry of gypsum, a solid fraction consisting of gypsum, carbon particles and unaffected rock existed. The reaction was carried out in a single stage in a stirred tank reactor in the usual manner using an amount of sulfuric acid equivalent to 102% based on the calcium content of the rock. The phosphoric acid obtained as product contained 28-30% P ₉ O ₁ . and no appreciable amounts of oxidizable carbon. No antifoam agent was required in the leach container, compared to the addition of 0.6% oleic acid (based on the weight of P ₉ O _{1. In} the rock) if rock that was not treated with heat was used. The rate of filtration of the gypsum slurry was also significantly faster than when using non-heat treated rock.

Examples 43 and 44

In the same manner as in Example 42 was Florida II 'phosphate heat treated at 500 ⁰ C continuously in accordance with Example 40 and Moroccan rocks (Khouribga) was continuously heat-treated according to Example 41 and both transferred tontlnuier lent in Naßphosphor acid. The phosphoric acids obtained contained 28-30% P 0 _g and no noticeable oxidizable carbon. No antifoam agents were required in the lye container, compared to the addition of 1.0 or 0.6% oleic acid (based on the weight ^ ₂ ⁰ S * ^{m of} rock) when using rock that has not been heat-treated. The filtration rates of the gypsum slurry were also significantly faster than when using non-heat treated rock.

Example 45

Wet phosphoric acid was purified according to Example 42 by solvent extraction. It became an acid of 54.7% P ₂ ° 5 '1.5% SO ,; 0.32% Fe: 0.24% Mg and 0.07% Al and less than 50 ppm

13Ö046 / 052S / 38

COPY 1

concentrated oxidizable carbon. This acid was concentrated in a system consisting of two countercurrent extraction stages using methyl isobutyl ketone to give an extract and an aqueous raffinate, followed by four countercurrent washes with the extract, with purified product acid serving as the washing liquid and one purified extract and used aqueous wash liquor were obtained, which latter was returned to the extraction. Thereafter, a two-stage release in countercurrent was performed with water, wherein formed in wesentlichcneine acid-free solvent layer was recycled for extraction, and a purified acid was obtained, the 41, 2 'H ^ ₂ ⁰ S' ° ^{'50! I s0} 3 ' ^4U PP ^{m Fe} ' contained < 6 ppm Mg and 1 ppm Al and 0.4 ppm As and had a pale yellow color. The purification process corresponded to that of US Pat. No. 3,914,382, the ^ ₂ ⁰ S ^{in the} product acid and in the raffinate being split in a ratio of 65:35. The color of the purified acids could possibly be improved by treatment with 1% activated carbon, compared to the need for 5% activated carbon in the case of acid, which had been obtained from a corresponding process, but not heat-treated rock. There were no phase separation problems, such as formation of persistent emulsions at the solvent / water interface, while significant problems arose with an acid obtained from rock that had not been heat treated.

Examples 46 to 48

The wet phosphoric acids according to Examples 42 and 44 were each converted into sodium phosphate and sodium tripolyphosphate. Any acid was used to reduce the anti-pollution levels of sulphate and fluorine treated and reacted with sodium carbonate in the ratio Na: Pvon 5: 3 and then filtered the precipitated solids, wherein • an aqueous solution of the mixed sodium hydrogen phosphates in the ratio Na: P of 5: 3 remained, which was dried and calcined for one hour whereupon the sodium tripolyphosphate was formed. The salt the acid from Example 42 was white and less colored than the salt from non-heat treated rock. The color can be changed by treatment the alkalis with a Na: P ratio such as 5: 3 with up to 0.5% activated carbon be improved, compared to the use of 5% activated carbon or more in a product made from a corresponding but not heat-treated Rock. The salts of the acids of both Examples 43 and 44 were white.

