WO2019028958A1 - 一种利用盐酸与磷矿生产磷酸钙盐的方法 - Google Patents

一种利用盐酸与磷矿生产磷酸钙盐的方法 Download PDF

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WO2019028958A1
WO2019028958A1 PCT/CN2017/100667 CN2017100667W WO2019028958A1 WO 2019028958 A1 WO2019028958 A1 WO 2019028958A1 CN 2017100667 W CN2017100667 W CN 2017100667W WO 2019028958 A1 WO2019028958 A1 WO 2019028958A1
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calcium
phosphate
hydrochloric acid
phosphoric acid
producing
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PCT/CN2017/100667
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English (en)
French (fr)
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李进
王佳才
邹建
吴生平
侯隽
黄恒
张希阳
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川恒生态科技有限公司
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B25/00—Phosphorus; Compounds thereof
    • C01B25/16—Oxyacids of phosphorus; Salts thereof
    • C01B25/26—Phosphates
    • C01B25/32—Phosphates of magnesium, calcium, strontium, or barium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • C01P2006/82—Compositional purity water content

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  • the invention belongs to the technical field of feed and fertilizer, and particularly relates to a method for producing calcium phosphate salt by using hydrochloric acid and phosphate rock, especially medium and low grade phosphate rock.
  • Calcium phosphate salt can be used as fertilizer grade calcium phosphate salt, widely used in agricultural production, mainly used as raw material for compound fertilizer, and can also be directly applied to farmland; calcium phosphate salt can be used as feed grade calcium phosphate salt, suitable for Animals such as livestock and poultry, aquatic products, etc. are feed additives used to supplement calcium and phosphorus nutrition of livestock and poultry and aquatic animals.
  • China's phosphate rock must be subjected to beneficiation and enrichment to meet the demand for phosphoric acid and high-concentration phosphorus compound fertilizer production; more difficult to select ore, less easy to select, and less in China's phosphate reserves.
  • 90% of China's phosphate rock is high-magnesium phosphate, and the fine minerals in the ore are fine-grained. It is closely combined with gangue and is not easy to separate.
  • China Phosphate Ore is one of the most difficult phosphate ore in the world.
  • most of the methods for producing feed grade or fertilizer grade calcium phosphate salt are to firstly use sulfuric acid to react with phosphorus concentrate to form wet process phosphoric acid.
  • the wet process phosphoric acid is pretreated, defluorinated and purified, and then reacted with calcium source such as calcium carbonate to form calcium phosphate salt.
  • the slurry is dried by high temperature atomization to obtain a qualified product. The process is complicated, the cost is high, and the adaptability to the phosphate raw material is poor.
  • Patent CN105921259A discloses a method for producing feed grade calcium dihydrogen phosphate by using medium and low grade mixed phosphate rock, which seems to use medium and low grade phosphate rock as raw material, but actually the medium and low grade calcium magnesium phosphate rock ore is actually used.
  • the inhibitor and the collector are sequentially added to the slurry, and the flotation is reversed to obtain a phosphate concentrate which is further reacted with sulfuric acid.
  • most of the existing processes for producing calcium phosphate salt first convert calcium in phosphate rock into phosphogypsum (calcium sulfate with high impurity) as industrial waste, and the storage and digestion of phosphogypsum is a difficult point in the industry.
  • phosphogypsum calcium sulfate with high impurity
  • the present invention provides a method for producing phosphorus using hydrochloric acid and phosphate rock.
  • the method of calcium salt includes the following steps:
  • the filtrate obtained in the step A is concentrated and then mixed with phosphoric acid.
  • the mass concentration of the hydrochloric acid is 5% or more.
  • the hydrochloric acid has a mass concentration of 20 to 30%.
  • the reaction temperature is from room temperature to 80 °C.
  • the phosphoric acid is added in an amount such that the excess calcium is completely converted into a calcium phosphate salt; the excess calcium means the phosphoric acid in the filtrate obtained in the step A. Calcium remaining after calcium is converted to calcium phosphate.
  • step B adding excess phosphoric acid to completely convert excess calcium into calcium dihydrogen phosphate, through the step After the C fine slurry is dechlorinated, defluorinated and dehydrated, a phosphoric acid neutralizer is added to convert the remaining phosphoric acid into calcium dihydrogen phosphate.
  • the phosphoric acid neutralizing agent is at least one of lime, calcium carbonate, calcium phosphate or decalcified tricalcium phosphate.
  • the mixing temperature is from room temperature to 80 °C.
  • the heating dechlorination, defluorination, and dehydration are carried out by any one of negative pressure concentration, oven drying, atomization, a disk or a cylinder.
  • the hydrogen chloride gas recovery generated in the steps B and C is used for recycling in the step A.
  • the method of the invention is applicable not only to high-grade phosphate rock and phosphorus concentrate, but also has the effect of removing impurities and purifying in process step A, and is particularly suitable for low-grade phosphate rock, thereby eliminating the process investment for the selective treatment of raw material phosphate rock; Due to the high price of low-grade phosphate reserves, the process has significant cost advantages.
  • the calcium in the calcium phosphate salt prepared by the method of the invention is all derived from the calcium in the phosphate rock, does not add the calcium source, saves resources and reduces the cost; in step A, the calcium of the phosphate rock is completely converted into ionic calcium. Phosphoric acid and ionic calcium can fully react without encapsulation.
