阅读说明：本技术 一种浸取磷矿中钙离子的方法 (Method for leaching calcium ions in phosphorite ) 是由 张建军 黄德明 华建青 刘法安 于 2018-08-31 设计创作，主要内容包括：本发明提供了一种浸取磷矿中钙离子的方法,所述方法包括如下步骤,将含有氢氧化钙的磷矿的固液混合物与铵离子水溶液充分混合形成固液反应体系；控制所述固液反应体系中溶液的pH为9-11进行钙离子浸取反应；浸取时间T分钟后将固液反应体系进行固液分离,分别获得具有预设浸取率的含有可溶性钙离子的液体和浸钙后的固体磷矿,其中T为5-20。本发明提供的浸取磷矿中钙离子的方法能够高效浸取钙离子,并且其中钙离子溶液中的镁离子杂质较少,由于钙离子应用工艺中获得纯度较高的碳酸钙或者其他含钙肥料。(The invention provides a method for leaching calcium ions in phosphorite, which comprises the following steps of fully mixing a solid-liquid mixture of the phosphorite containing calcium hydroxide with an ammonium ion aqueous solution to form a solid-liquid reaction system; controlling the pH value of the solution in the solid-liquid reaction system to be 9-11 to carry out calcium ion leaching reaction; and after the leaching time is T minutes, carrying out solid-liquid separation on the solid-liquid reaction system to respectively obtain a liquid containing soluble calcium ions and solid phosphorite after calcium leaching with a preset leaching rate, wherein T is 5-20. The method for leaching calcium ions in phosphorite provided by the invention can efficiently leach calcium ions, and magnesium ion impurities in the calcium ion solution are less, and calcium carbonate or other calcium-containing fertilizers with higher purity are obtained in the calcium ion application process.)

1. A method for leaching calcium ions in phosphorite is characterized by comprising the following steps:

fully mixing the solid-liquid mixture of the phosphorite containing the calcium hydroxide with the ammonium ion aqueous solution to form a solid-liquid reaction system;

controlling the pH value of the solution in the solid-liquid reaction system to be 9-11 to carry out calcium ion leaching reaction;

and after the leaching time is T minutes, carrying out solid-liquid separation on the solid-liquid reaction system to respectively obtain a liquid containing soluble calcium ions and solid phosphorite after calcium leaching with a preset leaching rate, wherein T is 5-20.

2. The method according to claim 1, characterized in that when the mass ratio of the solid-liquid mixture of calcium hydroxide-containing phosphorus ore to the aqueous solution of ammonium ions is a preset mass ratio, the mass concentration of ammonium ions in the aqueous solution of ammonium ions is a preset concentration, and the average particle size of the solid particles in the solid-liquid mixture of calcium hydroxide-containing phosphorus ore is a preset particle size, the leaching time T is determined according to the leaching temperature of the calcium ion leaching reaction so that the leaching time T is 5 to 20 minutes.

3. The method according to claim 2, characterized in that when the solid-liquid ratio in the solid-liquid mixture of the calcium hydroxide-containing phosphorite is 1 to (1.2-1.8), when the preset mass ratio is 1: (0.5-3), wherein the preset concentration is 30-35%, and the preset particle size is 0.2-4 mm;

the leaching time T satisfies the following relation:

T＝45-(0.8-1.1)*C

wherein T is leaching time, T is unit of minute, C is leaching temperature, C is unit of centigrade, the leaching temperature is average temperature before leaching under leaching condition meeting pH requirement, and the value of C is 20-45.

4. The method according to claim 3, wherein the leaching time T satisfies the following relation:

T＝45-1*C。

5. the method according to claim 3, characterized in that said preset mass ratio is 1:1, the preset concentration is 30%, and the preset particle size is 0.2-1 mm.

6. The method according to claim 1, wherein the solid-liquid reaction system comprises an ammonium ion supply step, and the ratio of the molar quantity of ammonium ions in the ammonium ion supply step to the molar quantity of ammonia gas volatilized from the reaction system when the solid-liquid reaction system is subjected to the calcium ion leaching reaction is (0.1-1): 1.