1 S 0 Γι Λ 6/0 5 ί> §

COPY

Examples 49 to 51

There were rocks, according to Examples 19, 40 and 41 had been prepared, treated with 17% wt .-% hydrochloric acid, whereby reaction mixtures were obtained, the calcium chloride, Contained carbon particles, phosphoric acid, residual hydrochloric acid and unaffected rock. Each The reaction mixture was prepared by treating with a portion of an aqueous suspension of calcium hydroxide (equivalent to the Chlorine content and part of the acid) freed from fluorine and then the solids were separated and then a large amount of calcium hydroxide suspension (equivalent to most of the acid content) used to make dicalcium hydrogen phosphate added and the solid dicalcium hydrogen phosphate formed, which is suitable for animal feed is separated. Finally, the rest of the acid was reacted with the remaining part of the calcium hydroxide suspension, a final fraction of dicalcium hydrogen phosphate was obtained which was obtained from the mother liquor from calcium chloride solution was separated. The amount of calcium hydroxide suspension added in the 3 stages was 20%, 70% or 10% of the total amount. ■, "" "

Examples 52 to 54

Every reaction mixture of calcium chloride, carbon Particles, phosphoric acid, residual hydrochloric acid, unaffected rock according to Examples 49 to 51 filtered, to remove a solid fraction that is the rock and carbon particles, leaving an acid as a liquid. 5 parts by volume of this liquid were with 10 parts by volume of a mixture of 8 parts by volume of amyl alcohol and 2 parts by volume of 35% hydrochloric acid extracted, one organic phase was obtained which contained purified phosphoric acid and hydrochloric acid and an aqueous acid phase which phases were separated. The phases separated quickly with no interfacial problems. The organic phase was 2.5 parts by volume Water mixed to release the acids, with a

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130Ö46 / 0529

organic phase with reduced acid content and an aqueous one Phase was obtained as a mixture of hydrochloric acid and phosphoric acid. The phases were separated again without any interfacial problems occurred. The mixture from the aqueous phase was heated to evaporate hydrochloric acid, leaving purified wet phosphoric acid.

Examples 55, 56

In the same manner as in Example 45, the wet phosphoric acids from Examples 43 and 44 concentrated and purified by solvent extraction with methyl isobutyl ketone and release with water, purified aqueous phosphoric acids were obtained. The concentrated wet phosphoric acid obtained from Example 43 with

a content of 51.9% ^ ₂ ⁰ S ' ¹ ' ^{8% S0} 3 ^{; 1 '36% Fe;} ° ' ^{9% Mg; 1 '0% A1} ■ was purified to give an acid of 42.7% ^P 2 ^{O 5;} ^ / 54% ^s0 3 '185 ppm Fe; 9 ppm Mg and 12 ppm Λ1 and a raffinate with 41.3% ^p ₂ ° c / 2.7% SO-., 2.8% Fe, 2.0% Mg and 1.9% Al, with a split between Purified acid and raffinate in a ratio of 68:32 occurred. The concentrated wet phosphoric acid from Example 44 contained 56.0% P “0; 1.3% SO; 0.23% Fe and 0.6% Mg and was purified, using an acid with a content of 40.5% P ₂ ⁰ S '°' ^{7% S0} 3 ^{'28 ppm Fe and 1} ° ^ppr Mg and a raffinate 40% ^p ₂ ° 5 ' ¹ ' ^{7% S0} 3 '°' ^{6% Fe and 1} ' ^{4% Mg was} obtained, the ratio between purified acid and raffinate being 70:30. In no case problems arose because of the ^BiI-: dung on liquid-liquid emulsions at the interface.

Examples 57 to 59

Rocks that had been treated according to Examples 19, 40 and 41 were treated with 24.2 parts by weight of a 58% strength nitric acid 10.8 parts by weight of heat-treated Morocco rocks and the like Quantities implemented for the other two rocks, with an aqueous mixture of calcium nitrate, carbon dioxide in each case Particle, attacked rock was stopped. Each mixture was filtered to remove the carbon particles and the rock and to 0 C cooled and a solid fraction of calcium nitrate was separated from the aqueous acid solution, the solution being nitric acid, Contained phosphoric acid and calcium nitrate. Each aqueous acidic solution was mixed with 2.55 parts of anhydrous ammonia, which was continuously added

ORIGINAL INSPECTED ^C0PY

was set, treated. The resulting mixture contained ammonium hydrate and phosphate and calcium nitrate and was evaporated to give a melt with 0.5 to 5.0% water, which as such could be used as fertilizer. In any case it was the melt mixed with 5.8 parts of potassium chloride and the mixture granulated, a compound fertilizer with a NPK ratio 17:17:17 was obtained.

