Method for producing by-product yellow phosphorus slag from yellow phosphorus by unconventional electric furnace process, and use

Abstract

The present disclosure provides a method for producing value-added by-product yellow phosphorus slag through an unconventional electric furnace process, derived from yellow phosphorus. This method is related to the technical field of comprehensive utilization of mineral resources. The disclosed method involves the following steps: mixing mid-low-grade phosphate rock, silica, coke, and a cosolvent to create a blended material, subjecting the blended material to high-temperature reduction in a yellow phosphorus electric furnace to yield yellow phosphorus and water-quenched slag, and then drying the water-quenched slag using yellow phosphorus tail gas to obtain the yellow phosphorus slag. According to this disclosure, a P.sub.2O.sub.5CaOSiO.sub.2MgOR multi-component system is established using the blended material.

Claims

1. A method for: producing a by-product yellow phosphorus slag from said yellow phosphorus by an unconventional electric furnace process, comprising the following steps: mixing mid-low-grade phosphate rock, silica, coke, and a cosolvent to obtain a mixed material, and subjecting said mixed material to a high-temperature reduction in a yellow phosphorus electric furnace to obtain yellow phosphorus and a water-quenched slag; and drying said water-quenched slag with a yellow phosphorus tail gas to obtain said yellow phosphorus slag; wherein said cosolvent is one selected from a group consisting of boromagnesite, boric anhydride, borax, potassium sulfate, and sodium sulfate; said cosolvent is added at 0.1% to 10% of a weight of said mixed material based on a main oxide in said cosolvent; SiO.sub.2 and CaO in said mixed material are at a mass ratio of (0.7-0.9):1; and said high-temperature reduction is conducted at 1,450 C.

2. The method according to claim 1, wherein said mid-low-grade phosphate rock comprises P.sub.2O.sub.5 with a content of greater than or equal to 23%.

3. A fertilizer containing said yellow phosphorus slag prepared by the method according to claim 1, wherein said fertilizer comprises urea, monoammonium phosphate, potassium chloride, yellow phosphorus slag, a calcium magnesium phosphate fertilizer, zinc sulfate, ammonium chloride, and attapulgite that are at a mass ratio of (15-30):(10-15):(20-25):(15-25):(3-7):(0.1-2):(10-30):(1-5).

4. The fertilizer according to claim 3, wherein a preparation method of the fertilizer comprises: mixing said urea, said monoammonium phosphate, said potassium chloride, said yellow phosphorus slag, said calcium magnesium phosphate fertilizer, said zinc sulfate, said ammonium chloride, and said attapulgite to allow granulation, drying, cooling, sieving, and packaging to obtain said fertilizer.

5. The fertilizer according to claim 4, wherein said granulation refers to one selected from said group consisting of extrusion granulation, powder granulation, and coated fertilizer granulation with said urea as a core.

6. The fertilizer according to claim 5, wherein said fertilizer is used as a base fertilizer applied at 35 kg/mu to 50 kg/mu.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 shows a process schematic diagram of the method for producing a by-product yellow phosphorus slag from yellow phosphorus by an unconventional electric furnace process of the present disclosure in joint production of a fertilizer;

[0021] FIG. 2 shows a device for producing yellow phosphorus by an electric furnace process; 1-phosphorus recovery device, 2-nitrogen cylinder, 3-refractory material, 4-furnace body, 5-sample, 6-thermocouple, 7-graphite crucible, 8-base, 9-electric control cabinet;

[0022] FIG. 3 shows an influence of boromagnesite on a fusion characteristic temperature of materials under different additions; and

[0023] FIG. 4A shows an influence of a cosolvent on the deformation temperature DT, softening temperature ST, and fusion temperature FT;

[0024] FIG. 4B is another comparison diagram of showing an influence of a cosolvent on the deformation temperature DT, softening temperature ST, and fusion temperature FT;

[0025] FIG. 4C is still another comparison diagram of showing an influence of a cosolvent on the deformation temperature DT, softening temperature ST, and fusion temperature FT; and

