Method for integrated utilization of ulexite ore resources

Abstract

A method for integrated utilization of ulexite ore resources. The method comprises the following steps: subjecting ulexite as a raw material, in a production system, to a series of coupled processing procedures, so as to successively obtain boric acid meeting the quality index for superior products of the national standard for boric acid products, calcium sulfate hemihydrate whiskers reaching a purity of more than 99%, and sodium nitrate meeting the index of the national standard for sodium nitrate products, and other products. The beneficial effects are as follows: the method for integrated utilization of ulexite ore resources enables boron, calcium, sodium, magnesium and other elements in ulexite, and sulfuric acid, sulfate, nitric acid and other raw materials used therein to be incorporated into a product as much as possible, thus making full use of the ulexite ore resources, and greatly reducing the emission of "three wastes" in a production process.

Description

A method for comprehensive utilization of ulexite ore resources Technical Field

[0001] The present invention relates to the technical field of inorganic chemistry, in particular to a method for comprehensive utilization of ulexite ore resources. Background Art

[0002] According to the "China Boric Acid Market Forecast and Investment Strategy Report (2022 Edition)" released by Limu Information Consulting, global boron mining companies are currently concentrated in Turkey, the United States, Russia, South American countries, and China. Mining companies with global influence include Turkey's Eti Mining Group, American Borax Corporation, Argentina's Santa Rita Company, and Chile's Quimica Borax Company. Eti Mining Group is the world's largest boron mining and production company, producing 900,000 tons of boron annually, accounting for 30%-40% of the global total. Its products include boric acid, borax, boron oxide, and other concentrates.

[0003] my country has 63 boron mines, including three large mines, six medium-sized mines, and 54 small mines, with an annual output of 616,500 tons (of raw ore). There are over 40 boric acid companies operating in China. However, due to resource constraints and production technology limitations, domestic borax and boric acid manufacturers are relatively small, with only 10% of the boric acid industry boasting a production capacity exceeding 50,000 tons. Product quality still lags behind that of foreign countries, and high-quality boric acid still needs to be imported. Demand for both the quantity and quality of boric acid products is expected to continue to increase, along with requirements for comprehensive resource utilization and waste treatment. Therefore, the development of new boric acid production technologies is crucial.

[0004] Ulexite (NaCa[B3B2O7(OH)4]•6H2O) is a borate mineral with the theoretical composition (w%): Na2O 7.65, CaO 13.85, B2O342.95, H2O 35.55. Common ulexite in nature is a crystal aggregate, white in color, soluble in hot water, and partially dissolved and paste-like after long-term immersion in cold water. It is an important mineral resource. It is produced in arid areas and is formed by the decomposition of boron in sediments and volcanic debris by water. It is distributed in South America, Turkey, the western United States, and my country's Qinghai-Tibet Plateau. It is a major ore type of Qinghai Salt Lake boron mine.

[0005] Overview of Ulexite Resource Utilization Technologies: Several literature and patent reports disclose technical solutions for producing calcium borate from ulexite. For example, Wang Pei et al. used natural ulexite ore powder as raw material and produced calcium borate through hydrothermal depolymerization and phase transformation. The reaction system had a liquid-to-solid volume ratio of 250 mL / 100 g, a depolymerization temperature of 120°C, a drying time of 8 hours, and a drying temperature of approximately 200°C. The product had a sodium oxide mass fraction below 0.5%, meeting the requirements of the alkali-free glass fiber industry for boron-containing raw materials.

[0006] Numerous researchers have published literature and patents on the production of boric acid from ulexite. Chinese Patent 201310309554.5 discloses a process for decomposing ulexite with nitric acid to produce boric acid, calcium carbonate, and sodium nitrate. However, it does not address technical treatment measures for other impurities in the mineral, nor does it describe the quality indicators that can be achieved for the resulting product or the key technologies that may arise during engineering scale-up. Chinese Patent 201610890282.6 covers a method for producing boric acid from ulexite, but does not address the comprehensive utilization of other chemical components in the ulexite ore.

