公开(公告)号：US4668492A

公开(公告)日：1987-05-26

申请号：US801737

申请日：1985-11-26

申请人： G/u/ nther Schimmel ,  Reinhard Gradl ,  Gero Heymer

发明人： G/u/ nther Schimmel ,  Reinhard Gradl ,  Gero Heymer

IPC分类号： C01B25/237 ,  C01B25/238 ,  C01B25/30 ,  C01B25/46 ,  C01B25/16 ,  C01B25/26

CPC分类号： C01B25/237 ,  C01B25/238 ,  C01B25/308 ,  C01B25/461

摘要： Phosphoric acid solutions are dearsenified by treating them with a sulfide and separating the resulting precipitate from the purified solution. The sulfide is at least one compound of the general formula P.sub.4 S.sub.x in which x stands for a number of 3 to 10.

摘要翻译： 通过用硫化物处理磷酸溶液进行脱砷，并将所得沉淀物与纯化溶液分离。 硫化物是至少一种通式为P4Sx的化合物，其中x代表3至10个数。

公开(公告)号：US4640824A

公开(公告)日：1987-02-03

申请号：US682053

申请日：1984-12-14

申请人： Gunther Schimmel ,  Reinhard Gradl

发明人： Gunther Schimmel ,  Reinhard Gradl

IPC分类号： C01B25/237 ,  C01B25/30 ,  C01B25/46 ,  C01B25/16

CPC分类号： C01B25/46 ,  C01B25/308

摘要： The disclosure relates to a process for making alkali metal phosphate solutions containing little fluorine from pre-purified alkali metal phosphate solutions obtained from crude phosphoric acid by extracting the acid with an organic solvent being immiscible or only partially miscible with water, scrubbing the crude extract with water or an alkali metal solution, re-extracting the phosphoric acid from the scrubbed extract with the use of an aqueous alkali metal solution while establishing an alkali metal/P-molar ratio equal to or larger than 1:1, and separating the resulting organic phase from the pre-purified alkali metal phosphate solution obtained.To this end, the disclosure provides:(a) for the pre-purified alkali metal phosphate solution to be stirred at 60.degree.-120.degree. C. into a compound of an alkaline earth metal Me.sup.2+ with a solubility in water at 20.degree. C. of more than 0.01 mol Me.sup.2+ /1, alkaline earth metal compounds with a solubility in water of less than 5 g/l being used in the form of particles of which more than 50% have a size of less than 8 .mu.m, for the whole to be reacted over a period of 0.5 to 4 hours, and for the resulting precipitate to be separated from the alkali metal phosphate solution so purified, and(b) for the alkaline earth metal compound necessary for effecting the defluorination to be suspended or dissolved in the alkali metal phosphate solution needed for effecting the re-extraction, and for the reaction between the alkali metal phosphate solution and alkaline earth metal compound to be effected in the mixing zone of the re-extraction unit.

摘要翻译： 本公开涉及通过用与水不混溶或仅与水部分混溶的有机溶剂萃取酸来从粗磷酸获得的预纯化碱金属磷酸盐溶液中制备含少量氟的碱金属磷酸盐溶液的方法，用 水或碱金属溶液，使用碱金属水溶液从洗涤的提取物中再次提取磷酸，同时确定等于或大于1:1的碱金属/ P摩尔比，并分离所得的有机物 从预纯化的碱金属磷酸盐溶液获得。 为此，本公开内容提供：（a）将预纯化的在60-120℃下搅拌的碱金属磷酸盐溶液转变成在20℃在水中溶解度的碱土金属Me2 +的化合物。 大于0.01mol Me2 + / 1，在水中的溶解度小于5g / l的碱土金属化合物以超过50％的尺寸小于8μm的颗粒的形式使用，对于 整个反应0.5至4小时，并将所得沉淀物从纯化的碱金属磷酸盐溶液中分离出来，（b）对于实现脱氟所必需的碱土金属化合物悬浮或溶解 在进行再提取所需的碱金属磷酸盐溶液中，以及在再提取单元的混合区域中进行的碱金属磷酸盐溶液和碱土金属化合物之间的反应。