7. The method according to claim 6, wherein the ammonium ion in the ammonium ion replenishment step is derived from ammonia gas volatilized from the solid-liquid reaction system during the calcium ion leaching reaction of the reaction system.

8. The method according to any one of claims 1 to 7, wherein the preset percentage is greater than 75%.

Technical Field

The invention relates to the technical field of fertilizers, in particular to a method for leaching calcium ions in phosphorite.

Background

Phosphorite is a non-renewable resource, although the phosphorite resource in China is relatively rich, the grade of the phosphorite is low, most of the phosphorite can be used for producing phosphoric acid, high-concentration phosphate fertilizer and the like only after being subjected to mineral separation and enrichment, the actual utilization rate of the phosphorite in China is low due to more impurities in the phosphorite, the phosphorus demand in China is particularly large, and the phosphorite resource in China is gradually exhausted after being exploited and utilized for many years. Especially, calcium in phosphorite can be used for calcium fertilizer, but the leaching rate of calcium ions in the existing method for leaching calcium ions is lower.

CN201710909154.6 discloses a method for improving the leaching efficiency of calcium in phosphorite, and a product and application thereof, wherein the method comprises the following steps: adjusting and controlling the pH value of an aqueous solution system containing phosphorite solid particles to be 7.2-8.2 and the ammonium ion concentration to be 0.5-3 mol/L to carry out leaching reaction for 0.5-5 hours. However, the method in this patent has a low leaching rate for leaching calcium ions and is easy to leach magnesium ions.

CN201510226236.1 discloses a method for extracting phosphate concentrate and co-producing calcium carbonate and magnesium oxide from phosphate tailings, which comprises the steps of calcining the phosphate tailings at high temperature, adding hot water into the calcined material for digestion treatment, then adding an ammonium nitrate solution for stirring, leaching calcium at a certain temperature to obtain a calcium-containing leachate and leaching residues, leaching magnesium from the leaching residues by using an ammonium sulfate solution to obtain phosphate concentrate and a magnesium-containing leachate, precipitating the calcium-containing leachate by using an ammonium carbonate solution to obtain calcium carbonate, precipitating the magnesium-containing leachate by using an ammonium carbonate solution to obtain magnesium carbonate, and calcining the magnesium carbonate to obtain magnesium oxide. The leaching rate of calcium ions in the method of this patent is not high.

Disclosure of Invention

In view of the above, the invention provides a method for efficiently leaching calcium ions in phosphorite. The specific method is described below.

A method for leaching calcium ions in phosphorite, comprising the following steps:

fully mixing the solid-liquid mixture of the phosphorite containing the calcium hydroxide with the ammonium ion aqueous solution to form a solid-liquid reaction system;

controlling the pH value of the solution in the solid-liquid reaction system to be 9-11 to carry out calcium ion leaching reaction;

and after the leaching time is T minutes, carrying out solid-liquid separation on the solid-liquid reaction system to respectively obtain a liquid containing soluble calcium ions and solid phosphorite after calcium leaching with a preset leaching rate, wherein T is 5-20.

Preferably, when the mass ratio of the solid-liquid mixture of calcium hydroxide-containing phosphate ores to the aqueous solution of ammonium ions is a preset mass ratio, the mass concentration of ammonium ions in the aqueous solution of ammonium ions is a preset concentration, and the average particle size of solid particles in the solid-liquid mixture of calcium hydroxide-containing phosphate ores is a preset particle size, the leaching time T is determined according to the leaching temperature of the calcium ion leaching reaction so that the leaching time T is 5 to 20 minutes.

Preferably, when the solid-liquid ratio in the solid-liquid mixture of the phosphorite containing the calcium hydroxide is 1 to (1.2-1.8), when the preset mass ratio is 1: (0.5-3), wherein the preset concentration is 30-35%, and the preset particle size is 0.2-4 mm;

the leaching time T satisfies the following relation:

T＝45-(0.8-1.1)*C

wherein T is leaching time, T is unit of minute, C is leaching temperature, C is unit of centigrade, the leaching temperature is average temperature before leaching under leaching condition meeting pH requirement, and the value of C is 20-45.