Examples 60 to 62

The wet phosphoric acids which had been obtained according to Examples 42 to 44 were each concentrated to an acid content of 54% P ₂ ^O S. Each concentrated acid was treated by bubbling anhydrous ammonia to a NiP atomic ratio of 1.35: 1. The temperature rose to 115 ° C and water was added to keep the resulting slurry free flowing (22% free water). The hot slurry was spread over a bed of recycled ammonium phosphate as a fine particle product and the ammonization was completed with anhydrous ammonia to an N: P atomic ratio of 1.8: 1. The recycle ratio was 2.5 parts of recycled substance to one part of compound withdrawn as product. The product was transferred to a dryer at 85 ° C. and then to a cooler and then granulated, an ammonium phosphate having an NEK value of 18: 47: 0, which was useful as a fertilizer, was obtained.

Examples 63 to 65

The wet phosphoric acid obtained according to Examples 42 to 44 was concentrated to an acid content of 50% P ^ ⁰ C in each case. 50 parts of each of the concentrated acids were mixed with 12.5 parts of water and placed in one of the containers which contained a slurry of ammonium phosphate. 8 parts of anhydrous ammonia were added, an N: P atomic ratio of 1.3: 1 being maintained. Water was evaporated leaving an 80% slurry of ammonium phosphate. The slurry could be granulated into a granular ammonium phosphate fertilizer by mixing with recycled solid product. Solid potassium chloride and an 80% solution of ammonium nitrate could be added to the slurry and granulated to give an NPK fertilizer.

..A2

1 30ÖA6 / 052Ö

303215?

Examples 66 to 68

There was 6.2 parts of a concentrated acid containing

of 50% P ₀ Oc / which had been used in Examples 63-65, 2 5

mixed with 7 parts of a 95% ammonium nitrate solution and introduced into the mixture 0.8 part of anhydrous ammonia. The heat of reaction evaporated water, leaving a concentrated solution with 5% water which was fed into an evaporator in which a dry melt was produced. Each melt was mixed with 7.8 parts of potassium chloride and the mixture was granulated to give 20 parts of an NPK fertilizer 15:15:21.

Examples 69 to 71

6 parts of the heat-treated rocks of Example 41 (and corresponding amounts of the heat-treated rocks of Examples 19 and 40) each ground to a powder of which 80% passed through a sieve with a mesh size of 150 μm. Each powder was mixed with 4.8 parts of 72% sulfuric acid and gave a slurry which was continuously passed through a ripening chamber, wherein a solid product was obtained, which was broken up and stored in piles for a week to complete the superphosphate formation reaction. Any superphosphate could be used as a fertilizer as it was. Each superphosphate was made with solid potassium chloride and an 80% aqueous solution of ammonium nitrate in a weight ratio of 48: 17: 36 premixed and then granulated, chilled and dried using a free flowing NPK fertilizer 10.5: 10.5: 10.5 was obtained.

Examples 72 to 74

In the same manner as in Examples 69 to 71, 4.1 parts of the heat-treated rock of Example 41 (and corresponding amounts of the heat-treated rocks of Examples 19 and 41) were ground and mixed with 6 to 8 parts of wet phosphoric acid containing 50% P ₃ O ₅ mixed and the product worked up according to Examples 67 to 69. Each triple superphosphate obtained could be used as such as a fertilizer. Each triple Superoho.qnh?. + · Wn »- ^ _em it potassium chloride and

BATH ORIGINAL

an aqueous solution of ammonium nitrate in the ratio 30:25:54 and the mixture as before in a free-flowing NPK fertilizer 15:15:15 transferred.

130046/0529

Claims (47)