[0026] FIG. 4D is yet another comparison diagram of showing an influence of a cosolvent on the deformation temperature DT, softening temperature ST, and fusion temperature FT.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The present disclosure provides a method for producing a by-product yellow phosphorus slag from yellow phosphorus by an unconventional electric furnace process, including the following steps: mixing mid-low-grade phosphate rock, silica, coke, and a cosolvent to obtain a mixed material, and subjecting the mixed material to high-temperature reduction in a yellow phosphorus electric furnace to obtain yellow phosphorus and a water-quenched slag; and drying the water-quenched slag with a yellow phosphorus tail gas to obtain the yellow phosphorus slag; where the cosolvent is preferably one selected from the group consisting of boromagnesite, potassium feldspar, boric anhydride, borax, potassium sulfate, and sodium sulfate.

[0028] In the present disclosure, a P.sub.2O.sub.5CaOSiO.sub.2MgOR multi-component system (R includes one of Al.sub.2O.sub.3, Fe.sub.2O.sub.3, K.sub.2O, Na.sub.2O, B.sub.2O.sub.3, and MnO) is constructed with the mixed material. This system can not only reduce a fusion temperature, lower a quality requirement of the yellow phosphate rock, and ensure an extraction rate of yellow phosphorus. The elements contained in the system can also provide beneficial medium and trace elements for rice, promote the growth of rice, and improve the yield and quality of rice.

[0029] In the present disclosure, the cosolvent can promote the melting of calcium phosphate, wollastonite and other phases in the materials, thereby reducing the fusion temperature of the materials.

[0030] In the present disclosure, the content of P.sub.2O.sub.5 in the mid-low-grade phosphate rock is preferably greater than or equal to 23%. Based on a main oxide in the cosolvent, the cosolvent is added at preferably 0.1% to 10%, more preferably 8% of a weight of the mixed material. SiO.sub.2 and CaO in the mixed material are at a mass ratio of preferably (0.7-0.9):1, more preferably 0.8:1. A tail gas of the yellow phosphorus preferably includes 80% to 95% of CO, more preferably 90% of CO.

[0031] The present disclosure further provides use of a yellow phosphorus slag prepared by the method in preparation of a fertilizer. In the present disclosure, the by-product yellow phosphorus slag obtained during the preparation of yellow phosphorus mainly includes CaO and SiO.sub.2, and also contains a small amount of residual phosphorus, most of which exist in the form of P.sub.2O.sub.5. These elements can be better absorbed by rice to meet the various nutrients needed for rice growth.

[0032] In the present disclosure, the fertilizer is preferably applicable to rice.

[0033] In the present disclosure, the fertilizer includes preferably urea, monoammonium phosphate, potassium chloride, yellow phosphorus slag, a calcium magnesium phosphate fertilizer, zinc sulfate, ammonium chloride, and attapulgite that are at a mass ratio of (15-30):(10-15):(20-25):(15-25):(3-7):(0.1-2):(10-30):(1-5), more preferably 25:12:23:20:5:1:20:3. Urea provides a significant amount of elemental nitrogen required for rice growth; monoammonium phosphate supplies essential elements such as nitrogen and phosphorus necessary for rice growth. Potassium chloride furnishes the crucial macroelement potassium required by rice. Yellow phosphorus slag offers elemental calcium and silicon needed for rice growth. Calcium magnesium phosphate fertilizer delivers elements like calcium, magnesium, phosphorus, and silicon necessary for rice growth. Zinc sulfate contributes the essential zinc required for rice growth. Attapulgite enhances the absorption of nitrogen, phosphorus, and potassium by rice, promoting synergistic effects among the fertilizer components. Each ingredient of the fertilizer works together to fulfill the macro, medium, and trace element requirements during the rice growth process. Furthermore, these components contribute to upright plant growth, improved photosynthetic efficiency, lodging resistance, and enhanced resilience against diseases and pests. As a result, they contribute to the overall improvement of rice quality and yield.