[0007] Not only is boron in ulexite a valuable mineral resource, it also possesses significant application value. Due to its complex chemical composition, the utilization of its other chemical components has also become crucial for environmental protection, comprehensive resource utilization, and other socioeconomic development priorities. Therefore, it is necessary to continuously optimize ulexite utilization methods based on the varying chemical composition and properties of different ulexite species. Technical issues

[0008] The technical problems to be solved by the present invention are: first, to fully utilize the ulexite mineral resources, significantly reduce the emission of "three wastes", and realize green production; second, to optimize the production process of preparing boric acid, hemihydrate calcium sulfate whiskers and calcium nitrate products from ulexite ore, and optimize their coupling; third, to solve the engineering problems of industrial scale-up to achieve the above purposes. Technical Solutions

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for comprehensive utilization of ulexite ore resources, comprising the following steps:

[0010] 1) The ulexite ore is pre-treated by washing to obtain washed ore, and the washed ore is decomposed to produce boric acid by two-step nitric acid acidification;

[0011] In the first step of acid hydrolysis, the washed ore is added into water 3 to 7 times of its mass, and 75% to 85% of the total amount of nitric acid required to decompose the ore is added. The reaction time is 30-60 minutes and the reaction temperature is 70-85°C to obtain the first slurry; the solute mass concentration of the added nitric acid is 50%.

[0012] 2) filtering the first slurry using a vacuum filter to obtain a first filtrate and a solid phase, which is then washed and discharged;

[0013] 3) Add the remaining nitric acid required for acid hydrolysis to the first filtrate to complete the second step of acid hydrolysis, and cool to 10°C-30°C to precipitate boric acid crystals;

[0014] 4) filtering to obtain boric acid crystals and a second filtrate, washing and drying the boric acid crystals to obtain a boric acid product;

[0015] 5) The second filtrate reacts with a decalcifying agent to obtain calcium sulfate dihydrate whiskers or calcium sulfate hemihydrate whiskers under different process conditions, and a third filtrate is obtained;

[0016] 6) If the third filtrate contains Mg 2+ The concentration reaches 35g / L or Na + When the concentration reaches 40 g / L, the filtrate is concentrated, cooled and crystallized, and the mixture mainly composed of sodium nitrate and the fourth filtrate are filtered;

[0017] 7) preparing a sodium nitrate product from the mixture obtained in step 6);

[0018] 8) If the sodium and magnesium contents of the third filtrate in step 5) are not higher than the limit values ​​in step 6), proceed directly to step 10);

[0019] 10) Repeat steps 1) to 8), but before adding nitric acid to the washed ore in step 1), the third filtrate is used as the circulating mother liquor, and the washed ore and the circulating mother liquor are mixed in a mass ratio of 1: (3-8) to replace the mixture with water.

[0020] Preferably, in the above-mentioned method for comprehensive utilization of ulexite ore resources, in step 1), 75% to 85% of the total amount of nitric acid required to decompose the ore is added, the reaction time is 48 minutes, and the reaction temperature is 80° C. to obtain a first slurry;

[0021] Preferably, in the above-mentioned method for comprehensive utilization of ulexite ore resources, the step 4) of "washing and drying the boric acid crystals to obtain a boric acid product" is specifically as follows: the boric acid crystals are countercurrent washed three times, placed in an oven at 60°C and dried for 2 hours to obtain a boric acid product.

[0022] Preferably, in the above-mentioned method for comprehensive utilization of ulexite ore resources, the decalcifying agent in step 5) is sulfuric acid, sulfates or a mixture of several thereof.

[0023] Preferably, in the above-mentioned method for comprehensive utilization of ulexite ore resources, the sulfuric acid is a 30%-98% sulfuric acid aqueous solution.

[0024] Preferably, in the above-mentioned method for comprehensive utilization of ulexite ore resources, the step 7) is specifically as follows: the obtained mixed material is a solid phase with B2O3 less than 0.25%, which is discharged for the preparation of sodium nitrate product.

[0025] In the above-mentioned method for comprehensive utilization of ulexite ore resources, the decomposition of the ulexite ore is completed in two steps. In step 2), the resulting slurry can be separated using filtration equipment such as a vacuum filter, and the waste residue is discharged after countercurrent washing. In step 5), the decalcifying agent is sulfuric acid of varying concentrations. Calcium sulfate dihydrate whiskers are obtained when the decalcification operating temperature is less than 82°C, while calcium sulfate hemihydrate whiskers are obtained when the decalcification operating temperature is between 85°C and 98°C.

