WO2016202257A1 - 从含稀土磷矿中回收磷和稀土的方法及含稀土磷酸盐的物质 - Google Patents

从含稀土磷矿中回收磷和稀土的方法及含稀土磷酸盐的物质 Download PDF

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WO2016202257A1
WO2016202257A1 PCT/CN2016/085827 CN2016085827W WO2016202257A1 WO 2016202257 A1 WO2016202257 A1 WO 2016202257A1 CN 2016085827 W CN2016085827 W CN 2016085827W WO 2016202257 A1 WO2016202257 A1 WO 2016202257A1
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rare earth
phosphate
solution
acid
leaching
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PCT/CN2016/085827
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English (en)
French (fr)
Inventor
王良士
黄小卫
赵龙胜
巫圣喜
于瀛
王春梅
崔大立
冯宗玉
徐旸
龙志奇
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有研稀土新材料股份有限公司
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Priority claimed from CN201510347631.5A external-priority patent/CN106319247B/zh
Priority claimed from CN201510347681.3A external-priority patent/CN106319248B/zh
Application filed by 有研稀土新材料股份有限公司 filed Critical 有研稀土新材料股份有限公司
Priority to AU2016279392A priority Critical patent/AU2016279392B2/en
Publication of WO2016202257A1 publication Critical patent/WO2016202257A1/zh
Priority to ZA2018/00118A priority patent/ZA201800118B/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B3/00—Extraction of metal compounds from ores or concentrates by wet processes
    • C22B3/04—Extraction of metal compounds from ores or concentrates by wet processes by leaching
    • C22B3/06—Extraction of metal compounds from ores or concentrates by wet processes by leaching in inorganic acid solutions, e.g. with acids generated in situ; in inorganic salt solutions other than ammonium salt solutions
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B59/00—Obtaining rare earth metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to the field of rare earth recovery, and in particular to a method for recovering phosphorus and rare earth from a rare earth-containing phosphate ore and a rare earth phosphate-containing material.
  • Rare earth minerals often coexist with minerals such as barite, calcite, apatite, and silicate ore in nature. Due to the different mineralization reasons of minerals, the occurrence and content of rare earth elements in minerals are also different. Among the rare earth minerals currently mined, the grade of rare earth oxides is generally a few percent. In order to meet the needs of rare earth metallurgical production, it is necessary to separate the rare earth from other ores by smelting before smelting, so that the rare earth minerals are enriched. The rare earth concentrate in the rare earth concentrate after enrichment is usually 50% to 70%.
  • Rare earth minerals mainly include bastnasite, monazite, xenotime and ion-adsorbed rare earth ore.
  • the concentrated sulfuric acid roasting method decomposes the monazite ore, and the monazite concentrate is mixed with concentrated sulfuric acid at 200-230 ° C.
  • the concentrated sulfuric acid is 1.7 to 2 times the weight of the concentrate, and the decomposition product is 7 to 10 times after cooling.
  • the rare earth has a rare earth of about 50 g/L (REO), 25 g/LP 2 O 5 , 2.5 g/L Fe 2 O 3 , and an acidity of 2.5 mol/L.
  • the immersion liquid has high acidity, high impurity phosphorus and high enthalpy, and the rare earth and strontium are precipitated by sodium sulfate double salt, and then converted into hydroxide by alkali, and the rare earth is preferentially leached by acid to extract and separate rare earth and strontium.
  • the method is complicated in process, has many liquid-solid separation steps, and the process is discontinuous, and the rare earth recovery rate is low; in addition, the acid-base cross-use, the chemical raw material consumption cost is high, and the phosphorus is difficult to enter the wastewater treatment, and the radioactive element strontium is dispersed in the slag and the waste water. It is difficult to recycle effectively.
  • Phosphate rock is the main raw material for the production of phosphorus chemical products.
  • the world reserves of phosphate rock resources are large, often accompanied by trace rare earths.
  • the method for recovering rare earth in phosphate rock comprises the following processes: (1) a wet-process phosphoric acid process for treating phosphate rock by hydrochloric acid or nitric acid method, more than 95% of rare earth entering solution, and then solvent extraction, ion exchange, precipitation, crystallization, etc.
  • the method of recovering rare earth (2) the wet-process phosphoric acid process for treating phosphate rock by sulfuric acid method, the rare earth enters the solution and the phosphogypsum separately, and then the phosphogypsum is leached by sulfuric acid to make the rare earth enter the solution, and the rare earth in the solution can be extracted by solvent and ion exchange. Recovering rare earth by means of precipitation, crystallization, and the like. (3) Phosphoric acid treatment of phosphate rock process.
  • the rare earth-containing phosphorus concentrate is mixed with a phosphoric acid solution to carry out a reaction, and the rare earth in the phosphate rock is precipitated in the form of fluoride by controlling the process conditions, and more than 85% of the rare earth enters the slag.
  • the hydrochloric acid, nitric acid or sulfuric acid is used to dissolve the rare earth in the recovered slag, but the rare earth grade in the slag is very low, about 1%, the impurities such as phosphorus, calcium, aluminum, silicon, etc.
  • the rare earth fluoride is difficult to be dissolved by acid, acid
  • the consumption is high, the amount of slag is large, and the rare earth recovery rate is low; in addition, 15% of the rare earth entering the leachate is difficult to be recovered in the gypsum residue during the calcium removal process.
  • Phosphate containing monazite rare earth is a kind of more difficult to treat mineral.
  • This monazite-containing rare earth phosphate contains many components, including monazite, rare earth and phosphate rock. Since monazite and phosphate rock belong to the same phosphate mineral, the mineralogical properties of the two are relatively close.
  • monazite is closely related to the phosphate rock. Recovering rare earth elements and phosphorus in this mixed ore In the case of elements, it is difficult to achieve effective sorting of ore due to the difficulty in inlaying and disintegrating the various materials in the mixed ore.
  • monazite since the decomposition of monazite requires relatively harsh conditions and requires high temperature and pH, etc., when the phosphate rock containing monazite is treated by the sulfuric acid method in the prior art, the monazite cannot be completely decomposed. Can achieve its effective separation and utilization.
  • the main object of the present invention is to provide a method for recovering phosphorus and rare earth from rare earth-containing phosphate ore to solve the problem of low recovery efficiency of phosphorus and rare earth elements in rare earth phosphate ore in the prior art.
  • a method for recovering phosphorus and rare earth from a rare earth-containing phosphate ore comprising the following steps: Step S1, leaching a rare earth phosphate ore with a solution containing phosphoric acid to obtain The leachate and the acid leach residue, the leachate contains rare earth ions, Ca 2+ and H 2 PO 4 - ; and the step S2, the leaching solution is aged to obtain a rare earth phosphate precipitate and a monocalcium phosphate solution; the reaction temperature of the step S2 is higher than The reaction temperature of the step S1.
  • the step S1 comprises: leaching the rare earth phosphate rock with a solution containing phosphoric acid at a temperature of 10 ° C to 60 ° C for 0.5 to 8 hours, preferably 1 to 4 hours, to obtain a leachate and an acid leach residue.
  • the step S2 comprises: aging the leachate at a temperature of 60 ° C to 150 ° C, preferably 80 to 120 ° C for 0.5 to 24 hours, preferably 1 to 8 hours, to obtain a rare earth phosphate precipitate and a monocalcium phosphate solution.
  • the method further comprises: recovering the rare earth element in the rare earth phosphate precipitation; and recovering the phosphorus element in the monocalcium phosphate solution.
  • the method further comprises: mixing the acid leaching slag with the rare earth phosphate precipitate to obtain a rare earth mixed slag, and recovering the rare earth element in the rare earth mixed slag; The phosphorus element in the monocalcium phosphate solution is recovered.
  • the step of recovering the phosphorus element in the monocalcium phosphate solution comprises: adding concentrated sulfuric acid having a mass concentration of >90% to the monocalcium phosphate solution to obtain a solid-liquid mixture; and solid-liquid separation of the solid-liquid mixture to obtain the first A solution of monophosphate and calcium sulfate.
  • the method further comprises: returning the first phosphoric acid solution to step S1, leaching the rare earth phosphate ore; or The phosphoric acid solution is subjected to impurity removal to obtain a second phosphoric acid solution; the second phosphoric acid solution is returned to step S1 to leaching the rare earth phosphate rock.
  • the step of recovering the rare earth element in the rare earth mixed slag comprises: step A, adding an iron-containing substance to the rare earth mixed slag; adding concentrated sulfuric acid having a mass concentration of >90% to obtain a mixture; and step B, the mixture
  • the calcination is carried out to obtain a calcined product; in step C, the calcined product is leached with water to obtain a rare earth-containing aqueous immersion liquid and water leaching slag; in step D, the pH of the rare earth-containing aqueous immersion liquid is adjusted to 3.8 to 5, and a rare earth sulfate solution is obtained by filtration.
  • Step E preparing a rare earth compound by using a rare earth sulfate solution as a raw material; wherein, the step E comprises: extracting and separating the rare earth sulfate solution by using an acidic phosphorus extracting agent to obtain a mixed rare earth compound or a single rare earth compound; or The rare earth sulfate solution is added with carbonate or oxalate to precipitate rare earth carbonate to obtain rare earth carbonate or rare earth oxalate; and the rare earth carbonate or rare earth oxalate is calcined to obtain a rare earth oxide.
  • the iron-containing material is iron-containing tailings and/or iron-containing waste.
  • the mass ratio of the iron element in the iron-containing substance to the phosphorus element in the rare earth mixed slag is 2 to 4:1, preferably 2.5 to 3.5:1.
  • the step A includes mixing the concentrated sulfuric acid and the rare earth mixed slag in a ratio of 1 to 2:1 by mass.
  • the calcination temperature is 200 to 500 ° C
  • the time is 1 to 8 hours, preferably 250 to 400 ° C
  • the time is 2 to 4 hours.
  • the pH of the rare earth-containing aqueous extract is adjusted to 4 to 4.5 using at least one of magnesium oxide, magnesium hydroxide and light burnt dolomite.
  • the phosphoric acid-containing solution further contains hydrochloric acid and/or nitric acid.
  • the concentration of phosphoric acid in the phosphoric acid-containing solution is 15% to 50%, preferably 15% to 30%, based on P 2 O 5 .
  • the proportion of hydrochloric acid and/or nitric acid in the phosphoric acid-containing solution is ⁇ 30%, preferably 2-15%, based on the moles of the anion.
  • the method further comprises the step of mixing the phosphoric acid-containing solution and the rare earth phosphate rock in a liquid-solid ratio of 2 to 10 L: 1 kg, preferably a liquid-solid ratio of 3 to 6 L: 1 kg.
  • a rare earth phosphate-containing material comprising at least a first phase structure and a second phase structure, the first phase structure being an amorphous phase
  • the second phase structure comprises a monazite phase or/and a xenotime phase; the rare earth phosphate-containing material is isolated from a phosphate rock containing monazite and/or xenotime, from monazite and/or xenotime.
  • the method for separating the rare earth phosphate-containing material from the phosphate rock comprises: step S1, leaching the phosphate rock containing monazite and/or xenotime with a solution containing phosphoric acid to obtain a leaching solution and a rare earth acid leaching residue; the leaching solution containing the rare earth ion Calcium ion and dihydrogen phosphate ion; step S2, aging the leaching solution, solid-liquid separation to obtain a rare earth phosphate precipitate and a monocalcium phosphate solution; and step S3, mixing the rare earth acid leaching residue with the rare earth phosphate precipitate to obtain The substance of the rare earth phosphate; the reaction temperature of the step S2 is higher than the reaction temperature of the step S1.
  • the content of the amorphous phase in the rare earth phosphate is more than 1%, preferably 5 to 40% by weight.
  • the weight ratio of the first phase structure to the second phase structure in the rare earth phosphate-containing material is 1:1-20.
  • the rare earth phosphate-containing substance further includes an iron-containing and/or aluminum-containing impurity having an iron and/or aluminum content of from 1 to 50% by weight, preferably from 3 to 25% by weight, based on the oxide.
  • the weight ratio of the rare earth to iron and/or aluminum is from 2 to 20:1 in terms of the oxide.
  • the step S1 comprises: leaching the phosphate rock containing monazite and/or xenotime with a solution containing phosphoric acid at a temperature of 10 ° C to 60 ° C for 0.5 to 8 hours, preferably 1 to 4 hours, to obtain a leachate and a rare earth. Acid leaching residue.
  • the step S2 comprises: aging the first solution at a temperature of 60 ° C to 150 ° C, preferably 80 to 120 ° C for 0.5 to 24 hours, preferably 1 to 8 hours, and solid-liquid separation to obtain a rare earth phosphate precipitate and Monocalcium phosphate solution.
  • the phosphoric acid-containing solution further comprises hydrochloric acid and/or nitric acid; preferably, the proportion of hydrochloric acid and/or nitric acid in the phosphoric acid-containing solution is less than 30%, more preferably 2 to 15 in terms of the number of moles of the anion. %.
  • the concentration of phosphoric acid in the phosphoric acid-containing solution is 15% to 50%, preferably 15% to 30%, based on P 2 O 5 .
  • the method further comprises the step of mixing the phosphoric acid-containing solution with the monazite and/or xenotime-containing phosphate rock in a liquid-solid ratio of 2 to 10 L: 1 kg, preferably a liquid-solid ratio of 3 ⁇ 6L: 1kg.
  • the rare earth phosphate is leached by using a solution containing phosphoric acid at a relatively low reaction temperature, and the phosphorus in the phosphate rock is dissolved by the hydrogen ion in the phosphoric acid solution to form a monocalcium phosphate solution, and the rare earth element It is also dissolved and enters into a solution to form a leachate containing rare earth ions, Ca 2+ and H 2 PO 4 - ; further aging of the leaching solution facilitates the formation of rare earth elements to form a rare earth phosphate precipitate to achieve separation of rare earth elements and phosphorus elements. .
  • the reaction temperature has little effect on the leaching of phosphorus in acid leaching process, while the solubility of rare earth phosphate is relatively large at lower temperature, which is beneficial to the leaching of rare earth elements. At the same time, it can effectively inhibit the impurity elements such as iron and aluminum in phosphate rock. Leaching, so that the leaching rate of iron and aluminum elements ⁇ 5%, greatly reducing the burden of subsequent phosphoric acid purification and removal.
  • the rare earth phosphate has a small solubility product at a relatively high temperature, which is advantageous for precipitating the rare earth element in the leaching solution as a rare earth phosphate to further realize the rare earth.
  • the rare earth enrichment multiple is up to several tens of times or even hundreds of times.
  • the rare earth phosphate in the rare earth phosphate precipitation can reach more than 45%, even more than 55%, and the rare earth yield reaches over 80%, even More than 90%, improve the separation efficiency of rare earth, achieve the purpose of low-cost separation of rare earth, and facilitate the subsequent recycling of rare earth elements.
  • the rare earth-containing phosphate ore contains monazite
  • the monazite does not dissolve and remains in the slag during the acid leaching process, and the separation of the rare earth element and the phosphorus element is also achieved.
  • the rare earth phosphate precipitate can be mixed with the acid-containing leaching residue produced by the acid leaching process to form a rare earth mixed slag, and the rare earth mixed slag has a high rare earth content, which is also convenient for further recycling of the rare earth element.
  • FIG. 1 is a schematic flow chart showing a process for recovering phosphorus and rare earth from a rare earth-containing phosphate rock according to an exemplary embodiment of the present invention
  • FIG. 2 is a flow chart showing a process for recovering phosphorus and rare earth from a rare earth-containing phosphate ore when the rare earth-containing phosphate ore further contains monazite according to another exemplary embodiment of the present invention
  • Fig. 3 shows an X-ray diffraction spectrum of a rare earth phosphate-containing material obtained in Example 26 according to the present invention.
  • the molecular formula of monazite (English name: Monazite) is (Ln, Th)PO 4 , wherein Ln means at least one of rare earth elements other than cerium.
  • the leachate refers to a solution containing rare earth, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate, or impurities such as iron or aluminum in addition to monocalcium phosphate.
  • Leachate grade refers to the ratio of the content of useful elements or their compounds in the ore. The higher the content, the higher the grade.
  • rare earth phosphates such as mixed minerals containing a variety of minerals such as apatite and monazite are treated by existing separation methods, and it is difficult to effectively separate rare earth elements and phosphorus elements in such mixed ore.
  • a method for recovering phosphorus and rare earth from a rare earth-containing phosphate rock comprising the steps of: step S1, including The phosphoric acid solution leaches the rare earth phosphate rock to obtain a leachate and an acid leach residue, the leach solution contains rare earth ions, Ca 2+ and H 2 PO 4 ⁇ ; and step S2, the leaching solution is aged to obtain a rare earth phosphate precipitate and phosphoric acid a calcium solution; wherein the reaction temperature of step S2 is higher than the reaction temperature of step S1.
  • the above method leaches the rare earth phosphate ore by using a solution containing phosphoric acid at a relatively low reaction temperature, and dissolves the phosphorus in the phosphate rock by using hydrogen ions in the phosphoric acid solution to form a monocalcium phosphate solution, and the rare earth element in the acid leaching process It is dissolved and enters the solution in the form of ions to form a leaching solution; further aging of the leaching solution facilitates the formation of rare earth elements contained in the solution to form a rare earth phosphate precipitate, thereby achieving separation of the rare earth element and the phosphorus element.
  • the reaction temperature has little effect on the leaching of phosphorus in acid leaching process, while the relative solubility of rare earth phosphate is relatively high, which is beneficial to the leaching of rare earth.
  • low temperature can effectively inhibit the leaching of iron, aluminum and other impurity elements in phosphate rock, making iron
  • the leaching rate of elements and aluminum elements is ⁇ 5%, which greatly reduces the burden of subsequent phosphoric acid purification.
  • the rare earth phosphate has a small solubility product at a high temperature, which is advantageous for precipitating rare earth elements in the leaching solution in the form of rare earth phosphates, thereby realizing rare earth elements and phosphorus. Further efficient separation of elements.
  • the rare earth enrichment multiple is up to several tens of times or even hundreds of times, and the rare earth phosphate in the rare earth phosphate precipitation can reach more than 45%, or even more than 55%; and the rare earth yield reaches 80%. More than %, even more than 90%, greatly improve the separation efficiency of rare earths, achieve the purpose of low-cost separation of rare earths, and facilitate the subsequent recycling of rare earth elements.
