阅读说明：本技术 一种含钾岩石中协同提取钾、铷的方法 (Method for synergistically extracting potassium and rubidium from potassium-containing rock ) 是由 何瑞明 王勇 李爱民 史伟 李�诚 许亚军 于 2020-06-28 设计创作，主要内容包括：本发明涉及矿物加工和湿法冶金领域,具体是一种含钾岩石中协同提取钾、铷的方法。包括以下步骤：将含钾岩石破碎、磨矿,得到矿粉；取含钾岩石和碱性添加剂生石灰或熟石灰混合,加入水,置于熔盐炉内熔盐热活化；对活化后的混合物进行固液分离,得到含有铷、钾的过滤液和滤渣,滤渣用于生产硅钙肥；滤液加入碳酸钾水溶液进行碳化,过滤除去杂质,获得二次滤液；二次滤液蒸发结晶,获得钾、铷结晶物；钾、铷结晶物焙烧,获得含钾、铷富集物盐,提纯分离获得碳酸钾及碳酸铷。采用石灰为碱性添加剂,固液分离滤液为碱性,钙离子沉淀进入尾渣,尾渣用于制备硅钙肥,相比于采用氢氧化钠为碱性添加剂,成本较低,滤液中省去钾、钠分离工序,有利于钾、铷的提纯。(The invention relates to the field of mineral processing and hydrometallurgy, in particular to a method for synergistically extracting potassium and rubidium from potassium-containing rock. The method comprises the following steps: crushing and grinding potassium-containing rocks to obtain mineral powder; mixing potassium-containing rock and alkaline additive quicklime or slaked lime, adding water, and placing in a molten salt furnace for molten salt thermal activation; performing solid-liquid separation on the activated mixture to obtain filtrate containing rubidium and potassium and filter residue, wherein the filter residue is used for producing the calcium silicon fertilizer; adding potassium carbonate aqueous solution into the filtrate for carbonization, and filtering to remove impurities to obtain secondary filtrate; evaporating and crystallizing the secondary filtrate to obtain potassium and rubidium crystals; roasting potassium and rubidium crystals to obtain enriched salt containing potassium and rubidium, and purifying and separating to obtain potassium carbonate and rubidium carbonate. Compared with the method that the sodium hydroxide is used as the alkaline additive, the cost is lower, the potassium and sodium separation process is omitted from the filtrate, and the purification of potassium and rubidium is facilitated.)

1. A method for synergistically extracting potassium and rubidium from potassium-containing rock is characterized by comprising the following steps:

(1) crushing and grinding potassium-containing rocks to obtain mineral powder;

(2) mixing potassium-containing rock and alkaline additive quicklime or slaked lime, adding water, and placing in a molten salt furnace for molten salt thermal activation;

(3) performing solid-liquid separation on the activated mixture to obtain filtrate containing rubidium and potassium and filter residue, wherein the filter residue is used for producing the calcium silicon fertilizer;

(4) adding potassium carbonate aqueous solution into the filtrate or introducing CO₂Carbonizing the gas, and filtering to remove impurities to obtain secondary filtrate;

(5) evaporating and crystallizing the secondary filtrate to obtain potassium and rubidium crystals;

(6) roasting potassium and rubidium crystals to obtain enriched salt containing potassium and rubidium, and purifying and separating to obtain potassium carbonate and rubidium carbonate.

2. The method for synergistically extracting potassium and rubidium from potassium-containing rock according to claim 1, wherein the potassium-containing rock is potassium-containing sandstone, potassium-containing shale, potassium-rich syenite or potassium-rich volcanic rock, and K in the potassium-containing rock is K₂O is 7-13%, Rb₂O is 0.005-0.025%, SiO₂50 to 70 percent.

3. The method for synergistically extracting potassium and rubidium from potassium-containing rock according to claim 1 or 2, wherein in the step (1), the ore powder after ore grinding is sieved by a sieve of 200-325 meshes.

4. The method for synergistically extracting potassium and rubidium from potassium-containing rock according to claim 1 or 2, wherein in the step (2), the mass ratio of the potassium-containing rock ore to the alkaline additive is 1: 0.2-1: 1.5, and the mass ratio of water to the total mass of the potassium-containing rock ore and the alkaline additive quicklime is 5: 1-2: 1.

5. The method for synergistically extracting potassium and rubidium from potassium-containing rock according to claim 1 or 2, wherein in the step (2), the temperature of the molten salt heat activation is 160-300 ℃ and the time is 0.5-6 h.

6. The method for synergistically extracting potassium and rubidium from potassium-containing rock according to claim 1 or 2, wherein in the step (4), the concentration of the potassium carbonate aqueous solution is 0.1-0.5%.