  • the calcium phosphate product has high purity and low free acid content. The subsequent products are not easy to agglomerate and have excellent quality. It meets GBT22548-2008 feed grade dicalcium phosphate and GBT22549-2008. Requirements for feed grade monocalcium phosphate.
  • Part of the phosphorus in the calcium phosphate salt prepared by the method of the present invention is derived from phosphorus in the phosphate rock, and this part of P 2 O 5 is not obtained by preparing phosphoric acid by sulfuric acid, so that no difficult to treat phosphogypsum is produced, and industrial waste is reduced.
  • the discharge of materials, the implementation of this process has extremely high social and economic benefits.
  • Step C of the method of the invention completes the four purposes of dechlorination, defluorination, dehydration and promotion of product production by heating one process, improves production efficiency, realizes efficient production of calcium phosphate salt, and does not require external defluorination agent. Chemical defluorination optimizes processes and saves costs.
  • the hydrochloric acid produced by the method of the invention can be closed and recycled, reduce tail gas emissions, does not cause environmental pollution, and reduces consumption of other production factors, and has extremely high economic and environmental benefits.
  • Figure 1 is a schematic diagram of the process flow of the method of the present invention
  • A hydrochloric acid and phosphate rock reaction, filtering to obtain filter residue and filtrate; filter residue is discarded or used for other purposes, the filtrate is further processed, at this time the filtrate mainly contains Ca 2+ , Cl - , H + , phosphate, etc.;
  • the filtrate and phosphoric acid are mixed to prepare a fine slurry; at this time, the fine slurry mainly contains Ca 2+ , Cl - , H + , phosphate, a small amount of calcium dihydrogen phosphate;
  • the finely tuned slurry is heated to remove hydrogen chloride, hydrogen fluoride and water in the system, and simultaneously produces calcium phosphate salt, thereby obtaining a qualified calcium phosphate salt in one step.
  • the calcium phosphate salt refers to calcium monohydrogen phosphate, calcium dihydrogen phosphate or monocalcium phosphate.
  • the phosphate rock used is a phosphate concentrate, a high-middle and low-grade phosphate rock, and the active component is Ca 5 F(PO 4 ) 3 . It is generally accepted in the industry that P 2 O 5 is in the middle grade phosphate rock in 24-28%, low-grade phosphate rock in 18-24%, and high-grade phosphate rock in 28%.
  • the filtrate obtained in the step A is concentrated, it is mixed with phosphoric acid to remove most of the water in the filtrate, so that the step D is dechlorinated, defluorinated, and dehydrated without removing a large amount of water, thereby greatly saving the overall energy consumption.
  • the recovered hydrochloric acid has a higher concentration, which is more conducive to recycling.
  • the raw material phosphate rock is decomposed by hydrochloric acid, and the content of impurity ions such as Al 3+ , Mg 2+ , Fe 3+ in the filtrate can be reduced due to the high content of Cl ⁇ and F ⁇ , so that most of the impurities enter the filter residue, and the obtained A filtrate having a low impurity content, so that the method of the present invention does not require the addition of an additional purification step, and a calcium phosphate salt product of acceptable quality can be obtained.
  • impurity ions such as Al 3+ , Mg 2+ , Fe 3+ in the filtrate can be reduced due to the high content of Cl ⁇ and F ⁇ , so that most of the impurities enter the filter residue, and the obtained A filtrate having a low impurity content, so that the method of the present invention does not require the addition of an additional purification step, and a calcium phosphate salt product of acceptable quality can be obtained.
  • the amount of hydrochloric acid is not particularly limited, but if the amount of hydrochloric acid is too high, the equipment load is increased, and the hydrochloric acid recovery is not favorable, and the raw materials are wasted at the same time; if the amount of hydrochloric acid is too low, the decomposed phosphate rock may be incomplete.
  • the decomposition of the phosphate rock by hydrochloric acid is easy, and the normal concentration of hydrochloric acid is 20 to 30%, and the phosphate rock can be completely decomposed in a few minutes. Therefore, the concentration of the hydrochloric acid in the step A hydrochloric acid decomposition, the reaction temperature, and the reaction time are not particularly limited.
  • Low hydrochloric acid concentration can also decompose phosphate rock, but it is necessary to prolong the reaction time and / or increase the reaction temperature, and the amount of hydrochloric acid is increased, which is not conducive to the later dechlorination, defluorination, dehydration, increase equipment load and increase energy consumption;
  • the lower the reaction temperature the higher the concentration of hydrochloric acid is used and/or the reaction time is prolonged; however, the hydrochloric acid concentration, the reaction temperature, and the reaction time only affect the reaction efficiency, and have no effect on the quality of the obtained product itself. From the viewpoints of efficiency, economy, and the like, it is preferred that the mass concentration of hydrochloric acid is 5% or more. Further, the mass concentration of hydrochloric acid is 20 to 30%.
  • the reaction temperature is normal temperature, and the reaction temperature may be adjusted according to actual production requirements, such as controlling the reaction temperature to room temperature to 80 °C.
  • the decomposition rate of the phosphate rock is more than 95%, and the sufficient reaction can be judged. If the reaction is insufficient, the waste of the raw material phosphate rock may be caused, which affects the yield, but has no effect on the quality of the obtained product itself.
  • the source and concentration of the externally added phosphoric acid are not particularly limited, and the conventional concentration may be used.
  • Phosphoric acid produced by processes such as wet process phosphoric acid or thermal process phosphoric acid can be used.