  • the purpose of leaching with a solution containing phosphoric acid is to dissolve the phosphorus element and the rare earth element in the rare earth phosphate ore, and the impurity elements such as iron and aluminum remain in the slag to form the acid leaching residue. Therefore, any leaching process conditions capable of dissolving phosphorus and rare earth elements as much as possible and retaining impurity elements such as iron and aluminum as much as possible in the acid leaching residue are suitable for the present invention.
  • the rare earth phosphate rock is continuously leached with a solution containing phosphoric acid at a temperature of 10 ° C to 60 ° C for 0.5 to 8 hours, preferably 1 to 4 hours, to obtain a leachate and an acid leach residue.
  • the acid leaching residue can be selectively returned to the phosphorus recovery process for further leaching to recover residual phosphorus.
  • the reaction temperature has little effect on the dissolution of phosphorus in the rare earth phosphate ore, and the solubility of the rare earth phosphate is relatively large at this temperature, which is advantageous.
  • Leaching of rare earth, and the above-mentioned low temperature can effectively inhibit the leaching of iron and aluminum and other impurity elements in the rare earth phosphate rock, so that the leaching rate of iron and aluminum elements is less than 5%, which greatly reduces the subsequent impurity removal burden.
  • the leaching time is from 2 to 5 hours. Selecting the leaching time in this range not only dissolves the phosphorus element and the rare earth element, but also shortens the leaching period.
  • the specific time and temperature of the aging treatment can be adjusted according to the type of the rare earth phosphate ore.
  • the leaching solution is aged at a temperature of 60 ° C to 150 ° C, preferably 80 to 120 ° C for 0.5 to 24 hours, preferably 1 to 8 hours, to obtain a rare earth phosphate by solid-liquid separation. Precipitate and second solution.
  • the rare earth phosphate has a small solubility product.
  • the crystallization gradually grows, and the amorphous precipitate gradually transforms into the crystal form precipitate.
  • the rare earth element in the leachate can be precipitated more thoroughly, thereby more effectively separating the rare earth element from the phosphorus element.
  • the rare earth element is separated by precipitation of rare earth phosphate to obtain a monocalcium phosphate solution, and the main component is calcium ion and dihydrogen phosphate ion, and further contains a small amount of impurity ions such as monohydrogen phosphate ion, iron or aluminum. .
  • the above separation method can effectively separate the rare earth phosphate precipitated and the rare earth ion-extracted leachate, and the rare earth enrichment multiple is up to several tens of times or even hundreds of times from the rare earth phosphate ore to the rare earth phosphate precipitation, and the rare earth phosphate in the rare earth phosphate precipitate can reach more than 45%. Even reaching more than 55%, the rare earth yield reaches 80% or more, even more than 90%, improving the rare earth separation efficiency, achieving the purpose of low-cost separation of rare earth, and facilitating the subsequent recycling of rare earth elements.
  • the method further comprises: recovering rare earth elements in the rare earth phosphate precipitation; and in the monocalcium phosphate solution The phosphorus element is recycled.
  • the step of recovering the rare earth element is carried out by any one of acid dissolution, alkali conversion-acid dissolution, sulfuric acid roasting-water immersion, and then precipitating enrichment or extracting and purifying. On the basis of the above high separation efficiency, the recovery rates of rare earth elements and phosphorus elements are also relatively high.
  • the rare earth phosphates which can be separated by the above separation method of the present invention include, but are not limited to, rare earth-containing apatite ore, phosphorite or rare earth-containing collophosphate.
  • the rare earth phosphate ore separated in the above separation method is a rare earth phosphate ore containing monazite and/or xenotime. As shown in FIG. 2, when the above-mentioned rare earth phosphate ore contains monazite and/or xenotime, the above separation method is used for separation, and the monazite and/or xenotime are not dissolved in the acid leaching process and remain in the slag.
  • the separation of rare earth elements and phosphorus elements can be achieved.
  • the rare earth phosphate precipitate is mixed with the acid leaching residue produced by the acid leaching process to form a rare earth mixed slag.
  • the above rare earth mixed slag obtained by the two-step separation and aggregation has a high rare earth content (the rare earth yield of the rare earth phosphate ore can be more than 90%, and the leaching rates of Fe and Al can be less than 10%, respectively, based on the rare earth mixed slag;
  • the rare earth phosphate rare earth yield is greater than 97%, and the leaching rates of Fe and Al are less than 5%, respectively, thereby improving the rare earth separation efficiency, achieving the purpose of low-cost separation of rare earth, and facilitating subsequent rare earth
  • the elements are further recycled.
  • the above rare earth phosphate ore containing monazite and/or xenotime is a relatively difficult class of minerals.
  • monazite since monazite and phosphate rock belong to the same phosphate mineral, the mineralogical properties of the two are relatively close.
  • monazite and phosphate rock are closely related.
  • the decomposition of monazite requires relatively harsh conditions and requires high temperature, pH, etc.
  • the phosphate rock containing monazite is treated by the sulfuric acid method in the prior art, It is often impossible to decompose monazite completely and fail to achieve its effective separation and utilization.
  • the monazite is not dissolved in the acid leaching process, and is enriched in the slag, thereby realizing the separation of phosphorus and monazite.
  • the rare earth entering the solution is precipitated by the aging treatment, and the rare earth mixed slag is formed by the monazite which is insoluble in the acid leaching process, and the rare earth is recovered, thereby simplifying the recovery step, improving the rare earth recovery rate, and achieving low cost. Comprehensive recovery of rare earths.
  • the person skilled in the art can decide whether to further the rare earth element in the rare earth mixed slag and the phosphorus element in the monocalcium phosphate solution according to actual needs. Recycling is carried out separately, and a suitable recycling method can be selected in a targeted manner.
  • the method further comprises: recovering rare earth elements in the rare earth mixed slag; and The phosphorus in the solution is recovered to make full use of the rare earth and phosphorus in the rare earth phosphate rock.
  • the step of recovering the rare earth in the rare earth mixed slag comprises: step A, adding an iron-containing substance to the rare earth mixed slag (or simultaneously adding magnesium and/or Calcium substance), and adding concentrated sulfuric acid with a concentration of >90% to obtain a mixture; Step B, calcining the mixture to obtain a calcined product; Step C, adding water to the calcined product to obtain a rare earth-containing aqueous immersion liquid and water leaching residue Step D, adjusting the pH value of the rare earth-containing aqueous immersion liquid to 3.8 to 5, filtering to obtain a rare earth sulfate solution and a filter residue containing iron element, phosphorus element and strontium element; and step E, preparing a rare earth compound by using a rare earth sulfate solution Wherein, the step E
  • the rare earth in the rare earth phosphate ore is retained in the rare earth mixed slag, so that the rare earth grade in the rare earth mixed slag is increased, and the workload of the subsequent treatment is greatly reduced.
  • Phosphorus is solidified in the slag by using a unique iron-fixing phosphorus to avoid the loss of rare earth. If magnesium and/or calcium are added at the same time, the fluorine can be fixed, and the interference of phosphorus and fluorine can be eliminated, thereby effectively avoiding the loss of rare earth phosphate precipitation or precipitation of rare earth fluoride during the subsequent water leaching process.
  • the fluorine element is prevented from escaping in the form of hydrogen fluoride gas during the roasting process and pollutes the environment.
  • the recovery method of the rare earth element has less acid-base consumption, and the rare earth recovery rate can reach more than 90%.
  • the strontium element is converted into pyrophosphate and solidified in the slag to avoid the decentralized pollution of the radioactive cesium element in the process.
  • the purpose of adding the magnesium and/or calcium-containing substance is to fix the fluorine element in the mixed slag in the slag, thereby facilitating the separation of the rare earth element.
  • any magnesium and/or calcium containing material capable of retaining fluorine in the slag and separating the rare earth element is suitable for use in the present invention.
  • the magnesium and/or calcium-containing material is an oxide containing magnesium and/or calcium, a carbonate containing magnesium and/or calcium, and a mineral containing magnesium and/or calcium.
  • At least one of; more preferably, the mineral containing magnesium and/or calcium is dolomite and/or magnesite; the iron-containing material is iron-containing tailings and/or iron-containing waste, preferably tailings containing rare earth and iron .
  • the use of the above ore has the advantage of abundant resources, and the use of waste slag can save energy and reduce emissions, turning waste into treasure.
  • the ratio of the number of moles of magnesium and/or calcium in the magnesium and/or calcium-containing substance to the number of moles of fluorine in the rare earth mixed slag is 1 ⁇ 2:2.
  • magnesium/calcium-containing material and rare earth phosphate The mixing ratio of the slag is not limited to the above range, and by mixing the molar ratio of the two to 1 to 2:2, it is advantageous to form the fluorine in the ore during the roasting process under the premise of reducing the input amount of the magnesium/calcium-containing substance.
  • Magnesium fluoride/calcium, magnesium fluorophosphate/calcium solids are fixed in the slag, which slows down the problem of fluoride leaching out of the environment during the roasting process, and avoids the formation of rare earth precipitated by fluoride during the process of solution removal. Loss, thereby increasing the yield of rare earths.
  • the amount of the iron-containing substance added can be appropriately adjusted according to the content of the phosphorus element in the rare earth mixed slag.
  • the mass ratio of the iron element in the iron-containing substance to the phosphorus element in the rare earth mixed slag is from 2 to 4:1, preferably from 2.5 to 3.5:1.
  • controlling the Fe/P mass ratio can effectively form iron phosphate precipitation, and the phosphorus removal effect is good, and the excess iron can be hydrolyzed to form a precipitate under the pH condition, thereby avoiding the formation of rare earth phosphate precipitate, thereby avoiding the rare earth. Loss.
  • the amount of concentrated sulfuric acid can be appropriately adjusted according to the quality of the rare earth mixed slag.
  • concentrated sulfuric acid is added in a ratio of a mass ratio of concentrated sulfuric acid to rare earth mixed slag of from 1 to 2:1 to obtain a mixture. Controlling the mass ratio of the concentrated sulfuric acid to the rare earth mixed slag within the above range has an effect of effectively controlling the amount of sulfuric acid and improving the decomposition and leaching of the rare earth.
  • the calcination temperature can be appropriately selected depending on the kind and content of the rare earth element in the mixture.
  • the temperature of the calcined mixture is from 200 to 500 ° C, preferably from 250 to 400 ° C.
  • the calcination in this temperature range is beneficial for the precipitation of barium, iron and phosphoric acid to form phosphate and/or pyrophosphate, which is solidified in the slag without being leached, and the radioactive element lanthanum is also solidified in the slag to avoid radioactive cesium in the process. Dispersed pollution.
  • an appropriate substance may be selected according to the composition of the rare earth water immersion liquid and the pH value to adjust the rare earth water immersion liquid to a suitable pH value.
  • the pH of the rare earth-containing aqueous extract is adjusted to 4 to 4.5 using magnesium oxide and/or light burnt dolomite.
  • the magnesium oxide and/or light burnt dolomite is used to adjust the pH value of the rare earth-containing aqueous immersion liquid, so that the phosphorus element forms as much as possible to form iron phosphate and strontium phosphate precipitate, and the rare earth does not precipitate, thereby improving the recovery rate of the rare earth.
  • the step of recovering phosphorus element comprises: adding concentrated sulfuric acid having a mass concentration greater than 90% to a monocalcium phosphate solution to obtain a solid-liquid mixture; The solid-liquid separation was carried out to obtain a first phosphoric acid solution and calcium sulfate.
  • the above preferred embodiment has the beneficial effect of recovering the phosphorus element in the monocalcium phosphate solution in the form of a first phosphoric acid solution containing phosphoric acid, thereby realizing a low value strong acid to prepare a high value weak acid.
  • the method further comprises: directly returning the first phosphoric acid solution In the above step S1, the rare earth phosphate ore is used for leaching; or the first phosphoric acid solution is subjected to impurity removal to obtain a second phosphoric acid solution having a relatively high purity of phosphoric acid; and then the second phosphoric acid solution is returned to the above step S1 for The rare earth phosphate rock is leached, and the second phosphoric acid solution can be further used for the production of phosphate fertilizer or for phosphoric acid production such as phosphoric acid purification.
  • the recovered phosphoric acid solution containing impurities or impurities is used for the decomposition and leaching of rare earth phosphate rock, and the whole process is connected reasonably, thereby not only achieving efficient separation of rare earth elements and phosphorus elements, but also achieving recycling of phosphorus elements. use.
  • the impurity element removed in the above impurity removal step includes but It is not limited to elements such as iron, silicon, aluminum, calcium, magnesium, barium and uranium.
  • the specific impurity removal step may be carried out according to a conventional process in the prior art as needed.
  • the phosphoric acid-containing solution includes phosphoric acid, and hydrochloric acid and/or nitric acid may be appropriately added according to actual conditions.
  • the phosphoric acid containing solution further comprises hydrochloric acid and/or nitric acid.
  • the hydrochloric acid or nitric acid in the mixed acid solution is favorable for the decomposition of the apatite, thereby increasing the leaching rate of phosphorus and rare earth in the apatite.
  • hydrochloric acid or nitric acid can provide hydrogen ion H + , which can reduce the content of phosphate under the same acid amount, reduce the viscosity of the system, and facilitate the leaching of phosphorus; at the same time, the presence of chloride ion or nitrate ion is beneficial to improve
  • the solubility of calcium ions in solution is beneficial to the decomposition of apatite.
  • the proportion of hydrochloric acid and/or nitric acid in the moles of anion is from 0 to 30% (excluding 0), preferably from 2 to 15%.
  • the content of hydrochloric acid or nitric acid used in the present invention is not limited to the above range, and excessively high content of hydrochloric acid or nitric acid will simultaneously increase the solubility of the rare earth phosphate in the system, making it difficult for the rare earth to precipitate and precipitate during the above-mentioned aging treatment. As a result, the rare earth cannot be concentrated in the precipitation of the rare earth phosphate, resulting in a low yield of the rare earth.
  • the mass concentration of phosphoric acid can be appropriately selected depending on the composition of the rare earth phosphate ore to be leached.
  • the phosphoric acid-containing solution has a mass concentration of phosphoric acid of 15% to 50%, preferably 15% to 30%, based on P 2 O 5 .
  • the concentration of P 2 O 5 in the phosphoric acid-containing solution used in the present invention is not limited to the above range, and when the concentration of P 2 O 5 is within the above range, a higher acidity is advantageous for decomposition of phosphate rock, thereby improving The yield of phosphorus, but the excessively high phosphoric acid content has problems such as high viscosity and low mass transfer efficiency.
  • the phosphoric acid-containing solution and the rare earth phosphate ore may be reasonably proportioned according to the phosphoric acid concentration in the phosphoric acid-containing solution and the rare earth phosphate component, so that the phosphorus in the rare earth phosphate ore The rare earth element is dissolved.
  • the solid solution ratio of the phosphoric acid-containing solution to the rare earth phosphate ore is 2 to 10 L: 1 kg, preferably 3 to 6 L: 1 kg.
  • the phosphorus and calcium elements form soluble calcium monophosphate Ca(H 2 PO 4 ) 2 into the solution under the condition of reducing the amount of acid.
  • the solubility of the rare earth phosphate is high under the condition of high acidity, which is beneficial to phosphorus.
  • the rare earth leaching into the solution in the limestone, the above ratio is favorable for the sufficient dissolution of the phosphorus element and the rare earth element, and is favorable for the subsequent aging treatment to form the rare earth phosphate precipitated and enriched rare earth.
  • the mine also includes monazite, the insoluble monazite will remain in the slag, thereby achieving efficient separation and recovery of rare earth elements and phosphorus.
  • a rare earth phosphate-containing material comprising at least a first phase structure and a second phase structure, wherein the first phase The structure is an amorphous phase, and the second phase structure comprises a monazite phase or/and a xenotime phase; the rare earth phosphate-containing material is separated from the phosphate rock containing monazite and/or xenotime, and comprises monazite
  • the method for separating the phosphate minerals to obtain the rare earth phosphate-containing material comprises: step S1, leaching the phosphate rock containing monazite and/or xenotime with a solution containing phosphoric acid to obtain rare earth ions, calcium ions and dihydrogen phosphate a root ion leaching solution and a rare earth acid leaching residue; step S2, aging the leaching solution, solid-liquid separation to obtain a rare earth phosphate precipitate and a monocalc
  • the above-mentioned rare earth phosphate-containing material is rich in rare earth with various phase structures, has high rare earth enrichment and high grade, and is convenient for comprehensive recycling of rare earth.
  • the rare earth phosphate ore containing monazite and/or xenotime is leached by using a solution containing phosphoric acid at a relatively low reaction temperature, and the phosphoric acid containing solution is utilized.
  • the hydrogen ion dissolves the phosphorus in the phosphate rock to form a monocalcium phosphate solution, and the rare earth element is also dissolved into the solution to form a leachate containing rare earth ions, Ca 2+ and H 2 PO 4 - ; and the monazite is in the acid leaching process
  • the insoluble in the residue remains in the slag, achieving the separation of phosphorus from monazite.
  • the aging of the leachate is beneficial to the formation of rare earth elements to form a rare earth phosphate precipitate to further separate the rare earth element from the phosphorus element.
  • the reaction temperature has little effect on the leaching of phosphorus in acid leaching process, while the solubility of rare earth phosphate is relatively large at lower temperature, which is beneficial to the leaching of rare earth elements. At the same time, it can effectively inhibit the impurity elements such as iron and aluminum in phosphate rock. Leaching, so that the leaching rate of iron and aluminum elements ⁇ 5%, greatly reducing the burden of subsequent phosphoric acid purification and removal. Therefore, by controlling the temperature of the aging treatment to be higher than the temperature of the acid leaching step, the rare earth phosphate has a small solubility product at a relatively high temperature, which is advantageous for precipitating the rare earth element in the leaching solution as a rare earth phosphate to further realize the rare earth.
  • the rare earth enrichment multiple is up to several tens of times or even hundreds of times.
  • the rare earth phosphate in the rare earth phosphate precipitation can reach more than 45%, even more than 55%, and the rare earth yield reaches over 80%, even More than 90%, improve the separation efficiency of rare earth, achieve the purpose of low-cost separation of rare earth, and facilitate the subsequent recycling of rare earth elements.
