阅读说明：本技术 一种中性pH条件下从石英与长石混合矿中正浮选石英的方法 (Method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition ) 是由 陈健 蒋雪松 班伯源 于 2021-07-14 设计创作，主要内容包括：本发明公开了一种中性pH条件下从石英与长石混合矿中正浮选石英的方法。该方法是通过分别加入两种不同碳链长度胺类浮选剂,并控制它们的加入顺序,从而扩大石英和长石的浮选回收率差异实现的。该方法选用短碳链双胺作为长石抑制剂,长碳链胺作为捕收剂,在浮选时,先将短碳链双胺加入矿浆并搅拌均匀后,再加入长碳链胺进行浮选,使石英颗粒上浮,而长石颗粒则留在浮选槽底部,使二者实现分离。本发明为无氟无酸中性条件下正浮选石英法,是一种区别于传统石英与长石浮选分离技术的新方法。该方法绿色环保,去除了酸碱对环境的危害。同时,该方法对石英和长石的分离效率高,浮选药剂简单、用量小,成本低,操作方便,容易在实际生产中推广应用。(The invention discloses a method for performing direct flotation on quartz from quartz and feldspar mixed ore under a neutral pH condition. The method is realized by respectively adding two amine flotation agents with different carbon chain lengths and controlling the adding sequence of the two amine flotation agents, so that the difference of the flotation recovery rates of quartz and feldspar is enlarged. The method selects short-carbon-chain diamine as a feldspar inhibitor and long-carbon-chain diamine as a collector, and during flotation, the short-carbon-chain diamine is added into ore pulp and stirred uniformly, then the long-carbon-chain diamine is added for flotation, so that quartz particles float upwards, and the feldspar particles are left at the bottom of a flotation tank, so that the separation of the two is realized. The invention relates to a method for directly floating quartz under the conditions of no fluorine and no acid neutrality, which is a new method different from the traditional quartz and feldspar flotation separation technology. The method is green and environment-friendly, and eliminates the harm of acid and alkali to the environment. Meanwhile, the method has high separation efficiency on quartz and feldspar, and the flotation reagent is simple, small in dosage, low in cost, convenient to operate and easy to popularize and apply in actual production.)

1. A method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition is characterized by comprising the following steps: the method comprises the following steps:

(1) putting a mineral sample containing quartz and feldspar into a flotation tank, adding water, and uniformly mixing to obtain ore pulp A;

(2) adding short-carbon-chain diamine into the ore pulp A, and uniformly mixing to obtain ore pulp B;

(3) adding long carbon chain amine into the ore pulp B, uniformly mixing to obtain ore pulp C, performing flotation separation on the ore pulp C until no foam is scraped out, and obtaining a floating sample and a sample which is settled in a flotation tank, wherein the floating sample is quartz, and the sample which is settled in the flotation tank is feldspar;

(4) and respectively separating the floating sample and the sample settled in the flotation tank, and drying to complete the separation of quartz and feldspar.

2. The method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: and (3) repeating the step (2) and the step (3) at least once for the quartz separated in the step (4) to obtain a quartz separated sample with higher purity.

3. The method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: in the step (1), the mineral sample is crushed and screened before being placed in a flotation tank.

4. The method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: in the step (1), the mass ratio of the mineral sample to water in the ore pulp A is 1-20: 150.

5. the method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: in the step (2), the short carbon chain diamine is ethylenediamine or propylenediamine.

6. The method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: in the step (2), the concentration of the short-carbon-chain diamine in the ore pulp B is 0.5 multiplied by 10^-5mol/L～5×10^{- 5}mol/L。

7. The method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: in the step (3), the long-carbon chain amine is one of polyether amine, lauryl amine and stearyl amine.

8. The method for direct flotation of quartz from quartz and feldspar mixed ore under neutral pH condition according to claim 1, characterized by comprising the following steps: in the step (3), the concentration of the long carbon chain amine in the ore pulp C is 1 x 10^-5mol/L～1×10^-4mol/L。

Technical Field

The invention belongs to the field of mineral processing, and particularly relates to a method for direct flotation of quartz from quartz and feldspar mixed ore under a neutral pH condition.

