FLOTATION SEPARATION OF FELDSPAR
United States Patent 3844939
An improved process for separating feldspars from feldspathic ores by means of froth flotation wherein a combination of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate is used as a flotation reagent, eliminating the necessity for activation with hydrofluoric acid.
US Patent References:
Concentration of nonsulfide ores
Schilling - January 1949 - 2459967
Froth flotation of iron impurities from feldspar
Gieseke - September 1949 - 2483192
Froth flotation of ferruginous impurities from finely divided granite rock
Duke - December 1951 - 2578790
Froth flotation of iron-bearing minerals from feldspathic ores
Banks - March 1953 - 2633241
Froth flotation of micaceous minerals
O'Neal - October 1965 - 3214018
Concentration of nonsulfide ores
Schilling - January 1949 - 2459967
Froth flotation of iron impurities from feldspar
Gieseke - September 1949 - 2483192
Froth flotation of ferruginous impurities from finely divided granite rock
Duke - December 1951 - 2578790
Froth flotation of iron-bearing minerals from feldspathic ores
Banks - March 1953 - 2633241
Froth flotation of micaceous minerals
O'Neal - October 1965 - 3214018
Application Number:
05/232280
Publication Date:
10/29/1974
Filing Date:
03/06/1972
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Export Citation:
Primary Class:
International Classes:
B03D1/004; B03D1/02
Field of Search:
209/166,167
Other References:
Chem Abst. 28956g, 69, 1968. .
Chem. Abst, 15544b, 64, 1966..
Primary Examiner:
Halper, Robert
Attorney, Agent or Firm:
Daniel, William J.
Claims:
1. A froth flotation process for separating feldspar from quartz-feldspar sands ore consisting essentially of the steps of subdividing said ore to produce at least a fraction having a particle size less than about 1 mm, collecting said fraction and washing the same with water to effect desliming, introducing the washed fraction at a solid concentration of about 20-30 wt percent into an aqueous flotation medium acidified to a pH of about 2-3.5 with sulfuric acid in the absence of hydrofluoric acid, said flotation medium containing about 0.05-0.2 percent by weight of a froth-flotation reagent consisting essentially of (1) a salt with an inorganic or organic acid of an organic mono-, di- or triamine having attached an amino nitrogen atom a long chain aliphatic hydrocarbon group containing, at least about eight carbon atoms and (2) a higher aromatic or aliphatic sulfonate of an alkali metal in a proportion in the range of 5:95- 60:40 by weight, agitating said medium to produce a froth containing feldspar, and separating said froth from the medium containing quartz as
2. The process of claim 1 wherein each of said amine salt and said sulfonate include a saturated or unsaturated long chain hydrocarbon
3. The process of claim 2 in which said radical contains at least about 12
4. The process of claim 1 wherein said flotation reagent is a mixture of a beef tallow amine acetate and a aromatic sulfonate.
2. The process of claim 1 wherein each of said amine salt and said sulfonate include a saturated or unsaturated long chain hydrocarbon
3. The process of claim 2 in which said radical contains at least about 12
4. The process of claim 1 wherein said flotation reagent is a mixture of a beef tallow amine acetate and a aromatic sulfonate.
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved process for separating feldspars from feldspathic ores by means of flotation, especially froth flotation. More particularly, the present invention relates to a process for the flotation of feldspars contained in feldspathic ores by using a combination of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate as the flotation reagents so that activation with hydrofluoric acid is unnecessary.
2. Summary of the Prior Art
Flotation, especially froth flotation, is well known among the general mineral recovery processes like magnetic separation processes in which useful ore constituents are separated by utilizing a difference in the specific gravities of the ore constituents.