  • the amorphous phase of the rare earth phosphate-containing material containing the above phase structure is a phase structure formed by precipitation of rare earth phosphate, the content of the phase and the formation and content of rare earth in the rare earth phosphate ore, and the control of the rare earth phosphate in the leaching step Conditional.
  • the content of the rare earth phosphate is closely related to the rare earth taste of the obtained rare earth phosphate-containing material, and determines the comprehensive recovery and utilization ratio of the rare earth.
  • the rare earth phosphate-containing material having the above various phase structures has relatively relatively high.
  • the rare earth phosphate-containing material has a content of the amorphous phase in the rare earth phosphate of more than 1% by weight, preferably 5 to 40% by weight. .
  • the content of the amorphous phase is more than 1% by weight, it is advantageous for the recovery of the rare earth in the material containing the rare earth phosphate.
  • the amorphous phase content is 5-40% by weight, the rare earth grade is relatively higher, which is more favorable for the comprehensive recycling of rare earth elements.
  • the rare earth phosphate-containing material has a relatively high rare earth grade when the content of the rare earth phosphate is in the above range, and in order to further improve the utilization value of the substance, another aspect of the present invention
  • the weight ratio of the first phase structure to the second phase structure in the rare earth phosphate-containing material is 1:1-20.
  • the weight ratio of the first phase structure to the second phase structure in the rare earth phosphate-containing material is controlled within the above range, so that the rare earth phosphate-containing material has both of the above phase structures, and thus has a high rare earth grade.
  • the rare earth phosphate-containing material has a high rare earth grade, which facilitates comprehensive recycling of rare earths and has a high rare earth yield.
  • the rare earth phosphate ore since the rare earth phosphate ore is accompanied by iron and/or aluminum minerals, impurities of the above elemental species are inevitably contained in the separation process, and thus impurities containing iron and/or aluminum are also included.
  • the content of this part of impurities is related to the content of iron and/or aluminum associated with rare earth phosphate ore and the control of acid leaching process.
  • the iron-containing and/or aluminum-containing impurities are contained in the rare earth phosphate-containing material in an amount of from 1 to 50% by weight, preferably from 3 to 25% by weight, based on the oxide.
  • the content of impurities containing iron and/or aluminum in the above rare earth phosphate-containing material is controlled within a range of 1 to 50 wt%, and the rare earth content is relatively high, which facilitates recovery of rare earth; enrichment of impurities in the solid phase and reduction of impurity elements Entering the leachate, reducing the burden of subsequent phosphoric acid purification and impurity removal, and the presence of iron and aluminum in the rare earth phosphate-containing material is beneficial to the role of phosphorus fixation in the subsequent rare earth recovery process, thereby contributing to the improvement of the rare earth yield and the realization of iron and aluminum.
  • the material has a high rare earth grade, which facilitates the recovery of rare earths and realizes the comprehensive utilization of impurities iron and aluminum.
  • the rare earth phosphate-containing material of the present invention controls the impurity content within the above range enables the rare earth phosphate-containing material of the present invention to have a higher rare earth grade.
  • the above rare earth-containing phosphate The weight ratio of the rare earth to iron and/or aluminum is 2 to 20:1 in terms of oxide. Controlling the weight ratio of the rare earth to iron and/or aluminum within the above range enables the rare earth phosphate-containing material of the present invention to have a high rare earth content.
  • the purpose of leaching with a solution containing phosphoric acid is to dissolve the phosphorus element and the rare earth element in the rare earth-containing phosphate rock, and to remove the impurity element and the phosphoric acid insoluble matter (the rare earth and/or phosphorus of the monazite phase in the monazite).
  • the rare earth of the xenotime phase in the antimony ore is retained in the slag to form a rare earth-containing acid leach residue. Therefore, any leaching process conditions capable of dissolving as much as possible the soluble rare earth elements in the phosphorus element and the phosphate rock are suitable for the present invention.
  • the phosphate rock containing monazite and/or xenotime is leached with a solution containing phosphoric acid at a temperature of 10 ° C to 60 ° C for 0.5 to 8 hours, preferably 2 to 5 hours.
  • a solution containing phosphoric acid at a temperature of 10 ° C to 60 ° C for 0.5 to 8 hours, preferably 2 to 5 hours.
  • the lower reaction temperature enables the phosphorus element and the soluble rare earth element in the phosphate rock containing monazite and/or xenotime. It is completely dissolved as much as possible, and can effectively inhibit the leaching of impurity elements such as iron and/or aluminum in the phosphate rock, so that the leaching rate of iron element and/or aluminum element is less than 5%, which can greatly reduce the subsequent impurity removal burden. More preferably, the leaching time is from 2 to 5 hours. Selecting the leaching time in this range can completely dissolve the phosphorus element and the soluble rare earth, and shorten the leaching period.
  • the specific time and temperature of the aging treatment can be adjusted according to the type of the rare earth-containing phosphate rock.
  • the leachate is aged at a temperature of 60 ° C to 150 ° C, preferably 80 to 120 ° C for 0.5 to 24 hours, preferably 1 to 8 hours, and solid-liquid separation is carried out to obtain a rare earth phosphate precipitate. And a monocalcium phosphate solution.
  • the rare earth phosphate has a small solubility product at a high temperature, and by using the above-mentioned higher temperature, it is advantageous to precipitate the rare earth ions dissolved in the leachate in the form of rare earth phosphate, thereby further achieving effective separation of the rare earth element and the phosphorus element.
  • the rare earth element in the leachate can be precipitated more thoroughly, thereby more effectively separating the rare earth element and the phosphorus element, and the rare earth phosphate-containing material obtained has a relatively higher rare earth content. Conducive to the recycling of subsequent rare earth elements.
  • the monocalcium phosphate solution here is not a solution composed of calcium ions and dihydrogen phosphate ions, but the main body is a monocalcium phosphate solution containing a trace amount of monohydrogen phosphate, iron or aluminum.
  • a solution of impurity ions is not a solution composed of calcium ions and dihydrogen phosphate ions, but the main body is a monocalcium phosphate solution containing a trace amount of monohydrogen phosphate, iron or aluminum.
  • the phosphoric acid-containing solution includes phosphoric acid, and hydrochloric acid and/or nitric acid may be appropriately added according to actual conditions.
  • the phosphoric acid containing solution further comprises hydrochloric acid and/or nitric acid. Hydrochloric acid or nitric acid in the mixed acid solution facilitates the decomposition of the apatite, thereby increasing the phosphorus leaching rate.
  • hydrochloric acid or nitric acid can provide hydrogen ion H + , which can reduce the content of phosphate under the same acid amount, reduce the viscosity of the system, and facilitate the leaching of phosphorus; at the same time, the presence of chloride ion or nitrate ion is beneficial to improve
  • the solubility of calcium ions in solution is beneficial to the decomposition of apatite.
  • the proportion of hydrochloric acid and/or nitric acid is less than 30% (excluding 0), preferably 2 to 15%, based on the moles of anion.
  • the content of hydrochloric acid or nitric acid used in the present invention is not limited to the above range.
  • the mass concentration of phosphoric acid can be appropriately selected depending on the difference of the phosphate component to be leached containing monazite and/or xenotime.
  • the phosphoric acid-containing solution has a mass concentration of phosphoric acid of 15% to 50%, preferably 15% to 30%, based on P 2 O 5 .
  • the concentration of P 2 O 5 in the phosphoric acid-containing solution used in the present invention is not limited to the above range, and when the concentration of P 2 O 5 is within the above range, a higher acidity is advantageous for decomposition of phosphate rock, thereby improving The yield of phosphorus, but the excessively high phosphoric acid content has problems such as high viscosity and low mass transfer efficiency.
  • the phosphoric acid-containing solution and the phosphate rock can be reasonably proportioned according to the phosphoric acid-containing solution phosphoric acid concentration and the phosphate rock composition, so that phosphorus and rare earth The element is dissolved.
  • the solid solution ratio of the phosphoric acid-containing solution to the phosphate rock containing monazite and/or xenotime is 2 to 10 L: 1 kg, preferably 3 to 6 L: 1 kg.
  • the amount of acid By controlling the amount of acid, it is beneficial to make phosphorus and calcium form soluble monocalcium phosphate Ca(H 2 PO 4 ) 2 into solution under the condition of reducing the amount of acid.
  • the solubility of rare earth phosphate is high under high acidity conditions, which is beneficial to apatite.
  • the rare earth leaching into the solution, the above ratio is favorable for the sufficient dissolution of the phosphorus element and the rare earth element, and is favorable for the subsequent aging treatment, forming the rare earth phosphate precipitation and enriching the rare earth.
  • the insoluble monazite and/or xenotime will remain in the slag. Thereby achieving efficient separation of rare earth elements and phosphorus elements.
  • the mass concentration of phosphoric acid is based on P 2 O 5
  • hydrochloric acid or nitric acid is based on the number of moles of anion.
  • the contents of iron, aluminum, rare earth and other elements were tested by ICP, and the leaching rate and recovery rate of each element were calculated by this method.
  • the phosphorus test was carried out by GBT 1871.1-1995 method, and the calcium test was carried out by GBT 1871.4-1995 method.
  • the rare earth phosphate rock was leached with 1000g of phosphate ore containing 0.05wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 10:1, and the reaction was carried out at 10 °C for 1 hour. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution was aged at 60 ° C for 24 hours, and the rare earth element was precipitated as a rare earth phosphate precipitate. After solid-liquid separation, a monocalcium phosphate solution and 0.71 g of rare earth phosphate precipitate were obtained.
  • the impurity Fe leaching rate in the phosphate rock is 3.5%
  • the impurity Al leaching rate is 2.5%
  • the phosphorus element leaching rate is 95.3%
  • the rare earth phosphate precipitation content is 57.1%
  • the rare earth recovery rate is 81.08%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.2wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 6:1, and the reaction was carried out at 20 ° C for 6 hours. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 60 ° C for 1 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and a 3.30 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in phosphate rock was 4.1%
  • the Al leaching rate was 3.1%
  • the phosphorus leaching rate was 96.8%
  • the rare earth phosphate precipitation was 52.1%
  • the rare earth recovery rate was 85.97%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.2wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 6:1, and the reaction was carried out at 20 ° C for 6 hours. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 80 ° C for 1 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 3.40 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in phosphate rock was 4.1%
  • the Al leaching rate was 3.1%
  • the phosphorus leaching rate was 96.6%
  • the rare earth phosphate precipitation was 53.8%
  • the rare earth recovery rate was 91.46%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.3wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 4:1, and the reaction was carried out at 30 °C for 3 hours. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 100 ° C for 0.5 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution by solid-liquid separation. 4.98 g of rare earth phosphate precipitated.
  • the Fe leaching rate in the phosphate rock was 4.2%
  • the Al leaching rate was 3.2%
  • the phosphorus leaching rate was 96.5%
  • the rare earth phosphate precipitation was 55.3%
  • the rare earth recovery rate was 91.80%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.3wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 4:1, and the reaction was carried out at 30 °C for 3 hours. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 100 ° C for 3 hours, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 5.03 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in the phosphate rock was 4.2%, the Al leaching rate was 3.2%, the phosphorus leaching rate was 96.2%, the rare earth phosphate precipitation was 55.4%, and the rare earth recovery was 92.89%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.5wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 3:1, and the reaction was carried out at 25 ° C for 4 hours. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 4 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 8.10 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in the phosphate rock is 4.5%
  • the Al leaching rate is 3.6%
  • the phosphorus leaching rate is 95.8%
  • the rare earth content in the acid rare earth precipitation was 56.3%
  • the rare earth recovery rate was 91.21%.
  • the rare earth phosphate rock is leached by using a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 30%, wherein the number of moles of anions is The ratio of hydrochloric acid to mixed acid is 2%, the liquid-solid ratio of the control system is 4:1, and the reaction is carried out at 30 ° C for 3 hours. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 30%, wherein the number of moles of anions is The ratio of hydrochloric acid to mixed acid is 2%, the liquid-solid ratio of the control system is 4:1, and the reaction is carried out at 30 ° C for 3 hours. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 3 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 8.23 by solid-liquid separation.
  • the Fe leaching rate in the phosphate rock was 4.7%, the Al leaching rate was 3.8%, the phosphorus leaching rate was 97.1%, the rare earth phosphate precipitation was 56.8%, and the rare earth recovery was 93.49%.
  • the rare earth phosphate rock is leached by using a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 30%, wherein the number of moles of anions is The ratio of nitric acid to mixed acid is 2%, the liquid-solid ratio of the control system is 4:1, and the reaction is carried out at 30 ° C for 3 h. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 30%, wherein the number of moles of anions is The ratio of nitric acid to mixed acid is 2%, the liquid-solid ratio of the control system is 4:1, and the reaction is carried out at 30 ° C for 3 h. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 3 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 8.26 by solid-liquid separation.
  • the Fe leaching rate in the phosphate rock was 4.7%
  • the Al leaching rate was 3.8%
  • the phosphorus leaching rate was 97.3%
  • the rare earth phosphate precipitation was 56.3%
  • the rare earth recovery rate was 93.01%.
  • the rare earth phosphate rock is leached by using a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 30%, wherein the number of moles of anions is The ratio of hydrochloric acid to mixed acid is 15%, the liquid-solid ratio of the control system is 4:1, and the reaction is carried out at 30 ° C for 3 hours. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 30%, wherein the number of moles of anions is The ratio of hydrochloric acid to mixed acid is 15%, the liquid-solid ratio of the control system is 4:1, and the reaction is carried out at 30 ° C for 3 hours. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 3 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 8.38 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in the phosphate rock was 4.9%
  • the Al leaching rate was 4.6%
  • the phosphorus leaching rate was 98.5%
  • the rare earth phosphate precipitation was 56.8%
  • the rare earth recovery rate was 95.20%.
  • the rare earth phosphate rock is leached by using a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 40%, wherein the number of moles of anions is The ratio of hydrochloric acid to mixed acid is 25%, the liquid-solid ratio of the control system is 3:1, and the reaction is carried out at 25 ° C for 4 hours. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • a phosphoric acid solution (calculated as P 2 O 5 ) with a concentration of 40%, wherein the number of moles of anions is The ratio of hydrochloric acid to mixed acid is 25%, the liquid-solid ratio of the control system is 3:1, and the reaction is carried out at 25 ° C for 4 hours. After filtration, a monocalcium phosphate solution containing rare earth and acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 4 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and a solution by solid-liquid separation.
  • the Fe leaching rate in the phosphate rock is 5.0%
  • the Al leaching rate is 5.0%
  • the phosphorus leaching rate is 99.2%
  • the rare earth phosphate precipitation content is 55.9%
  • the rare earth recovery rate is 80.50%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 1wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 2:1, and the reaction was carried out at 60 ° C for 0.5 h. Thereafter, a monocalcium phosphate solution containing a rare earth and an acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 130 ° C for 1 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 16.9 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in phosphate rock was 8.0%
  • the Al leaching rate was 6.0%
  • the phosphorus leaching rate was 95.0%
  • the rare earth phosphate precipitation content was 47.8%
  • the rare earth recovery rate was 80.78%.
  • 1000 g of phosphate ore with a rare earth content of 7.4 wt% is used as a raw material, wherein the monazite content is 9.5 wt%, and the rare earth phosphate rock is leached by a phosphoric acid solution having a mass concentration of 20%, and the liquid-solid ratio of the control system is 6:1.
  • the reaction was carried out at 25 ° C for 2 h, and after filtration, a monocalcium phosphate solution containing rare earth and 205.0 g of acid leaching residue were obtained.
  • the rare earth phosphate-containing calcium phosphate solution was aged at 100 ° C for 1 h, and the rare earth element was precipitated by rare earth phosphate precipitation, and solid-liquid separation was carried out to obtain a monocalcium phosphate solution and a 15.8 g rare earth phosphate precipitate.
  • the impurity Fe leaching rate in the phosphate rock was 3.3%
  • the impurity Al leaching rate was 3.0%
  • the phosphorus element leaching rate was 96.5%
  • the rare earth phosphate precipitation in the rare earth content was 54.8%
  • the rare earth recovery rate was 97.80%.
  • phosphate rock containing 7.4 wt% of rare earth as raw material wherein the monazite content is 9.5 wt%, and a rare earth phosphate rock is mixed with a hydrochloric acid solution (as P 2 O 5 ) and a hydrochloric acid having a mass concentration of 15%.
  • the leaching is carried out, wherein the ratio of hydrochloric acid to the mixed acid is 10% by mole of the anion, the liquid-solid ratio of the control system is 10:1, and the reaction is carried out at 20 ° C for 8 hours, and after filtration, a monocalcium phosphate solution containing rare earth and 178.0 g are obtained. Acid leaching residue.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 70 ° C for 8 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 16.5 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in the phosphate rock was 4.4%
  • the Al leaching rate was 4.2%
  • the phosphorus leaching rate was 98.2%
  • the rare earth phosphate precipitation was 52.8%
  • the rare earth recovery was 98.10%.
  • phosphate rock containing 7.4 wt% of rare earth as raw material wherein the monazite content is 9.5 wt%, and a rare earth phosphate rock is mixed with a hydrochloric acid solution (as P 2 O 5 ) and a hydrochloric acid having a mass concentration of 15%.
  • the leaching is carried out, wherein the ratio of hydrochloric acid to the mixed acid is 25% by mole of the anion, the liquid-solid ratio of the control system is 8:1, and the reaction is carried out at 20 ° C for 8 hours, and after filtration, a monocalcium phosphate solution containing rare earth and 154.0 g are obtained. Acid leaching residue.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 70 ° C for 12 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 17.3 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in the phosphate rock was 5.0%
  • the Al leaching rate was 5.0%
  • the phosphorus leaching rate was 98.9%
  • the rare earth phosphate precipitation was 52.5%
  • the rare earth recovery rate was 97.75%.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 150 ° C for 0.5 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution by solid-liquid separation. 17.5 g of rare earth phosphate was precipitated.