7. The method for synergistically extracting potassium and rubidium from potassium-containing rock according to claim 6, wherein the concentration of calcium ions in the filtrate after carbonization is lower than 0.05 g/L.

8. The method for synergistically extracting potassium and rubidium from potassium-containing rock as claimed in claim 1 or 2, wherein in the step (6), the roasting temperature of the potassium and rubidium crystals is 160-260 ℃, and the roasting time is 30-150 minutes.

Technical Field

The invention relates to the field of mineral processing and hydrometallurgy, in particular to a method for synergistically extracting potassium and rubidium from potassium-containing rock.

Background

The water-soluble potassium salt resources in China are poor, and the dependence of potassium fertilizer import is over 50 percent in the past year. The water-insoluble potassium ore (potassium-containing rock) is rich in resources, a large amount of potassium extraction researches are carried out at home and abroad, the processes of an acid method, a limestone sintering method, a sodium carbonate sintering method and the like are successively developed, and the potassium extraction is realized, but the problems of high energy consumption, high cost, single product, low additional value, poor economic benefit and the like exist, and the large-scale application cannot be obtained.

Rubidium is an extremely important rare metal resource, has unique photoelectric properties and excellent chemical activity, and is widely applied to the fields of war industry, electronic instruments and meters, electric light sources, medicine and the like. The potassium-containing rock generally contains 0.005-0.025% of rubidium, and because the content is low, the minimum industrial grade requirement is not met, and the potassium-containing rock is not comprehensively recycled by the existing process. The prior art mainly extracts rubidium from salt lake brine and rubidium-containing lepidolite, the salt lake brine has complex components, low content and high extraction cost, the rubidium-containing lepidolite is extracted by adopting a chlorination roasting method, a limestone sintering method, a sulfuric acid method and the like, the ore decomposition rate is low, the environment is polluted, the energy consumption is high, the cost is high, the rubidium metal price is extremely high, and the application of rubidium products is limited.

Disclosure of Invention

The invention aims to overcome the defects of high energy consumption, high cost, single product, low additional value, serious environmental pollution, poor economic benefit and the like in the prior art, and provides the method for synergistically extracting potassium and rubidium from potassium-containing rock mineral products, which has low energy consumption, low cost, meets the requirement of clean production and has certain economic benefit.

The invention is realized by the following technical scheme: a method for synergistically extracting potassium and rubidium from potassium-containing rock comprises the following steps:

(1) crushing and grinding potassium-containing rocks to obtain mineral powder;

(2) mixing potassium-containing rock and alkaline additive quicklime or slaked lime, adding water, and placing in a molten salt furnace for molten salt thermal activation;

(3) performing solid-liquid separation on the activated mixture to obtain filtrate containing rubidium and potassium and filter residue, wherein the filter residue is used for producing the calcium silicon fertilizer;

(4) adding potassium carbonate aqueous solution into the filtrate or introducing CO₂Carbonizing the gas, and filtering to remove impurities to obtain secondary filtrate;

(5) evaporating and crystallizing the secondary filtrate to obtain potassium and rubidium crystals;

(6) roasting potassium and rubidium crystals to obtain enriched salt containing potassium and rubidium, and purifying and separating to obtain potassium carbonate and rubidium carbonate.

As a further improvement of the technical scheme of the invention, the potassium-containing rock is potassium-containing sandstone, potassium-containing shale, potassium-rich syenite and potassium-rich volcanic rock, and K in the potassium-containing rock₂O is 7-13%, Rb₂O is 0.005-0.025%, SiO₂50 to 70 percent.

As a further improvement of the technical scheme of the invention, in the step (1), the ore powder after being ground is sieved by a 200-325-mesh sieve.

As a further improvement of the technical scheme of the invention, in the step (2), the mass ratio of the potassium-containing rock ore to the alkaline additive is 1: 0.2-1: 1.5, and the mass ratio of water to the total mass of the potassium-containing rock ore and the alkaline additive quicklime is 5: 1-2: 1.

As a further improvement of the technical scheme of the invention, in the step (2), the temperature of the molten salt heat activation is 160-300 ℃, and the time is 0.5-6 h.

As a further improvement of the technical scheme of the invention, in the step (4), the concentration of the potassium carbonate aqueous solution is 0.1-0.5%.

As a further improvement of the technical scheme of the invention, after carbonization, the concentration of calcium ions in the filtrate is lower than 0.05 g/L.

As a further improvement of the technical scheme of the invention, in the step (6), the roasting temperature of the potassium and rubidium crystal is 160-260 ℃, and the roasting time is 30-150 minutes.