In conventional froth flotation, feldspars have been separated from the feldspathic ores in which they occur generally by pulverizing an ore into a proper particle range, classifying the particles according to size, subjecting them to an activation treatment with hydrofluoric acid, admixing them in water together with a collector (for example, an aliphatic amine) and a foaming agent (for example, pine oil), introducing air therein to cause bubbling, and recovering the feldspars in the froth or foam thus generated, leaving other constituents, such as quartz, as tailings. However, the hydrofluoric acid used as the activator in this process reacts violently with other substances due to its high reactivity. Further, hydrofluoric acid is a highly poisonous reagent and, therefore, must be handled with the greatest possible care. In addition, hydrofluoric acid has the disadvantage of attacking and dissolving the surface of the quartz with a reduction in the yield of the product. Complications are therefore presented in carrying out this process on a commercial scale.
Accordingly, an object of the present invention is to provide an improved process for the flotation, especially froth flotation, of feldspars from feldspathic ores.
Another object of the invention is to provide a process for the flotation of feldspar which does not require activation with hydrofluoric acid.
Still another object of the invention is to provide a novel flotation process for separating feldspars from feldspathic ores wherein a combination of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate is used as the flotation reagent under an acidic condition provided by sulfuric acid.
Further objects of the invention will be apparent from the following description.
GENERAL DESCRIPTION OF THE INVENTION
It has been found that feldspars can be separated efficiently from feldspathic ores and minerals by means of froth flotation when a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate are used in conjunction as flotation reagents in a flotation medium made acidic with sulfuric acid, without the necessity for using hydrofluoric acid. The present invention has been accomplished on the basis of this finding.
According to the process of the present invention, the above objects may be attained by substituting sulfuric acid for hydrofluoric acid as the activating agent and effecting the flotation using a combination of a higher aliphatic amine and a higher aliphatic or aromatic sulfonate as the flotation reagent in the separation of feldspars from feldspathic minerals and ores.
The higher aliphatic amine salt used as one component of the flotation reagent in the present invention may be any higher aliphatic amine salt known to have utility as the so-called collector in conventional flotation processes. These salts are cationic surfactants containing at least one amino group and having attached to the nitrogen atoms of one amino group thereof a long chain hydrocarbon group, saturated, unsaturated and mixtures thereof, containing at least about eight carbon atoms and preferably at least about 12 carbons. The maximum number of carbon atoms in this chain is not particularly critical and may be selected in accordance with the usual practical limits in the art, say up to about 22-24 carbon atoms, for most purposes. The other substituents on this nitrogen atom may be hydrogen atoms or short chain hydrocarbon groups with up to about five carbon atoms and preferably one or two carbon atoms. Quaternary ammonium derivatives of such salts may also be useful.
Examples of suitable amine salts include salts of amines, for example, higher alkylamines such as dodecylamine, pentadecylamine and octadecylamine; primary amines such as mixed amines, for example, coconut oil amines, beef tallow amines and soybean oil amines; secondary amines such as N-dodecylpropylenediamine, N-pentadecylethylenediamine, N-decylhexamethylenediamine and beef tallow propylenediamine; and tertiary amines such as condensate of stearic acid with N-oleyl-N', N'-diethylethylenediamine or triethanolamine and N-acylates of alkylenetriamines, with inorganic acids such as hydrochloric acid and phosphoric acid or with organic acids such as acetic acid, propionic acid, tertaric acid and succinic acid.
A higher aliphatic or aromatic sulfonate serves as the other constituent of the flotation reagent in the present invention. These surfactants, often referred to as the alkane sulfonates, have a long chain hydrocarbon group, either saturated, unsaturated or mixtures thereof, connected to a sulfonate radical. The hydrocarbon group should contain at least about eight carbon atoms, and preferably at least about 12, up to the usual limits of the art, with an average of about 22-24 carbons being the normal upper limit as a practical matter, although longer chain compounds would not be excluded where available. Compounds of this type having intermediate linkages, such as ester, amide, or either groups, between the long chain group and the sulfonate radical can also be employed. These higher aliphatic or aromatic sulfonates or alkane sulfonates are used in the form of their salts of an alkali metal, preferably sodium, but also potassium, lithium and the like. Sulfonates obtained by sulfonation of higher aliphatic or aromatic hydrocarbons such as higher paraffinic and higher olefinic hydrocarbons are preferred, particularly sodium salts of petroleum sulfonic acids obtained by treatment of petroleum with concentrated sulfuric acid.