Background

Quartz has very stable physical and chemical properties. It has the advantages of heat resistance, low expansibility, corrosion resistance, high light transmittance and the like. The high-purity quartz sand is an indispensable raw material in the fields of semiconductors (chips), new energy sources (photovoltaics and the like), aerospace (special glass) and the like. Feldspar is rich in earth crust and widely used in the ceramic and glass industries, and some feldspars containing rare elements such as rubidium, cesium and the like can be used as raw materials for extracting the elements. Therefore, it is of great significance to develop a technology that is environmentally friendly, low in cost, and capable of effectively separating quartz and feldspar. However, quartz and feldspar are often associated minerals in nature. The feldspar and the quartz have similar mineralogical structures and belong to framework silicate minerals, and one fourth of Si in the quartz structure⁴⁺Is covered with Al³⁺Instead of feldspar, such a similar structure is disadvantageous for mineral separation, and since two minerals have similar density, hardness, magnetism and the like, they are difficult to separate by physical methods, and are currently mainly separated by flotation, which is classified into three types, namely an acid feldspar method, an alkaline pumice method and a neutral feldspar method.

The most common industrial type is the first type of flotation separation: acid-floatage process (reverse flotation for the quartz phase). The method is divided into a fluorine acid flotation method and a fluorine-free acid flotation method. The fluoric acid method is characterized in that under the condition of strong acidity (pH 2-3), hydrofluoric acid is used as an activating agent, and a cation collecting agent is used for preferentially floating feldspar; the fluoride-free acid method is characterized in that under the condition of strong acid (pH 2-3), feldspar is preferentially floated by using a cation and anion mixed collector. Although the two methods have good effect of separating quartz and feldspar, the harm of strong acid to the environment cannot be avoided, and particularly, the use of hydrofluoric acid has great harm to the environment and is a dangerous chemical strictly regulated and controlled by the country. In the actual production process, the corrosion of equipment by strong acid and the treatment of the flotation waste liquid increase the production cost.

To overcome the problem of acid flotation, a second type of flotation separation process has been developed: the alkaline floatstone process (for the quartz phase, positive flotation). The patent application with publication number CN103736596A discloses a feldspar and quartz flotation separation technology, which comprises grinding feldspar and quartz raw ore, pulping, adding sodium carbonate, mixing, adding N-acyl sarcosine sodium, and adding one or more of naphthenic acid soap, oxidized paraffin soap, oleic acid and hydroximic acid as collecting agent to float quartz upwards to obtain the product, i.e. feldspar. In the method, the pulp is alkaline due to the use of sodium carbonate for size mixing. The patent application with publication number CN105618271A discloses a method for separating quartz from low-grade potassium-sodium feldspar ore, which comprises the steps of mixing slurry by using sodium carbonate or sodium hydroxide to an alkaline condition that the pH value is 8-10, activating the quartz by using alkaline earth metal ions such as calcium chloride, lime or barium chloride, using sodium dodecyl sulfate, water glass and sodium hexametaphosphate as inhibitors, and floating the quartz by using amine collectors such as dodecylamine, octadecylamine and etheramine to separate the quartz and the feldspar. In patent application with publication No. CN 107899753A, an anion combined collector for fluorine-free floatation separation of quartz and feldspar is disclosed, NaOH is used as a pH regulator to float quartz in an alkaline condition, CaCl2 is added as an activator, and the collector is dissolved in warm water at 50-60 ℃. The alkaline floatstone method still has pollution to the environment, various medicament types and complicated operation, and is difficult to apply in industrial production due to harsh process conditions.

On the basis, a third type of flotation separation method is further developed: neutral anorthite method (reverse flotation for the quartz phase). Patent application with publication number CN108580050A discloses a method for floating potassium feldspar under the condition of neutral pH, which comprises adding sodium oleate into ore pulp as a collecting agent, amine substances such as dodecylamine and the like as activating agents, and sodium hexametaphosphate or water glass as an inhibitor, and floating the potassium feldspar in the flotation process to realize the separation from quartz. However, the price of the collecting agent sodium oleate is not low, 1000-1600 g/T of the collecting agent containing potassium feldspar material needs to be added, the using amount is large, the sodium oleate is unstable and easy to decay and deteriorate after being placed for a long time, insoluble calcium and magnesium soap precipitates are easy to generate with calcium and magnesium salts in hard water, and liquid becomes opaque. The feldspar obtained by the method is high in purity, but the purity of the separated quartz phase is not guaranteed, the types of added medicaments are various, the operation is complicated, and the feldspar is difficult to apply to industrial production due to harsh process conditions.