Compared with the prior art, the method for synergistically extracting potassium and rubidium from the potassium-containing rock has the following beneficial effects:

(1) the method adopts a molten salt thermal activation method to treat the potassium-containing rock to synergistically extract potassium and rubidium, and the temperature is 160-300 ℃, so that the energy consumption is lower compared with a conventional high-temperature roasting method (1300 ℃) and a medium-high temperature roasting method (900-1300 ℃). Compared with the method that the sodium hydroxide is used as the alkaline additive, the cost is lower, the potassium and sodium separation process is omitted from the filtrate, and the purification of potassium and rubidium is facilitated. The whole process flow has low energy consumption, low cost, simple process flow, less required equipment and easy popularization of the technology, and meets the requirement of clean production and environmental protection.

(2) Realizes the synergistic extraction of the valuable metal potassium and the rare metal rubidium in the potassium-containing rock. The obtained rubidium-containing crude ore reaches the industrial grade, has less impurities of rubidium and potassium enrichment substances, is easy to purify and obtain high-purity rubidium salt compared with the traditional salt lake brine salt for rubidium extraction. The rubidium salt has high price, about 6000 yuan/kg in 2019, greatly improves the economic benefit of the process, and is beneficial to realizing large-scale development and utilization of potassium-containing rocks. The reserves of potassium-bearing rocks in China reach more than 200 hundred million tons, and rubidium is extracted from the potassium-bearing rocks, so that the method is a new industrialized path of rubidium resources.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic flow chart of the method for synergistically extracting potassium and rubidium from potassium-containing rock.

FIG. 2 is a graph comparing the effect of different molten salt thermal activation temperatures on potassium activation rate and rubidium leaching rate.

FIG. 3 is a graph comparing the effect of different molten salt thermal activation reaction times on potassium activation rate and rubidium leaching rate.

FIG. 4 is a graph showing the effect of different amounts of quicklime on potassium activation and rubidium leaching rate.

FIG. 5 is a graph comparing the effect of different liquid-solid ratios on potassium activation rate and rubidium leaching rate.

FIG. 6 is a graph showing the results of X-ray diffraction analysis of the filter residue.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

The invention provides a method for synergistically extracting potassium and rubidium from potassium-containing rock, which comprises the following steps:

(1) crushing and grinding potassium-containing rocks to obtain mineral powder;

(2) mixing potassium-containing rock and alkaline additive quicklime or slaked lime, adding water, and placing in a molten salt furnace for molten salt thermal activation;

(3) performing solid-liquid separation on the activated mixture to obtain filtrate containing rubidium and potassium and filter residue, wherein the filter residue is used for producing the calcium silicon fertilizer;

(4) adding potassium carbonate aqueous solution into the filtrate or introducing CO₂Carbonizing the gas, and filtering to remove impurities to obtain secondary filtrate;

(5) evaporating and crystallizing the secondary filtrate to obtain potassium and rubidium crystals;

(6) roasting potassium and rubidium crystals to obtain enriched salt containing potassium and rubidium, and purifying and separating to obtain potassium carbonate and rubidium carbonate.

In the technical schemeThe potassium-containing rock is sandstone containing potassium, shale containing potassium, potassium-rich syenite and potassium-rich volcanic rock. The main components in these potassium-containing rocks: k₂O is 7-13%, Rb₂O is 0.005-0.025%, SiO₂50 to 70 percent.

In one embodiment of the present invention, in step (1), the ore powder after being ground is sieved with a 325-mesh sieve. In another embodiment provided by the present invention, in the step (1), the ore powder after being ground is sieved by a 200-mesh sieve.

In one embodiment provided by the present invention, in step (2), the mass ratio of the potassium-bearing rock ore and the alkaline additive comprises 1:0.2, and the mass ratio of water to the total mass of the potassium-bearing rock ore and the alkaline additive quicklime is 2: 1. In another embodiment provided by the present invention, in step (2), the mass ratio of the potassium-bearing rock ore and the alkaline additive comprises 1:1, and the mass ratio of water to the total mass of the potassium-bearing rock ore and the alkaline additive quicklime is 3: 1. In other embodiments provided by the present invention, in step (2), the mass ratio of the potassium-bearing rock ore and the alkaline additive comprises 1:1.5, and the mass ratio of water to the total mass of the potassium-bearing rock ore and the alkaline additive quicklime is 5: 1.

In one embodiment provided by the present invention, in step (2), the temperature of the molten salt thermal activation is 160 ℃ and the time is 6 h. In another embodiment provided by the present invention, in the step (2), the temperature of the molten salt heat activation is 280 ℃ and the time is 3 h. In other embodiments provided by the present invention, in step (2), the temperature of the molten salt thermal activation is 300 ℃ and the time is 0.5 h.