Claims 1. Method for opening up phosphate rock, wherein the phosphate rock, which contains organic compounds, is heated to 380 to 60 ° C until at least some of the organic compounds are converted to carbon, according to patent (patent application P 30 07 131.9), characterized in that a calcium phosphate rock is heated. 2. The method according to claim 1, characterized in that the rock is heated in that it is continuously passed through at least one heated zone at 380 to 600 ⁰ C and the heated rock is withdrawn. 3. The method according to claim 1 or 2, characterized in that the rock is heated to 380 to 480 ° C. 4. The method according to claim 1 or 2, characterized in that the rock is heated to 460 to 540 ° C. 5. The method according to claim 1, characterized in that the rock does not come from Florida or Egypt when ^{heated to 490-510 °} C and does not come from Russia when heated to 490-540 ° C is carried out and is not from Utah or Morocco, who:
will lead. originates when the heating to 540 to 560 ⁰ C is carried out * 6. The method according to any one of claims 1 to 5, characterized characterized in that the rock is heated in the presence of a gas containing molecular oxygen. 1300A6 / 052§ ORIGINAL INSPECTED 7. The method according to any one of claims 1 to 6, characterized in 3032157 characterized in that the rock total 0.05 to Contains 0.4% organic compounds (expressed as carbon) and acid-soluble organic compounds components. 8. The method according to any one of claims 1 to 7, characterized in that the rock 30 to 40% Ρ _? Ο, - and 45 to 55% calcium (expressed as CaO). 9. The method according to any one of claims 1 to 8, characterized in that the phosphate rock before heating is one that gives a brown liquid with 27% hydrochloric acid. 10. The method according to any one of claims 1 to 9, characterized in that a rock is heated, the Origin Idaho, North Carolina, Tennessee (United States of America) or Tunisia, Jordan, Algeria, Senegal, Youssoufia in Morocco, Kola, Nauru, Oceania or Zin (Israel) is. 11. The method according to claim 2, 7 or 8, characterized in that rock from Florida is continuously ^{heated to 450 to 550 0} C for 15 minutes to 2 hours. 12. The method according to claim 2 or 8, characterized in that rock from Morocco continuously 15 minutes 2 hours to 380 to 440 ⁰ C is heated. 13. The method according to any one of claims 1 to 12, characterized in that a rock is heated, the organic Compounds and an acid-insoluble, heat-labile iron sulfide and the heating to a temperature takes place, which is not sufficient to convert all acid-insoluble iron sulfide into acid-soluble iron sulfide and that a heated rock is produced which is composed of phosphate rock, carbon particles and acid-insoluble Consists of iron sulfide. 130046/0529 " .ORIGINAL INSPECIEa 14. The method according to claim 13, characterized in that O η q <y ι r that a rock is heated which contains at least 500 ppm of acid-insoluble iron sulfide (expressed as sulfur) prior to heating. 15. Heat-treated calcium phosphate rock produced by a method according to any one of claims 1 to 14. 16. Heat-treated calcium phosphate rock containing carbon particles and practically no acid-soluble ^. organic compounds. 17. Rock according to claim 16, characterized in that it is also acid-insoluble, heat-labile iron sulfide contains. 18. Rock according to claim 17, characterized in that it contains at least 500 ppm of the iron sulfide (expressed as S) contains. 19. Rock according to claim 17 or 18, characterized in that at least 80% of the iron sulfide is acid-insoluble, the remainder, if any, is acid soluble. 20. A method for the production of phosphates from phosphate rock, characterized in that a phosphate rock, the carbon particle contains and according to the methods according to claim 1 to 14 has been obtained, or such a rock according to claims 15 to 19 with at least an acid selected from phosphoric acid or sulfuric acid is reacted to form a calcium phosphate fertilizer. 21. The method according to claim 20, characterized in that the rock does not come from Morocco or Utah, unless the rock has been heated as part of a continuous process or that it has been heated to 380 to 440 C or 460 to 540 ⁰ C or 560 to 600 ⁰ C has been heated or if the rock has not been reacted with sulfuric acid or a mixture of sulfuric acid and phosphoric acid. 22. The method according to claim 20 or 21, characterized / that the rock has been heated ^{to 460 to 540 0 C.} 23. The method according to claim 21 or 22, characterized in that the rock and the heating of the rock according to claim 2 » 11 or 12 is carried out. 24. The method according to any one of claims 20 to 23, characterized in that that the rock containing carbon particles is reacted with an amount of phosphoric acid which is 80 to 120% of the amount that is required to with the Rock to react to form calcium dihydrogen phosphate or to react with an amount of sulfuric acid, which 80 to 120% of the amount required to react with the rock to form calcium sulphate and calcium dihydrogen sulfate. 