[0034] In the present disclosure, a preparation method of the fertilizer includes preferably: mixing the urea, the monoammonium phosphate, the potassium chloride, the yellow phosphorus slag, the calcium magnesium phosphate fertilizer, the zinc sulfate, the ammonium chloride, and the attapulgite to allow granulation, drying, cooling, sieving, and packaging to obtain the fertilizer.

[0035] In the present disclosure, the granulation refers to preferably extrusion granulation, powder granulation, and coated fertilizer granulation with the urea as a core.

[0036] In the present disclosure, the fertilizer is preferably used as a base fertilizer applied at preferably 35 kg/mu to 50 kg/mu, more preferably 40 kg/mu.

[0037] The technical solution provided by the present disclosure will be described in detail below with reference to the examples, but they should not be construed as limiting the claimed scope of the present disclosure.

[0038] In the examples, the mid-low-grade phosphate rock is Yunnan yellow phosphorus rock, and its main chemical composition is shown in Table 1; a main chemical composition of silica is shown in Table 2; a main chemical component of coke is shown in Table 3; a main chemical composition of boromagnesite is shown in Table 4; a main chemical composition of potassium feldspar is shown in Table 5.

TABLE-US-00001 TABLE 1 Chemical composition of Yunnan yellow phosphorus rock. Component P.sub.2O.sub.5 SiO.sub.2 CaO MgO Fe.sub.2O.sub.3 Al.sub.2O.sub.3 K.sub.2O Na.sub.2O MnO Content/% 26.49 18.97 40.28 1.93 1.1 1.43 0.32 0.16 0.1

TABLE-US-00002 TABLE 2 Main chemical composition of silica Component SiO.sub.2 CaO Al.sub.2O.sub.3 P.sub.2O.sub.5 MgO Fe.sub.2O.sub.3 K.sub.2O Na.sub.2O MnO Content/% 87.3 2.22 3.35 1.6 0.36 0.93 0.6 0.21 0.01

TABLE-US-00003 TABLE 3 Main chemical composition of coke Component volatile Fixed Ash Chemical composition of ash matter carbon content TFe SiO.sub.2 CaO Al.sub.2O.sub.3 MgO Content 2.85 74.52 17.95 3.60 6.52 1.69 3.83 0.21

TABLE-US-00004 TABLE 4 Main chemical composition of boromagnesite Component CaO MgO B.sub.2O.sub.3 Loss on ignition Content/% 4.43 59.69 15.96 12.44

TABLE-US-00005 TABLE 5 Main chemical composition of potassium feldspar Component P.sub.2O.sub.5 SiO.sub.2 CaO MgO Al.sub.2O.sub.3 K.sub.2O Loss on ignition Content/% 0.74 76.82 0.204 0.076 4.57 9.34 6.17

[0039] In the present disclosure, there is no special limitation on raw materials whose sources are not mentioned, and conventional commercially available products in this field can be used.

Example 1

[0040] Preparation of materials: 35.3017 g of mid-low-grade phosphate rock, 7.0225 g of silica, 6.2192 g of coke, and 1.4567 g of boromagnesite were used. A mass ratio of SiO.sub.2 and CaO in the material was 0.8:1.

[0041] The above materials were mixed and placed in a graphite crucible, placed in a constant-temperature zone at a preset temperature of 800 C. and filled with nitrogen, heated to a melting point and reacted at a constant temperature for 1 h; the crucible was quickly taken out and a resulting molten slag was poured into water, and dried with 90% CO-containing yellow phosphorus tail gas to obtain a yellow phosphorus slag.

Examples 2 to 6

[0042] A preparation method of the yellow phosphorus in Examples 2 to 6 was identical with Example 1, except that the preparation of materials was different. The preparation of materials in Examples 2 to 6 was shown in Table 6.