In the flotation reagent, the proportion of the higher aliphatic amine salt to the higher aliphatic or aromatic sulfonate is in the range of 5:95- 60:40 by weight. The flotation reagents are used in the form of a 10-50 wt. percent solution in water.
With a combination of the above-described components are the flotation reagent, resort to hydrofluoric acid as an activating agent is not required. It is sufficient to adjust the pH of the flotation medium to the desired acidity according to the practice of the art by means of sulfuric acid. The acidity will be usually a pH of, at least, about 4.5 and preferably 3.5-2.
GENERAL DESCRIPTION OF PREFERRED EMBODIMENT
A preferred embodiment of the process of the present invention will be illustrated below.
A raw ore is finely divided and then a fraction having a particle size less than about 1 mm is collected and washed thoroughly with water to effect desliming. Thereafter, the water in a flotator is adjusted to pH 2-3.5 with sulfuric acid. Next, there is added a water solution of a mixture of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate (5:95- 60:40 ) of a concentration less than 50 percent. Pulp concentration is about 20-30 wt. percent. An impeller is rotated to effect sufficient foaming and the resulting froth is separated from the tailings. Thus, feldspar and quartz, i.e., siliceous sand, are obtained as froth and tailings, respectively. If the amount of the flotation reagent is increased, the resulting feldspar has a reduced content of Al 2 O 3 and Fe 2 O 3 , although the yield of feldspar itself is increased. Therefore, the amount of the flotation reagent should be selected depending upon desired quality of the recovered feldspar and the separation efficiency.
In general, the aggregate amount of the flotation reagents used here, on a dry basis, should not exceed about 0.15-0.2 percent by weight of ore and smaller quantities in the order of 0.05-0.10 may be preferable in accordance with the usual practice of the art regarding weights of foaming agent and collector together.
According to the process of the present invention, safe operation is assured, since hydrofluoric acid is not used and, in addition, an offensive smell peculiar to pine oil is not present since pine oil is not used as the foaming agent.
The process of the present invention will be illustrated by an example which is intended to illustrate but not to limit the scope of the present invention. Unless otherwise stated, all parts and percentages are by weight.
EXAMPLE
A raw ore containing 88.71 percent of SiO 2 , 9.40 percent of Al 2 O 3 and 0.142 percent of Fe 2 O 3 is divided finely and a fraction of a size below 1190μ is collected and washed with water. Separately, 23 parts of 1 percent aqueous beef tallow amine acetate (Diomin T) solution are mixed with 77 parts of 1 percent aqueous sodium petroleum sulfonate (Aeropromotor No. 825, a product of American Cyanamide Co.) solution to obtain flotation reagent.
The ore washed with water is charged in a F-W flotator to obtain a pulp of 25 percent concentration. The pulp is then adjusted to pH 2.5 with sulfuric acid and kept at a temperature of 12.5°-13.5°C. The flotation reagent, as constituted above, is introduced therein in quantities of 10, 20, 30 and 40 cc per Kg of the washed ore. Flotation is carried out in a usual manner. The results thus obtained are shown in the following Table.
________________________________________________________ __________________ Quantity Separa- of re- Composition of Composition of tion agent isolated si- isolated rate of (cc/Kg liceous sand (%) feldspar Feldspar ore) SiO 2 Al 2 O 3 Fe 2 O 3 SiO 2 Al 2 O 3 Fe 2 O 3 (%) ____________________________________________________________ ______________ 10 97.50 1.65 0.096 75.00 19.30 0.24 4 20 98.00 0.95 0.088 77.50 17.50 0.20 13 30 98.50 0.75 0.075 78.50 16.20 0.18 18 40 99.10 0.49 0.067 80.50 13.68 0.15 26 ____________________________________________________________ ______________
As apparent from the above Table, as the quantity of the flotation reagent is increased, the separation rate of the feldspar increases but Al 2 O 3 and Fe 2 O 3 content of the separated feldspar froth are reduced.