公开(公告)号：US4636372A

公开(公告)日：1987-01-13

申请号：US709166

申请日：1985-03-07

申请人： Elie Chemtob ,  Gary L. Beer

发明人： Elie Chemtob ,  Gary L. Beer

IPC分类号： C01B7/19 ,  C01B25/225 ,  C01B25/237 ,  C01B25/30 ,  C01B25/16

CPC分类号： C01B7/191 ,  C01B25/225 ,  C01B25/237 ,  C01B25/30

摘要： Alkali metal phosphates and HF can be produced from a substantially calcium-free fluoroaluminum phosphate precipitate (which also contains iron) made by the aging of wet process phosphoric acid containing iron, fluorine and aluminum, preferably phosphoric acid analyzing in the range of about 15%-45 weight percent P.sub.2 O.sub.5, 2-4% Al.sub.2 O.sub.3 and 1-2% fluorine. One process involves digestion of phosphate ore matrix in recycled phosphoric acid, filtration to remove the insoluble residue, precipitation and filtration to remove gypsum, and aging of the product acid to precipitate the aluminum impurity as a fluoroaluminum phosphate compound. The fluoroaluminum phosphate can be decomposed (as by heating at above 195.degree. C.) to produce HF and aluminum phosphate. The aluminum phosphate can be contacted with alkali metal hydroxide under conditions which produce an alkali metal phosphate.

摘要翻译： 碱金属磷酸盐和HF可以由通过老化含铁，氟和铝的湿法磷酸制成的基本上不含钙的磷酸铝磷酸盐沉淀（其也含有铁）制备，优选在约15％的范围内分析磷酸， -45重量％的P2O5，2-4％的Al2O3和1-2％的氟。 一个过程包括在回收磷酸中消化磷酸盐矿石基质，过滤除去不溶残渣，沉淀和过滤以除去石膏，并老化产物酸以沉淀作为氟化磷酸铝化合物的铝杂质。 磷酸氟铝可以分解（通过在195℃以上加热）以产生HF和磷酸铝。 在产生碱金属磷酸盐的条件下，磷酸铝可与碱金属氢氧化物接触。

公开(公告)号：US4439408A

公开(公告)日：1984-03-27

申请号：US384008

申请日：1982-06-01

申请人： Avraham M. Baniel ,  Aharon M. Eyal

发明人： Avraham M. Baniel ,  Aharon M. Eyal

IPC分类号： C01B25/237 ,  C01B25/16 ,  C01B7/00

CPC分类号： C01B25/2375

摘要： The invention provides a process for removing fluorine compounds from aqus phosphoric acid containing the same, which process comprises contacting the phosphoric acid with a water insoluble extractant comprising phosphoric acid and an oil soluble amine, the amine being substantially water insoluble both in free and in salt form and the extractant being substantially free of fluorine, sulfate and metal impurities. The invention also provides an extractant for use in the above process comprising an oil soluble amine, which amine is substantially water insoluble both in free and in salt form and a phosphoric acid.

摘要翻译： 本发明提供了一种从含有它们的酸性磷酸中除去氟化合物的方法，该方法包括使磷酸与包含磷酸和油溶性胺的水不溶性萃取剂接触，该胺在游离盐和盐中基本上不溶于水 形式，萃取剂基本上不含氟，硫酸盐和金属杂质。 本发明还提供一种用于上述方法的提取剂，其包含油溶性胺，该胺基本上不溶于游离盐和盐形式的水溶性胺和磷酸。