Preferably, the leaching time T satisfies the following relation:

T＝45-1*C。

preferably, the preset mass ratio is 1:1, the preset concentration is 30%, and the preset particle size is 0.2-1 mm.

Preferably, the solid-liquid reaction system comprises an ammonium ion supply step, and the ratio of the molar weight of ammonium ions in the ammonium ion supply step to the molar weight of ammonia gas volatilized from the reaction system in the calcium ion leaching reaction of the solid-liquid reaction system is (0.1-1): 1.

Preferably, the ammonium ion in the ammonium ion supplying step is derived from ammonia gas volatilized from the solid-liquid reaction system during the calcium ion leaching reaction of the solid-liquid reaction system.

Preferably, the preset percentage is greater than 75%.

The invention has the beneficial effects that: the method for leaching calcium ions in phosphorite provided by the invention can efficiently leach calcium ions, and magnesium ion impurities in the calcium ion solution are less, and calcium carbonate or other calcium-containing fertilizers with higher purity are obtained in the calcium ion application process.

Drawings

FIG. 1 is a flow chart of the method for leaching calcium ions in phosphorite.

Detailed Description

While the following is a description of the preferred embodiments of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Referring to fig. 1, the present invention provides a method for leaching calcium ions from phosphate ore, which includes steps S100, S200 and S300. The details are as follows.

And step S100, fully mixing the solid-liquid mixture of the phosphorite containing the calcium hydroxide with the ammonium ion aqueous solution to form a solid-liquid reaction system. It will be appreciated that the ammonium ion solution is derived from ammonium nitrate. The calcium ion leaching reaction is a reaction in which calcium hydroxide and ammonium ions react to form calcium ions and ammonium hydroxide, wherein the ammonium hydroxide is partially decomposed into water and ammonia gas. It is understood that the solid-liquid mixture of the phosphate rock containing calcium hydroxide is obtained by wet ball milling the phosphate rock, and the solid-liquid mixture of the phosphate rock containing calcium hydroxide comprises solid and liquid of the phosphate rock.

And S200, controlling the pH value of the solution in the solid-liquid reaction system to be 9-11 to carry out calcium ion leaching reaction.

And step S300, after the leaching time is T minutes, carrying out solid-liquid separation on the solid-liquid reaction system to respectively obtain a liquid containing soluble calcium ions and solid phosphorite after calcium leaching with a preset leaching rate, wherein T is 5-20. The preset leaching rate refers to the mole percentage of calcium ions in the liquid containing soluble calcium ions and calcium ions in the solid-liquid mixture of the phosphorite containing calcium hydroxide, and can also be referred to as the decalcification rate of the phosphorite solid in the solid-liquid mixture of the phosphorite containing calcium hydroxide.

The calcium content in the solid phosphorite after calcium leaching is obviously lower than that of the solid phosphorite before calcium leaching, preferably, after calcium ions are leached by the method, the percentage of the calcium ions in the obtained soluble calcium ion liquid in the solid phosphorite before calcium leaching is more than 75 percent, namely the preset leaching rate is more than 75 percent, and more preferably, the calcium ions can be leached by more than 80 percent (the preset leaching rate). In the method, calcium ions and ammonium hydroxide are generated by the reaction of ammonium ions and calcium hydroxide, the pH value of a reaction system needs to be strictly controlled, namely, the calcium ion leaching effect is better by adopting the conditions in the invention.