[0026] In the above-mentioned method for comprehensive utilization of ulexite ore resources, the sodium nitrate-based material obtained after concentration of the decalcified third filtrate in step 7) contains less than 0.25% B₂O₃ and a low total amount, resulting in a total boron utilization rate exceeding 98%. However, the content of other magnesium and calcium salts is approximately 3.5%, which does not meet the quality standards of industrial sodium nitrate products. Therefore, it is sent out of the system and processed using traditional purification methods. Beneficial effects

[0027] The beneficial effects of the present invention are as follows: the method for comprehensive utilization of ulexite ore resources of the present invention has the following advantages:

[0028] 1. The main technical solution is to use ulexite as raw material and adopt a two-step nitric acid decomposition method to prepare boric acid, which reduces the decomposition temperature and makes the liquid-solid separation of the decomposition slurry very simple, making it easy to achieve large-scale industrial production;

[0029] 2. The present invention utilizes nitric acid to decompose ulexite ore and sulfuric acid as a decalcifying agent. This has the following effects: First, sulfuric acid, as a decalcifying agent, can remove calcium from the circulating mother liquor. Second, the calcium sulfate whiskers obtained by this decalcification process are directly used as a product. Third, decalcification with sulfuric acid simultaneously regenerates nitric acid, saving nitric acid consumption.

[0030] 3. Due to the reduction in the amount of nitric acid added, the generation of nitrates is greatly reduced, the processing difficulty, process energy consumption and production costs are reduced, which has a positive effect on reducing the loss of boron;

[0031] 4. In the comprehensive utilization method for ulexite ore resources, the solid obtained after concentration of the decalcified filtrate is primarily sodium nitrate, containing approximately 3.5% other calcium and magnesium salts, a B2O3 content of less than 0.25%, and a total boron utilization rate greater than 98%. This material discharge system helps optimize the system's continuous operating conditions. After discharge, this material can be processed using traditional and proven methods to produce sodium nitrate products.

[0032] 5. The present invention utilizes a series of coupled processes within a single production system to produce boric acid and calcium sulfate whiskers with a purity exceeding 99%. The boron, calcium, and sodium elements in the ulexite ore, as well as the sulfuric acid and nitric acid used in this process, are all utilized, improving mineral resource utilization and significantly reducing emissions of the "three wastes." BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic flow diagram of a method for comprehensive utilization of ulexite ore resources in a specific embodiment of the present invention. Modes for Carrying Out the Invention

[0034] To illustrate the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and accompanying drawings.

[0035] This invention focuses on the comprehensive utilization of mineral resources and studies key technologies for engineering scale-up and large-scale production. It develops a novel decomposition system, leveraging the physicochemical properties of ulexite. This two-step decomposition process simplifies solid-liquid separation of the slurry after ore decomposition, facilitating industrialization. The invention also utilizes sulfuric acid as a decalcifying agent, producing high-value calcium sulfate hemihydrate whiskers while simultaneously regenerating nitric acid. This reduces nitric acid consumption and sodium nitrate production, optimizes the mother liquor circulation process, and contributes to increasing boric acid production capacity and reducing process energy consumption.

[0036] The present invention reduces the consumption of high-value nitric acid, fully utilizes elements such as boron, calcium, sodium and the like in the minerals, saves production costs and realizes comprehensive utilization of resources.

[0037] The present invention proposes a series of new process schemes that can be used for expanding scale production, aiming to provide reference for large-scale industrial production.

[0038] Since there is no quality standard for ulexite ore, targeted solutions are needed for mineral materials with different chemical compositions.

[0039] The main composition of the ulexite ore targeted by the present invention is shown in Table 1 below (mass percentage, the rest are impurities, including crystallization water and attached water)

[0040] Table 1

[0041] B2O3Na2OCaOCl-MgOSiO2CO2Full water25~40%4~8%10~20%1~4%1~5%2~10%1~5%30~35%

[0042] Please refer to Figure 1. The present invention provides a method for comprehensive utilization of ulexite ore resources, comprising the following steps:

[0043] 1) Wash the ulexite ore by adding clean water at a mass ratio of 1: (4-8), grinding, washing, liquid-solid separation, and discharging the filtrate after treatment. The washed ore is dried for later use;

[0044] 75% to 85% of the total amount of nitric acid required for decomposition is added to the washed ore, the reaction time is 20-40 minutes, the reaction temperature is 60-80°C, and the first slurry is obtained; the solute mass concentration of the added nitric acid is 50%.

[0045] The above parameter limits optimize the acid hydrolysis process of ulexite ore, controlling the acid hydrolysis reaction to proceed in two steps. First, 75% to 85% nitric acid is added to complete the first decomposition reaction.