Disclosure of Invention

The invention aims to provide a method for positively floating quartz from quartz and feldspar mixed ore under a neutral pH condition, and the inventor conducts a great deal of research on the adsorption behaviors of amine flotation agents with different carbon chain lengths on the surfaces of quartz and feldspar, and finds that the adsorption behaviors of the amine flotation agents with different carbon chain lengths on the surfaces of quartz and feldspar are greatly different, short-carbon-chain amines, particularly ethylenediamine, have strong adsorption capacity on the surfaces of minerals such as quartz, feldspar and the like, but the floating capacity provided by the short carbon chain is weak, and long-carbon-chain amine flotation agents, such as polyetheramine, dodecylamine, octadecylamine and the like, have weak adsorption capacity on the surfaces of the minerals, but can provide larger buoyancy after the minerals are adsorbed on the surfaces due to the long carbon chain. If only chooseing ethylenediamine alone as the collector, under normal collector concentration, because it is weak to go up buoyancy, be not enough to let quartz or feldspar granule come-up, if choose long carbon chain amine such as polyetheramine D400 alone as the collector, under enough high collector concentration, quartz and feldspar can both come-up, but the difference of rate of recovery is very little, is not enough to separate the two. Our research found that the addition of ethylenediamine, which has a small molecular weight and is more easily adsorbed on the surface of the mineral, reduces the adsorption sites of the long carbon chain amine on the surface of the mineral during the flotation process by adding the ethylenediamine and the long carbon chain amine mixed flotation agent. Quartz is less inhibited by ethylenediamine because the adsorption sites of long carbon chain amines are more abundant than feldspar. Therefore, when long carbon chain amine is used as a collecting agent for flotation, the preferential addition of the ethylenediamine can obviously reduce the recovery rate of feldspar, and has little influence on the recovery rate of quartz. On the basis, the invention provides a fourth method for separating quartz and feldspar by flotation, which comprises the following steps: neutral floatstone process (for the quartz phase, positive flotation). And a set of green, environment-friendly and efficient flotation separation method for quartz and feldspar is designed, so that the defects in the prior art are overcome, and a selection scheme of the used cationic flotation agent is provided.

In order to achieve the purpose, the invention adopts the technical scheme that:

a method for positively floating quartz from quartz and feldspar mixed ore under neutral pH condition comprises the following steps:

(1) putting a mineral sample containing quartz and feldspar into a flotation tank, adding water, and uniformly mixing to obtain ore pulp A; preferably, the mineral sample is crushed and screened before being placed into the flotation tank, so that the particle size range of the selected sample is not too large; the mass ratio of the mineral sample to the water in the ore pulp A is 1-20: 150.

(2) adding short-carbon-chain diamine into the ore pulp A, and uniformly mixing to obtain ore pulp B; preferably, the short-carbon-chain diamine is ethylenediamine or propylenediamine, wherein ethylenediamine is the most preferred choice; the concentration of the short carbon chain diamine in the ore pulp B is 0.5 multiplied by 10^{- 5}mol/L～5×10^-5mol/L。

(3) Adding long carbon chain amine into the ore pulp B, uniformly mixing to obtain ore pulp C, performing flotation separation on the ore pulp C until no foam is scraped out, and obtaining a floating sample and a sample which is settled in a flotation tank, wherein the floating sample is quartz, and the sample which is settled in the flotation tank is feldspar; preferably, the long-carbon chain amine is one of polyetheramine D400, dodecylamine and octadecylamine; the concentration of the long carbon chain amine in the ore pulp C is 1 multiplied by 10^-5mol/L～1×10^-4mol/L。

(4) And respectively separating the floating sample and the sample settled in the flotation tank, and drying to complete the separation of quartz and feldspar.

As a preferable technical scheme, the quartz obtained by separating in the step (4) can be repeatedly subjected to the step (2) and the step (3) at least once according to the purity requirement of a final required product, so that a quartz separation sample with higher purity can be obtained.

The dosage of the short-carbon chain diamine and the long-carbon chain diamine in the step (2) and the step (3) is adjustable. When the concentration of the short-carbon chain diamine is increased and the concentration of the long-carbon chain diamine is reduced, quartz with higher purity can be obtained; when the concentration of the short-carbon chain diamine is reduced and the concentration of the long-carbon chain diamine is increased, feldspar with higher purity is obtained. However, the purity and recovery of the product are inversely related and should be adjusted according to the actual application.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a method for direct flotation of quartz from quartz and feldspar mixed ore under a neutral pH condition. In the flotation process of the invention, flotation is carried out under the condition of neutral pH value, and no pH value regulator is required to be added. Compared with the traditional acid feldspar method, the method avoids the harm of strong acid such as hydrofluoric acid, sulfuric acid, hydrochloric acid and the like to the environment. Compared with the alkali pumice method, the method has simple process and eliminates the pollution of alkali to the environment.

