Potassium-containing phosphorite mineral-based soil conditioner and preparation method thereof

Abstract

The invention discloses a potassium-containing phosphorite mineral-based soil conditioner and a preparation method thereof.The preparation method comprises the steps that firstly, potassium-containing phosphorite is smashed and sieved, then the potassium-containing phosphorite, an alkali roasting agent and an activating auxiliary are mixed in proportion, water is added for full stirring, then calcination is conducted, roasted clinker is obtained, the roasted clinker is cooled and smashed, and the soil conditioner is obtained. According to the technical scheme, the potassium-containing phosphorite is subjected to alkali roasting to prepare the soil conditioner for the first time, dissolution of soluble potassium is promoted through an alkali roasting agent and an activating auxiliary agent, and loose and porous filter residues which contain citric potassium, phosphorus, silicon and calcium and are high in water absorption and slow in ion release are generated and used as the soil conditioner; the preparation process of the soil conditioner has the advantages of simplicity in operation, low reaction temperature, less pollution, low requirements on equipment and the like, realizes pollution-free and zero-emission high-added-value comprehensive utilization of potassium-containing phosphorite resources, and has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection and chemical material production, and more particularly to a soil conditioner based on potassium-containing phosphate rock and a preparation method thereof. Background Art

[0002] Lack of phosphorus and potassium is a prominent problem faced by crop cultivation. Phosphorus and potassium resources restrict the development of the fertilizer industry and also restrict the development of agriculture to a great extent. Most of the phosphorus and potassium resources are medium- and low-grade phosphate ore and insoluble potash ore. As early as 2002, the Ministry of Land and Resources listed phosphorus and potassium ore as urgently needed and important mineral resources in the "Overall Implementation Plan for National Mineral Resource Potential Assessment". The demand for phosphorus and potassium ore resources is increasing with the rapid development of the national economy.

[0003] In potassium phosphate ore, potassium feldspar is difficult to decompose under relatively mild conditions due to its high melting point and thermal stability. Therefore, how to decompose potassium feldspar and convert insoluble potassium, silicon and aluminum into soluble salts is the first step to achieve high-value utilization of potassium phosphate ore. Alkali decomposition has become a decomposition method that scholars have studied more in recent years. Sub-molten salt media such as NaOH or KOH have been successfully used to refine insoluble minerals such as chromium, vanadium, and aluminum. Its characteristics are low energy consumption at low temperature and high metal dissolution rate. However, when it is applied to the decomposition of potassium feldspar ore, there are still problems such as high alkalinity, inability to recycle raw materials, and low product added value.

[0004] Chinese patent application 201310317683.9 uses a ratio of potassium feldspar: potassium hydroxide: deionized water of 1:5-10:15-20, and conducts a hydrothermal reaction at 105-115°C for 2-6 hours to obtain soluble potassium. The patent involves a large amount of potassium hydroxide in the soluble potassium extraction process, high requirements on equipment, and the reaction slag produced is difficult to recycle and has poor actual production capacity.

[0005] There is no report on the preparation of soil conditioner by alkaline roasting of potassium-containing phosphate ore. Summary of the invention

[0006] In view of this, the present invention provides a potassium-containing phosphate rock-based soil conditioner and a preparation method thereof. The method solves the problems of high energy consumption, high cost, serious pollution, low potassium extraction rate, etc. in the prior art for extracting soluble potassium to a certain extent. At the same time, the reaction product is used to prepare a soil conditioner having beneficial effects on plant growth and soil improvement, thereby realizing the comprehensive utilization of potassium-containing phosphate rock with high added value.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] First, the present invention provides a potassium-containing phosphate mineral-based soil conditioner and a preparation method thereof, comprising the following steps:

[0009] S1. The potassium phosphate ore is crushed and ground and then passed through a 100-mesh sieve;

[0010] S2. The potassium-containing phosphate rock, the alkali roasting agent, and the activating aid are mixed in proportion to obtain a mixed material;

[0011] S3. Add water to the mixture, stir thoroughly and calcine to obtain a clinker;

[0012] S4. The roasted clinker is cooled naturally, crushed, ground, and sieved through a 20-100 mesh sieve to obtain a soil conditioner.

[0013] Preferably, the alkaline roasting agent is NaOH. Using NaOH as the alkaline roasting agent has the characteristics of high reaction activity and small amount of alkali, and can effectively destroy the molecular structure of potassium feldspar. The dissolution rate of potassium oxide in potassium phosphate ore can reach 90%.

[0014] Preferably, the activation aid is Na2CO3.

[0015] Preferably, in terms of weight ratio, potassium-containing phosphate ore: alkali roasting agent: activation aid = (30-80): (10-60): (3-30).

[0016] Preferably, the weight ratio is: mixed material: water = 5: (1-10).

[0017] Preferably, the calcination temperature in step S3 is 160-430° C. and the calcination time is 0.5-3 h.

[0018] Preferably, in step S4, the temperature is cooled to 20-50°C.

[0019] In addition, the present invention also provides a potassium-containing phosphate rock mineral-based soil conditioner prepared using the above technical solution.

[0020] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a potassium phosphate mineral-based soil conditioner and a preparation method thereof, which has the following beneficial effects:

[0021] The technical solution of the present invention is to prepare a soil conditioner by alkali roasting potassium-containing phosphate ore for the first time. By adding an alkali roasting agent and an activation aid, the dissolution of soluble potassium can be promoted, and a filter residue containing citric potassium, phosphorus, silicon and calcium can be generated. The filter residue has the characteristics of looseness and porosity, high water absorption rate, slow release of ions, etc., and has a water-retaining, fertilizer-retaining and air-permeable functional structure similar to the soil aggregate structure. The product contains many types of nutrients, including phosphorus, potassium, silicon, calcium, magnesium and other nutrients, has a long fertilizer effect, and the effective ingredients are not easy to be lost. It can be slowly and long-term supplied to crops for absorption, and can be used as a soil conditioner.

