A method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate by-product

Abstract

The invention discloses a method for preparing potassium-containing calcium sulfate from phosphate ore flotation tailings and potassium dihydrogen phosphate byproducts, and relates to the technical field of potassium-containing calcium sulfate preparation. The tailings after phosphate ore flotation are placed in a drying box, dried at 105-180°C for 0.5-3h, and then crushed to pass through a 100-mesh sieve to obtain tailings powder; the potassium dihydrogen phosphate byproduct phosphate and potassium fertilizer are placed in a drying box, dried at 100-120°C for 1.5-2h, and then passed through a 100-mesh sieve to obtain phosphate and potassium fertilizer powder; the tailings powder and the phosphate and potassium fertilizer powder are mixed, sulfuric acid is added, and the mixture is kept warm in a constant temperature water bath for 10-12 days, and the potassium-containing calcium sulfate product is obtained after cooling. The phosphate ore flotation tailings and the potassium dihydrogen phosphate byproduct phosphate and potassium fertilizer are dried separately, mixed in a certain proportion, and then sulfuric acid is added, and the mixture is kept warm in a constant temperature water bath for a certain period of time to convert the insoluble phosphorus and potassium therein into water-soluble components to obtain potassium-containing calcium sulfate. By making full use of the tailings with low phosphorus content after phosphate ore flotation, and using potassium dihydrogen phosphate with large specific surface area as a by-product of phosphorus and potassium fertilizer, low-cost potassium-containing calcium can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of potassium-containing calcium carbonate preparation, and in particular to a method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate by-product. Background Art

[0002] Ordinary superphosphate, referred to as superphosphate, is a phosphate fertilizer directly produced by decomposing phosphate rock with sulfuric acid. The main useful components are calcium dihydrogen phosphate hydrate Ca(H2PO4)2·H2O and a small amount of free phosphoric acid, and also contain anhydrous calcium sulfate (beneficial to sulfur-deficient soil). CN101913571A discloses a process for producing superphosphate using low-grade phosphate ore, which is crushed, dried and ground into powder after phosphate ore with a P2O5 content of less than 20%, then mixed with sulfuric acid, and then dried and matured to obtain the finished superphosphate product. However, this type of superphosphate has a single nutritional component and lacks the potassium element required by plants.

[0003] The main by-product of potassium dihydrogen phosphate is phosphorus-potassium fertilizer, of which effective P2O5 is about 42% and total K2O is about 10%, but the water-soluble potassium and water-soluble phosphorus account for a small proportion, and most of them are insoluble or slightly soluble in water. Citrate-soluble potassium and phosphorus, if they can be fully converted and utilized, can greatly improve the utilization rate of potassium dihydrogen phosphate by-products. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate by-product, so as to solve the problem that the existing calcium carbonate has a single nutrient component and the potassium dihydrogen phosphate by-product is difficult to utilize.

[0005] In order to solve the above technical problems, the present invention adopts the following technical scheme: a method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate by-product, characterized in that it comprises the following steps:

[0006] S1. Place the tailings after phosphate ore flotation in a drying oven, dry at 105-180°C for 0.5-3h, and then crush through a 100-mesh sieve to obtain tailings powder;

[0007] S2. Place the potassium dihydrogen phosphate byproduct phosphate and potash fertilizer in a drying oven, dry at 100 to 120° C. for 1.5 to 2 hours, and then pass through a 100-mesh sieve to obtain phosphate and potash fertilizer powder;

[0008] S3. After the tailings powder and phosphorus-potassium fertilizer powder are mixed, sulfuric acid is added, and the mixture is kept warm in a constant temperature water bath for 7 to 12 days. After cooling, a potassium-containing calcium product is obtained.

[0009] A further technical solution is that the mass ratio of the tailings powder to the phosphate-potassium fertilizer powder is 3.5-4.5:1, and the amount of sulfuric acid used is 0.6-0.9 of the weight of the mixture of the tailings powder and the phosphate-potassium fertilizer powder.

[0010] A further technical solution is that the sulfuric acid is a sulfuric acid solution with a mass concentration of 70%.

[0011] A further technical solution is that the P2O5 content in the tailings is 8.61%, the MgO content is 15.17%, the CaO content is 33.67%, and the SiO2 content is 6.01%.

[0012] A further technical solution is that the effective P2O5 content in the by-product phosphorus-potassium fertilizer of potassium dihydrogen phosphate is 40.59%, the citrate-soluble phosphorus content is 25.02%, the total K2O content is 10.02%, and the citrate-soluble potassium content is 5.42%.

[0013] A further technical solution is that the constant temperature water bath has a heat preservation temperature of 60-70°C.