(2) Compared with the existing neutral anorthite method, the method has the advantages that the floating phase is changed from feldspar to quartz, the collecting agent can be saved for separating materials containing more feldspar, sodium oleate is changed into an amine cation collecting agent (long-carbon-chain amine) by the collecting agent, sodium hexametaphosphate or water glass is changed into short-carbon-chain diamine by the inhibitor, an activating agent is not needed, the short-carbon-chain diamine is used as the inhibitor, and the long-carbon-chain amine is used as the collecting agent.

(3) The high-purity quartz sand is an indispensable raw material in the fields of semiconductors (chips), new energy sources (photovoltaics and the like), aerospace (special glass) and the like. Feldspar is abundant in earth crust and widely used. However, quartz and feldspar are normally associated minerals in nature. Therefore, according to actual needs, the method can directionally obtain high-purity quartz or high-purity feldspar by adjusting the using amounts of the ethylene diamine or the propylene diamine and the polyether amine D400 or other long-carbon chain amines.

Drawings

FIG. 1 is a flow chart of the process for flotation of quartz in the mixed ore of quartz and feldspar in example 2 of the invention.

Detailed Description

The present invention will be further described with reference to the following examples. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1:

the embodiment is flotation of quartz and feldspar mixed ore, the polyetheramine D400 is used as a collecting agent, the ethylenediamine is used as a feldspar inhibitor, and the specific steps and test results are as follows:

(1) quartz with the grain size of 180-270 mu m and feldspar according to the weight ratio of 1: 1, mixing to obtain a mixed ore sample; mixing the mixed ore sample with pure water according to the weight ratio of 1: 100, adding the mixture into a flotation tank, and mixing and stirring for 1min to obtain ore pulp A;

(2) adding ethylenediamine into the ore pulp A to make the concentration of ethylenediamine be 1 x 10^-5mixing and stirring for 1min at mol/L to obtain ore pulp B;

(3) adding the polyetheramine D400 into the ore pulp B to ensure that the concentration of the polyetheramine D400 is 2 x 10^-5mixing and stirring for 1min to obtain ore pulp C; carrying out flotation separation on the ore pulp C for at least 5min until no foam is scraped out of the flotation tank, wherein the floating sample is quartz, and the sample deposited in the flotation tank is feldspar;

(4) and collecting the floating quartz sample and the feldspar sample precipitated in the flotation tank, drying, weighing and carrying out ICP-OES detection.

The ICP-OES test results for the quartz obtained in this example are shown in table 1, with the main elements listed in table 1 and other elements not listed. The impurity content is reduced from 43442.2ppmw of the mixed ore sample to 5364.0ppmw of the floating quartz sample, and the purity of the quartz obtained by separation reaches 99.5%. Meanwhile, the recovery rate of the quartz concentrate is 36.7 percent. The results show that the method of the invention is used for successfully separating quartz from the mixed ore of quartz and feldspar, and the purity of the quartz reaches 99.5 percent.

TABLE 1 ICP-OES test results (ppmw) for mixed ore samples and float quartz products of example 1

	Al	Fe	Na	K	Ca	Σ
							Mixed ore sample	20036.6	551.2	6382.2	15832.3	628.7	43442.2
Floating quartz	2152.6	82.2	736.1	2321.6	60.7	5364.0

Example 2:

granite separation

The embodiment is an application of the method in separating quartz from granite pegmatite, the granite pegmatite is a natural mineral formed by mixing feldspar and quartz, the natural mineral is crushed to form mixed sand of the feldspar and the quartz, in the embodiment, polyetheramine D400 is used as a collecting agent, ethylenediamine is used as a feldspar inhibitor, and flotation is performed twice according to the method steps, and the specific steps and test results are as follows:

(1) the method comprises the following steps of mixing a granite pegmatite sample with the particle size of 180-250 mu m according to a slurry ratio of 1: 30, adding the mixture into a flotation tank, and mixing and stirring for 1min to obtain ore pulp A;

(2) adding ethylenediamine into the ore pulp A to make the concentration of ethylenediamine be 1.5X 10^-5mixing and stirring for 1min at mol/L to obtain ore pulp B;

(3) adding the polyetheramine D400 into the ore pulp B to ensure that the concentration of the polyetheramine D400 is 6 x 10^-5mixing and stirring for 1min to obtain ore pulp C; carrying out flotation separation on the ore pulp C for at least 5min until no foam is scraped out of the flotation tank, wherein the floating sample is quartz, and the sample deposited in the flotation tank is feldspar;

(4) collecting a floating quartz sample and a feldspar sample which is sunk in the flotation tank.