公开(公告)号：US4330517A

公开(公告)日：1982-05-18

申请号：US248097

申请日：1981-03-27

申请人： Dennis H. Michalski

发明人： Dennis H. Michalski

IPC分类号： C01B25/237 ,  C01B25/16

CPC分类号： C01B25/2375

摘要： An improved method of defluorinating wet process phosphoric acid using silica-containing dust which is obtained as a waste product collected from the fumes of a submerged arc furnace process of making silicon metal alloys. The silica-containing dust has a very small particle size, and contains at least about 60% by weight silica (SiO.sub.2), and has a very high surface/mass ratio which increases the efficiency of the defluorination reaction.The defluorination reaction using this silica-containing fume takes less time than required using prior methods employing diatomaceous earth as the silica source. The presence of silicon metal alloy particles in the dust are thought to have a catalytic effect on the defluorination reaction.

摘要翻译： 一种改进的使用含硅粉尘脱氟湿法磷酸的方法，该方法是从制造硅金属合金的浸没电弧炉工艺的烟气中收集的作为废物产生的。 含二氧化硅的粉尘具有非常小的粒度，并且含有至少约60重量％的二氧化硅（SiO 2），并且具有非常高的表面/质量比，这增加了脱氟反应的效率。 使用这种含二氧化硅的烟雾的脱氟反应比使用硅藻土作为二氧化硅源的现有方法所需的时间更短。 认为粉尘中硅金属合金粒子的存在对脱氟反应具有催化作用。