In the present invention, the molten salt is potassium nitrate (KNO)₃) Sodium nitrite (NaNO)₂) And sodium nitrate (NaNO)₃) Providing a heating effect. The molten salt furnace equipment is not limited to a molten salt furnace and comprises a high-temperature reaction kettle, a high-pressure reaction kettle and the like.

In step (3) of the present invention, the solid-liquid separation of the mixture comprises filtration, centrifugation, filter pressing and other methods.

After the technical means of the invention is adopted, the concentration of potassium ions in the filtering liquid containing rubidium and potassium is 5-25g/L, the concentration of rubidium ions is 0.01-0.05g/L, the concentration of calcium ions is 0.01-0.5g/L, and the concentrations of impurity ions such as sodium ions, magnesium ions, sulfate ions and the like are all lower than 0.1 g/L.

In one embodiment of the present invention, in the step (4), the concentration of the potassium carbonate aqueous solution is 0.1%. In another embodiment provided by the present invention, in step (4), the concentration of the aqueous potassium carbonate solution is 0.3%. In other embodiments provided herein, in step (4), the concentration of the aqueous potassium carbonate solution is 0.5%.

In the step (4) of the present invention, the carbonization may be performed by adding an aqueous solution of potassium carbonate or introducing carbon dioxide. After the treatment of the steps (1) to (3) of the invention and carbonization, the concentration of calcium ions in the filtrate is lower than 0.05 g/L.

In one embodiment provided by the present invention, in step (6), the calcination temperature for calcining the potassium and rubidium crystals is 260 ℃ and the calcination time is 30 minutes. In another embodiment provided by the present invention, in step (6), the calcination temperature for calcining the potassium and rubidium crystals is 160 ℃ and the calcination time is 150 minutes. In another embodiment provided by the present invention, in step (6), the calcination temperature for calcining the potassium and rubidium crystals is 200 ℃ and the calcination time is 100 minutes.

According to the method for synergistically extracting potassium and rubidium from potassium-containing rock, provided by the invention, in the step (6), the potassium-containing and rubidium-containing enriched salt has the potassium carbonate content of more than 90% and the rubidium carbonate content of more than 0.1%, so that the minimum industrial grade of rubidium recovery in a salt lake is 0.06%. The rubidium is further purified by adopting a mature production process for extracting the rubidium from the salt lake, and can be used for preparing high-purity rubidium oxide or metal rubidium.

The method for synergistically extracting potassium and rubidium from potassium-containing rocks provided by the invention provides a new comprehensive development and utilization idea for synergistically extracting potassium and rubidium from potassium-containing rocks to obtain potassium and rubidium concentrates and used for preparing high-purity potassium products and rubidium products and coproducing silicon-calcium fertilizer.

For the sake of clarity, the following examples are given in detail:

all examples use a molten salt furnace, using a molten salt as sodium nitrite(NaNO₂) And sodium nitrate (NaNO)₃). The maximum working temperature is 300 ℃. And crushing and preparing the potassium-containing sand shale sample, and enabling the sample to pass through a standard sieve with 200 meshes. Putting a proper amount of sample and CaO into a molten salt furnace steel bomb, adding distilled water according to a certain liquid-solid ratio, heating at constant temperature, starting rotation, stopping after reaction time is reached, taking out the sample, filtering, washing and drying.

The solid phase mineral components are analyzed by adopting an X diffraction analyzer, and the working parameters are as follows: a Cu target; working voltage: 40 kV; current: 200 mA; scanning speed: 7 deg/min. And measuring the content of the potassium by using an atomic absorption spectrophotometer and calculating the activation rate of the potassium. The effective potassium activation rate is calculated according to the formula (1). And measuring the rubidium content by adopting ICP-MS and calculating the leaching rate of the rubidium. The rubidium leaching rate calculation method is shown in a formula (2):

Y₁＝100(1-m₂(x₂-x₃)/x₁/m₁) (1)

Y₂＝100(1-m₂x₅/x₄/m₁) (2)

in the formula: y is₁-effective potassium activation,%;

Y₂rubidium leaching rate,%;

m₁-mass of potassium-containing rock, g;

m₂-mass of solid phase slag, g;

x₁-mass fraction of total potassium oxide in potassium-containing rock,%;

x₂-mass fraction of total potassium oxide in the solid phase slag,%;

x₃mass fraction of effective potassium oxide in the solid phase slag,%.

x₄-mass fraction of rubidium in potassium-bearing rocks,%;

x₅mass fraction of rubidium in solid phase slag,%.