  • the Fe leaching rate in the phosphate rock was 4.8%
  • the Al leaching rate was 4.5%
  • the phosphorus leaching rate was 98.6%
  • the rare earth phosphate precipitation was 53.5%
  • the rare earth recovery rate was 98.50%.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 90 ° C for 2 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 16.7 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the Fe leaching rate in the phosphate rock was 3.8%
  • the Al leaching rate was 2.9%
  • the phosphorus leaching rate was 98.4%
  • the rare earth phosphate precipitation was 55.7%
  • the rare earth recovery rate was 98.30%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.3wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 6:1, and the reaction was carried out at 30 °C for 4 hours. Thereafter, a solution containing rare earth and acid leaching slag are obtained.
  • the rare earth-containing solution was aged at 120 ° C for 3 h, and the rare earth element was precipitated as a rare earth phosphate precipitate, and solid-liquid separation was carried out to obtain 0.5 g of a rare earth phosphate precipitate.
  • the impurity Fe leaching rate in phosphate rock is 68%
  • the impurity Al leaching rate is 56%
  • the phosphorus element leaching rate is 99.5%
  • the rare earth phosphate precipitation content is 46.3%
  • the rare earth recovery rate is 7.72%.
  • the rare earth phosphate rock was leached with 1000g of phosphate rock containing 0.3wt% rare earth content as raw material, and the liquid-solid ratio of the control system was 4:1, and the reaction was carried out at 100 °C for 3 hours. Thereafter, a monocalcium phosphate solution and 65.8 g of acid leaching residue were obtained.
  • the impurity Fe leaching rate in phosphate rock was 54.2%
  • the impurity Al leaching rate was 43.7%
  • the phosphorus element leaching rate was 96.7%
  • the rare earth recovery rate was 96.7%.
  • the low temperature can effectively inhibit the leaching of iron, aluminum and other impurity elements in the phosphate rock, so that the leaching rate of iron and aluminum elements is less than 5%, which greatly reduces the subsequent purification of phosphoric acid.
  • the impurity burden increases the rare earth grade of the rare earth phosphate precipitate obtained in the subsequent aging process.
  • hydrochloric acid or nitric acid in the mixed acid solution is beneficial to the decomposition of the apatite, thereby increasing the leaching rate of phosphorus and rare earth in the apatite.
  • the rare earth-containing monocalcium phosphate solution is beneficial to the rare earth element contained in the solution to form a rare earth phosphate precipitate, thereby realizing the separation of the rare earth element and the phosphorus element.
  • the yield of the rare earth and the rare earth grade are improved, and the rare earth phosphate has a small solubility product at a high temperature, which is favorable for the rare earth element in the leaching solution to precipitate as a rare earth phosphate. Thereby achieving effective separation of rare earth elements and phosphorus elements.
  • Example 13 Further, the inventors further mixed the acid leaching slag and the rare earth phosphate precipitate in Example 13 to obtain a rare earth mixed slag, and 15 g of the rare earth element was recovered.
  • the specific recovery steps are shown in the following Examples 17 to 23.
  • the mixture is calcined at 200 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid is adjusted to 4.0 by using magnesium oxide, and the rare earth sulfate solution and the filter residue are obtained by filtration, and the filter residue contains iron phosphate and barium phosphate precipitate;
  • the rare earth sulfate solution is oxide, and the content of Fe is 0.02 g. / L, P content is 0.005g / L, Th content ⁇ 0.05mg / L;
  • the rare earth sulfate solution is extracted and separated by an acidic phosphorus extracting agent to obtain a mixed rare earth chloride compound or a single rare earth compound; wherein the rare earth yield is 92.5%.
  • the mixture is calcined at 250 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid is adjusted to 4.0 by using magnesium oxide, and the rare earth sulfate solution and the filter residue are obtained by filtration, and the filter residue contains iron phosphate and barium phosphate precipitate;
  • the rare earth sulfate solution has an oxide content of 0.03 g. / L, P content is 0.004g / L, Th content ⁇ 0.05mg / L;
  • the rare earth carbonate product was obtained by adding a carbonate to the rare earth sulfate solution to obtain a rare earth carbonate product, and the recovery rate of the rare earth in the whole process was 94.1%.
  • the mixture is calcined at 500 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid is adjusted to 4.0 by using magnesium oxide, and the rare earth sulfate solution and the filter residue are obtained by filtration, and the filter residue contains iron phosphate and barium phosphate precipitate;
  • the rare earth sulfate solution is oxide, and the content of Fe is 0.05 g. / L, P content is 0.004g / L, Th content ⁇ 0.04mg / L;
  • the rare earth sulfate solution is extracted and separated by an acidic phosphorus extractant to obtain a mixed rare earth compound or a single rare earth compound; wherein the rare earth yield is 95.8%.
  • the mixture is calcined at 350 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid is adjusted to 4.5 by using magnesium oxide, and the rare earth sulfate solution and the filter residue are obtained by filtration, and the residue is contained in the filter residue.
  • the rare earth yield in the rare earth sulfate solution was 94.2%.
  • the mixture is calcined at 350 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid is adjusted to 4.5 by light burning dolomite, and the rare earth sulfate solution and the filter residue are obtained by filtration, and the precipitated residue contains iron phosphate and barium phosphate precipitate; the rare earth sulfate solution is determined by the oxide, and the content of Fe is 0.01. g/L, P content is 0.007g / L, Th content ⁇ 0.04mg / L;
  • the rare earth yield in the rare earth sulfate solution was 97.3%.
  • the mixture is calcined at 400 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid was adjusted to 3.8 with magnesium hydroxide, and the rare earth sulfate solution and the filter residue were obtained by filtration, and the precipitated residue contained iron phosphate and strontium phosphate precipitate; the rare earth sulfate solution was determined by the oxide, and the content of Fe was 0.04 g. / L, P content is 0.002g / L, Th content ⁇ 0.05mg / L;
  • the rare earth yield in the rare earth sulfate solution was 97.5%.
  • the mixture is calcined at 450 ° C to obtain a calcined product
  • the pH value of the rare earth-containing aqueous immersion liquid is adjusted to 3.8 with magnesium hydroxide, and the rare earth sulfate solution and the filter residue are obtained by filtration, and the residue is filtered.
  • the content of Fe is 0.04 g / L
  • the content of P is 0.002 g / L
  • the content of Th is ⁇ 0.05 mg / L;
  • the rare earth yield in the rare earth sulfate solution was 96.1%.
  • the monazite-containing rare earth phosphate rock was leached with a phosphoric acid solution having a monolithic content of 23 g% and a total rare earth content of 16.4% by weight as a raw material, using a phosphoric acid solution (as P 2 O 5 ) having a mass concentration of 15%.
  • the liquid-solid ratio of the control system is 10:1, and the reaction is carried out at 10 ° C for 8 hours. After filtration, a monocalcium phosphate solution containing rare earth and 330 g of rare earth acid leaching residue are obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 60 ° C for 24 hours, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and a solid solution by solid-liquid separation.
  • g phosphoric acid rare earth precipitation is obtained.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the content of the amorphous phase in the rare earth phosphate-containing material is 4.27 wt%
  • the impurity content of iron and aluminum in terms of oxide
  • the weight ratio of the first phase structure to the second phase structure is 0.045.
  • the weight ratio of rare earth to iron and aluminum impurities was 5.04 in terms of oxide.
  • the concentration of phosphoric acid in the mixed acid is 50% (based on the P 2 O 5 content), using 1000 g of a rock with a monazite content of 15 wt% and a total rare earth content of 11.1 wt% as a raw material, using a mixed acid solution of phosphoric acid and hydrochloric acid.
  • the ratio of hydrochloric acid to the mixed acid solution is 2%, the liquid-solid ratio of the control system is 2:1, and the reaction is carried out at 60 ° C for 0.5 h. After filtration, a monocalcium phosphate solution containing rare earth and 267 g of acid are obtained. Leaching.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 150 ° C for 0.5 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution by solid-liquid separation. 18.9 g of rare earth phosphate precipitated.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the content of iron and aluminum impurities (in terms of oxide) is 1.9 wt%
  • the content of amorphous phase is 8.82 wt%
  • the weight ratio of the first phase structure to the second phase structure is 0.097.
  • the weight ratio of rare earth to iron and aluminum impurities was 19.73 in terms of oxide.
  • the rare earth phosphate-containing calcium phosphate solution was aged at 80 ° C for 8 h, and the rare earth element was separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 15.6 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the X-ray diffraction spectrum of the rare earth phosphate-containing material of this example was examined as shown in FIG. It can be calculated from Fig. 3 that the rare earth phosphate-containing substance has an iron and aluminum impurity content (in terms of oxide) of 5.2% by weight and an amorphous phase content of 10.92% by weight; the first phase structure and the second phase The phase structure weight ratio was 0.123. The weight ratio of rare earth to iron and aluminum impurities was 6.23 in terms of oxide.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 100 ° C for 1 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 21.7 by solid-liquid separation.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the rare earth phosphate-containing material was found to have an iron and aluminum impurity content (as an oxide) of 23 wt% and an amorphous phase content of 5.66 wt%; a first phase structure to a second phase structure weight ratio of 0.060.
  • the weight ratio of rare earth to iron and aluminum impurities was 2.10 in terms of oxide.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 75 ° C for 2 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 19.3 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the rare earth phosphate-containing material was found to have an iron and aluminum impurity content (in terms of oxide) of 23% by weight, an amorphous phase content of 4.07% by weight, and a first phase structure to second phase structure weight ratio of 0.042.
  • the mass concentration of phosphoric acid in the mixed acid is 25% (with P 2 O 5 content meter), in terms of the number of moles of anion, hydrochloric acid in the mixed acid solution ratio of 10% (based on the number of moles of anion), control system liquid-solid ratio of 3:1, reaction at 15 ° C for 2h, after filtration A monocalcium phosphate solution containing rare earth and 143 g of acid leaching residue were obtained.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 2 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 18.6 by solid-liquid separation. g phosphoric acid rare earth precipitation.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the content of iron and aluminum impurities (calculated as oxide) is 5.8 wt%, and the content of amorphous phase is 28.66 wt%; the weight ratio of the first phase structure to the second phase structure is 0.402. .
  • the weight ratio of rare earth to iron and aluminum impurities was 3.46 based on the oxide.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 120 ° C for 2 h, and the rare earth element is separated from the monocalcium phosphate solution by precipitation of rare earth phosphate, thereby obtaining a monocalcium phosphate solution and 22.5 by solid-liquid separation.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the content of iron and aluminum impurities (in terms of oxide) is 5.6 wt%, and the content of amorphous phase is 49.56 wt%; the weight ratio of the first phase structure to the second phase structure is 0.983. .
  • the weight ratio of rare earth to iron and aluminum impurities was 2.77 based on the oxide.
  • the content of iron and aluminum impurities (in terms of oxide) in the rare earth-containing phosphoric acid slag was 31% by weight, and the content of the amorphous phase was 3.6% by weight; the weight ratio of the first phase structure to the second phase structure was 0.037.
  • the weight ratio of rare earth to iron and aluminum impurities was 2.20 in terms of oxide.
  • the rare earth phosphate-containing calcium phosphate solution is aged at 55 ° C for 2 h to precipitate the rare earth element with rare earth phosphate.
  • the form is separated from the monocalcium phosphate solution, and thus solid-liquid separation is carried out to obtain a monocalcium phosphate solution and a precipitate of 2.4 g of rare earth phosphate.
  • the rare earth acid leaching residue is mixed with the rare earth phosphate precipitate to obtain a rare earth phosphate-containing substance.
  • the content of iron and aluminum impurities (in terms of oxide) is 1.3 wt%, and the content of amorphous phase is 3.7 wt%; the weight ratio of the first phase structure to the second phase structure is 0.038. .
  • the weight ratio of rare earth to iron and aluminum impurities was 19.90 in terms of oxide.
  • the content of the amorphous phase in the rare earth phosphate is 5-40% by weight, which is more favorable for subsequent Recovery of rare earth in the rare earth phosphate-containing material; controlling the content of impurities containing iron and/or aluminum in the above rare earth phosphate-containing material in the range of 3 to 25 wt%, having a relatively high rare earth content, and facilitating rare earth recovery,
  • the impurities are enriched in the solid phase, reducing the entry of impurity elements into the leachate, reducing the burden of subsequent phosphoric acid purification and removal, and the presence of iron and aluminum in the rare earth phosphate-containing material is beneficial to the role of fixing phosphorus in the subsequent rare earth recovery process. In turn, it is beneficial to increase the yield of rare earth and realize the comprehensive utilization of iron and aluminum.
  • the rare earth element therein can be further recycled, and the specific recycling step is shown in FIG. Adding iron-containing substances to the rare earth phosphate-containing material or simultaneously adding calcium and magnesium-containing substances, and adding concentrated sulfuric acid having a mass concentration of more than 90% for acidification roasting, and then leaching the calcined product with water to obtain a rare earth water immersion liquid and Water leaching slag; adjusting the pH value of the rare earth-containing water immersion liquid to 3.8 to 5, filtering to obtain a rare earth sulfate solution and a filter residue containing iron element, phosphorus element and strontium element; using an acidic phosphorus type extracting agent to the rare earth sulphate solution finally Using extraction separation to obtain mixed or single rare earth chloride; or, adding rare earth carbonate or oxalate to precipitate rare earth to obtain rare earth carbonate or rare earth oxalate; further to rare earth carbonate or rare earth The oxalate is calc
  • the monocalcium phosphate solution obtained in the above Examples 24-32 is treated with sulfuric acid to obtain calcium sulfate and a phosphorus-containing solution, and the calcium sulfate can be used to prepare a commercially available gypsum product, and the phosphorus-containing solution can be purified to remove impurities to obtain a phosphoric acid solution. It is used in the acid leaching step of phosphate rock to realize the recycling of materials.
  • the above-mentioned embodiments of the present application achieve the following technical effects: leaching rare earth phosphate ore by using a solution containing phosphoric acid, and utilizing hydrogen ions in the phosphoric acid-containing solution to dissolve phosphorus in the phosphate rock At the same time, the monocalcium phosphate dissolves the rare earth element into the solution to form a leaching solution containing rare earth ions, Ca 2+ and H 2 PO 4 - , and further aging the leaching solution, which is favorable for forming rare earth ions in the leaching solution to form rare earth phosphate Precipitation separates the rare earth element from the phosphorus element.
  • the temperature of the controlled aging treatment is higher than the temperature of the acid leaching step, and the leaching of iron, aluminum and other impurity elements in the rare earth phosphate rock can be effectively suppressed at a low temperature, so that the leaching rate of iron and aluminum elements is less than 5%, which greatly reduces the subsequent
  • the impurity removal capacity of the rare earth phosphate at a high temperature is favorable for the rare earth element dissolved in the leachate to be precipitated as a rare earth phosphate, thereby further realizing the effective separation of the rare earth element and the phosphorus element.
  • the monazite When the monazite is contained in the rare earth phosphate ore, the monazite does not dissolve in the acid leaching process and remains in the slag, thereby achieving separation of the rare earth element and the phosphorus element. Then, the rare earth phosphate precipitate is mixed with the rare earth-containing leaching residue produced by the acid leaching process to form a rare earth mixed slag.
  • the above separation method improves the separation efficiency of the rare earth, makes the rare earth phosphate precipitation and the rare earth content in the rare earth mixed slag high, and achieves the purpose of separating rare earth at a low cost, and is convenient for further recycling of the rare earth element.