公开(公告)号：US3972982A

公开(公告)日：1976-08-03

申请号：US554810

申请日：1975-03-03

申请人： Louis F. Centofanti

发明人： Louis F. Centofanti

IPC分类号： C01B25/237 ,  C01B25/16

CPC分类号： C01B25/2375

摘要： Fluorine compounds are removed from aqueous phosphoric acid by extraction with a mixture of a silane and a long-chain hydrocarbyl amine.BACKGROUND OF THE INVENTIONThis invention relates to a process for removing fluorine from aqueous phosphoric acid.It is known that wet-process phosphoric acid obtained by acidulation of phosphate rock contains substantial amounts of fluorine, predominantly in the form of fluorine compounds such as fluorophosphates and various metal fluorides. Even following purification by known extraction processes, for example, extraction with various organic amines, ethers, etc., such phosphoric acid generally remains contaminated with undesirably high quantities of fluorine compounds with fluorine contents of 1,000 parts per million (ppm) by weight or more not being uncommon.Fluorine contents of this magnitude introduce complications relative to the use of the acid in various applications. For example, if the acid is to be converted into alkali metal polyphosphates by neutralization and calcination, fluorine will be released in the calcination step and it may be necessary to provide expensive fluorine recovery steps to preclude release of undesirably large amounts of fluorine into the atmosphere.It is known that fluorine compounds can be extracted from aqueous phosphoric acid containing the same by use of organic silanes [See Bock et al., Fresenius' Z. Anal. Chem. 230 (3), 161-84 (1967)]; however, lower molecular weight silanes such as triethyl silanol, diethyl silane diol, etc. cannot be economically separated from the fluorine compounds for reuse in the extraction process. When such low molecular weight silanes are contacted with basic solutions to neutralize and separate the fluorine compounds, the silanes tend to dissolve or polymerize in such basic solutions to an undesirably high degree. Higher molecular weight silanes have been found not to reduce the fluorine compound content of phosphoric acid to desirably low levels.It is apparent therefore that practical methods for removing fluorine compounds from phosphoric acid are needed in the art.SUMMARY OF THE INVENTIONIt is an object of the present invention to provide methods for removing fluorine compounds from aqueous phosphoric acid. Particularly, it is an object of the invention to provide methods suitable for reducing fluorine content of phosphoric acid to levels of 300 parts per million or lower. These objects are obtained by extracting aqueous phosphoric acid containing fluorine compounds with a mixture of silanes and amines as hereinafter described.The practice of the invention will be understood from the following description of the preferred embodiments.DESCRIPTION OF THE PREFERRED EMBODIMENTSThe process of this invention can be effectively employed to remove fluorine compounds from any aqueous phosphoric acid containing the same. However, the process is most desirably employed to treat wet-process phosphoric acid which has been previously treated, for example, by hitherto known solvent extraction processes, to remove a major portion of the organic and inorganic impurities contained therein.In accordance with this invention, fluorine compounds are extracted from the phosphoric acid with an extractant comprising a mixture of a silane and an amine compound.The silane utilized in the extractant is represented by the formula ##STR1##In the above formula, one or two of the R.sub.I, R.sub.II, R.sub.III and R.sub.IV groups are --OH, --Cl or --OR (R being an alkyl group containing from 1 to 4 carbon atoms). The remaining R.sub.I, R.sub.II, R.sub.III and R.sub.IV groups, in combination, contain a total of from 12 to 25 carbon atoms and are each alkyl, phenyl or alkyl phenyl groups. The limitation that such alkyl, phenyl, or alkyl phenyl groups, in combination, contain a total of from 12 to 25 carbon atoms is critical. If the carbon atom content is lower, the silane will be too unstable in aqueous base to be readily separated from the fluorine compounds which it extracts. If the carbon atom content is higher, extraction of fluorine compounds is undesirably inefficient.Examples of silane suitable for use in the present invention are tri-n-butyl silanol, tri-n-hexyl silanol, tri-n-pentyl silanol, tri-n-heptyl silanol, tri-n-octyl