TABLE-US-00006 TABLE 6 Preparation of materials in Examples 2 to 6. Mid-low- grade Addition Mass phosphate Cosolvent amount of ratio of Group rock/g Silica/g Coke/g Type Dosage/g cosolvent/% SiO.sub.2/CaO Example 2 37.575 5.826 6.5971 Boric 1.5306 3 (based on B.sub.2O.sub.3 0.80 anhydride content) Example 3 37.575 5.826 6.5971 Borax 4.1085 3 (based on B.sub.2O.sub.3 0.80 content) Example 4 37.242 1.4408 6.4806 Potassium 4.8356 1 (based on K.sub.2O 0.80 feldspar content) Example 5 37.575 5.826 6.5971 Potassium 4.2956 3 (based on K.sub.2O 0.80 sulfate content) Example 6 37.575 5.826 6.5971 Sodium 3.4723 3 (based on Na.sub.2O 0.80 sulfate content)

Example 7

[0043] 30 kg of urea, 12 kg of monoammonium phosphate, 23 kg of potassium chloride, 15 kg of the yellow phosphorus slag in Example 1, 5 kg of calcium magnesium phosphate fertilizer, 1 kg of zinc sulfate, 10 kg of ammonium chloride, and 3 kg of attapulgite were weighed.

[0044] The above materials were uniformly mixed to allow extrusion granulation, drying, cooling, sieving, and packaging to obtain the fertilizer.

Example 8

[0045] 25 kg of urea, 10 kg of monoammonium phosphate, 20 kg of potassium chloride, 20 kg of the yellow phosphorus slag in Example 2, 3 kg of calcium magnesium phosphate fertilizer, 0.1 kg of zinc sulfate, 20 kg of ammonium chloride, and 1 kg of attapulgite were weighed.

[0046] The above materials were pulverized and mixed evenly, subjected to powder granulation by a disk granulator, followed by drying, cooling, sieving, and packaging to obtain the fertilizer.

Example 9

[0047] 15 kg of urea, 10 kg of monoammonium phosphate, 20 kg of potassium chloride, 25 kg of the yellow phosphorus slag in Example 2, 3 kg of calcium magnesium phosphate fertilizer, 0.1 kg of zinc sulfate, 25 kg of ammonium chloride, and 1 kg of attapulgite were weighed.

[0048] The above materials were pulverized and mixed evenly, subjected to powder granulation by a rotor drum granulator, followed in the drying, cooling, sieving, and packaging to obtain the fertilizer.

Example 10

[0049] 26 kg of urea, 15 kg of monoammonium phosphate, 20 kg of potassium chloride, 20 kg of yellow phosphorus slag in Example 2, 7 kg of calcium magnesium phosphate fertilizer, 2 kg of zinc sulfate, 15 kg of ammonium chloride, and 3 kg of attapulgite were weighed.

[0050] Among the raw materials, urea should be in a granular form, while other raw materials should be in a powder form. All powdery raw materials were mixed to form a mixed material for subsequent use. The granular urea and powdery materials were added in sequence, subjected to coated fertilizer granulation with the urea as a core, followed in the drying, cooling, sieving, and packaging to obtain the fertilizer.

Experimental Example 1

[0051] Influence of different additions of cosolvent on a fusion characteristic temperature of the material and a yield of yellow phosphorus.

[0052] 1. Influence of Different Ratios of Boromagnesite on a Fusion Characteristic Temperature and a Yield of Yellow Phosphorus.

[0053] The yellow phosphorus was prepared at the amounts of raw materials according to Table 7, and a preparation method of the yellow phosphorus was the same as that in Example 1.

TABLE-US-00007 TABLE 7 Matching of materials after adding different ratios of boromagnesite. Mid-low-grade Addition of phosphate rock/g Silica/g Coke/g Boromagnesite/g boromagnesite/% SiO.sub.2/CaO 36.7458 6.5422 6.4631 0.2488 0.5 0.85 36.4601 6.6302 6.4147 0.4951 1 0.85 35.8735 6.8304 6.3154 0.9807 2 0.87 35.3017 7.0225 6.2192 1.4567 3 0.89 34.7572 7.1927 6.1269 1.9231 4 0.90

[0054] In preparing the yellow phosphorus, a temperature change of the phase melting point and the yield of yellow phosphorus were observed under adding different proportions of boromagnesite by using a computerized ash melting point instrument. The specific results were shown in Table 8, Table 9, and FIG. 3.