  • the amount of phosphoric acid is determined depending on the particular calcium phosphate salt species to be produced. Specifically, from the theoretical calculation amount, it is assumed that the filtrate obtained in the step A contains 3 mol of phosphoric acid and 5 mol of calcium chloride. When the product is monocalcium phosphate, 3 mol of phosphoric acid needs to consume 3 mol of calcium, and 2 mol of calcium remains. An additional 2 mol of phosphoric acid is required to react with the remaining 2 mol of calcium so that the resulting product is completely monocalcium phosphate.
  • the amount of phosphoric acid added in step B is such that the excess calcium is completely converted to the calcium phosphate salt; the excess calcium refers to the calcium remaining after the conversion of the phosphoric acid and calcium into the calcium phosphate salt in the filtrate obtained in step A.
  • step B an excessive amount of phosphoric acid is added to completely convert the excess calcium into calcium dihydrogen phosphate, and then the finely adjusted slurry in step C is heated, dechlorinated, defluorinated, dehydrated, and then added.
  • the amount of phosphoric acid neutralizing agent converts the remaining phosphoric acid into calcium dihydrogen phosphate; the phosphoric acid neutralizing agent is at least one of lime, calcium carbonate, calcium phosphate or decalcified tricalcium phosphate.
  • step B when additional phosphoric acid is added in step B, the phosphoric acid and calcium in the filtrate of step A itself do not form calcium phosphate salt.
  • the phosphoric acid and calcium in the filtrate of step A itself do not form calcium phosphate salt.
  • only part of the calcium ion is removed by theoretical calculation, and the remaining calcium needs additional phosphoric acid.
  • the reaction is carried out to form the corresponding calcium phosphate salt.
  • the mixing temperature and the mixing time are not particularly limited. Simply mix at room temperature, or adjust the mixing temperature and mixing time as needed. For example, adjust the mixing temperature to room temperature to 80 °C.
  • the heating dechlorination, defluorination, and dehydration are not particularly limited as long as the water, hydrogen chloride, and hydrogen fluoride in the system can be removed, and the reaction can be carried out to the right.
  • Conventional methods such as crystallization, disc, and cylinder can be used, and the heating temperature and time are determined according to different heating methods and without decomposing the calcium phosphate salt.
  • the reaction is promoted to the right due to the reduction of hydrogen chloride, which is equivalent to one step of heating step, simultaneously achieving dechlorination, defluorination, dehydration and promoting product production.
  • the relatively small amount of hydrogen chloride produced in the step B of the method of the invention and the relatively large amount of hydrogen chloride produced in the step C can be recovered for the decomposition of the phosphate rock in the step A, thereby realizing the recycling of the hydrogen chloride and saving the cost.
  • the main components of the phosphate rock used in this example are shown in Table 1 below.
  • the main components of the phosphoric acid used are shown in Table 2 below:
  • A. Mix the medium grade phosphate rock with the mass concentration of 21% hydrochloric acid by CaO..HCl 1..2.1, that is, weigh 5000g of medium grade ore, 13221g of 21% hydrochloric acid, and carry out acid hydrolysis reaction at 35 °C for 1h.
  • the slurry is filtered and washed with 1500 g of clear water three times to obtain a filtrate and a filter residue; after testing, the main indexes of the filtrate obtained in the step A are: P 2 O 5 is 7.84%, and Ca is 8.73%;
  • Fine-tuning slurry is deoxidized, defluorinated and dried by high-temperature atomization in the atomization tower.
  • the atomization inlet air temperature is controlled at 340 °C and the exhaust gas temperature is 140 °C.
  • fluorine and chlorine are carried away with evaporation of water vapor.
  • the white, powdery, and highly mobile calcium dihydrogen phosphate receives about 2,500 g of product, and the exhaust gas is recovered by using a washing tower.
  • the main components of the phosphate rock used in this embodiment are shown in Table 4 below.
  • the main components of the phosphoric acid used are shown in Table 5 below:
  • A. Mix the phosphate concentrate with the mass concentration of 30% hydrochloric acid by CaO..HCl 1..1.8, that is, weigh 5000g of phosphate concentrate, 9077g of 30% hydrochloric acid, and carry out acid hydrolysis reaction at 60 °C for 0.5h.
  • the slurry is filtered and 1500g of water is washed three times to obtain filtrate and filter residue; after testing, the main indexes of the filtrate obtained in step A are: P 2 O 5 is 10.80%, Ca is 11.16%;
  • Fine-tuning slurry is dechlorinated, defluorinated and dried in the disc drying equipment.
  • the heating temperature is controlled at 80 °C.
  • fluorine and chlorine are carried away with evaporation of water vapor to obtain white, powdery and highly mobile phosphoric acid.
  • Hydrogen calcium the exhaust gas is recovered by using a washing tower and discharged to the standard.
  • the main components of the phosphate rock used in this embodiment are shown in Table 7 below.
  • the main components of the phosphoric acid used are shown in Table 8 below:
  • Fine-tuning slurry is dechlorinated, defluorinated and dried in a negative pressure concentrating device.
  • the temperature of the slurry is controlled at 90 ° C and the degree of vacuum is -0.06 MPa.
  • fluorine and chlorine are carried away with evaporation of water vapor to obtain white and powder.
  • the first-two-calcium phosphate which has good fluidity, is discharged after using the lye to absorb the standard.
  • the main components of the phosphate rock used in this example are shown in Table 10 below.