[0014] Compared with the prior art, the invention has the following beneficial effects: after the phosphate ore flotation tailings and the potassium dihydrogen phosphate by-product phosphorus and potassium fertilizer are dried separately, mixed in a certain proportion, sulfuric acid is added, and kept warm in a constant temperature water bath for a certain period of time, the insoluble phosphorus and potassium therein are converted into water-soluble components to obtain potassium-containing calcium. The tailings with low phosphorus content after phosphate ore flotation are fully utilized, and the potassium dihydrogen phosphate by-product phosphorus and potassium fertilizer with a large specific surface area is utilized to obtain low-cost potassium-containing calcium, which has more comprehensive nutritional components and is convenient for its market promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] Example 1

[0018] S1. Place the tailings after phosphate ore flotation in a drying oven, dry at 105°C for 3 hours, and then crush through a 100-mesh sieve to obtain tailings powder. The composition of the tailings after phosphate ore flotation is as follows:

[0019] Sample name <![CDATA[P2O5%]]> MgO% <![CDATA[Fe2O3%]]> <![CDATA[Al2O3%]]> CaO% <![CDATA[SO3%]]> <![CDATA[K2O%]]> <![CDATA[Na2O%]]> MnO% <![CDATA[SiO2%]]> Tailings 8.61 15.17 0.69 0.40 33.67 0.36 0.21 0.27 0.21 6.01

[0020] S2. Place the potassium dihydrogen phosphate byproduct phosphate and potash fertilizer in a drying oven, dry at 105°C for 2 hours, and then pass through a 100-mesh sieve to obtain phosphate and potash fertilizer powder. The components of the potassium dihydrogen phosphate byproduct phosphate and potash fertilizer are as follows:

[0021]

[0022] S3. After the tailings powder and phosphorus-potassium fertilizer powder are mixed at a mass ratio of 4:1, sulfuric acid with a mass concentration of 70% is added, which is 0.64 times the mass of the mixture, and the mixture is kept warm at 60°C in a constant temperature water bath for 10 days. After cooling, the finished potassium-containing calcium product is obtained. The ingredients of the finished potassium-containing calcium product are as follows, which meet the requirements of Class I qualified products in the "GB 20413-2017 Superphosphate Standard":

[0023] <![CDATA[Available P2O5%]]> <![CDATA[Water-soluble P2O5%]]> <![CDATA[Free acid P2O5%]]> S％ <![CDATA[Free water H2O%]]> 13.88 9.36 Not detected 13.61 2.88

[0024] Example 2

[0025] S1. Place the tailings after phosphate ore flotation in a drying oven, dry them at 120°C for 0.5h, and then crush them through a 100-mesh sieve to obtain tailings powder.

[0026] S2. Place the potassium dihydrogen phosphate by-product phosphate and potash fertilizer in a drying oven, dry at 100°C for 2 hours, and then pass through a 100-mesh sieve to obtain phosphate and potash fertilizer powder.

[0027] S3. After the tailings powder and the phosphate-potassium fertilizer powder are mixed in a mass ratio of 4.5:1, sulfuric acid with a mass concentration of 70% which is 0.6 times the mass of the mixture is added, and the mixture is kept warm at 70°C in a constant temperature water bath for 10 days, and the potassium-containing calcium product is obtained after cooling.

[0028] Example 3

[0029] S1. Place the tailings after phosphate ore flotation in a drying oven, dry them at 180°C for 0.5h, and then crush them through a 100-mesh sieve to obtain tailings powder.

[0030] S2. Place the potassium dihydrogen phosphate by-product phosphate and potash fertilizer in a drying oven, dry at 120°C for 1.5 hours, and then pass through a 100-mesh sieve to obtain phosphate and potash fertilizer powder.

[0031] S3. After the tailings powder and the phosphate-potassium fertilizer powder are mixed in a mass ratio of 3.8:1, sulfuric acid with a mass concentration of 70% which is 0.75 times the mass of the mixture is added, and the mixture is kept warm at 65°C in a constant temperature water bath for 12 days. After cooling, a potassium-containing calcium product is obtained.

[0032] Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope of this disclosure.

Claims

1. A method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate by-products, characterized in that The steps include: S1. Place the tailings after phosphate ore flotation in a drying oven, dry at 105-180°C for 0.5-3h, and then crush through a 100-mesh sieve to obtain tailings powder; S2. Place the potassium dihydrogen phosphate byproduct phosphate and potash fertilizer in a drying oven, dry at 100 to 120° C. for 1.5 to 2 hours, and then pass through a 100-mesh sieve to obtain phosphate and potash fertilizer powder; S3. The tailings powder and the potassium phosphate fertilizer powder were mixed and sulfuric acid was added, and the mixture was kept warm in a constant temperature water bath for 7 to 12 days, and the potassium-containing calcium product was obtained after cooling; The mass ratio of the tailings powder to the phosphate-potassium fertilizer powder is 3.5-4.5:1, the amount of sulfuric acid used is 0.6-0.9 of the weight of the mixture of the tailings powder and the phosphate-potassium fertilizer powder; the sulfuric acid is a sulfuric acid solution with a mass concentration of 70%; the insulation temperature of the constant temperature water bath is 60-70°C.

2. The method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate byproduct according to claim 1, characterized in that: The tailings contain 8.61% P2O5, 15.17% MgO and 33.67% CaO. The SiO2 content is 6.01%.

3. The method for preparing potassium-containing calcium carbonate from phosphate ore flotation tailings and potassium dihydrogen phosphate byproduct according to claim 1, characterized in that: The potassium dihydrogen phosphate by-product phosphorus-potassium fertilizer has an effective P2O5 content of 40.59%, a citrate-soluble phosphorus content of 25.02%, a total K2O content of 10.02%, and a citrate-soluble potassium content of 5.42%.

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