Abstract

一种从含稀土磷矿中回收磷和稀土的方法及含稀土磷酸盐的物质。方法包括：步骤S1，用含磷酸的溶液对稀土磷矿进行浸出，得到酸浸渣以及浸出液；步骤S2，将浸出液进行陈化处理得到磷酸稀土沉淀；步骤S2的反应温度高于步骤S1的反应温度。采用含磷酸的溶液在相对较低的反应温度下对稀土磷矿进行酸浸，然后在较高温度下对浸出液进行陈化处理，使稀土离子形成磷酸稀土沉淀，实现稀土与磷的高效分离回收。

Description

从含稀土磷矿中回收磷和稀土的方法及含稀土磷酸盐的物质 技术领域
本发明涉及稀土回收领域，具体而言，涉及一种从含稀土磷矿中回收磷和稀土的方法及含稀土磷酸盐的物质。
背景技术
稀土矿物在自然界中常与重晶石、方解石、磷灰石、硅酸盐矿石等矿物共生在一起。由于矿物的成矿原因不同，稀土元素在矿物中的赋存状态和含量也不同。当前所开采的稀土矿物中，稀土氧化物的品位一般为百分之几。为了满足稀土冶金生产的需要，在冶炼之前须先经选矿方法，将稀土与其他矿石分离，使稀土矿物得到富集。经选矿富集后的稀土精矿中稀土氧化物的含量通常为50％～70％。
稀土矿物主要有氟碳铈矿、独居石、磷钇矿和离子吸附型稀土矿等。目前，回收独居石中稀土的方法主要有以下两种方式：(1)碱法分解处理独居石(适用于高品位的独居石矿)，独居石与液碱反应过程中，稀土生成不溶于水的氢氧化物，磷转变为磷酸三钠，稀土氢氧化物再经过盐酸优溶、除杂得到混合氯化稀土。若精矿中铁、硅等杂质含量高，易形成硅酸钠、氢氧化铁等胶态物质，沉淀过滤分离工序难以进行，因此该工艺无法正常运行。(2)浓硫酸焙烧法分解独居石矿，将独居石精矿与浓硫酸混合在200～230℃分解，浓硫酸用量为精矿重量的1.7～2倍，分解物冷却后用7～10倍于精矿重量的水浸取，浸出液中稀土约50g/L(REO)，25g/L P2O5，2.5g/L Fe2O3，酸度为2.5mol/L。该浸液酸度高，杂质磷、钍高，采用硫酸钠复盐沉淀稀土和钍，然后经过碱转为氢氧化物，再采用酸优先浸出稀土，萃取分离稀土、钍。该方法工艺复杂，液固分离步骤多，工艺不连续，稀土回收率低；另外，酸碱交叉使用，化工原料消耗成本高，且磷进入废水处理难度大，放射性元素钍分散在渣和废水中难以有效回收。
磷矿是生产磷化工产品的主要原料，世界磷矿资源储量大，常伴生微量稀土。目前，回收磷矿中稀土的方法包括以下工艺：(1)盐酸、硝酸法处理磷矿的湿法磷酸工艺，95％以上的稀土进入溶液中，再采用溶剂萃取、离子交换、沉淀、结晶等方式回收稀土；(2)硫酸法处理磷矿的湿法磷酸工艺，稀土分别进入溶液和磷石膏中，再采用硫酸浸取磷石膏使稀土进入溶液，溶液中的稀土可采用溶剂萃取、离子交换、沉淀、结晶等方式回收稀土。(3)磷酸处理磷矿工艺，现有技术中通过将含稀土的磷精矿与磷酸溶液混合进行反应，通过控制工艺条件使磷矿中稀土以氟化物形式沉淀，85％以上稀土进入渣中，再采用盐酸、硝酸或硫酸溶解回收渣中的稀土，但是渣中稀土品位很低，约1％，杂质磷、钙、铝、硅等含量高，而且氟化稀土很难用酸溶解，酸耗高，渣量大，稀土回收率低；另外，进入浸出液中的15％的稀土在除钙过程中易进入石膏渣中难以回收。
含独居石稀土的磷矿是一类比较难处理的矿物，这种含独居石稀土磷矿同时含有多种组分，包括独居石、稀土以及磷矿等。由于独居石与磷矿同属于磷酸盐矿物，两者矿物学性质较为接近，在其共生的矿物中独居石与磷矿嵌布关系密切。回收这种混合矿中稀土元素和磷 元素时，由于混合矿中各物质包裹镶嵌解离难度较大，物理选矿很难实现对矿石的有效分选。特别是，由于分解独居石需要相对苛刻的条件，需要较高的温度及酸碱度等，采用现有技术中的硫酸法湿法处理含有独居石的磷矿时，往往无法使独居石分解完全，未能实现其有效分离利用。
因此，如何有效分离回收稀土磷矿中的磷元素和稀土元素，特别是含独居石稀土磷矿这类品质较低，矿物成分复杂的混合磷矿中的稀土，已成为一个亟待解决的技术问题。
发明内容
本发明的主要目的在于提供一种从含稀土磷矿中回收磷和稀土的方法，以解决现有技术中的稀土磷矿中的磷和稀土元素回收效率低的问题。
为了实现上述目的，根据本发明的一个方面，提供了一种从含稀土磷矿中回收磷和稀土的方法，该方法包括以下：步骤S1，用含磷酸的溶液对稀土磷矿进行浸出，得到浸出液和酸浸渣，浸出液中含有稀土离子、Ca2+和H2PO4 -；以及步骤S2，对浸出液进行陈化处理，得到磷酸稀土沉淀和磷酸一钙溶液；步骤S2的反应温度高于步骤S1的反应温度。
进一步地，步骤S1包括：在10℃～60℃的温度下，用含磷酸的溶液对稀土磷矿浸出0.5～8小时，优选1～4小时，得到浸出液和酸浸渣。
进一步地，步骤S2包括：对浸出液在60℃～150℃，优选为80～120℃的温度下陈化处理0.5～24小时，优选为1～8小时，得到磷酸稀土沉淀和磷酸一钙溶液。
进一步地，当稀土磷矿中不含独居石和/或磷钇矿时，该方法还包括：对磷酸稀土沉淀中的稀土元素进行回收；以及对磷酸一钙溶液中的磷元素进行回收。
进一步地，当稀土磷矿含有独居石和/或磷钇矿时，该方法还包括：将酸浸渣与磷酸稀土沉淀混合，得到稀土混合渣，对稀土混合渣中的稀土元素进行回收；以及对磷酸一钙溶液中的磷元素进行回收。
进一步地，对磷酸一钙溶液中的磷元素进行回收的步骤包括：向磷酸一钙溶液中加入质量浓度>90％的浓硫酸，得到固液混合物；对固液混合物进行固液分离，得到第一磷酸溶液和硫酸钙。
进一步地，在对磷酸一钙溶液中的磷元素进行回收的步骤中，在得到第一磷酸溶液后，还包括：将第一磷酸溶液返回步骤S1，对稀土磷矿进行浸出；或者对第一磷酸溶液进行除杂，得到第二磷酸溶液；将第二磷酸溶液返回步骤S1，对稀土磷矿进行浸出。
进一步地，对稀土混合渣中的稀土元素进行回收的步骤包括：步骤A，向稀土混合渣中添加含铁的物质；并加入质量浓度>90％的浓硫酸，得到混合物；步骤B，对混合物进行焙烧，得到焙烧产物；步骤C，对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；步骤D，调节含稀土水浸液的pH值至3.8～5，过滤得到硫酸稀土溶液与滤渣，该滤渣中含铁元素、磷元素和 钍元素；以及步骤E，以硫酸稀土溶液为原料制备稀土化合物；其中，步骤E包括：采用酸性磷类萃取剂对硫酸稀土溶液进行萃取分离，得到混合氯化稀土化合物或单一稀土化合物；或者向硫酸稀土溶液中加入碳酸盐或草酸盐沉淀稀土，获得稀土碳酸盐或稀土草酸盐；并对稀土碳酸盐或稀土草酸盐进行煅烧，得到稀土氧化物。
进一步地，含铁物质为含铁尾矿和/或含铁废渣。
进一步地，含铁的物质中的铁元素与稀土混合渣中的磷元素的质量比为2～4：1，优选为2.5～3.5：1。
进一步地，步骤A包括：将浓硫酸与稀土混合渣的按照质量比为1～2：1的比例进行混合。
进一步地，步骤B中，焙烧的温度为200～500℃,时间为1～8小时，优选250～400℃，时间为2～4小时。
进一步地，步骤D中，采用氧化镁、氢氧化镁和轻烧白云石中的至少一种将含稀土水浸液的pH值调节至4～4.5。
进一步地，含磷酸的溶液中还包含盐酸和/或硝酸。
进一步地，以P2O5计，含磷酸的溶液中磷酸的质量浓度为15％～50％，优选为15％～30％。
进一步地，以阴离子的摩尔数计，含磷酸的溶液中盐酸和/或硝酸所占的比例<30％，优选2-15％。
进一步地，在步骤S1之前，该方法还包括将含磷酸的溶液与稀土磷矿按照液固比为2～10L：1kg的比例混合的步骤，优选液固比为3～6L：1kg。
根据本发明的一个方面，提供了一种含稀土磷酸盐的物质，该含稀土磷酸盐的物质中的稀土磷酸盐至少含有第一相结构和第二相结构，第一相结构为无定形相，第二相结构包括独居石相或/和磷钇矿相；含稀土磷酸盐的物质是从含独居石和/或磷钇矿的磷矿中分离得到，从含独居石和/或磷钇矿的磷矿中分离得到含稀土磷酸盐的物质的方法包括：步骤S1，用含磷酸的溶液对含独居石和/或磷钇矿的磷矿进行浸出，得到浸出液和稀土酸浸渣；浸出液含有稀土离子、钙离子和磷酸二氢根离子；步骤S2，对浸出液进行陈化处理，固液分离得到磷酸稀土沉淀和磷酸一钙溶液；以及步骤S3，将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质；步骤S2的反应温度高于步骤S1的反应温度。
进一步地，以重量含量计，无定形相在稀土磷酸盐中的含量大于1％，优选为5～40％。
进一步地，含稀土磷酸盐的物质中第一相结构与第二相结构的重量比为1：1～20。
进一步地，含稀土磷酸盐的物质中还包括含铁和/或铝的杂质，以氧化物计，铁和/或铝含量为1～50wt％，优选为3～25wt％。
进一步地，在含稀土磷酸盐的物质中，以氧化物计，稀土与铁和/或铝的重量比为2～20：1。
进一步地，步骤S1包括：在10℃～60℃的温度下，用含磷酸的溶液对含独居石和/或磷钇矿的磷矿浸出0.5～8小时，优选1～4小时，得到浸出液和稀土酸浸渣。
进一步地，步骤S2包括：对第一溶液在60℃～150℃，优选为80～120℃的温度下陈化处理0.5～24小时，优选为1～8小时，固液分离得到磷酸稀土沉淀和磷酸一钙溶液。
进一步地，含磷酸的溶液中还包含盐酸和/或硝酸；优选地，以阴离子的摩尔数计，含磷酸的溶液中盐酸和/或硝酸所占的比例小于30％，更优选为2～15％。
进一步地，以P2O5计，含磷酸的溶液中磷酸的质量浓度为15％～50％，优选为15％～30％。
进一步地，在步骤S1之前，方法还包括将含磷酸的溶液与含独居石和/或磷钇矿的磷矿按照液固比为2～10L：1kg的比例混合的步骤，优选液固比为3～6L：1kg。
应用本发明的技术方案，通过在相对较低的反应温度下，采用含磷酸的溶液浸出稀土磷矿，利用含磷酸溶液中的氢离子溶解磷矿中的磷形成磷酸一钙溶液，同时稀土元素也被溶解，进入溶液中形成含有稀土离子、Ca2+和H2PO4 -的浸出液；进一步对浸出液进行陈化处理，有利于将稀土元素形成磷酸稀土沉淀而实现稀土元素与磷元素的分离。反应温度对酸浸过程中磷元素的浸出影响较小，而在较低温度下磷酸稀土溶解度相对较大，有利于稀土元素的浸出，同时低温下能有效抑制磷矿中铁、铝等杂质元素的浸出，使得铁元素和铝元素的浸出率<5％，大大减轻了后续磷酸净化除杂负担。并且，通过控制陈化处理的温度高于酸浸步骤的温度，在相对较高的温度下磷酸稀土溶度积小，有利于使浸出液中的稀土元素以稀土磷酸盐形式沉淀下来，进一步实现稀土元素与磷元素的有效分离。从含稀土的磷矿到磷酸稀土沉淀，稀土富集倍数高达几十倍甚至上百倍，磷酸稀土沉淀中稀土品位可达45％以上，甚至达到55％以上，稀土收率达到80％以上，甚至达到90％以上，提高稀土分离效率，实现了低成本分离稀土的目的，便于后续对稀土元素进一步回收利用。当含稀土的磷矿中含有独居石时，在酸浸过程中独居石不溶解而保留在渣中，同样实现稀土元素与磷元素的分离。可将磷酸稀土沉淀与酸浸过程产生的含酸浸渣混合，形成稀土混合渣，且稀土混合渣稀土含量高，同样便于后续对稀土元素进一步回收利用。
附图说明
构成本申请的一部分的说明书附图用来提供对本发明的进一步理解，本发明的示意性实施例及其说明用于解释本发明，并不构成对本发明的不当限定。在附图中：
图1示出了根据本发明的一种典型的实施例中从含稀土磷矿中回收磷和稀土的方法流程示意图；
图2示出了根据本发明的另一种典型的实施例中当含稀土的磷矿中还含有独居石时，从含稀土磷矿中回收磷和稀土的方法流程示意图；以及
图3示出了根据本发明的实施例26获得的含稀土磷酸盐的物质的X射线衍射谱图。
具体实施方式
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。下面将结合实施例来详细说明本发明。
在以下描述中，独居石(英文名为Monazite)的分子式为(Ln，Th)PO4，式中Ln是指除钷以外的稀土元素中的至少一种。
浸出液是指溶液中除含有磷酸一钙外，还含有稀土、磷酸、磷酸一氢盐、磷酸二氢盐、或铁、铝等杂质的溶液。
浸出液品位，指矿石中有用元素或其化合物的含量比率。含量愈大，品位愈高。
正如背景技术所指出的，稀土磷矿如含有磷灰石和独居石等多种矿物的混合矿在采用现有的分离方法进行处理，难以有效分离这类混合矿中稀土元素和磷元素。为了改善现有技术中的上述缺陷，在本发明的一种典型的实施方式中，提供了一种从含稀土磷矿中回收磷和稀土的方法，该方法包括以下步骤：步骤S1，用含磷酸的溶液对稀土磷矿进行浸出，得到浸出液和酸浸渣，浸出液中含有稀土离子、Ca2+和H2PO4 -；以及步骤S2，对浸出液进行陈化处理，得到磷酸稀土沉淀和磷酸一钙溶液；其中步骤S2的反应温度高于步骤S1的反应温度。
上述方法在相对较低的反应温度下，通过采用含磷酸的溶液浸出稀土磷矿，利用含磷酸溶液中的氢离子溶解磷矿中的磷形成磷酸一钙溶液，同时酸浸过程中稀土元素也被溶解，以离子的形式进入溶液中，形成浸出液；进一步对浸出液进行陈化处理，有利于将溶液中含有的稀土元素形成磷酸稀土沉淀，从而实现稀土元素与磷元素的分离。反应温度对酸浸过程中磷元素的浸出影响较小，而在相对低温下磷酸稀土溶解度较大，有利于稀土的浸出，同时低温能有效抑制磷矿中铁、铝等杂质元素的浸出，使得铁元素和铝元素的浸出率<5％，大大减轻了后续磷酸净化除杂负担。并且，通过控制陈化处理的温度高于酸浸步骤的温度，在高温下磷酸稀土溶度积小，有利于使浸出液中的稀土元素以稀土磷酸盐的形式沉淀下来，从而实现稀土元素与磷元素的进一步有效分离。
上述分离方法中，从稀土磷矿到磷酸稀土沉淀，稀土富集倍数高达几十倍甚至上百倍，磷酸稀土沉淀中稀土品位可达45％以上，甚至达到55％以上；而稀土收率达到80％以上，甚至达到90％以上，大大提高了稀土分离效率，实现了低成本分离稀土的目的，便于后续对稀土元素进一步回收利用。
上述步骤S1中，用含磷酸的溶液浸出的目的是将稀土磷矿中磷元素与稀土元素溶出，而铁和铝等杂质元素留在渣中形成酸浸渣。因而，任何能够使磷元素与稀土元素尽可能地溶出而铁和铝等杂质元素尽可能保留在酸浸渣中的浸出工艺条件均适合于本发明。在本发明的一种优选实施方式中，在10℃～60℃的温度下，用含磷酸的溶液对稀土磷矿持续浸出0.5～8小时，优选1～4小时，得到浸出液和酸浸渣。酸浸渣可选择性返回进入磷元素回收工序，以进一步浸出回收残留的磷元素。
上述采用含磷酸的溶液浸出步骤中，通过控制反应温度在10℃～60℃范围内，反应温度对稀土磷矿中磷元素溶出影响较小，而该温度下磷酸稀土溶解度相对较大，有利于稀土的浸出，且上述低温下能有效抑制稀土磷矿中铁和铝等杂质元素的浸出，使得铁元素和铝元素的浸出率<5％，大大减轻了后续的除杂负担。更优选地，浸出时间为2～5小时。选择该范围的浸出时间，既能使磷元素与稀土元素溶出完全，又能缩短浸出周期。
上述陈化处理的步骤中，陈化处理的具体时间和温度可以根据稀土磷矿种类的不同进行调整。在本发明一种优选实施例中，在60℃～150℃，优选为80～120℃的温度下对浸出液陈化处理0.5～24小时，优选为1～8小时，经固液分离得到磷酸稀土沉淀和第二溶液。在高温下磷酸稀土溶度积小，通过采用上述较高的温度，有利于使浸出液中的稀土元素以稀土磷酸盐形式沉淀下来，从而实现稀土元素与磷元素的有效分离。随着陈化时间增加，结晶逐渐长大，且无定型状沉淀逐渐向晶型沉淀转化。在上述陈化时间范围内，能够使得浸出液中的稀土元素沉淀得较为彻底，从而更有效实现稀土元素与磷元素的分离。
上述步骤S2将稀土元素以磷酸稀土沉淀的形式分离后得到磷酸一钙溶液，主要成分是钙离子和磷酸二氢根离子，此外，还含有少量的磷酸一氢根离子、铁或铝等杂质离子。
上述分离方法能够有效地分离得到磷酸稀土沉淀和除去稀土离子的浸出液，从稀土磷矿到磷酸稀土沉淀，稀土富集倍数高达几十倍甚至上百倍，磷酸稀土沉淀中稀土品位可达45％以上，甚至达到55％以上，稀土收率达到80％以上，甚至达到90％以上，提高稀土分离效率，实现了低成本分离稀土的目的，便于后续对稀土元素进一步回收利用。在本发明一种优选的实施例中，当稀土磷矿中不含独居石和/或磷钇矿时，上述方法还包括：对磷酸稀土沉淀中的稀土元素进行回收；以及对磷酸一钙溶液中的磷元素进行回收。回收稀土元素的步骤采用酸溶、碱转-酸溶、硫酸焙烧-水浸中任一种方式进行处理，再进行沉淀富集或萃取分离提纯即可。在上述分离效率较高的基础上，稀土元素和磷元素的回收率也相对较高。
本发明的上述分离方法所能够分离的稀土磷矿包括但不仅限于含稀土的磷灰石矿、磷块岩或者含稀土的胶磷矿。而在本发明的一种优选实施例中，上述分离方法中所分离的稀土磷矿为含有独居石和/或磷钇矿的稀土磷矿。如图2所示，当上述稀土磷矿中含有独居石和/或磷钇矿时，采用上述分离方法进行分离，独居石和/或磷钇矿在酸浸过程中不溶解而保留在渣中，同样能够实现稀土元素与磷元素的分离。然后，将磷酸稀土沉淀与酸浸过程产生的酸浸渣混合，形成稀土混合渣。上述将两步分离汇总得到的稀土混合渣中稀土含量高(以稀土混合渣计，上述稀土磷矿的稀土收率能够达到大于90％，Fe和Al的浸出率也分别能够小于10％；甚至在有些更优选的实施例中，稀土磷矿的稀土收率大于97％，Fe和Al的浸出率分别小于5％)，提高稀土分离效率，实现了低成本分离稀土的目的，便于后续对稀土元素进一步回收利用。
上述含独居石和/或磷钇矿的稀土磷矿是一类比较难处理的矿物。以独居石为例，由于独居石与磷矿同属于磷酸盐矿物，两者矿物学性质较为接近，在其共生的矿物中独居石与磷矿嵌布关系密切。回收这种混合矿中稀土元素和磷元素时，由于混合矿中各物质包裹镶嵌解离难度较大，物理选矿很难实现对矿石的有效分选。特别是，由于分解独居石需要相对苛刻的条件，需要较高的温度及酸碱度等，采用现有技术中的硫酸法湿法处理含有独居石的磷矿时， 往往无法使独居石分解完全，未能实现其有效分离利用。本发明利用酸浸过程中独居石不溶解，进入渣中富集，实现了磷与独居石的分离。通过陈化处理将进入溶液中的稀土以磷酸稀土沉淀析出，与酸浸过程不溶解的独居石形成稀土混合渣后共同回收稀土，从而简化了回收步骤，提高了稀土回收率，实现了低成本综合回收稀土的目的。
在得到具有上述高品位的稀土混合渣及纯度较高的磷酸一钙溶液之后，本领域技术人员可根据实际需要决定是否进一步对上述稀土混合渣中的稀土元素以及磷酸一钙溶液中的磷元素分别进行回收，并能够有针对性地选择合适的回收方法。在本发明一种优选实施例中，如图2所示，上述方法在得到上述稀土混合渣和磷酸一钙溶液后，还包括：对稀土混合渣中的稀土元素进行回收；以及对磷酸一钙溶液中的磷元素进行回收，以充分利用稀土磷矿中的稀土和磷。