  • the main components of the phosphoric acid used are shown in Table 11 below:
  • A. Mix the low-grade phosphate rock with the mass concentration of 10% hydrochloric acid by CaO..HCl 1..1.6, that is, weigh 5000g of low grade ore, 24960.2g of 10% hydrochloric acid, and carry out acid hydrolysis reaction at 50 °C. h, the slurry is filtered and washed with 1500 g of clear water three times to obtain a filtrate and a filter residue; after testing, the main indexes of the filtrate obtained in the step A are: P 2 O 5 is 6.12%, and Ca is 7.91%;
  • the finely tuned slurry is deoxidized, defluorinated and dried by high temperature atomization in the atomization tower.
  • the atomization inlet air temperature is controlled at 300 ° C and the exhaust gas temperature is 90 ° C.
  • fluorine and chlorine are carried away with evaporation of water vapor to obtain white.
  • the powdered calcium dihydrogen phosphate with good fluidity receives about 2500g of product, and the exhaust gas is recycled after using the washing tower for recycling.
  • the main components of the phosphate rock used in this example are shown in Table 13 below.
  • the main components of the phosphoric acid used are shown in Table 14 below:
  • A. Mix low-grade phosphate rock with 21% hydrochloric acid molar ratio CaO..HCl 1..2.1, ie weigh 5000g of low grade ore, 15398.4g of 21% hydrochloric acid, and carry out acid hydrolysis reaction at 30 °C. h, the slurry is filtered and washed with 1500 g of clear water three times to obtain a filtrate and a filter residue; after testing, the main indexes of the filtrate obtained in the step A are: P 2 O 5 is 5.11%, and Ca is 9.12%;
  • the finely tuned slurry is deoxidized, defluorinated and dried by high temperature atomization in the atomization tower.
  • the atomization inlet air temperature is controlled at 300 ° C and the exhaust gas temperature is 110 ° C.
  • fluorine and chlorine are carried away with evaporation of water vapor to obtain white.
  • the powdered calcium dihydrogen phosphate with good fluidity is exhausted after using the washing tower for recovery.
  • the invention not only has the advantages of simple operation, energy saving, high utilization rate of raw materials, but also excellent quality of the prepared products and meets the requirements for use.

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Abstract