[0046] 2) Use a filter to separate the reaction slurry to obtain a first filtrate and acid-insoluble matter. The acid-insoluble matter has a B₂O₃ content of less than 0.25% and is then washed and discharged from the system. Vacuum filters and other liquid-solid separation equipment can be used for separation. Stepwise acid addition facilitates liquid-solid separation of the first slurry, allowing acid-insoluble impurities to be easily discharged from the system.

[0047] 3) Add the remaining nitric acid required for decomposition to the first filtrate to complete the second decomposition step, and cool to 10°C - 30°C to obtain boric acid crystals. Cooling crystallization can obtain flaky boric acid crystals that are easy to filter and wash. The amount of nitric acid added in both steps is controlled by the system pH.

[0048] 4) Separating the slurry obtained in step 3) to obtain a second filtrate and a solid. The solid is washed and dried to obtain a boric acid product that meets national standards. Multiple countercurrent washings are used to ensure product quality, and the washing liquid is used in the system.

[0049] 5) The second filtrate reacts with a decalcifying agent. Under controlled conditions, calcium sulfate dihydrate or calcium sulfate hemihydrate whiskers can be obtained. The decalcifying agent is sulfuric acid of varying concentrations, with the added amount being 90%-105% of the gypsum produced. Calcium sulfate dihydrate whiskers can be obtained by controlling the reaction temperature below 82°C, while calcium sulfate hemihydrate whiskers can be obtained when the temperature is between 85°C and 98°C.

[0050] The slurry is separated to obtain calcium sulfate whiskers and a third filtrate, and the whiskers are countercurrently washed and dried to obtain a calcium sulfate whisker product.

[0051] The filtration and washing of calcium sulfate hemihydrate whiskers should be carried out at a temperature above 95°C.

[0052] 6) Mg in the third filtrate 2+ The concentration reaches 35g / L or Na + When the concentration reaches 40 g / L, the filtrate is concentrated, cooled, and separated to obtain a material mainly composed of sodium nitrate and a fourth filtrate.

[0053] 7) The sodium nitrate-based material obtained in step 6) contains small amounts of sulfuric acid, hydrochloric acid, and calcium and magnesium salts of boric acid. After deep liquid separation, it is sent out of the system and purified using well-known mature technologies to produce sodium nitrate products, completing the comprehensive utilization of this mineral resource.

[0054] 8) If the calcium and magnesium content of the filtrate is not higher than the limit in step 6), proceed directly to the next step;

[0055] 9) The third filtrate is used as the mother liquor to decompose the minerals for recycling at a mass ratio of ore to liquid of 1:(3-8).

[0056] Each washing step utilizes countercurrent washing, and the washing water is not discharged, which reduces water consumption, avoids pollution, and improves the comprehensive utilization of resources.

[0057] Example 1

[0058] A method for comprehensive utilization of ulexite ore resources comprises the following steps:

[0059] The composition of ulexite ore is shown in Table 2 below (mass percentage on dry basis, the remainder is impurities, including crystal water)

[0060] Table 2

[0061] B2O3Na2OCaOCl-SiO2MgOCO2 water 30%6%15%1.5%5%2.5%10%28%

[0062] 1) Take 100g of ulexite ore, add 500g of tap water, grind, wash, filter press, separate liquid and solid, treat the filtrate and discharge it, dry the washed ore at 50℃ for later use.

[0063] 2) The pretreated ore is added to 500 grams of tap water, and 36 grams of 50% nitric acid is gradually added. The temperature is raised to 85°C and the reaction is carried out for 48 minutes to obtain a first slurry. The total amount of nitric acid required in this embodiment is the amount required to convert all calcium, magnesium, and sodium ions in the water-washed ore reaction materials into nitrates, and is calculated based on the actual chemical composition of the materials. The chemical composition of minerals in nature is relatively complex, especially minerals from different origins have very different compositions. Nitric acid decomposes boride to produce boric acid while also decomposing other components in the mineral. The total amount of nitric acid required can only be determined experimentally based on different minerals. For every 100 grams of boron ore used in this specific embodiment, 46 grams of 50% nitric acid is required.

[0064] 3) The first slurry was separated by vacuum filtration to obtain a first filtrate and acid-insoluble matter. The acid-insoluble matter was washed three times in countercurrent and dried and then discharged from the system. The mass of the matter was 3.1 g and contained 0.13% B2O3.

[0065] 4) Add 10 g of 50% nitric acid to the first filtrate while stirring and cool to 10°C, then cool and crystallize.