In order to further improve the purity of the quartz sample, the floating quartz sample is subjected to secondary flotation by using ethylenediamine and polyetheramine D400, and the steps are as follows:

(5) and (3) mixing the quartz sample collected in the step (4) according to a slurry ratio of 1: 30, adding the mixture into a flotation tank, mixing and stirring for 1min to obtain ore pulp D;

(6) adding ethylenediamine into the ore pulp D to make the concentration of ethylenediamine be 1.5X 10^-5mixing and stirring for 1min to obtain ore pulp E;

(7) adding the polyetheramine D400 into the ore pulp E to ensure that the concentration of the polyetheramine D400 is 2 x 10^-5mixing and stirring for 1min at mol/L to obtain ore pulp F; and carrying out flotation separation on the ore pulp F for at least 5min until no foam is scraped out of the flotation tank, wherein the floating sample is quartz concentrate, and the sample which is settled in the flotation tank is feldspar.

The ICP-OES test results for the quartz obtained in this example are shown in table 2, with the main elements listed in table 2 and other elements not listed. The quartz concentrate extracted from granite pegmatite by the method has the impurity content of 8831.7ppmw, and the purity reaches 99.1%. The recovery of the quartz concentrate was 16.8%. The results show that the quartz sand was successfully separated from the granite pegmatite mixed sand using the method of the present invention.

TABLE 2 ICP-OES test results (ppmw) for separation of the quartz from granite pegmatite in example 2

Example 3:

the embodiment is flotation of quartz and feldspar mixed ore, dodecylamine is used as a collecting agent, ethylenediamine is used as a feldspar inhibitor, and the specific steps and test results are as follows:

(1) quartz with the grain size of 180-270 mu m and feldspar according to the weight ratio of 1: 1, mixing to obtain a mixed ore sample; mixing the mixed ore sample with pure water according to the weight ratio of 1: 100, adding the mixture into a flotation tank, and mixing and stirring for 1min to obtain ore pulp A;

(2) adding ethylenediamine into the ore pulp A to make the concentration of ethylenediamine be 1 x 10^-5mixing and stirring for 1min at mol/L to obtain ore pulp B;

(3) adding dodecylamine DDA into the ore pulp B to ensure that the concentration of the dodecylamine DDA is 2 x 10^-5mixing and stirring for 1min to obtain ore pulp C; carrying out flotation separation on the ore pulp C for at least 5min until no foam is scraped out of the flotation tank, wherein the floating sample is quartz, and the sample deposited in the flotation tank is feldspar;

(4) and collecting the floating quartz sample and the feldspar sample precipitated in the flotation tank, drying, weighing and carrying out ICP-OES detection.

The ICP-OES test results for the quartz obtained in this example are shown in table 3, with the main elements listed in table 3 and other elements not listed. The impurity content is reduced from 43442.2ppmw of the mixed ore sample to 4001.6ppmw of the floating quartz sample, and the purity of the quartz obtained by separation reaches 99.6%. Meanwhile, the recovery rate of the quartz concentrate is 26.6%. The results show that the method of the invention is used for successfully separating quartz from the mixed ore of quartz and feldspar, and the purity of the quartz reaches 99.6 percent.

TABLE 3 ICP-OES test results (ppmw) for mixed ore samples and float quartz products in example three

	Al	Fe	Na	K	Ca	Σ
							Mixed ore sample	20036.6	551.2	6382.2	15832.3	628.7	43442.2
Floating quartz	1788.3	84.8	442.5	1519.7	45.6	4001.6

The above embodiments are merely preferred conditions for carrying out the present invention, and do not limit the scope of the present invention. Various modifications and improvements of the technical solution of the present invention may be made by those skilled in the art without departing from the spirit of the present invention, and the technical solution of the present invention is to be covered by the protection scope defined by the claims of the present invention.