提供一种利用盐酸与磷矿生产磷酸钙盐的方法，包括A.盐酸与磷矿反应，过滤得滤渣和滤液；B. 滤液与磷酸混合得精调料浆；C. 精调料浆经加热脱氯、脱氟、脱水，得磷酸钙盐。本方法可以以中低品位磷矿为原料，步骤简便，成本低，通过调整磷酸用量可制备不同种类的磷酸钙盐，所得产品品质优异。

Description

一种利用盐酸与磷矿生产磷酸钙盐的方法 技术领域
本发明属于饲料及肥料技术领域，具体涉及一种利用盐酸与磷矿尤其是中低品位磷矿生产磷酸钙盐的方法。
背景技术
磷酸钙盐可用作肥料级磷酸钙盐，广泛适用于农业生产中，主要用作配置复混肥的原料，也可直接施用于农田；磷酸钙盐可用作饲料级磷酸钙盐，适用于畜禽、水产等动物，是一种用于补充畜禽、水产动物钙磷营养的饲料添加剂。
行业内普遍认为P2O5在24％-28％为中品位磷矿，18％-24％为低品位磷矿。中国磷矿资源比较丰富，已探明资源总量仅次于摩洛哥，位居世界第二位。中国磷矿资源总体上具有以下几个主要特征：储量较大，分布集中；中低品位矿多，富矿少，中国磷矿品位较差，P2O5平均含量在17％左右，富矿仅占磷矿石总量的约8.5％，因此中国大部分的磷矿必须经过选矿富集后才能满足磷酸和高浓度磷复合肥生产的需求；难选矿多，易选矿少，在中国磷矿储量中，沉积型磷块盐(胶磷矿)多，占全国总储量的85％，其中大部分为中低品位矿石，同时中国磷矿90％是高镁磷矿，其矿石中有用矿物的粒度细，和脉石结合紧密，不易分离，中国磷矿石属世界上难选的磷矿石之一。
目前生产饲料级或肥料级磷酸钙盐的方法多为先使用硫酸与磷精矿反应生成湿法磷酸，湿法磷酸经过预处理、脱氟净化，再与碳酸钙等钙源反应生成磷酸钙盐料浆，经高温雾化烘干得到合格产品。该工艺流程复杂，成本高，对磷矿原料的适应性差。专利CN105921259A公开了一种利用中低品位混合磷矿石生成饲料级磷酸二氢钙的方法，看似采用中低品位磷矿作为原料，然而实际上还是将该中低品位钙镁质磷矿石矿浆中依次加入抑制剂和捕收剂，反浮选，制得磷精矿再进一步与硫酸反应。同时现有生产磷酸钙盐的工艺大多先将磷矿中的钙转化成磷石膏(杂质很高的硫酸钙)作为工业废弃物而排除掉，磷石膏的堆存和消化是本行业的难点，已经影响到本行业的可持续发展，而在后续生产磷酸钙盐的过程中又需要加入大量的碳酸钙等作为钙源，从而造成了资源的极大浪费。
发明内容
针对现有技术制备磷酸钙盐存在的问题，本发明提供了一种利用盐酸和磷矿生产磷 酸钙盐的方法。该方法包括以下步骤：
A、盐酸与磷矿反应，过滤得滤渣和滤液；
B、滤液与磷酸混合得到精调料浆；
C、精调料浆经加热脱氯、脱氟、脱水，即得磷酸钙盐。
其中，上述利用盐酸和磷矿制备磷酸钙盐的方法中，将步骤A所得滤液浓缩后再与磷酸混合。
优选的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤A中，所述磷矿与盐酸按摩尔比计CaO︰HCl＝1︰0.8～3。
进一步的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤A中，所述磷矿与盐酸按摩尔比计CaO︰HCl＝1︰1.6～2.4。
具体的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤A中，所述盐酸的质量浓度在5％以上。
优选的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤A中，所述盐酸的质量浓度为20～30％。
具体的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤A中，所述反应温度为常温～80℃。
具体的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤B中，所述磷酸的加入量使过量的钙完全转化为磷酸钙盐；所述过量的钙是指步骤A所得滤液中磷酸与钙转化为磷酸钙盐后剩余的钙。
进一步的，上述利用盐酸和磷矿生产磷酸钙盐的方法中，当磷酸钙盐为磷酸二氢钙时，步骤B中，加入过量的磷酸使过量的钙完全转化为磷酸二氢钙，经步骤C精调料浆加热脱氯、脱氟、脱水后，再加入磷酸中和剂使剩余的磷酸转化为磷酸二氢钙。所述磷酸中和剂为石灰、碳酸钙、磷酸钙或脱氟磷酸三钙中的至少一种。
具体的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤B中，所述混合温度为常温～80℃。
优选的，上述利用盐酸和磷矿生产磷酸钙盐的方法步骤C中，所述加热脱氯、脱氟、脱水采用负压浓缩、烘箱干燥、雾化、圆盘或圆筒中任意一种实现。
其中，上述利用盐酸和磷矿生产磷酸钙盐的方法中，步骤B、C产生的氯化氢气体回收用于步骤A中循环使用。
本发明方法具有以下有益效果：
1、本发明方法不但适用于高品位磷矿和磷精矿，由于工艺步骤A具有除杂提纯的作用特别适用于中低品位磷矿，省去了对原料磷矿精选处理的工序投资；由于中低品位磷矿储量大价格低，因此本工艺具有显著的成本优势。
2、本发明方法制备得到的磷酸钙盐中的钙全部来源于磷矿中的钙，不会外加钙源，节约资源，降低成本；步骤A中磷矿的钙全部转化为离子态的钙，磷酸与离子态的钙能充分反应，不产生包裹，磷酸钙盐产品纯度高，游离酸含量低，后续产品不易结块，质量优异，满足GBT22548-2008对饲料级磷酸二氢钙和GBT22549-2008对饲料级磷酸一氢钙的要求。
3、本发明方法制备得到的磷酸钙盐中的部分磷来源于磷矿中的磷，此部分P2O5没有通过硫酸制取磷酸获得，从而不产生难以处理的磷石膏，减少了工业废弃物的排放，实施本工艺具有极高的社会效益和经济效益。