silanol, tri-phenyl silanol, di-n-octyl disilanol, methyl diphenyl silanol, octadecyl phenyl disilanol, octadecyl methyl disilanol, octadecyl dimethyl silanol, dodecyl phenyl disilanol, phenyl dibutyl silanol, phenyl dihexyl silanol, phenyl dioctyl silanol, phenyl methyl hexyl silanol, phenyl methyl octyl silanol, diphenyl methyl, ethyl, propyl, butyl, hexyl or octyl silanol, etc.Silanes which are particularly preferred from the standpoint of process efficiency and extractant recoverability are those represented by the formula ##STR2## for example methyl diphenyl silanol, ethyl diphenyl silanol, butyl diphenyl silanol, etc., ##STR3## for example phenyl methyl dodecyl silanol, phenyl methyl decyl silanol, etc., ##STR4## for example phenyl dodecyl disilanol, phenyl pentadecyl disilanol, phenyl oct-n-decyl disilanol, etc.The amines suitable for use in the present invention are, in general, water-insoluble and/or capable of forming desired water-insoluble salts. In general, amine compounds containing a terminal polar nitrogen containing group and at least 2 hydrophobic substituent groups, such as those compounds derived from fatty acids of varying molecular weights and different degrees of saturation, are suitable for use. The suitable amines may be secondary or tertiary amines.In particular, secondary and tertiary aliphatic amines having two substituent groups, each containing about 7 to about 15 carbon atoms, and including branch chain structures as well as straight chain structures, are quite suitable for use in the present invention. Mixtures of amines are suitable when containing to a predominant extent the foregoing structures. It should be noted that for tertiary aliphatic amines the third substituent group may contain any number of carbon atoms but preferably should not contain over about 15 carbon atoms. Further, the OH, COOH, OCH.sub.3, halogen, NO.sub.2 and SO.sub.3 substituted derivatives of the substituent groups may, in most cases, be used, as well as the substituent groups containing alkoxy radicals, as long as at least two of the groups are hydrophobic, thus rendering the compound water-insoluble to the desired degree. The primary aliphatic amines are less suitable because of their tendency to precipitate as the amine salts when in contact with wet phosphoric acid. The secondary or tertiary aliphatic amines containing less than about 7 carbon atoms on each of at least two substituent groups exhibit the undesirable tendency to be water-soluble. The secondary or tertiary aliphatic amines containing more than about 15 carbon atoms on each of at least two substituent groups exhibit the undesirable tendency to form salts which are relatively insoluble in the extractant phase. Aromatic amines, whether primary, secondary or tertiary, exhibit undesirable tendencies, such as either poor extractant properties, poor water-insoluble salt forming properties or poor salt solubilities in the extractant phase.All of the immediately foregoing relating to the amines is, in general, applicable to the amine salts which are suitable for use in the instant invention. In addition, the amine salts suitable for use in the present invention can, in general, be formed from many organic and inorganic acids and preferably those acids which are stronger than phosphoric acid, i.e., having a K.sub..alpha. greater than about 8 .times. 10.sup.-.sup.3, such as sulfuric acid, hydrochloric acid and the like. Ionization constant of an acid (K.sub..alpha.) as used herein refers to the dissociation of an acidic electrolyte at room temperature, i.e., about 25.degree.C., and is equal to the product of the activities of each of the ions produced by the dissociation (if more than one ion of a given kind is produced, its activity is raised to the corresponding power) divided by the activity of the undissociated molecules with the activities assumed to be in their standard states at infinite dilution.The term "water-insoluble" as used herein with respect to the amines and/or amine salts does not necessarily require complete insolubility. It merely requires that the material be sufficiently immiscible with the phosphoric acid phase to allow physical separation of the liquids into two distinct phases.Suitable amines useful as extractants are long chain hydrocarbyl amines represented by the formula ##STR5## wherein R.sub.1 and R.sub.2 are saturated or ethylenically unsaturated aliphatic hydrocarbyl groups containing from about 7 to about 15 carbon atoms and R.sub.3 is hydrogen or a saturated or ethylenically unsaturated aliphatic hydrocarbyl group containing from 1 to about 18 carbon atoms.The preferred amine salts useful as extractants are long chain hydrocarbyl amine salts of the following formula ##STR6## wherein R.sub.1, R.sub.2 and R.sub.3 are as defined above, n is an integer from 1 to 3 inclusive and X is an anion of a mineral acid having a K.sub..alpha. greater than about 8 .times. 