[0055] A determination method of yellow phosphorus yield (phosphorus escape rate) was as follows:

[0056] During the smelting reduction of phosphate, when a certain temperature was reached, phosphorus might volatilize. Therefore, the volatilization and migration of phosphorus could be characterized by measuring a phosphorus content of the sample before and after reduction by chemical analysis. According to the law of material conservation, a calculation formula was shown in formula (1):

X=w.sub.0w.sub.1/w.sub.1100%formula (1) [0057] in formula (1): [0058] X represented the yellow phosphorus yield (phosphorus escape rate), in %; [0059] W.sub.0 represented a mass of phosphorus in a furnace pre-slag, in g; and [0060] W.sub.1 represented a residual mass of phosphorus in a resulting residue, in g.

TABLE-US-00008 TABLE 8 Influence of different boromagnesite additions on fusion characteristic temperature of materials. Deformation Softening Fusion Boromagnesite temperature temperature temperature addition/% DT/ C. ST/ C. FT/ C. 0 1414 1458 1479 0.5 1410 1441 1462 1.00 1395 1445 1467 2.00 1390 1460 1465 3.00 1380 1420 1437 4.00 1340 1413 1439

[0061] As shown in Table 8 and FIG. 3, the boromagnesite had a significant fluxing effect. When adding 3% of boromagnesite, the fusion temperature of the material could be reduced by 42 C.

TABLE-US-00009 TABLE 9 Influence of different boromagnesite additions on yellow phosphorus yield. Yellow phosphorus yield/% Reaction Reaction Reaction Addition of temperature temperature temperature boromagnesite/% at 1,350 C. at 1,400 C. at 1,450 C. 0 78.45 89.48 92.14 0.5 80.08 88.17 97.86 1 77.93 91.88 97.33 2 85.73 94.04 96.01 3 82.07 94.04 94.36 4 86.50 94.08 90.90

[0062] As shown in Table 9, with an increase of the added amount of boromagnesite, the yellow phosphorus yield changed irregularly. In this experiment, when the amount of boromagnesite was added to 0.5% and the reaction temperature was 1,450 C., the yellow phosphorus yield could reach 97.86%.

[0063] 2. Influence of Different Proportions of Boric Anhydride, Potassium Sulfate, and Sodium Sulfate on Fusion Characteristic Temperature and Yellow Phosphorus Yield

[0064] When an addition amount of cosolvents, boric anhydride, potassium sulfate, and sodium sulfate, was 2%, 3%, 5%, and 8% separately (Table 10), the yellow phosphorus was prepared by the method of Example 1. The results of the cosolvents, boric anhydride, potassium sulfate, and sodium sulfate on the reflow characteristic temperature of the materials were shown in Table 11, Table 12, and FIGS. 4A-D.

TABLE-US-00010 TABLE 10 Matching of materials after adding different ratios of cosolvents. Mid-low- grade Cosolvent Addition/ phosphate Cosolvent SiO.sub.2/ type % rock/g Silica/g Coke/g addition/g CaO Boric 2 37.575 5.826 6.5971 1.0204 0.80 anhydride 3 37.575 5.826 6.5971 1.5306 0.80 5 37.575 5.826 6.5971 2.5510 0.80 8 37.575 5.826 6.5971 4.0816 0.80 Potassium 2 37.575 5.826 6.5971 2.8637 0.80 sulfate 3 37.575 5.826 6.5971 4.2956 0.80 5 37.575 5.826 6.5971 7.1593 0.80 8 37.575 5.826 6.5971 11.4548 0.80 Sodium 2 37.575 5.826 6.5971 2.3148 0.80 sulfate 3 37.575 5.826 6.5971 3.4723 0.80 5 37.575 5.826 6.5971 5.7871 0.80 8 37.575 5.826 6.5971 9.2594 0.80