4、本发明方法步骤C通过加热一个工序过程完成了脱氯、脱氟、脱水以及促进产品生产四个目的，提升了生产效率，实现了磷酸钙盐的高效生产；同时无需外加脱氟剂进行化学脱氟，优化了流程，节约了成本。
5、本发明方法产生的盐酸能够封闭循环回收利用，减少尾气排放，不会造成环境污染，同时减少了对其它生产要素的消耗，具有极高的经济效益和环保效益。
附图说明
图1本发明方法的工艺流程示意图
具体实施方式
一种利用盐酸和磷矿(尤其是中低品位磷矿)生产磷酸钙盐的方法，包括以下步骤：
A、盐酸与磷矿反应，过滤得滤渣和滤液；滤渣弃除或另作它用，滤液进行下一步处理，此时滤液中主要含有Ca2+、Cl-、H+、磷酸根等；
B、滤液与磷酸混合制备精调料浆；此时精调料浆中主要含有Ca2+、Cl-、H+、磷酸根、少量磷酸二氢钙等；
C、精调料浆经加热脱除体系中的氯化氢、氟化氢和水，并同时产生了磷酸钙盐，从而一步即得合格的磷酸钙盐。
本发明方法中，所述磷酸钙盐是指磷酸一氢钙、磷酸二氢钙或磷酸一二钙。
本发明方法中，所述采用的磷矿为磷精矿、高中低品位磷矿均可，有效成分均为Ca5F(PO4)3。行业内普遍认为P2O5在24～28％为中品位磷矿，18～24％为低品位磷矿，高于28％为高品位磷矿。
上述方法中，将步骤A所得滤液浓缩后，再与磷酸混合，除去了滤液中的大部分水，从而使步骤D脱氯、脱氟、脱水不用脱除大量的水，大大节约了整体能耗，并且回收得到的盐酸浓度较高，更有利于循环使用。
上述方法步骤A中，采用盐酸分解原料磷矿，由于Cl-、F-含量高，可降低滤液中Al3+、Mg2+、Fe3+等杂质离子含量，使杂质大部分进入滤渣，获得杂质含量少的滤液，因此本发明方法后续不需要加入额外纯化步骤，就能够获得质量合格的磷酸钙盐产品。
上述方法步骤A中，对盐酸用量无特别限定，但是如盐酸用量过高，会增大设备负荷，也不利于后期盐酸回收，同时浪费原料；如盐酸用量过低，会造成分解磷矿不完全，分解率低，造成磷矿浪费。所以，优选的，按摩尔比计，磷矿中的钙按CaO计，控制磷矿与盐酸CaO︰HCl＝1︰0.8～3。进一步优选的，CaO︰HCl＝1︰1.6～2.4。
上述方法步骤A中，盐酸分解磷矿很容易进行，在常温下，盐酸质量浓度为20～30％，一般几分钟就能够完全分解磷矿。所以，步骤A盐酸分解磷矿对盐酸的浓度、反应温度、反应时间都没有特别限定。低盐酸浓度也能分解磷矿，但需延长反应时间和/或升高反应温度，且盐酸用量增大，不利于后期加热脱氯、脱氟、脱水，增大设备负荷，增加能耗；同样，反应温度越低，则需使用高浓度盐酸和/或延长反应时间；但盐酸浓度、反应温度、反应时间仅影响反应效率，对所得产品本身的品质没有影响。从效率、经济等方面考虑，优选盐酸的质量浓度在5％以上。进一步的，盐酸的质量浓度为20～30％。优选反应温度常温即可，也可根据实际生产需要对反应温度进行一定调整，如控制反应温度为室温～80℃。
本发明方法中以磷矿分解率达到95％以上即可判断充分反应，如反应不够充分，可能会造成原料磷矿的浪费，影响产率，但对所得产品本身的品质没有影响。
上述方法步骤B中，对外加磷酸的来源及浓度均没有特别限制，常规浓度即可。采用湿法磷酸、热法磷酸等工艺生产出的磷酸均可。
此步骤B中，磷酸的用量根据需要生产的具体磷酸钙盐种类而定。具体的，从理论计算量来看，假设经测定，步骤A所得滤液中含有3mol磷酸和5mol氯化钙，当产品为磷酸一氢钙时，3mol磷酸需要消耗3mol钙，则还剩余2mol钙，则需要额外加入2mol磷酸与剩余的2mol钙反应，从而所得产物完全为磷酸一氢钙。当产品为磷酸二氢钙时，3mol磷酸需要消耗1.5mol钙，则还剩余3.5mol钙，则需要额外加入7mol磷酸与剩余的3.5mol钙反应，从而所得产物完全为磷酸二氢钙。如果欲得两者混合物，那么额外加入2与7mol之间的磷酸量即可。如果外加磷酸低于2mol，即磷酸不足，则会导致产 品中钙偏高，磷不足，无法达到国家标准；如果外加磷酸高于7mol，即磷酸过量，则会导致产品中游离酸过高，影响产品品质，需要再加入磷酸中和剂进行反调。总而言之，步骤B中磷酸的加入量为使过量的钙完全转化为磷酸钙盐；过量的钙是指步骤A所得滤液中磷酸与钙转化为磷酸钙盐后剩余的钙。
进一步的，由于氯化钙与磷酸反应生成磷酸钙盐和盐酸的反应为中强酸制强酸的反应，为可逆反应，所以，当产品为磷酸二氢钙时，若磷酸与钙离子比例仅仅根据理论计算刚好完全反应，可能导致反应不彻底，造成磷酸二氢钙产品不合格。所以，实际生产中为了保证产品合格，步骤B中需加入过量的磷酸使过量的钙完全转化为磷酸二氢钙，再经步骤C中精调料浆加热脱氯、脱氟、脱水后，加入相应量的磷酸中和剂使剩余的磷酸转化为磷酸二氢钙；所述磷酸中和剂为石灰、碳酸钙、磷酸钙或脱氟磷酸三钙中的至少一种。
实际上，步骤B中额外加入磷酸时，本身存在步骤A滤液中的磷酸与钙并未生成磷酸钙盐，此处只是通过理论计算将该部分钙离子刨除，剩余的钙则需要额外加磷酸与其进行反应生成相应的磷酸钙盐。
上述数据均是理论计算量，在实际的操作和反应过程中，可能存在一定偏差，只要保证制备得到的产品磷酸钙盐质量合格即可。
此步骤B中，对混合温度和混合时间无特别限定。常温下简单混合即可，也可根据需要调整混合温度和混合时间，如调整混合温度为室温～80℃。
此步骤C中，所述的加热脱氯、脱氟、脱水的方式无特别限定，只要能够使体系中的水、氯化氢、氟化氢除去，从而使反应向右进行即可，采用负压浓缩、雾化、圆盘、圆筒等常规方式均可，至于加热温度和时间根据不同的加热方式和不使磷酸钙盐分解而定。本发明方法步骤C在脱氯、脱氟、脱水时，由于氯化氢的减少，促进了反应向右进行，相当于一个加热步骤一步同时达到了脱氯、脱氟、脱水以及促进产品生产四个目的，有别于常规加入脱氟剂除去氟的化学脱氟，不仅操作简单、节约步骤，而且省去了大量脱氟剂的使用，节约原料，且获得了性能优异的磷酸钙盐产品。