10.sup.-.sup.3.The following long chain hydrocarbyl amines are representative of suitable extractants for use in the present invention.di-n-decylamine [CH.sub.3 (CH.sub.2).sub.9 ].sub.2 NHdi-n-decylammonium sulfate 2[[CH.sub.3 (CH.sub.2).sub.9 ].sub.2 NH]-H.sub.2 SO.sub.4tri-n-octylamine [CH.sub.3 (CH.sub.3).sub.7 ].sub.3 N-HClmethyldioctylamine [CH.sub.3 (CH.sub.2).sub.7 ].sub.2 (CH.sub.3)Ndi-n-dodecylamine [CH.sub.3 (CH.sub.2).sub.11 ].sub.2 NHtri-n-dodecylamine [CH.sub.3 (CH.sub.2).sub.11 ].sub.3 Ntricaprylyl amine R.sub.3 Nwhere R is a mixture of C.sub.8 H.sub.17 and C.sub.10 H.sub.21 but predominantly C.sub.8 H.sub.17.tricaprylyl amine sulfate 2(R.sub.3 N).sup.. H.sub.2 SO.sub.4where R is a mixture of C.sub.8 H.sub.17 and C.sub.10 H.sub.21 but predominantly C.sub.8 H.sub.17.tri iso-octyl amine [CH.sub.3 (CH.sub.2).sub.7 ].sub.3 Nwhere C.sub.8 H.sub.17 groups are comprised of mixed isomers.N,n-didodecenyl-N-m-butyl amine (C.sub.4 H.sub.9) (C.sub.12 H.sub.23).sub.2 Nn-dodecenyl-N-trialkylmethyl amine (C.sub.12 H.sub.23) (R.sub.1 R.sub.2 R.sub.3 C)NHwhere R.sub.1 + R.sub.2 + R.sub.3 equal C.sub.11 H.sub.23 to C.sub.14 H.sub.29.n-lauryl-N-trialkylmethyl amine (C.sub.12 H.sub.26) (R.sub.1 R.sub.2 R.sub.+ C)NHwhere R.sub.1 + R.sub.2 +R.sub.3 equal C.sub.11 H.sub.23 to C.sub.14 H.sub.29.tricoco amine R.sub.3 Nwhere R is a mixture of Percent C.sub.8 H.sub.17 to C.sub.10 H.sub.21 15 C.sub.12 H.sub.25 48 C.sub.14 H.sub.29 18 C.sub.16 H.sub.33 9 C.sub.18 H.sub.37 (stearyl-oleyl) 10 tri lauryl amine R.sub.3 Nwhere R is a mixture of Percent C.sub.12 H.sub.26 88 C.sub.14 H.sub.29 isomers 10 C.sub.10 H.sub.21 2 Particularly preferred amines are: ##STR7## where R' is an alkyl group containing 8 or 9 carbon atoms.The weight ratio of silane to amine in the mixture should be from 20 to 1 to 1 to 20. If lower amounts of amine are employed the extractivity of the mixture for fluorine compounds will be lower than desired whereas the employment of greater amounts of amine will tend to result in concomitant extraction of undesirably large amounts of phosphate values.In the practice of the invention the silane and amine mixture is desirably dissolved in an organic diluent capable of dissolving such mixture and which is substantially water insoluble. A wide range of organic solvents are effective including kerosene, mineral spirits, naphtha, benzene, xylene, toluene, nitrobenzene, carbon tetrachloride, chloroform, trichloroethylene and the like. The amount of amine silane mixture dissolved in the solvent may be from about 1/2 percent to an amount sufficient to form a saturated solution.The volume of extractant used for extracting a given volume of phosphoric acid is not critical and optimum ratios for particular extraction conditions can be determined by routine tests. In general, it is only necessary to use an amount of extractant sufficient to extract fluorine compounds from the phosphoric acid and to form a water immiscible extractant phase.The extractant can be contacted with the phosphoric acid in accordance with conventional solvent extraction technique either in batch extraction operations or in continuous countercurrent extraction operations.In general, the temperature of which the extraction is conducted is not critical but with some silanes, particularly those of high molecular weight, improved extraction is obtained at elevated temperatures in the range of 50.degree. to 100.degree.C. If the extraction is conducted at elevated temperatures, it may be desirable to conduct the extraction under reflux or elevated pressure to present undue material loss.Following the extraction the extractant phase is allowed to separate and this phase containing the extracted fluorine compounds is separated from the phosphoric acid. The extractant can then be recovered by admixture with sufficient base to convert the fluorine compounds contained therein to water soluble salts and separating the organic extractant phase from the aqueous phase.