[0022] The soil conditioner preparation process of the present invention has the advantages of simple operation, low reaction temperature, less pollution, low equipment requirements, etc., realizes the pollution-free, zero-emission high-value-added comprehensive utilization of potassium-containing phosphate resources, and has good industrial application prospects. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] S1. The potassium phosphate ore is crushed and ground and then passed through a 100-mesh sieve;

[0026] S2. According to 100 parts by total weight, 55 parts of potassium phosphate rock, 40 parts of NaOH and 5 parts of Na2CO3 were proportioned to obtain a mixed material;

[0027] S3. 100 parts of water were added to the mixture and stirred thoroughly, and calcined at 210 ° C for 2.5h to obtain a clinker;

[0028] S4. The roasted clinker is naturally cooled to 20-50°C, crushed, ground and passed through a 20-mesh sieve to obtain a soil conditioner.

[0029] According to tests, the conversion rate of potassium in the prepared soil conditioner reached 90%. At the same time, P2O5, K2O, SiO2, CaO, and MgO were all converted into effective ingredients that can be absorbed by crops, and the total content of effective ingredients reached 75%.

[0030] Example 2

[0031] S1. The potassium phosphate ore is crushed and ground and then passed through a 100-mesh sieve;

[0032] S2. According to 100 parts by total weight, 80 parts of potassium phosphate rock, 15 parts of NaOH and 5 parts of Na2CO3 were proportioned to obtain a mixed material;

[0033] S3. 100 parts of water was added to the mixture and stirred thoroughly, and calcined at 300 ° C for 2.5h to obtain a clinker;

[0034] S4. The roasted clinker is naturally cooled to 20-50°C, crushed, ground and sieved through a 100-mesh sieve to obtain a soil conditioner.

[0035] According to tests, the conversion rate of potassium in the prepared soil conditioner reached 94%. At the same time, P2O5, K2O, SiO2, CaO, and MgO were all converted into effective ingredients that can be absorbed by crops, and the total content of effective ingredients reached 78%.

[0036] Comparative Example 1

[0037] The prepared potassium hydroxide solution with a mass concentration of 1g / L is added to a reactor with a cooling device, and potassium feldspar powder with a potassium oxide content of 13.94% and a silicon dioxide content of 66.41% (after crushing and passing through a 100-mesh sieve) is added according to a volume mass ratio (mL / g) of potassium hydroxide solution: potassium feldspar = 20:1, and calcium hydroxide is added to adjust the Ca / Si molar ratio in the mixture to 0.9, and the mixture is mixed evenly and reacted at 190°C for 6h, fully stirred, and cooled to below 100°C after the reaction is completed. The filtrate obtained by suction filtration of the reaction product is the soluble potassium solution; the filter residue is pulped twice, and the filter residue is dried at 100°C after suction filtration. After testing, the dissolution rate of K2O in the filter residue is 92.78%; the citric acid-soluble silicon dioxide in the filter residue contains 26.88% and the calcium oxide content is 32.01%.

[0038] Compared with the technology of comparative example 1, the technical scheme of the present invention does not need to use a pressure reactor, and the soil conditioner is directly roasted to obtain the soil conditioner. The P2O5, K2O, SiO2, CaO, and MgO in the obtained soil conditioner are all converted into effective components that can be absorbed by crops, and the total content of effective components can reach 78%. The preparation scheme of the present invention is simple, and the effect of the soil conditioner produced is better than the soil conditioner produced by the comparative example method.

[0039] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0040] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a potassium phosphate mineral-based soil conditioner, characterized in that: The following steps are involved: S1. The potassium phosphate ore is crushed and ground and then passed through a 100-mesh sieve; S2. The potassium-containing phosphate rock, the alkali roasting agent, and the activating aid are mixed in proportion to obtain a mixed material; S3. Add water to the mixture, stir thoroughly and calcine to obtain a clinker; S4. The roasted clinker is cooled naturally, crushed, ground, and sieved through a 20-100 mesh sieve to obtain a soil conditioner.

2. The method for preparing a potassium-containing phosphate mineral-based soil conditioner according to claim 1, characterized in that: The alkaline roasting agent is NaOH.

3. The method for preparing a potassium-containing phosphate mineral-based soil conditioner according to claim 1, characterized in that: The activation aid is Na2CO3.

4. The method for preparing a potassium-containing phosphate mineral-based soil conditioner according to claim 1, characterized in that: In terms of weight ratio, potassium-containing phosphate ore: alkali roasting agent: activation aid = (30-80): (10-60): (3-30).

5. The method for preparing a potassium-containing phosphate mineral-based soil conditioner according to claim 1, characterized in that: By weight ratio, mixed material: water = 5: (1-10).

6. The method for preparing a potassium-containing phosphate mineral-based soil conditioner according to claim 1, characterized in that: The calcination temperature in step S3 is 160-430° C. and the calcination time is 0.5-3 h.

7. The method for preparing a potassium-containing phosphate mineral-based soil conditioner according to claim 1, characterized in that: In step S4, the mixture is cooled to 20-50°C.

8. A potassium-containing phosphate mineral-based soil conditioner prepared by the method according to any one of claims 1 to 7.