上述对稀土混合渣中的稀土元素进行回收的具体回收工艺可以根据对稀土元素利用方式的不同进行合理选择。在本发明的一种优选实施例中，如图2所示，上述回收稀土混合渣中稀土的步骤包括：步骤A，向稀土混合渣中添加含铁的物质(或者同时加入含镁和/或钙的物质)，并加入质量浓度>90％的浓硫酸，得到混合物；步骤B，对混合物进行焙烧，得到焙烧产物；步骤C，对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；步骤D，调节含稀土水浸液的pH值至3.8～5，过滤得到硫酸稀土溶液与滤渣，该滤渣中含铁元素、磷元素和钍元素；以及步骤E，利用硫酸稀土溶液制备稀土化合物；其中，步骤E包括：采用酸性磷类萃取剂对硫酸稀土溶液进行萃取分离，得到混合氯化稀土化合物或单一稀土化合物；或者，向硫酸稀土溶液中加入碳酸盐或草酸盐沉淀稀土，获得稀土碳酸盐或稀土草酸盐；并对稀土碳酸盐或稀土草酸盐经过煅烧，得到稀土氧化物。
上述优选实施例将稀土磷矿中的稀土保留在稀土混合渣中，使稀土混合渣中稀土品位提高，大幅度减少后续处理的工作量。通过采用独特的加铁固磷，将磷固化在渣中，避免稀土的损失。若同时加镁和/或钙，能够固氟，消除磷和氟的干扰，从而有效避免后续加水浸出过程中稀土形成磷酸稀土沉淀或氟化稀土沉淀而造成损失。同时，也避免了焙烧过程中氟元素以氟化氢气体的形式逸出而污染环境。该稀土元素的回收方法酸碱消耗少，稀土回收率可达90％以上；同时将钍元素转化为焦磷酸钍固化在渣中，避免放射性钍元素在工艺流程中的分散污染。
上述在对稀土混合渣中的稀土元素进行回收的过程中，所添加的含镁和/或钙的物质的目的是为了将混合渣中的氟元素仍固定在渣中，而使稀土元素便于分离出来，因而任何能够使氟元素保留在渣中，而使稀土元素分离出来的含镁和/或钙的物质均适用于本发明。在本发明一种优选的实施例中，上述含镁和/或钙的物质为含镁和/或钙的氧化物、含镁和/或钙的碳酸盐以及含镁和/或钙的矿物中的至少一种；更优选地，含镁和/或钙的矿物为白云石和/或菱镁矿；含铁物质为含铁尾矿和/或含铁废渣，优选含有稀土和铁的尾矿。采用上述矿石具有资源丰富的优势，而采用废渣能够节能减排，变废为宝。
优选地，上述添加含镁和/或钙的物质的过程中，含镁和/或钙的物质中的镁和/或钙元素的摩尔数与稀土混合渣中氟元素的摩尔数之比为1～2：2。在本发明中含镁/钙物质与磷酸稀土 渣的混合比例并不限于上述范围，通过将两者按摩尔比为1～2：2混合，有利于在降低含镁/钙物质的投入量的前提下，可将矿中氟在焙烧过程形成氟化镁/钙、氟磷酸镁/钙固体固定在渣中，减缓了氟在焙烧过程中以氟化氢气体逸出污染环境问题，同时避免氟在溶液除杂过程中形成氟化稀土沉淀造成的稀土损失，从而提高了稀土的收率。
在上述混合渣中添加含铁物质的过程中，含铁的物质的添加量可根据稀土混合渣中的磷元素的含量进行适当调整。在本发明一种优选实施例中，含铁的物质中的铁元素与稀土混合渣中的磷元素的质量比为2～4：1，优选2.5～3.5：1。在上述范围内添加含铁稀土尾矿进行处理，不仅提高了稀土收率，且实现了该尾矿中稀土的回收利用，同时大幅降低了运行成本；且在后续在调节pH值为3.8～5除杂过程中，控制Fe/P质量比可有效形成磷酸铁沉淀，除磷效果好，而过量的铁在该pH值条件下可水解形成沉淀，避免了磷酸稀土沉淀的形成，从而避免了稀土的损失。
同样的，在向上述稀土混合渣中加入浓硫酸过程中，浓硫酸的用量可以根据与稀土混合渣的质量进行适当调整。在本发明一种优选实施例中，按照浓硫酸与稀土混合渣的质量比为1～2：1的比例加入浓硫酸，得到混合物。将浓硫酸与稀土混合渣的质量比控制在上述范围内具有有效控制硫酸用量的同时，提高稀土分解浸出的效果。
在上述焙烧混合物的过程中，焙烧温度根据混合物中稀土元素种类及含量的不同可以进行合理选择。在本发明的一种优选实施例中，焙烧混合物的温度为200～500℃，优选250～400℃。在该温度范围内进行焙烧有利于将钍、铁与磷酸形成磷酸盐和/或焦磷酸盐沉淀固化在渣中不被浸出，同时放射性元素钍也固化在渣中，避免放射性钍在工艺流程中的分散污染。
在上述调节含稀土水浸液的pH值的过程中，可以根据稀土水浸液成分及pH值而选择适当物质调节稀土水浸液至合适pH值。在本发明的一种优选实施例中，采用氧化镁和/或轻烧白云石将含稀土水浸液的pH值调节至4～4.5。采用氧化镁和/或轻烧白云石调节含稀土水浸液的pH值，使磷元素尽可能多地形成磷酸铁和磷酸钍沉淀，而稀土不沉淀，从而提高稀土的回收率。
上述对磷酸一钙溶液中的磷元素回收的具体回收工艺可以根据对磷元素利用方式的不同进行合理选择。在本发明的一种优选实施方式中，如图1所示，该回收磷元素的步骤包括：向磷酸一钙溶液中加入质量浓度大于90％的浓硫酸，得到固液混合物；对固液混合物进行固液分离，得到第一磷酸溶液和硫酸钙。上述优选实施例具有将磷酸一钙溶液中的磷元素以含有磷酸的第一磷酸溶液的形式回收，从而实现低价值的强酸制备高价值弱酸的有益效果。
在本发明的一种更优选的实施例中，在对上述磷酸一钙溶液中的磷元素进行回收的步骤中，在得到上述第一磷酸溶液后，还包括：将上述第一磷酸溶液直接返回上述步骤S1中用于对稀土磷矿进行浸出；或者，将上述第一磷酸溶液进行除杂，得到磷酸纯度相对较高的第二磷酸溶液；然后再将第二磷酸溶液返回上述步骤S1用于对稀土磷矿进行浸出，第二磷酸溶液可进一步进行磷肥生产或用于磷酸精制等磷化工生产。在上述方法中，将回收的含杂质或除杂后的磷酸溶液用于稀土磷矿的分解浸取，整个流程衔接合理，不仅实现稀土元素和磷元素的高效分离，而且实现了磷元素的循环利用。在上述除杂的步骤中所除去的杂质元素包括但 不限于铁、硅、铝、钙、镁、钍和铀等元素。具体除杂的步骤根据需要采用现有技术中的常规工艺即可。
在上述含磷酸的溶液浸出稀土磷矿的过程中，含磷酸的溶液中包括磷酸，也可根据实际情况适当加入盐酸和/或硝酸。在本发明的一种优选实施例中，上述含磷酸的溶液还包含盐酸和/或硝酸。混合酸溶液中的盐酸或硝酸有利于磷灰石的分解，从而提高磷灰石中磷与稀土的浸出率。而且盐酸或硝酸可提供氢离子H+，在相同酸量条件下，可降低磷酸根的含量，降低了体系粘度，有利于磷的浸出；同时，氯离子或硝酸根离子的存在，有利于提高钙离子在溶液中的溶解度，有利于磷灰石的分解。在本发明的一种更优选实施例中，以阴离子的摩尔数计，盐酸和/或硝酸所占的比例为0～30％(不包括0)，优选2～15％。本发明中所使用的盐酸或硝酸的含量并不限于上述范围，采用过高含量的盐酸或硝酸将同时增加磷酸稀土在该体系中的溶解度，使稀土在上述陈化处理过程中较难沉淀析出，导致稀土无法富集在磷酸稀土沉淀中，造成稀土收率偏低。
在上述含磷酸的溶液中，磷酸的质量浓度可以根据所浸出稀土磷矿成分的不同进行合理选择。在本发明的一种优选实施例中，上述含磷酸的溶液中，以P2O5计，磷酸的质量浓度为15％～50％，优选为15％～30％。在本发明中所使用含磷酸的溶液中P2O5质量浓度并不限于上述范围，在采用P2O5质量浓度在上述范围内时，较高的酸度有利于磷矿的分解，从而提高磷的收率，但过高的磷酸含量则存在粘度高导致传质效率低等问题。
在上述含磷酸的溶液浸出稀土磷矿过程前，含磷酸的溶液与稀土磷矿可根据含磷酸的溶液中磷酸浓度及稀土磷矿成分不同进行合理配比，以使得稀土磷矿中的磷与稀土元素溶出。本发明的一种优选实施例中，含磷酸的溶液与稀土磷矿混合液固比为2～10L：1kg，优选为3～6L：1kg。通过控制酸用量，有利于在降低酸用量的情况下，使磷元素和钙元素生成可溶性磷酸一钙Ca(H2PO4)2进入溶液，高酸度条件下磷酸稀土的溶解度大，有利于磷灰石中稀土浸出进入溶液，上述范围配比有利于磷元素与稀土元素的充分溶出，有利于后续陈化处理，形成磷酸稀土沉淀富集稀土。当矿中还包括独居石时，难溶解的独居石将留在渣中，从而实现稀土元素和磷元素的有效分离回收。
在本发明另一种典型的实施方式中，还提供了一种一种含稀土磷酸盐的物质，该物质中的稀土磷酸盐至少含有第一相结构和第二相结构，其中，第一相结构为无定形相，第二相结构包括独居石相或/和磷钇矿相；该含稀土磷酸盐的物质是从含独居石和/或磷钇矿的磷矿中分离得到，从含独居石的磷酸盐矿物分离得到含稀土磷酸盐的物质的方法包括：步骤S1，用含磷酸的溶液对含独居石和/或磷钇矿的磷矿进行浸出，得到含稀土离子、钙离子和磷酸二氢根离子的浸出液和稀土酸浸渣；步骤S2，对浸出液进行陈化处理，固液分离得到磷酸稀土沉淀和磷酸一钙溶液；以及步骤S3，将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质；步骤S2的反应温度高于步骤S1的反应温度。
上述含稀土磷酸盐的物质富含多种相结构的稀土，稀土富集度高，品位高，便于对稀土进行综合回收利用。上述从磷矿中分离得到含稀土磷酸盐的物质的步骤中，在相对较低的反应温度下，通过采用含磷酸的溶液浸出含独居石和/或磷钇矿的稀土磷矿，利用含磷酸溶液中 的氢离子溶解磷矿中的磷形成磷酸一钙溶液，同时稀土元素也被溶解进入溶液中，形成含有稀土离子、Ca2+和H2PO4 -的浸出液；而独居石在酸浸过程中不溶解保留在渣中，实现了磷与独居石的分离。对浸出液进行陈化处理，有利于将稀土元素形成磷酸稀土沉淀而进一步实现稀土元素与磷元素的分离。反应温度对酸浸过程中磷元素的浸出影响较小，而在较低温度下磷酸稀土溶解度相对较大，有利于稀土元素的浸出，同时低温下能有效抑制磷矿中铁、铝等杂质元素的浸出，使得铁元素和铝元素的浸出率<5％，大大减轻了后续磷酸净化除杂负担。因而，通过控制陈化处理的温度高于酸浸步骤的温度，在相对较高的温度下磷酸稀土溶度积小，有利于使浸出液中的稀土元素以稀土磷酸盐形式沉淀下来，进一步实现稀土元素与磷元素的有效分离。从含稀土的磷矿到磷酸稀土沉淀，稀土富集倍数高达几十倍甚至上百倍，磷酸稀土沉淀中稀土品位可达45％以上，甚至达到55％以上，稀土收率达到80％以上，甚至达到90％以上，提高稀土分离效率，实现了低成本分离稀土的目的，便于后续对稀土元素进一步回收利用。
包含上述相结构的含稀土磷酸盐的物质中无定形相是磷酸稀土沉淀所形成的相结构，其含量的高低与稀土磷矿中稀土赋存形态与含量，以及稀土磷矿在浸出步骤的控制条件有关。但其含量的高低与所得到的含稀土磷酸盐的物质的稀土品味的高低密切相关，并决定了稀土的综合回收利用率，具有上述多种相结构的含稀土磷酸盐的物质已经具有相对较高的品位，为了进一步提高其品位，在本发明一种优选的实施例中，上述含稀土磷酸盐的物质中，无定形相在稀土磷酸盐中的含量大于1wt％，优选为5～40wt％。无定形相含量大于1wt％时，有利于后续含稀土磷酸盐的物质中稀土的回收。而无定形相含量为5～40wt％时，稀土品位相对更高，更有利于稀土元素的综合回收利用。
上述优选实施例中，无定形相占稀土磷酸盐的含量在上述范围内时的含稀土磷酸盐的物质稀土品位已经是相对较高，为了进一步提高该物质的利用价值，在本发明另一种优选的实施例中，上述含稀土磷酸盐的物质中，第一相结构与第二相结构的重量比为1：1～20。将上述含稀土磷酸盐的物质中的第一相结构与第二相结构的重量比控制在上述范围内，使得该含稀土磷酸盐的物质同时具备上述两种相结构，因而具有稀土品位高的优势。含稀土磷酸盐的物质稀土品位高，便于对稀土进行综合回收利用，且具有较高的稀土收率。
上述含稀土磷酸盐的物质中，由于稀土磷矿中伴生铁和/或铝矿物，因而分离过程中仍不可避免地含有上述元素种类的杂质，因而还包括了含铁和/或铝的杂质。这部分杂质的含量的高低与稀土磷矿所伴生的铁和/或铝的含量以及酸浸过程控制有关。在本发明一种优选的实施例中，以氧化物计，上述含铁和/或铝的杂质在含稀土磷酸盐的物质中的含量为1～50wt％，优选为3～25wt％。将上述含稀土磷酸盐的物质中含铁和/或铝的杂质含量控制在1～50wt％范围内，具有稀土含量相对较高，便于稀土回收；将杂质富集在固相中，减少杂质元素进入浸出液中，减少后续磷酸净化除杂负担，且含稀土磷酸盐的物质中铁铝的存在，有利于在后续的稀土回收过程起到固磷的作用，进而有利于提高稀土收率并实现铁铝的综合利用；而将上述含稀土磷酸盐的物质中含铁和/或铝的杂质的含量控制在3～25wt％的范围内，具有稀土含量高的优势，具有上述杂质含量的含稀土磷酸盐的物质稀土品位高，便于稀土回收，并实现杂质铁铝的综合利用。
同样，控制杂质含量在上述范围内能够使得本发明的含稀土磷酸盐的物质具有较高的稀土品位，为了进一步提高稀土品位，在本发明又一种优选的实施例中，上述含稀土磷酸盐的物质中，以氧化物计，稀土与铁和/或铝的重量比为2～20：1。将稀土与铁和/或铝的重量比控制在上述范围内，能够使本发明的含稀土磷酸盐的物质具有较高的稀土含量。有利于后续的硫酸焙烧处理回收稀土工艺的处理，可实现铁铝资源的综合利用，以及将杂质铁铝富集在固相中，减少杂质元素进入浸出液中，减少后续磷酸净化除杂负担。
上述步骤S1中，用含磷酸的溶液浸出的目的是将含稀土的磷矿中磷元素和稀土元素溶出，而将杂质元素及磷酸不溶物(独居石中的独居石相的稀土和/或磷钇矿中的磷钇矿相的稀土)保留在渣中形成含稀土的酸浸渣。因而任何能够使磷元素和磷矿中可溶的稀土元素尽可能地溶出的浸出工艺条件均适合于本发明。在本发明的一种优选实施方式中，在10℃～60℃的温度下，用含磷酸的溶液对含独居石和/或磷钇矿的磷矿浸出0.5～8小时，优选2～5小时，得到上述浸出液和稀土酸浸渣。
上述采用含磷酸的溶液浸出步骤中，通过控制反应温度在10℃～60℃范围内，较低的反应温度能够使得含独居石和/或磷钇矿的磷矿中磷元素和可溶的稀土元素尽可能地溶解完全，并能有效抑制磷矿中铁和/或铝等杂质元素的浸出，使得铁元素和/或铝元素的浸出率<5％，能够大大减轻了后续的除杂负担。更优选地，浸出时间为2～5小时。选择该范围的浸出时间，既能使磷元素和可溶稀土完全溶出，又能缩短浸出周期。
上述陈化处理的步骤中，陈化处理的具体时间和温度可以根据含稀土的磷矿种类不同进行调整。在本发明一种优选实施例中，对浸出液在60℃～150℃，优选为80～120℃的温度下陈化处理0.5～24小时，优选为1～8小时，固液分离得到磷酸稀土沉淀和磷酸一钙溶液。在高温下磷酸稀土溶度积小，通过采用上述较高的温度，有利于使溶于浸出液中的稀土离子以稀土磷酸盐形式沉淀，从而进一步实现稀土元素与磷元素的有效分离。在上述陈化时间范围内，能够使得浸出液中的稀土元素沉淀得较为彻底，从而更有效实现稀土元素与磷元素的分离，进而得到的含稀土磷酸盐的物质中，稀土含量相对更高，更有利于后续稀土元素的回收利用。容易理解的是，此处的磷酸一钙溶液并非100％由钙离子和磷酸二氢根离子组成的溶液，而是主体为磷酸一钙溶液，同时含有微量磷酸一氢根离子、铁或铝等杂质离子的溶液。
在上述含磷酸的溶液浸出含独居石和/或磷钇矿的磷矿的过程中，含磷酸的溶液中包括磷酸，也可根据实际情况适当加入盐酸和/或硝酸。在本发明的一种优选实施例中，上述含磷酸的溶液还包含盐酸和/或硝酸。混合酸溶液中的盐酸或硝酸有利于磷灰石的分解，从而提高磷的浸出率。而且盐酸或硝酸可提供氢离子H+，在相同酸量条件下，可降低磷酸根的含量，降低了体系粘度，有利于磷的浸出；同时，氯离子或硝酸根离子的存在，有利于提高钙离子在溶液中的溶解度，有利于磷灰石的分解。在本发明的一种更优选实施例中，以阴离子的摩尔数计，盐酸和/或硝酸所占的比例小于30％(不包括0)，优选2～15％。本发明中所使用的盐酸或硝酸的含量并不限于上述范围。但若采用过高含量的盐酸或硝酸将同时增加磷酸稀土在该体系中的溶解度，使稀土在上述陈化处理过程中较难沉淀析出，导致稀土无法富集在磷酸稀土沉淀中，造成稀土收率偏低。
在上述含磷酸的溶液中，磷酸的质量浓度可以根据所浸出含独居石和/或磷钇矿的磷矿成分的不同进行合理选择。在本发明的一种优选实施例中，上述含磷酸的溶液中，以P2O5计，磷酸的质量浓度为15％～50％，优选为15％～30％。在本发明中所使用含磷酸的溶液中P2O5质量浓度并不限于上述范围，在采用P2O5质量浓度在上述范围内时，较高的酸度有利于磷矿的分解，从而提高磷的收率，但过高的磷酸含量则存在粘度高导致传质效率低等问题。
在上述含磷酸的溶液浸出含独居石和/或磷钇矿的磷矿前，含磷酸的溶液与磷矿可根据含磷酸的溶液磷酸浓度及磷矿成分不同进行合理配比，以使得磷与稀土元素溶出。本发明的一种优选实施例中，含磷酸的溶液与含独居石和/或磷钇矿的磷矿混合液固比为2～10L：1kg，优选为3～6L：1kg。通过控制酸用量，有利于在降低酸用量的情况下，使磷和钙生成可溶性磷酸一钙Ca(H2PO4)2进入溶液，高酸度条件下磷酸稀土的溶解度大，有利于磷灰石中稀土浸出进入溶液，上述范围配比有利于磷元素与稀土元素的充分溶出，有利于后续陈化处理，形成磷酸稀土沉淀富集稀土。难溶解的独居石和/或磷钇矿将留在渣中。从而实现稀土元素和磷元素的有效分离。
以下将结合具体的实施例进一步说明本发明的有益效果。
下列实施例中，磷酸的质量浓度是以P2O5计，盐酸或硝酸是以阴离子摩尔数计。而铁、铝、稀土等元素含量采用ICP测试，并由此计算获得各元素浸出率及回收率，磷测试则采用GBT 1871.1-1995方法，钙测试采用GBT 1871.4-1995方法。
实施例1
以1000g含稀土含量为0.05wt％的磷矿为原料，采用质量浓度为15％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为10：1，在10℃下反应1h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于60℃下进行陈化处理24h，使稀土元素以磷酸稀土沉淀的形式析出，经固液分离，得到磷酸一钙溶液和0.71g磷酸稀土沉淀。
经检测，磷矿中的杂质Fe浸出率为3.5％，杂质Al浸出率为2.5％，磷元素的浸出率为95.3％；磷酸稀土沉淀中稀土的含量为57.1％，稀土回收率为81.08％。
实施例2
以1000g含稀土含量为0.2wt％的磷矿为原料，采用质量浓度为20％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为6：1，在20℃下反应6h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于60℃下进行陈化处理1h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和3.30g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.1％，Al浸出率为3.1％，磷元素的浸出率为96.8％；磷酸稀土沉淀中稀土的含量为52.1％，稀土回收率为85.97％。
实施例3
以1000g含稀土含量为0.2wt％的磷矿为原料，采用质量浓度为20％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为6：1，在20℃下反应6h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于80℃下进行陈化处理1h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和3.40g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.1％，Al浸出率为3.1％，磷元素的浸出率为96.6％；磷酸稀土沉淀中稀土的含量为53.8％，稀土回收率为91.46％。