摘要翻译： 通过用硅烷和长链烃基胺的混合物萃取，从磷酸水溶液中除去氟化合物。

公开(公告)号：US3784678A

公开(公告)日：1974-01-08

申请号：US3784678D

申请日：1971-09-20

申请人： BUDENHEIM RUD A OETKER CHEMIE

发明人： BELTZ K ,  FRANKENFELD K ,  GOTZMANN K

IPC分类号： C01B25/237 ,  C01B25/46 ,  C01B25/16

CPC分类号： C01B25/461 ,  C01B25/237 ,  C01B25/462

摘要： A PROCESS FOR REMOVING IRON FROM PHOSPHORIC ACID. A BARIUM COMPOUND IS ADDED TO THE PHOSPHORIC ACID INCLUDING SULFATE IONS TO PRECIPITATE BARIUM SULFATE WHEREBY THE IRON CONTENT OF THE PHOSPHORIC ACID IS SUBSTANTIALLY REDUCED.

公开(公告)号：US3676061A

公开(公告)日：1972-07-11

申请号：US3676061D

申请日：1970-09-21

申请人： KONOSHIMA CHEM CO LTD

发明人： TAGA KOJI ,  NOGUCHI MASAHIKO

IPC分类号： C01B25/237 ,  C01B33/10 ,  C01F7/54 ,  C01B9/08

CPC分类号： C01B25/2375 ,  C01B33/103 ,  C01F7/54

摘要： HIGH PURITY SYNTHETIC CRYOLITE IS PREPARED FROM WET PROCESS PHOSPHORIC ACID SOLUTION THROUGH TREATMENT OF THE SOLUTION WITH AN ALKALI SALT SO AS TO FORM CRYSTALLINE ALKALI FLUOSILICATE, HEATING THE ALKALI FLUOSILICATE THUS OBTAINED WITH CONCENTRATED SULFURIC ACID AND AT LEAST ONE ALKALI SALT SELECTED FROM THE GROUP CONSISTING OF ALKALI CHLORIDE AND ALKALI NITRATE AND ABSORBING THE GAS THEREBY EVOLVED SO AS TO PROVIDE A SOLUTION OF HYDROFLUOSILICIC ACID AND EITHER HYDROCHLORIC OR NITRIC ACID, AND REACTING THIS SOLUTION OF HYDROFLUOSILICIC ACID WITH SODIUM ALUMINATE SOLUTION.

公开(公告)号：US3554694A

公开(公告)日：1971-01-12

申请号：US3554694D

申请日：1969-06-02

申请人： CITIES SERVICE CO

发明人： BARKER JAMES E ,  ROBINSON JULIAN H

IPC分类号： C01B25/237 ,  C01B33/10 ,  C01D3/02 ,  C01F11/22

CPC分类号： C01B33/103 ,  C01B25/2372

摘要： A PROCESS FOR THE MANUFACTURE OF COMMERCIALLY PURE SODIUM FLUOSILICATE FROM WET PROCESS PHOSPHORIC ACID (WPA) BY REACTING A SODIUM SALT PREFERABLY SODIUM CHLORIDE WITH THE FLUOSILICIC ACID PRESENT IN THE PHOSPHORIC ACID UNDER CONDITIONS OF MODERATE AGITATION CHARACTERIZED BY A REYNOLDS NUMBER OF BETWEEN 7600 AND 8300, THEREBY PRECIPITATING THE SODIUM FLUOSILICATES AS A PARTICLE HAVING A SIZE BETWEEN 200 MESH AND 325 MESH. THE REACTANT CONTAINING THE PRECIPITATE IS DISCHARGED AS A SLURRY TO A SETTLING TANK WHERE THE PRECIPITATE IS SETTLED OUT AND THE CLARIFIED DEFLUORINATED ACID PASSED OUT IN A SEPARATE STREAM FOR FURTHER PROCESSING. THE SETTLED MUD IS THEN PASSED TO A CLASSIFIER WHERE GYPSUM AND OTHER SOLIDS ARE FLOATED OUT IN THE WASH, THE WASH AS OVERFLOW BEING RECYCLED TO THE MIXING REACTOR. THE CLASSIFIED SODIUM FLUOSILICATE IS FILTERED AND DRIED TO OBTAIN A COMMERCIALLY PURE SODIUMFLUOSILICATE. WET PROCESS PHOSPHORIC ACID CAN ALSO BE DEFLUORINATED BY REACTION WITH EITHER POTASSIUM OR BARIUM SALTS UNDER LIKE CONDITIONS. IN THE INSTANCE, EITHER POTASSIUM OR BARIUM FLUOSILICATE MAY BE RECOVERED. BY REACTING THE WET ACID WITH A MIXTURE OF SODIUM, POTASSIUM AND/OR BARIUM SALTS, A MIXED FLUOSILICATE PRODUCT CAN ALSO BE OBTAINED.

公开(公告)号：US3124419A

公开(公告)日：1964-03-10

申请号：US3124419D

IPC分类号： C01B25/22 ,  C01B25/225 ,  C01B25/237

CPC分类号： C01B25/237 ,  C01B25/22 ,  C01B25/225