25. Process for the production of phosphoric acid from phosphate rock, being calcium phosphate rock, the carbon particle contains and has been obtained by heating phosphate rock to 380 to 600 C, or a rock according to the claims Chen 15 to 19 is reacted with a mineral acid, characterized in that the mineral acid is hydrochloric acid, nitric acid or sulfuric acid is used and a mixture of Calcium salts of these acids is generated in addition to phosphoric acid and carbon particles and a solid fraction that contains them Holds particles and is separated from the mixture. 26. The method according to claim 25, characterized in that the phosphate rock has been continuously heated according to claim 2 " is. 27. The method according to claim 25 or 26, characterized in that the phosphate rock to 380
the acid alone is hydrochloric acid. that the phosphate rock is ^{heated to 380 to 590 0} C when 28. The method according to claim 25, 26 or 27, characterized in that that the rock containing carbon particles is reacted with an amount of acid which is at least 90% of the calcium content " halts of the rock is equivalent. 130046/0529 29. The method according to claim 28, characterized in that the rock from Florida or originates in Morocco and has been heated to 380-550 ⁰ C. 30. The method according to claims 25, 26, 28 or 29, characterized in that that the acid is selected from the group consisting of nitric acid and sulfuric acid. 31. The method according to claim 30, characterized in that the rock, which contains carbon particles, is reacted with a mixture of sulfuric acid and phosphoric acid to form a solid fraction consisting of calcium sulfate and carbon particles and that the wet phosphoric acid produced is separated from the solid fraction. 32. The method according to any one of claims 25 to 31, characterized in that that a solid fraction is separated, the carbon particles and acid-insoluble iron sulfide if the heat-treated rock contains this un- ■■ Contains soluble, heat-labile iron sulfide. 33. The method according to any one of claims 25 to 32, characterized in that that after separating the solid fraction, the phosphoric acid with a water-immiscible organic Solvent is treated to produce an organic phase and an aqueous phase and that the Acid is isolated from at least one of these phases. 34. The method according to claim 33, characterized in that the phosphoric acid contains uranium and that with or without prior Concentration of the acid after separating the solid fraction of this phosphoric acid with a solvent is extracted in order to extract at least part of the uranium into the organic phase, from which a uranium-containing product is isolated. 35. The method according to claim 33 or 34, characterized in that the phosphoric acid with or without concentration after Separation of the solid fraction is extracted with a water-immiscible organic solvent, a organic phase is produced, the purified phosphoric acid 13004 6/0529 _ORielNAUNS p _EC TEO and a layer of aqueous raffinate contains that these two are separated and phosphoric acid from the organic phase is isolated in the form of phosphoric acid or a salt thereof. 36. The method according to any one of claims 25 to 34, characterized in that that after separating the solid fraction with or without concentrating the acid, the phosphoric acid is treated with at least one nitrogen-containing compound containing ammonia to at least one Form ammonium phosphate salt. 37. The method according to any one of claims 25 to 34, characterized in that that after separation of the solid fraction, the phosphoric acid is treated with an alkali to to form at least one alkali metal phosphate salt from any solids that are formed alongside, is separated. 38. The method according to any one of claims 25 to 34, characterized in that that after the solid fraction has been separated off, the wet phosphoric acid is mixed with calcium hydroxide and the precipitated calcium hydrogen phosphate is separated off. 39. The method according to any one of claims 20 to 38, characterized in that that the rock is heated by continuously passing it through at least one heated zone 380 to 60 ° C is passed through and the heated rock is removed from the zone or zones. 40. Calcium phosphate fertilizer, produced by a method according to any one of claims 20 to 24 or 39. 41. Liquid mixture containing a calcium salt and phosphoric acid, produced by a method according to any one of claims 25 to 30 or 39. 42. Wet phosphoric acid, prepared by a process according to one of claims 30 to 32 or 39. • • / 7 130046/0529 43. Purified wet phosphoric acid or a salt thereof, prepared by a process according to any one of claims 33 to 35 or 44. Product containing uranium and obtained by a method according to claim 34 or 39. 45. Ammonium phosphate, produced by a method according to claim 36 or 39. 46. Alkali metal phosphate, produced by a method according to claim 37 or 39. 47. Calcium hydrogen phosphate, prepared by a method according to Claim 38 or 39. 6/0529 _{OR | Q} , _{NAL | NSPECTED}