It will be appreciated that the solid phosphate rock includes calcium ions and magnesium ions, and the present invention is a calcium ion solution with higher leaching purity, because if magnesium ions stay in the liquid after the magnesium ions and calcium ions are leached out simultaneously, the liquid containing magnesium ions has an influence on the subsequent application of calcium ions, for example, when the leached calcium ion-containing solution is used for the subsequent preparation of calcium carbonate, the magnesium ions contained therein influence the purity of the calcium carbonate product. In order to prevent the magnesium ions in the solid phosphate ore from being leached out, or the leaching amount of the magnesium ions is small enough not to influence the application effect of the subsequent calcium ion product. The method controls the pH value of the solution in the solid-liquid reaction system to be 9-11 to carry out calcium ion leaching reaction, and magnesium ions cannot be easily leached out at the pH value. More preferably, under continuous trial and experiment of the applicant of the invention, the calcium ion leaching reaction is carried out by controlling the pH of the solution in the solid-liquid reaction system to be 10-10.5, so that the calcium ion solution with higher purity can be obtained.

It can be understood that the method of the invention can control the leaching time to be 5-20 minutes while obtaining the calcium ion solution with higher purity, so as to ensure the leaching efficiency of leaching calcium ions from solid phosphorite.

In a further embodiment, when the mass ratio of the solid-liquid mixture of calcium hydroxide-containing phosphate ores to the aqueous solution of ammonium ions is a predetermined mass ratio, the mass concentration of ammonium ions in the aqueous solution of ammonium ions is a predetermined concentration, and the average particle size of solid particles in the solid-liquid mixture of calcium hydroxide-containing phosphate ores is a predetermined particle size, the leaching time T is determined according to the leaching temperature of the calcium ion leaching reaction so that the leaching time T is 5 to 20 minutes. It will be appreciated that the leaching time and leaching temperature of the calcium ion leaching reaction have a significant effect when other conditions are fixed in the leaching reaction of calcium ions, and that suitable leaching temperatures enable rapid leaching of calcium ions from phosphate ores containing calcium hydroxide. It is understood that when ammonium ions are derived from ammonium nitrate, the mass concentration of the ammonium ions refers to the mass concentration of ammonium nitrate.

It can be understood that the solid phosphorus ore in the solid-liquid mixture of the phosphorus ore containing calcium hydroxide contains 20 to 30 mass percent of phosphorus pentoxide, 41 to 55 mass percent of calcium oxide, 5 to 13 mass percent of magnesium oxide, 0.2 to 0.9 mass percent of iron oxide and 0.4 to 0.8 mass percent of aluminum oxide.

In a further embodiment, when the solid-liquid ratio in the solid-liquid mixture of the calcium hydroxide-containing phosphorite is 1: (1.2-1.8), when the preset mass ratio is 1: (0.5-3), wherein the preset concentration is 30-35%, and the preset particle size is 0.2-4 mm;

the leaching time T satisfies the following relation:

T＝45-(0.8-1.1)*C

wherein T is leaching time, T is unit of minute, C is leaching temperature, C is unit of centigrade, the leaching temperature is average temperature before leaching under leaching condition meeting pH requirement, and the value of C is 20-45.

It can be understood that, in order to complete the calcium ion leaching process within the controllable leaching time (T minutes) and ensure the leaching efficiency of calcium ions, the relationship between the leaching temperature and the leaching time is controlled by the above relation, so that the controllable and adjustable calcium ion leaching process is realized, and the process efficiency of the phosphate concentrate is further improved.

In a further embodiment, the leaching time T satisfies the following relation:

T＝45-1*C。

the above relationship between the leaching time and the leaching temperature can be satisfied by strictly controlling the conditions of the calcium ion leaching reaction, such as the above-mentioned predetermined mass ratio, predetermined concentration, and predetermined particle diameter.

In a further embodiment, the predetermined mass ratio is 1:1, the predetermined concentration is 30%, and the predetermined particle size is 0.2-1 mm. The particle size of the solid phosphate ore particles containing calcium hydroxide affects the surface contact area of the solid phosphate ore with the ammonium ion solution, and thus affects the calcium ion leaching reaction rate. The leaching effect is better by adopting the grain size range.

Reference may be made specifically to the following specific example 1.

The following will illustrate, by way of specific example 1 and experimental data, the relationship between leaching time and leaching temperature in the above examples: T45-1C, enables the calcium ion leaching process to complete within T minutes. And can ensure the purity of the calcium ion solution.