TABLE-US-00011 TABLE 11 Influence of cosolvents boric anhydride, potassium sulfate, and sodium sulfate on reflow characteristic temperature of materials. Deformation Softening Fusion temperature temperature temperature Cosolvent Addition/% DT/ C. ST/ C. FT/ C. Boric 2 1375 1410 1436 anhydride 3 1364 1410 1429 5 1360 1396 1425 8 1355 1385 1400 Potassium 2 1363 1417 1444 sulfate 3 1359 1416 1440 5 1338 1407 1435 8 1331 1388 1414 Sodium 2 1324 1401 1434 sulfate 3 1269 1394 1415 5 1252 1345 1399 8 1239 1323 1335

TABLE-US-00012 TABLE 12 Influence of cosolvents boric anhydride, potassium sulfate, and sodium sulfate on yellow phosphorus yield. Yellow phosphorus yield/% Reaction Reaction Reaction Cosolvent temperature temperature temperature type Addition/% at 1,350 C. at 1,400 C. at 1,450 C. No 0 79.46 89.47 96.93 cosolvent Potassium 2 72.76 88.58 92.21 sulfate 3 76.78 82.13 88.37 Boric 2 82.60 92.24 96.33 anhydride 3 88.15 91.50 97.43 Sodium 2 82.31 91.55 93.49 sulfate 3 77.90 83.15 90.74

[0065] As shown in Table 11 and FIGS. 4A-D, as the amount of cosolvent added increased, the deformation temperature DT, softening temperature ST, and fusion temperature FT of the material gradually decreased. When the addition was 8%, the cosolvents boric anhydride, potassium sulfate, and sodium sulfate reduced the fusion temperature of the material by 55 C., 41 C., and 120 C., respectively.

[0066] Moreover, as shown in FIGS. 4A-D, different cosolvents had different effects on the deformation temperature DT, softening temperature ST, and fusion temperature FT of the material. When the cosolvent was the sodium sulfate added at 8%, the fusion temperature decreased to a maximum extent.

[0067] As shown in Table 12, when the cosolvent was boric anhydride added at 3%, and the reaction temperature was 1,450 C., the yellow phosphorus yield was as high as 97.43%.

Experimental Example 2

[0068] A rice test field in Zhengzhou, Henan was divided into 4 pieces on average, each of which was 1 mu, and the 4 test fields (with no significant difference in soil composition) were planted with rice and applied with different fertilizers: [0069] CK: no fertilization; [0070] T-1: a compound fertilizer produced by an enterprise in Shandong (19-10-17); [0071] T-2: a compound fertilizer produced by an enterprise in Hubei (22-10-20); [0072] T-3: 10 groups for the example: the compound fertilizer (16-8-11) prepared in Example 10 of the present disclosure; and

[0073] Each group was planted with rice and fertilized according to the method in Table 13, and other conditions were the same. After harvesting, the rice yield of each group was counted.

TABLE-US-00013 TABLE 13 Fertilizer application method and yield of each group. Nutrient input (kg/mu) Fertilization Fertilizer dosage Pure Yield Group method (kg/mu) N P.sub.2O.sub.5 K.sub.2O (kg/mu) CK 433.8 T-1 One base Base fertilizer: 7.75 4.08 6.94 636.3 fertilizer with 28.6 one top Top dressing: dressing 12.2 T-2 One base Base fertilizer: 7.94 3.61 7.22 622.3 fertilizer with 25.3 one top Top dressing: dressing 10.8 T-3 One-time base 40 6.4 3.2 4.4 640.1 fertilizer application

[0074] As shown in Table 13, compared with the control group CK and T-1 and T-2 groups, the fertilizer prepared by the present disclosure could still increase the yield of rice at a low nutrient input.

[0075] The above descriptions are merely preferred implementations of the present disclosure. It should be noted that a person of ordinary skill in the art may further make several improvements and modifications without departing from the principle of the present disclosure, but such improvements and modifications should be deemed as falling within the protection scope of the present disclosure.