[0066] 5) Vacuum filtration was performed to obtain boric acid crystals and a second filtrate. The boric acid crystals were countercurrent washed three times and dried in an oven at 60°C for 2 hours to obtain 31 g of boric acid product.

[0067] 6) The second filtrate was added dropwise to 83 g of 30% dilute sulfuric acid at room temperature for decalcification for 30 min. The mixture was then vacuum filtered to obtain a third filtrate and calcium sulfate dihydrate whiskers. The whiskers were countercurrent washed three times and dried in an oven at 60°C for 2 hours to obtain 42 g of calcium sulfate dihydrate whiskers with a B2O3 content of 0.41%.

[0068] 7) The third filtrate is mixed with the new washed ore and decomposed with acid.

[0069] Example 2

[0070] A method for comprehensive utilization of ulexite ore resources comprises the following steps:

[0071] 1) Take 100 g of the washed and dried ore, add 500 g of the third filtrate in Example 1, gradually add 13.6 g and 36 g of 50% nitric acid, raise the temperature to 80°C, and react for 40 min.

[0072] 2) The slurry was separated by vacuum filtration to obtain a first filtrate and acid-insoluble matter. The acid-insoluble matter was washed and dried once and then discharged from the system. The mass of the filtrate was 3.5 g and the B2O3 content was 0.11%.

[0073] 3) Add 3.8 g and 36 g of 50% nitric acid to the first filtrate while stirring, cool to 10°C, and cool to crystallize boric acid crystals.

[0074] 5) Vacuum filtration was used to separate boric acid crystals and a second filtrate; the boric acid crystals were countercurrent washed three times and dried in an oven at 60°C for 2 hours to yield 49 g of boric acid product.

[0075] 6) The second filtrate was added to 80 g of 30% sulfuric acid at room temperature for decalcification for 30 min. The slurry was then filtered through a vacuum filter to obtain a third filtrate and calcium sulfate dihydrate whiskers. The whiskers were countercurrent washed three times and dried in an oven at 60°C for 2 hours to obtain 42.2 g of calcium sulfate dihydrate whiskers with a B2O3 content of 0.048%.

[0076] 7) The third filtrate is used to decompose the washed ore newly entering the system.

[0077] Example 3

[0078] A method for comprehensive utilization of ulexite ore resources comprises the following steps:

[0079] 1) 100 g of the washed and dried ore was added to the third filtrate of Example 2, and 13.6 g and 36 g of 50% nitric acid were gradually added. The temperature was raised to 80°C and the reaction was carried out for 60 min.

[0080] 2) The slurry was separated by vacuum filtration to obtain a first filtrate and acid-insoluble matter. The acid-insoluble matter was washed and dried once and then discharged from the system. The mass of the filtrate was 3.6 g and the B2O3 content was 0.098%.

[0081] 3) Add 3.8 g of 50% nitric acid to the first filtrate while stirring, cool to 10°C, and cool to crystallize boric acid crystals.

[0082] 4) Vacuum filtration was used to separate boric acid crystals and a second filtrate. The boric acid crystals were countercurrent washed three times and dried in an oven at 60°C for 2 hours to yield 52 g of boric acid product with a B2O3 content of 56.10%.

[0083] 5) Add the second filtrate to 88.8 g of 30% sulfuric acid, heat to 90-95°C, and react for 30 minutes to obtain calcium sulfate hemihydrate whiskers.

[0084] 6) Filtering the slurry from step 5) through a vacuum filter to obtain a third filtrate and calcium sulfate hemihydrate whiskers. The whiskers were countercurrent washed three times and dried in an oven at 60°C for 2 hours to obtain a calcium sulfate hemihydrate whisker product having a B2O3 content of 0.052%.

[0085] 7) The third filtrate is used to decompose the washed ore newly entering the system.

[0086] Purification of circulating fluid

[0087] 1) In the embodiment, the third filtrate is continuously circulated for the decomposition of new minerals. To ensure the quality of boric acid, when Mg 2+ Concentration up to 35g / L or Na + When the concentration reaches 40 g / L, the filtrate is heated to 90-95°C and saturated sodium sulfate solution is added according to the metered amount to generate calcium sulfate hemihydrate whiskers.

[0088] 2) The whisker filtrate was concentrated to 50% volume, and the temperature was lowered for crystallization to obtain a fourth filtrate and 4.3 g of a white dry solid. The test results (w%) are as follows (Table 3);

[0089] Table 3

[0090] CaSO42-MgOB2O3NaCl-NO3-Water1.381.180.180.9323.450.6761.959

[0091] 3) The fourth filtrate is used to decompose new minerals and is recycled.