本发明方法步骤B产生的相对少量氯化氢、步骤C产生的相对大量氯化氢能够回收用于步骤A中分解磷矿，从而实现了氯化氢的循环使用，节约了成本。
本发明方法涉及的主要的反应方程式如下：
磷矿分解：Ca5F(PO4)3+10HCl→3H3PO4(酸解)+5CaCl2+HF↑
产品为磷酸一氢钙时的化学方程式：
5CaCl2+3H3PO4(酸解)+2H3PO4(外加)→5CaHPO4+10HCl
产品为磷酸二氢钙时的化学方程式：
5CaCl2+3H3PO4(酸解)+7H3PO4(外加)→5Ca(H2PO4)2+HCl
产品为磷酸一二钙时的化学方程式：
CaCl2+H3PO4(酸解)+H3PO4(外加)→CaHPO4+Ca(H2PO4)2+HCl
实施例1
本实施例所采用磷矿主要成分见下表1，所采用的磷酸主要成分见下表2：
表1
原料名称 P2O5％ MgO％ CaO％ Fe2O3％ Al2O3％
中品位磷矿 26.32 1.78 40.98 1.73 1.53
表2
原料名称 P2O5％ CaO％ MgO％ Fe2O3％ Al2O3％
浓缩磷酸 54.88 未检出 2.35 0.30 0.20
A、将中品位磷矿与质量浓度为21％的盐酸按摩尔比CaO︰HCl＝1︰2.1混合，即称取中品位矿5000g，21％盐酸13221g，35℃条件下进行酸解反应1h，料浆经过滤、1500g清水分三次洗涤得到滤液与滤渣；经检测，步骤A所得滤液主要指标为：P2O5为7.84％、Ca为8.73％；
B、设定生成磷酸二氢钙产品的磷和钙的摩尔比P2O5/Ca＝1.1︰1，根据步骤A所得滤液中P2O5和Ca的量，计算浓缩磷酸的加入量，即取滤液5000g，需要加入浓缩磷酸2392.3g，在温度35℃条件下混合搅拌10min制得精调料浆；
C、精调料浆在雾化塔中经高温雾化脱氯、脱氟、干燥，控制雾化进风温度340℃、尾气温度140℃，雾化过程中氟、氯随水汽蒸发带走，得到白色、粉状、流动性佳的磷酸二氢钙，收到产品约2500g，尾气使用洗涤塔进行回收后达标排放。
本实施例所得产品磷酸二氢钙的主要成分见下表3：
表3
P总％ P水％ Ca％ F％ Cl％ 水份％ pH值
24.65 22.96 14.49 0.06 0.33 未检出 3.74
实施例2
本实施例所采用磷矿主要成分见下表4，所采用的磷酸主要成分见下表5：
表4
原料名称 P2O5％ MgO％ CaO％ Fe2O3％ Al2O3％
磷精矿 31.96 0.62 46.42 0.88 0.81
表5
原料名称 P2O5％ CaO％ MgO％ Fe2O3％ Al2O3％
湿法磷酸 42.16 0.10 2.09 0.44 0.37
A、将磷精矿与质量浓度为30％的盐酸按摩尔比CaO︰HCl＝1︰1.8混合，即称取磷精矿5000g，30％盐酸9077g，60℃条件下进行酸解反应0.5h，料浆经过滤、1500g清水分三次洗涤得到滤液与滤渣；经检测，步骤A所得滤液主要指标为：P2O5为10.80％、Ca为11.16％；
B、设定生成磷酸一氢钙产品的磷和钙的摩尔比P2O5/Ca＝1︰2，根据步骤A所得滤液中P2O5和Ca的量，计算湿法磷酸的加入量，即取滤液5000g，需要加入湿法磷酸3418.65g，在温度60℃条件下混合搅拌10min制得精调料浆；
C、精调料浆在圆盘干燥设备中进行脱氯、脱氟、干燥，控制加热温度80℃，加热过程中氟、氯随水汽蒸发带走，得到白色、粉状、流动性佳的磷酸一氢钙，尾气使用洗涤塔进行回收后达标排放。
本实施例所得产品磷酸一氢钙的主要成分见下表6所示：
表6
P总％ P枸％ Ca％ F％ Cl％ 水份％
17.2 15.9 21.86 0.13 0.88 0.6
实施例3
本实施例所采用磷矿主要成分见下表7，所采用磷酸主要成分见下表8：
表7
原料名称 P2O5％ MgO％ CaO％ Fe2O3％ Al2O3％
中品位磷矿 26.32 1.78 40.98 1.73 1.53
表8
原料名称 P2O5％ CaO％ MgO％ Fe2O3％ Al2O3％
湿法磷酸 42.16 0.10 2.09 0.44 0.37
A、将中品位磷矿与质量浓度为25％的盐酸按摩尔比CaO︰HCl＝1︰2.3混合，即称取中品位磷矿500g，25％盐酸1216g，40℃条件下进行酸解反应0.5h，料浆经过滤、150g清水分三次洗涤得到滤液与滤渣；经检测，步骤A所得滤液主要指标为：P2O5为8.81％、Ca为9.82％；
B、设定生成磷酸一二钙产品的磷和钙的摩尔比P2O5/Ca＝1︰1.5，根据步骤A所得滤液中P2O5和Ca的量，计算湿法磷酸的加入量，即取滤液500g，需要加入湿法磷酸192.6g，在温度60℃条件下混合搅拌10min制得精调料浆；
C、精调料浆在负压浓缩装置中进行脱氯、脱氟、干燥，控制料浆温度90℃，真空度-0.06MPa，浓缩过程中氟、氯随水汽蒸发带走，得到白色、粉状、流动性佳的磷酸一二钙，尾气使用碱液吸收后达标排放。
本实施例所得产品磷酸一二钙的主要成分见下表9：
表9
P总％ P水％ Ca％ F％ Cl％ 水份％ pH值
21.33 11.95 17.88 0.09 0.32 0.25 3.71
实施例4
本实施例所采用磷矿主要成分见下表10，所采用磷酸主要成分见下表11：
表10
原料名称 P2O5％ MgO％ CaO％ Fe2O3％ Al2O3％
低品位磷矿 23.42 1.78 42.55 1.73 1.53
表11
原料名称 P2O5％ CaO％ MgO％ Fe2O3％ Al2O3％
湿法磷酸 42.16 0.10 2.09 0.44 0.37