实施例4
以1000g含稀土含量为0.3wt％的磷矿为原料，采用质量浓度为30％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为4：1，在30℃下反应3h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于100℃下进行陈化处理0.5h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和4.98g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.2％，Al浸出率为3.2％，磷元素的浸出率为96.5％；磷酸稀土沉淀中稀土的含量为55.3％，稀土回收率为91.80％。
实施例5
以1000g含稀土含量为0.3wt％的磷矿为原料，采用质量浓度为30％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为4：1，在30℃下反应3h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于100℃下进行陈化处理3h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和5.03g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.2％，Al浸出率为3.2％，磷元素的浸出率为96.2％；磷酸稀土沉淀中稀土的含量为55.4％，稀土回收率为92.89％。
实施例6
以1000g含稀土含量为0.5wt％的磷矿为原料，采用质量浓度为40％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为3：1，在25℃下反应4h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理4h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和8.10g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.5％，Al浸出率为3.6％，磷元素的浸出率为95.8％；磷 酸稀土沉淀中稀土的含量为56.3％，稀土回收率为91.21％。
实施例7
以1000g含稀土含量为0.5wt％的磷矿为原料，采用质量浓度为30％的磷酸溶液(以P2O5计)与盐酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为2％，控制体系液固比为4：1，在30℃下反应3h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理3h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和8.23g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.7％，Al浸出率为3.8％，磷元素的浸出率为97.1％；磷酸稀土沉淀中稀土的含量为56.8％，稀土回收率为93.49％。
实施例8
以1000g含稀土含量为0.5wt％的磷矿为原料，采用质量浓度为30％的磷酸溶液(以P2O5计)与硝酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计硝酸占混合酸的比例为2％，控制体系液固比为4：1，在30℃下反应3h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理3h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和8.26g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.7％，Al浸出率为3.8％，磷元素的浸出率为97.3％；磷酸稀土沉淀中稀土的含量为56.3％，稀土回收率为93.01％。
实施例9
以1000g含稀土含量为0.5wt％的磷矿为原料，采用质量浓度为30％的磷酸溶液(以P2O5计)与盐酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为15％，控制体系液固比为4：1，在30℃下反应3h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理3h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和8.38g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.9％，Al浸出率为4.6％，磷元素的浸出率为98.5％；磷酸稀土沉淀中稀土的含量为56.8％，稀土回收率为95.20％。
实施例10
以1000g含稀土含量为0.5wt％的磷矿为原料，采用质量浓度为40％的磷酸溶液(以P2O5计)与盐酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为25％，控制体系液固比为3：1，在25℃下反应4h，过滤后获得含有稀土的磷酸一钙溶液和酸 浸渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理4h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和7.2g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为5.0％，Al浸出率为5.0％，磷元素的浸出率为99.2％；磷酸稀土沉淀中稀土的含量为55.9％，稀土回收率为80.50％。
实施例11
以1000g含稀土含量为1wt％的磷矿为原料，采用质量浓度为50％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为2：1，在60℃下反应0.5h，过滤后获得含有稀土的磷酸一钙溶液和酸浸渣。
对含有稀土的磷酸一钙溶液置于130℃下进行陈化处理1h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和16.9g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为8.0％，Al浸出率为6.0％，磷元素的浸出率为95.0％；磷酸稀土沉淀中稀土的含量为47.8％，稀土回收率为80.78％。
实施例12
以1000g稀土含量为7.4wt％的磷矿为原料，其中独居石含量为9.5wt％，采用质量浓度为20％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为6：1，在25℃下反应2h，过滤后获得含有稀土的磷酸一钙溶液和205.0g酸浸渣。
对含有稀土的磷酸一钙溶液置于100℃下进行陈化处理1h，使稀土元素以磷酸稀土沉淀析出，经固液分离，得到磷酸一钙溶液和15.8g磷酸稀土沉淀。
经检测，磷矿中的杂质Fe浸出率为3.3％，杂质Al浸出率为3.0％，磷元素的浸出率为96.5％；磷酸稀土沉淀中稀土的含量为54.8％，稀土回收率为97.80％。
实施例13
以1000g含稀土含量为7.4wt％的磷矿为原料，其中独居石含量为9.5wt％，采用质量浓度为15％的磷酸溶液(以P2O5计)与盐酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为10％，控制体系液固比为10：1，在20℃下反应8h，过滤后获得含有稀土的磷酸一钙溶液和178.0g酸浸渣。
对含有稀土的磷酸一钙溶液置于70℃下进行陈化处理8h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和16.5g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.4％，Al浸出率为4.2％，磷元素的浸出率为98.2％；磷酸稀土沉淀中稀土的含量为52.8％，稀土回收率为98.10％。
实施例14
以1000g含稀土含量为7.4wt％的磷矿为原料，其中独居石含量为9.5wt％，采用质量浓度为15％的磷酸溶液(以P2O5计)与盐酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为25％，控制体系液固比为8：1，在20℃下反应8h，过滤后获得含有稀土的磷酸一钙溶液和154.0g酸浸渣。
对含有稀土的磷酸一钙溶液置于70℃下进行陈化处理12h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和17.3g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为5.0％，Al浸出率为5.0％，磷元素的浸出率为98.9％；磷酸稀土沉淀中稀土的含量为52.5％，稀土回收率为97.75％。
实施例15
以1000g含稀土含量为9.0wt％的磷矿为原料，其中独居石含量为11.9wt％，采用质量浓度为15％的磷酸溶液(以P2O5计)与盐酸、硝酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为15％，硝酸占15％，控制体系液固比为6：1，在20℃下反应4h，过滤后获得含有稀土的磷酸一钙溶液和167.0g酸浸渣。
对含有稀土的磷酸一钙溶液置于150℃下进行陈化处理0.5h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和17.5g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为4.8％，Al浸出率为4.5％，磷元素的浸出率为98.6％；磷酸稀土沉淀中稀土的含量为53.5％，稀土回收率为98.50％。
实施例16
以1000g含稀土含量为14.7wt％的磷矿为原料，其中独居石含量为20.5wt％，采用质量浓度为25％的磷酸溶液(以P2O5计)与盐酸混合液对该稀土磷矿进行浸出，其中以阴离子的摩尔数计盐酸占混合酸的比例为10％，控制体系液固比为3：1，在15℃下反应2h，过滤后获得含有稀土的磷酸一钙溶液和258.0g酸浸渣。
对含有稀土的磷酸一钙溶液置于90℃下进行陈化处理2h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和16.7g磷酸稀土沉淀。
经检测，磷矿中的Fe浸出率为3.8％，Al浸出率为2.9％，磷元素的浸出率为98.4％；磷酸稀土沉淀中稀土的含量为55.7％，稀土回收率为98.30％。
对比例1
以1000g含稀土含量为0.3wt％的磷矿为原料，采用质量浓度为20％的盐酸溶液对该稀土磷矿进行浸出，控制体系液固比为6：1，在30℃下反应4h，过滤后获得含有稀土的溶液和酸浸渣。
对含有稀土的溶液置于120℃下进行陈化处理3h，使稀土元素以磷酸稀土沉淀的形式析出，经固液分离，得到0.5g磷酸稀土沉淀。
经检测，磷矿中的杂质Fe浸出率为68％，杂质Al浸出率为56％，磷元素的浸出率为99.5％；磷酸稀土沉淀中稀土的含量为46.3％，稀土回收率为7.72％。
对比例2
以1000g含稀土含量为0.3wt％的磷矿为原料，采用质量浓度为30％的磷酸溶液对该稀土磷矿进行浸出，控制体系液固比为4：1，在100℃下反应3h，过滤后获得磷酸一钙溶液和65.8g酸浸渣。
经检测，磷矿中的杂质Fe浸出率为54.2％，杂质Al浸出率为43.7％，磷元素的浸出率为96.7％，稀土回收率为96.7％。
从上述实施例1-16与对比例1和2的比较可以看出，本发明的方法对磷和稀土元素的分离效率较高，能够得到较高的稀土元素和磷元素回收率。而且，从实施例1至11可以看出，在相对较低的反应温度下，通过采用含磷酸的溶液浸出稀土磷矿，反应温度对酸浸过程中磷元素的浸出影响较小，而在相对低温下磷酸稀土溶解度较大，有利于稀土的浸出，同时低温能有效抑制磷矿中铁、铝等杂质元素的浸出，使得铁元素和铝元素的浸出率<5％，大大减轻了后续磷酸净化除杂负担，提高了后续陈化过程得到的磷酸稀土沉淀的稀土品位。而且混合酸溶液中的盐酸或硝酸有利于磷灰石的分解，从而提高磷灰石中磷与稀土的浸出率。进一步对含稀土磷酸一钙溶液进行陈化处理，有利于将溶液中含有的稀土元素形成磷酸稀土沉淀，从而实现稀土元素与磷元素的分离。并且，通过控制较高的陈化处理的温度有利于提高稀土的收率及稀土品位，在高温下磷酸稀土溶度积小，有利于使浸出液中的稀土元素以稀土磷酸盐的形式沉淀下来，从而实现稀土元素与磷元素的有效分离。而从实施例12至16可以看出，当稀土磷矿含有独居石时，利用酸浸过程中独居石不溶解，进入渣中富集，实现了磷与独居石的分离。通过陈化处理将进入溶液中的稀土以磷酸稀土沉淀析出，与酸浸过程不溶解的独居石形成稀土混合渣后共同回收稀土，从而简化了回收步骤，提高了稀土回收率，实现了低成本综合回收稀土的目的。
此外，发明人进一步对实施例13中的酸浸渣和磷酸稀土沉淀进行混合，得到稀土混合渣，并取15g进行稀土元素的回收，具体回收步骤见下列实施例17至23。
实施例17
根据混合渣中磷含量添加含铁渣，控制Fe/P质量比为2.5：1，然后加入质量浓度98％的浓硫酸混合，浓硫酸与稀土混合渣的质量比为1：1；
将混合物在200℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用氧化镁对含稀土水浸液的pH值调节至4.0，过滤得到硫酸稀土溶液和滤渣，滤渣中含有含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.02g/L，P的含量为0.005g/L，Th的含量<0.05mg/L；
采用酸性磷类萃取剂对硫酸稀土溶液进行萃取分离，得到混合氯化稀土化合物或单一稀土化合物；其中，稀土收率为92.5％。
实施例18
根据混合渣中磷含量添加含铁渣，控制Fe/P质量比为2.5：1，然后加入质量浓度95％的浓硫酸混合；浓硫酸与稀土混合渣的质量比为1：1；
将混合物在250℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用氧化镁对含稀土水浸液的pH值调节至4.0，过滤得到硫酸稀土溶液和滤渣，滤渣中含有含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.03g/L，P的含量为0.004g/L，Th的含量<0.05mg/L；
在硫酸稀土溶液中加入碳酸盐沉淀稀土，获得稀土碳酸盐产品，整个工艺过程中稀土的回收率为94.1％。
实施例19
根据混合渣中磷含量添加含铁稀土尾矿以及白云石，控制Fe/P质量比为2.5：1，白云石中Mg和Ca元素与F元素的摩尔比为1：2，然后加入质量浓度99％的浓硫酸混合，浓硫酸与稀土混合渣的质量比为1：1；
将混合物在500℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用氧化镁对含稀土水浸液的pH值调节至4.0，过滤得到硫酸稀土溶液和滤渣，滤渣中含有含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.05g/L，P的含量为0.004g/L，Th的含量<0.04mg/L；
采用酸性磷类萃取剂对硫酸稀土溶液进行萃取分离，得到混合氯化稀土化合物或单一稀土化合物；其中，稀土收率为95.8％。
实施例20
根据混合渣中磷含量添加含铁稀土尾矿以及白云石，控制Fe/P质量比为2：1，白云石中Mg和Ca元素与F元素的摩尔比为1.5：2，然后加入质量浓度99％的浓硫酸混合；浓硫酸与稀土混合渣的质量比为1.5：1；
将混合物在350℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用氧化镁对含稀土水浸液的pH值调节至4.5，过滤得到硫酸稀土溶液和滤渣，滤渣中含 有含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.008g/L，P的含量为0.004g/L，Th的含量<0.05mg/L；
其中，硫酸稀土溶液中的稀土收率为94.2％。
实施例21
根据混合渣中磷含量添加含铁稀土尾矿以及白云石，控制Fe/P质量比为4：1，白云石中Mg和Ca元素与F元素的摩尔比为1.5：2，然后加入质量浓度99％的浓硫酸混合；浓硫酸与稀土混合渣的质量比为1.5：1；
将混合物在350℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用轻烧白云石对含稀土水浸液的pH值调节至4.5，过滤得到硫酸稀土溶液和滤渣，滤渣中含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.01g/L，P的含量为0.007g/L，Th的含量<0.04mg/L；
其中，硫酸稀土溶液中的稀土收率为97.3％。
实施例22
根据混合渣中磷含量添加含铁稀土尾矿以及白云石，控制Fe/P质量比为3.5：1，白云石中Mg和Ca元素与F元素的摩尔比为1：1，然后加入质量浓度99％的浓硫酸，浓硫酸与稀土混合渣的质量比为2：1；
将混合物在400℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用氢氧化镁对含稀土水浸液的pH值调节至3.8，过滤得到硫酸稀土溶液和滤渣，滤渣中含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.04g/L，P的含量为0.002g/L，Th的含量<0.05mg/L；
其中，硫酸稀土溶液中的稀土收率为97.5％。
实施例23
根据混合渣中磷含量添加含铁渣以及白云石，控制Fe/P质量比为3：1，白云石中Mg和Ca元素与F元素的摩尔比为1.5：2，然后加入质量浓度99％的浓硫酸混合；浓硫酸与稀土混合渣的质量比为1.5：1；
将混合物在450℃进行焙烧，得到焙烧产物；
对焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
用氢氧化镁对含稀土水浸液的pH值调节至3.8，过滤得到硫酸稀土溶液和滤渣，滤渣中 含磷酸铁和磷酸钍沉淀；硫酸稀土溶液中以氧化物计，Fe的含量为0.04g/L，P的含量为0.002g/L，Th的含量<0.05mg/L；
其中，硫酸稀土溶液中的稀土收率为96.1％。
需要说明的是，下列实施例24-32中相结构及其含量的检测方法是通过X射线衍射(XRD)进行检测，而元素含量的检测方式是通过ICP或XRF的方法检测获得。下列实施例中的XRD图谱的峰图都非常相似，具体参见如图3所示的实施例26的峰图结果。
实施例24
以1000g独居石含量为23wt％，稀土总含量为16.4wt％的磷矿为原料，采用质量浓度为15％的磷酸溶液(以P2O5计)对该含独居石的稀土磷矿进行浸出，控制体系液固比为10：1，在10℃下反应8h，过滤后获得含有稀土的磷酸一钙溶液和330g稀土酸浸渣。
对含有稀土的磷酸一钙溶液置于60℃下进行陈化处理24h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和13.6g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，无定形相的含量为4.27wt％，铁和铝杂质含量(以氧化物计)为9.2wt％，第一相结构与第二相结构重量比为0.045，以氧化物计，稀土与铁和铝杂质的重量比为5.04。
实施例25
以1000g独居石含量为15wt％，稀土总含量为11.1wt％的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为50％(以P2O5含量计)，以阴离子的摩尔数计盐酸占混合酸溶液的比例为2％，控制体系液固比为2：1，在60℃下反应0.5h，过滤后获得含有稀土的磷酸一钙溶液和267g酸浸渣。
对含有稀土的磷酸一钙溶液置于150℃下进行陈化处理0.5h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和18.9g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为1.9wt％，无定形相的含量为8.82wt％；第一相结构与第二相结构重量比为0.097。以氧化物计，稀土与铁和铝杂质的重量比为19.73。
实施例26
以1000g独居石含量为9.5wt，稀土总含量为7.4wt％和的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为30％(以P2O5含量计)，以阴离子的摩尔数计，盐酸占混合酸溶液的比例为25％，控制体系液固比为8：1，在20℃下反应1h，过滤后获得含有稀土的磷酸一钙溶液和205g酸浸渣。
对含有稀土的磷酸一钙溶液置于80℃下进行陈化处理8h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和15.6g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，该实施例的含稀土磷酸盐的物质的X射线衍射谱图如图3所示。从图3可以计算得出，该含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为5.2wt％，无定形相的含量为10.92wt％；第一相结构与第二相结构重量比为0.123。以氧化物计，稀土与铁和铝杂质的重量比为6.23。
实施例27
以1000g独居石含量为28wt％，稀土总含量为19.8wt％和的磷矿为原料，采用磷酸、盐酸和硝酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为15％(以P2O5含量计)，以阴离子的摩尔数计，盐酸和硝酸占混合酸溶液的比例均为15％，控制体系液固比为6：1，在20℃下反应4h，过滤后获得含有稀土的磷酸一钙溶液和375g酸浸渣。
对含有稀土的磷酸一钙溶液置于100℃下进行陈化处理1h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和21.7g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为23wt％，无定形相的含量为5.66wt％；第一相结构与第二相结构重量比为0.060。以氧化物计，稀土与铁和铝杂质的重量比为2.10。
实施例28
以1000g磷钇矿含量为35.0wt，稀土总含量为24.5wt％和的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为25％(以P2O5含量计)，以阴离子的摩尔数计，盐酸占混合酸溶液的比例为20％(以阴离子的摩尔数计)，控制体系液固比为2：1，在15℃下反应0.5h，过滤后获得含有稀土的磷酸一钙溶液和463g酸浸渣。
对含有稀土的磷酸一钙溶液置于75℃下进行陈化处理2h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和19.3g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为23wt％，无定形相的含量为4.07wt％；第一相结构与第二相结构重量比为0.042。
实施例29
以1000g磷钇矿含量为3.5wt％，稀土总含量为3.3wt％和的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为25％(以P2O5含量计)，以阴离子的摩尔数计，盐酸占混合酸溶液的比例为10％(以阴离子的摩尔数计)，控制体系液固比为3：1，在15℃ 下反应2h，过滤后获得含有稀土的磷酸一钙溶液和143g酸浸渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理2h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和18.6g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为5.8wt％，无定形相的含量为28.66wt％；第一相结构与第二相结构重量比为0.402。以氧化物计，稀土与铁和铝杂质的重量比为3.46。
实施例30
以1000g含独居石2.0wt％，稀土总含量为2.3wt％的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为30％(以P2O5含量计)，以阴离子的摩尔数计，盐酸占混合酸溶液的比例为25％(以阴离子的摩尔数计)，控制体系液固比6：1，在15℃下反应2h，过滤后获得含有稀土的磷酸一钙溶液和124g含磷酸稀土渣。
对含有稀土的磷酸一钙溶液置于120℃下进行陈化处理2h，使稀土元素以磷酸稀土沉淀的形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和22.5g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为5.6wt％，无定形相的含量为49.56wt％；第一相结构与第二相结构重量比为0.983。以氧化物计，稀土与铁和铝杂质的重量比为2.77。
实施例31
以1000g含独居石35wt％，稀土总含量为24.5wt％的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为25％(以P2O5含量计)，以阴离子的摩尔数计，盐酸占混合酸溶液的比例为10％(以阴离子的摩尔数计)，控制体系液固比3：1，在90℃下反应10h，过滤后获得磷酸一钙溶液和483g含磷酸稀土渣。
经检测，含稀土磷酸渣中，铁和铝杂质含量(以氧化物计)为31wt％，无定形相的含量为3.6wt％；第一相结构与第二相结构重量比为0.037。以氧化物计，稀土与铁和铝杂质的重量比为2.20。
实施例32
以1000g含独居石3.5wt％，稀土总含量为3.3wt％的磷矿为原料，采用磷酸和盐酸的混合酸溶液浸出，混合酸中磷酸的质量浓度为10％(以P2O5含量计)，以阴离子的摩尔数计，盐酸占混合酸溶液的比例为30％(以阴离子的摩尔数计)，控制体系液固比3：1，在5℃下反应2h，过滤后获得含有稀土的磷酸一钙溶液和123g含磷酸稀土渣。
对含有稀土的磷酸一钙溶液置于55℃下进行陈化处理2h，使稀土元素以磷酸稀土沉淀的 形式与磷酸一钙溶液分离开来，因而经固液分离，得到磷酸一钙溶液和2.4g磷酸稀土沉淀。
将稀土酸浸渣与磷酸稀土沉淀混合，得到含稀土磷酸盐的物质。
经检测，含稀土磷酸盐的物质中，铁和铝杂质含量(以氧化物计)为1.3wt％，无定形相的含量为3.7wt％；第一相结构与第二相结构重量比为0.038。以氧化物计，稀土与铁和铝杂质的重量比为19.90。
上述实施例24-32中，根据稀土磷矿中稀土赋存形态与含量以及通过稀土磷矿浸出过程的过程控制，无定形相在稀土磷酸盐中的含量为5～40wt％，更有利于后续含稀土磷酸盐的物质中稀土的回收；将上述含稀土磷酸盐的物质中含铁和/或铝的杂质含量控制在3～25wt％范围内，具有稀土含量相对更高，便于稀土回收，将杂质富集在固相中，减少杂质元素进入浸出液中，减少后续磷酸净化除杂负担，且含稀土磷酸盐的物质中铁铝的存在，有利于在后续的稀土回收过程起到固磷的作用，进而有利于提高稀土收率并实现铁铝的综合利用。
在得到上述实施例24-32的含稀土磷酸盐的物质后，可以进一步对其中的稀土元素进行回收利用，具体回收利用的步骤如图1所示。向含稀土磷酸盐的物质中添加含铁物质或者同时加入含钙和镁的物质，并加入质量浓度大于90％的浓硫酸进行酸化焙烧，然后用水对焙烧产物进行浸出，得到稀土水浸液和水浸渣；调节含稀土水浸液的pH值至3.8～5，过滤得到硫酸稀土溶液与滤渣，该滤渣中含铁元素、磷元素和钍元素；采用酸性磷类萃取剂对硫酸稀土溶液最后采用进行萃取分离，得到混合或单一氯化稀土；或者，向硫酸稀土溶液中加入碳酸盐或草酸盐沉淀稀土，获得稀土碳酸盐或稀土草酸盐；进一步对稀土碳酸盐或稀土草酸盐进行煅烧，可以得到稀土氧化物。
同理，上述实施例24-32得到的磷酸一钙溶液经硫酸处理得到硫酸钙和含磷溶液，硫酸钙可以用来制备市售石膏产品，而含磷溶液经净化除杂得到磷酸溶液可以进一步用于磷矿的酸浸步骤，从而实现物料的循环利用。
从以上的描述中，可以看出，本申请上述的实施例实现了如下技术效果：通过采用含磷酸的溶液浸出稀土磷矿，利用含磷酸溶液中的氢离子使得磷矿中的磷被溶解形成磷酸一钙，同时使稀土元素溶解进入溶液中，形成含有稀土离子、Ca2+和H2PO4 -的浸出液，并进一步对浸出液进行陈化处理，有利于将浸出液中的稀土离子形成磷酸稀土沉淀而将稀土元素与磷元素分离。并且，控制陈化处理的温度高于酸浸步骤的温度，低温下能有效抑制稀土磷矿中铁、铝等杂质元素的浸出，使得铁元素和铝元素的浸出率<5％，大大减轻了后续的除杂负担；在高温下磷酸稀土溶度积小，有利于使溶于浸出液中的稀土元素以磷酸稀土的形式沉淀下来，从而进一步实现稀土元素与磷元素的有效分离。当稀土磷矿中含有独居石时，在酸浸过程中独居石不溶解而保留在渣中，从而实现稀土元素与磷元素的分离。然后，将磷酸稀土沉淀与酸浸过程产生的含稀土酸浸渣混合，形成稀土混合渣。上述分离方法提高了稀土分离效率，使得磷酸稀土沉淀以及稀土混合渣中稀土含量高，实现了低成本分离稀土的目的，便于后续对稀土元素进一步回收利用。
以上所述仅为本发明的优选实施例而已，并不用于限制本发明，对于本领域的技术人员 来说，本发明可以有各种更改和变化。凡在本发明的精神和原则之内，所作的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (21)

  1. 一种从含稀土磷矿中回收磷和稀土的方法，其特征在于，所述方法包括：
    步骤S1，用含磷酸的溶液对所述稀土磷矿进行浸出，得到浸出液和酸浸渣，所述浸出液中含有稀土离子、Ca2+和H2PO4 -；以及
    步骤S2，对所述浸出液进行陈化处理，得到磷酸稀土沉淀与磷酸一钙溶液；其中，
    所述步骤S2的反应温度高于所述步骤S1的反应温度。
  2. 根据权利要求1所述的方法，其特征在于，所述步骤S1包括：
    在10℃～60℃的温度下，用所述含磷酸的溶液对所述稀土磷矿浸出0.5～8小时，优选1～4小时，得到所述浸出液和所述酸浸渣。
  3. 根据权利要求1或2所述的方法，其特征在于，所述步骤S2包括：
    在60℃～150℃，优选为80～120℃的温度下对所述浸出液陈化处理0.5～24小时，优选为1～8小时，得到所述磷酸稀土沉淀与所述磷酸一钙溶液。
  4. 根据权利要求1所述的方法，其特征在于，当所述稀土磷矿中不含独居石和/或磷钇矿时，所述方法还包括：
    对所述磷酸稀土沉淀中的稀土元素进行回收；以及
    对所述磷酸一钙溶液中的磷元素进行回收。
  5. 根据权利要求1所述的方法，其特征在于，当所述稀土磷矿含有独居石和/或磷钇矿时，所述方法还包括：
    将所述酸浸渣与所述磷酸稀土沉淀混合，得到稀土混合渣；
    对所述稀土混合渣中的稀土元素进行回收；以及
    对所述磷酸一钙溶液中的磷元素进行回收。
  6. 根据权利要求4或5所述的方法，其特征在于，对所述磷酸一钙溶液中的磷元素进行回收的步骤包括：
    向所述磷酸一钙溶液中加入质量浓度>90％的浓硫酸，得到固液混合物；
    对所述固液混合物进行固液分离，得到第一磷酸溶液和硫酸钙。
  7. 根据权利要求6所述的方法，其特征在于，对所述磷酸一钙溶液中的磷元素进行回收的步骤中，在得到所述第一磷酸溶液后，还包括：
    将所述第一磷酸溶液返回所述步骤S1，对所述稀土磷矿进行浸出；或者
    对所述第一磷酸溶液进行除杂，得到第二磷酸溶液，并将所述第二磷酸溶液返回所述步骤S1，对所述稀土磷矿进行浸出。
  8. 根据权利要求5所述的方法，其特征在于，对所述稀土混合渣中的稀土元素进行回收的 步骤包括：
    步骤A，向所述稀土混合渣中添加含铁的物质，并加入质量浓度>90％的浓硫酸，得到混合物；
    步骤B，对所述混合物进行焙烧，得到焙烧产物；
    步骤C，对所述焙烧产物加水浸出，得到含稀土水浸液和水浸渣；
    步骤D，调节所述含稀土水浸液的pH值至3.8～5，过滤得到硫酸稀土溶液和滤渣，所述滤渣中含有铁元素、磷元素和钍元素；以及
    步骤E，以所述硫酸稀土溶液为原料制备稀土化合物，
    其中，所述步骤E包括：
    采用酸性磷类萃取剂对所述硫酸稀土溶液进行萃取分离，得到混合氯化稀土化合物或单一稀土化合物；或者
    向所述硫酸稀土溶液中加入碳酸盐或草酸盐沉淀稀土元素，获得稀土碳酸盐或稀土草酸盐；并对所述稀土碳酸盐或所述稀土草酸盐进行煅烧，得到稀土氧化物。
  9. 根据权利要求1所述的方法，其特征在于，所述含磷酸的溶液中还包含盐酸和/或硝酸。
  10. 根据权利要求1或9所述的方法，其特征在于，以P2O5计，所述含磷酸的溶液中磷酸的质量浓度为15％～50％，优选为15％～30％。
  11. 根据权利要求9所述的方法，其特征在于，以阴离子的摩尔数计，所述含磷酸的溶液中盐酸和/或硝酸所占的比例<30％，优选2～15％。
  12. 根据权利要求1所述的方法，其特征在于，在所述步骤S1之前，所述方法还包括：将所述含磷酸的溶液与所述稀土磷矿按照液固比为2～10L：1kg的比例进行混合的步骤，优选所述液固比为3～6L：1kg。
  13. 一种含稀土磷酸盐的物质，其特征在于，所述含稀土磷酸盐的物质中稀土磷酸盐至少含有第一相结构和第二相结构，所述第一相结构为无定形相，所述第二相结构包括独居石相或/和磷钇矿相；所述含稀土磷酸盐的物质是从含独居石和/或磷钇矿的磷矿中分离得到，所述从含独居石和/或磷钇矿的磷矿中分离得到所述含稀土磷酸盐的物质的方法包括：
    步骤S1，用含磷酸的溶液对所述含独居石和/或磷钇矿的磷矿进行浸出，得到浸出液和稀土酸浸渣；所述浸出液含有稀土离子、钙离子和磷酸二氢根离子；
    步骤S2，对所述浸出液进行陈化处理，经固液分离得到磷酸稀土沉淀和磷酸一钙溶液；以及
    步骤S3，将所述稀土酸浸渣与所述磷酸稀土沉淀混合，得到所述含稀土磷酸盐的物质；
    所述步骤S2的反应温度高于所述步骤S1的反应温度。
  14. 根据权利要求13所述的含稀土磷酸盐的物质，其特征在于，以重量含量计，所述无定形相在所述稀土磷酸盐中的含量大于1％，优选为5～40％。
  15. 根据权利要求13所述的含稀土磷酸盐的物质，其特征在于，所述含稀土磷酸盐的物质中所述第一相结构与所述第二相结构的重量比为1：1～20。
  16. 根据权利要求13所述的含稀土磷酸盐的物质，其特征在于，所述含稀土磷酸盐的物质中还包括含铁和/或铝的杂质，以氧化物计，铁和/或铝含量为1～50wt％，优选为3～25wt％。
  17. 根据权利要求13所述的含稀土磷酸盐的物质，其特征在于，在所述含稀土磷酸盐的物质中，以氧化物计，稀土与铁和/或铝的重量比为2～20：1。
  18. 根据权利要求13所述的含稀土磷酸盐的物质，其特征在于，所述步骤S1包括：
    在10℃～60℃的温度下，用所述含磷酸的溶液对所述含独居石和/或磷钇矿的磷矿浸出0.5～8小时，优选1～4小时，得到所述浸出液和所述稀土酸浸渣。
  19. 根据权利要求13所述的含稀土磷酸盐的物质，其特征在于，所述步骤S2包括：
    对所述浸出液在60℃～150℃，优选为80～120℃的温度下陈化处理0.5～24小时，优选为1～8小时，固液分离得到所述磷酸稀土沉淀和所述磷酸一钙溶液。
  20. 根据权利要求14所述的含稀土磷酸盐的物质，其特征在于，所述含磷酸的溶液中还包含盐酸和/或硝酸；优选地，以阴离子的摩尔数计，所述含磷酸的溶液中盐酸和/或硝酸所占的比例小于30％，更优选为2～15％。
  21. 根据权利要求18至20中任一项所述的含稀土磷酸盐的物质，其特征在于，以P2O5计，所述含磷酸的溶液中磷酸的质量浓度为15％～50％，优选为15％～30％；所述含磷酸的溶液与所述含独居石和/或磷钇矿的磷矿按照液固比为2～10L：1kg的比例混合的步骤，优选所述液固比为3～6L：1kg。
PCT/CN2016/085827 2015-06-19 2016-06-15 从含稀土磷矿中回收磷和稀土的方法及含稀土磷酸盐的物质 WO2016202257A1 (zh)

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