[0092] In the above-mentioned method for comprehensive utilization of ulexite ore resources, during the entire boron ore processing process, no other wastewater is discharged except the wastewater from washing NaCl in the ore with clean water at room temperature in step 1, which is treated and discharged to meet the standards.

[0093] The B2O3 loss rate is: (total boron amount discharged from the system) × 100 / total boron amount entering the system;

[0094] The B2O3 loss rates in the above embodiments are shown in Table 4.

[0095] Table 4

[0096] Example 1 Example 2 Example 3 Circulating liquid purification B2O3 loss rate 0.07% 0.08% 0.08% 0.04%

[0097] The B2O3 loss rate of the technical solution of the present invention is low, and elements such as boron, calcium, and sodium in the ulexite ore and raw materials such as sulfuric acid and nitric acid used in the processing of this solution are all incorporated into the product as much as possible, thereby improving the utilization rate of mineral resources and significantly reducing the emission of "three wastes". The above description is only an embodiment of the present invention and does not limit the scope of the patent of the present invention. Any equivalent transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in related technical fields, is also included in the scope of patent protection of the present invention.

Claims

1. A method for comprehensive utilization of ulexite ore resources, characterized in that: The following steps are involved: 1) The ulexite ore is pre-treated by washing to obtain washed ore, and the washed ore is decomposed to produce boric acid by two-step nitric acid acidification; The first step is acid hydrolysis. The washed ore is added into water of 3 to 7 times its mass, and 75% to 85% of the total amount of nitric acid required to decompose the ore is added. The reaction time is 30-60 minutes and the reaction temperature is 70-85°C to obtain the first slurry. The solute mass concentration of the added nitric acid is 50%. 2) filtering the first slurry using a vacuum filter to obtain a first filtrate and a solid phase, and the solid phase is discharged after washing; 3) Add the remaining nitric acid required for acid hydrolysis to the first filtrate to complete the second step of acid hydrolysis, cool to 10°C - 30°C, and precipitate boric acid crystals; 4) filtering to obtain boric acid crystals and a second filtrate, washing and drying the boric acid crystals to obtain a boric acid product; 5) The second filtrate reacts with a decalcifying agent to obtain calcium sulfate dihydrate whiskers or calcium sulfate hemihydrate whiskers under different process conditions, and obtain a third filtrate; 6) If the third filtrate contains Mg 2+ The concentration reaches 35g / L or Na + When the concentration reaches 40 g / L, the filtrate is concentrated, cooled and crystallized, and the mixture mainly composed of sodium nitrate and the fourth filtrate are filtered; 7) preparing sodium nitrate product from the mixture obtained in step 6); 8) If the sodium and magnesium contents of the third filtrate in step 5) are not higher than the limit values ​​in step 6), proceed directly to step 10); 10) Repeat steps 1) to 8), but before adding nitric acid to the washed ore in step 1), the third filtrate is used as the circulating mother liquor, and the washed ore and the circulating mother liquor are mixed in a mass ratio of 1: (3-8) to replace the mixture with water.

2. The method for comprehensive utilization of ulexite ore resources according to claim 1, characterized in that: In step 1), 75% to 80% of the total amount of nitric acid required to decompose the ore is added, the reaction time is 48 minutes, the reaction temperature is 80° C., and a first slurry is obtained; the solute mass concentration of the added nitric acid is 50%.

3. The method for comprehensive utilization of ulexite ore resources according to claim 1, characterized in that: Step 4) of "washing and drying the boric acid crystals to obtain a boric acid product" specifically includes: the boric acid crystals are countercurrent washed three times, placed in an oven at 60°C and dried for 2 hours to obtain a boric acid product.

4. The method for comprehensive utilization of ulexite ore resources according to claim 1, characterized in that: The decalcifying agent in step 5) is sulfuric acid, sulfate or a mixture of several thereof.

5. The method for comprehensive utilization of ulexite ore resources according to claim 4, characterized in that: The sulfuric acid is a 30%-98% sulfuric acid aqueous solution.

6. The method for comprehensive utilization of ulexite ore resources according to claim 1, characterized in that: Step 7) is specifically as follows: the obtained mixed material is a solid phase with B2O3 less than 0.25%, which is discharged for preparing sodium nitrate product.

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