A、将低品位磷矿与质量浓度为10％的盐酸按摩尔比CaO︰HCl＝1︰1.6混合，即称取低品位矿5000g，10％盐酸24960.2g，50℃条件下进行酸解反应1.5h，料浆经过滤、1500g清水分三次洗涤得到滤液与滤渣；经检测，步骤A所得滤液主要指标为：P2O5为6.12％、Ca为7.91％；
B、设定生成磷酸二氢钙产品的磷和钙的摩尔比P2O5/Ca＝1︰1，根据步骤A所得滤液中P2O5和Ca的量，计算湿法磷酸的加入量，即取滤液5000g，需要加入湿法磷酸2605.10g，在温度35℃条件下混合搅拌10min制得精调料浆；
C、精调料浆在雾化塔经高温雾化脱氯、脱氟、干燥，控制雾化进风温度300℃、尾气温度90℃，雾化过程中氟、氯随水汽蒸发带走，得到白色、粉状、流动性佳的磷酸二氢钙，收到产品约2500g，尾气使用洗涤塔进行回收后达标排放。
本实施例所得产品磷酸二氢钙的主要成分见下表12：
表12
P总％ P水％ Ca％ F％ Cl％ 水份％ pH值
23.34 22.98 13.82 0.15 0.86 0.89 3.45
实施例5
本实施例所采用磷矿主要成分见下表13，所采用磷酸主要成分见下表14：
表13
原料名称 P2O5％ MgO％ CaO％ Fe2O3％ Al2O3％
低品位磷矿 18.82 1.98 47.25 2.83 1.83
表14
原料名称 P2O5％ CaO％ MgO％ Fe2O3％ Al2O3％
湿法磷酸 42.16 0.10 2.09 0.44 0.37
A、将低品位磷矿与质量浓度为21％的盐酸按摩尔比CaO︰HCl＝1︰2.1混合，即称取低品位矿5000g，21％盐酸15398.4g，30℃条件下进行酸解反应0.5h，料浆经过滤、1500g清水分三次洗涤得到滤液与滤渣；经检测，步骤A所得滤液主要指标为：P2O5为5.11％、Ca为9.12％；
B、设定生成磷酸二氢钙产品的磷和钙的摩尔比P2O5/Ca＝1.2︰1，根据步骤A所得滤液中P2O5和Ca的量，计算湿法磷酸的加入量，即取滤液5000g，需要加入湿法磷酸4002.51g，在温度35℃条件下混合搅拌10min制得精调料浆；
C、精调料浆在雾化塔经高温雾化脱氯、脱氟、干燥，控制雾化进风温度300℃、尾气温度110℃，雾化过程中氟、氯随水汽蒸发带走，得到白色、粉状、流动性佳的磷酸二氢钙，尾气使用洗涤塔进行回收后达标排放。
本实施例所得产品磷酸二氢钙的主要成分见下表15：
表15
Figure PCTCN2017100667-appb-000001
Figure PCTCN2017100667-appb-000002
综上可以看出，本发明不仅操作简单、节约能耗、原料利用率高，而且制备得到的产品质量优异，满足使用要求。

Claims (10)

  1. 利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：包括以下步骤：
    A、盐酸与磷矿反应，过滤得滤渣和滤液；
    B、滤液与磷酸混合得到精调料浆；
    C、精调料浆经加热脱氯、脱氟、脱水，即得磷酸钙盐。
  2. 根据权利要求1所述的利用盐酸和磷矿制备磷酸钙盐的方法，其特征在于：将步骤A所得滤液浓缩后再与磷酸混合。
  3. 根据权利要求1或2所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤A中，所述磷矿与盐酸按摩尔比计CaO︰HCl＝1︰0.8～3；优选为1︰1.6～2.4。
  4. 根据权利要求1～3任一项所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤A中，所述盐酸的质量浓度在5％以上；优选为20～30％。
  5. 根据权利要求1～4任一项所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤A中，所述反应温度为室温～80℃。
  6. 根据权利要求1～5任一项所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤B中，所述磷酸的加入量为使过量的钙完全转化为磷酸钙盐；所述过量的钙是指步骤A所得滤液中磷酸与钙转化为磷酸钙盐后剩余的钙。
  7. 根据权利要求6所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：当磷酸钙盐为磷酸二氢钙时，步骤B中，加入过量的磷酸使过量的钙完全转化为磷酸二氢钙，经步骤C精调料浆加热脱氯、脱氟、脱水后，再加入磷酸中和剂使剩余的磷酸转化为磷酸二氢钙。
  8. 根据权利要求1～7任一项所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤B中，所述混合温度为室温～80℃。
  9. 根据权利要求1～8任一项所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤C中，所述加热脱氯、脱氟、脱水采用负压浓缩、烘箱干燥、雾化、圆盘或圆筒中任意一种实现。
  10. 根据权利要求1～9任一项所述的利用盐酸和磷矿生产磷酸钙盐的方法，其特征在于：步骤B、C产生的氯化氢气体回收用于步骤A中循环使用。
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CN1803589A (zh) * 2006-01-25 2006-07-19 四川省犍为明丰化工有限公司 磷矿盐酸回收法生产饲料级磷酸氢钙和工业级磷酸的方法
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