1. Field of the Invention
The present invention relates to an improved process for separating feldspars from feldspathic ores by means of flotation, especially froth flotation. More particularly, the present invention relates to a process for the flotation of feldspars contained in feldspathic ores by using a combination of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate as the flotation reagents so that activation with hydrofluoric acid is unnecessary.
2. Summary of the Prior Art
Flotation, especially froth flotation, is well known among the general mineral recovery processes like magnetic separation processes in which useful ore constituents are separated by utilizing a difference in the specific gravities of the ore constituents.
In conventional froth flotation, feldspars have been separated from the feldspathic ores in which they occur generally by pulverizing an ore into a proper particle range, classifying the particles according to size, subjecting them to an activation treatment with hydrofluoric acid, admixing them in water together with a collector (for example, an aliphatic amine) and a foaming agent (for example, pine oil), introducing air therein to cause bubbling, and recovering the feldspars in the froth or foam thus generated, leaving other constituents, such as quartz, as tailings. However, the hydrofluoric acid used as the activator in this process reacts violently with other substances due to its high reactivity. Further, hydrofluoric acid is a highly poisonous reagent and, therefore, must be handled with the greatest possible care. In addition, hydrofluoric acid has the disadvantage of attacking and dissolving the surface of the quartz with a reduction in the yield of the product. Complications are therefore presented in carrying out this process on a commercial scale.
Accordingly, an object of the present invention is to provide an improved process for the flotation, especially froth flotation, of feldspars from feldspathic ores.
Another object of the invention is to provide a process for the flotation of feldspar which does not require activation with hydrofluoric acid.
Still another object of the invention is to provide a novel flotation process for separating feldspars from feldspathic ores wherein a combination of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate is used as the flotation reagent under an acidic condition provided by sulfuric acid.
Further objects of the invention will be apparent from the following description.
GENERAL DESCRIPTION OF THE INVENTION
It has been found that feldspars can be separated efficiently from feldspathic ores and minerals by means of froth flotation when a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate are used in conjunction as flotation reagents in a flotation medium made acidic with sulfuric acid, without the necessity for using hydrofluoric acid. The present invention has been accomplished on the basis of this finding.
According to the process of the present invention, the above objects may be attained by substituting sulfuric acid for hydrofluoric acid as the activating agent and effecting the flotation using a combination of a higher aliphatic amine and a higher aliphatic or aromatic sulfonate as the flotation reagent in the separation of feldspars from feldspathic minerals and ores.
The higher aliphatic amine salt used as one component of the flotation reagent in the present invention may be any higher aliphatic amine salt known to have utility as the so-called collector in conventional flotation processes. These salts are cationic surfactants containing at least one amino group and having attached to the nitrogen atoms of one amino group thereof a long chain hydrocarbon group, saturated, unsaturated and mixtures thereof, containing at least about eight carbon atoms and preferably at least about 12 carbons. The maximum number of carbon atoms in this chain is not particularly critical and may be selected in accordance with the usual practical limits in the art, say up to about 22-24 carbon atoms, for most purposes. The other substituents on this nitrogen atom may be hydrogen atoms or short chain hydrocarbon groups with up to about five carbon atoms and preferably one or two carbon atoms. Quaternary ammonium derivatives of such salts may also be useful.
Examples of suitable amine salts include salts of amines, for example, higher alkylamines such as dodecylamine, pentadecylamine and octadecylamine; primary amines such as mixed amines, for example, coconut oil amines, beef tallow amines and soybean oil amines; secondary amines such as N-dodecylpropylenediamine, N-pentadecylethylenediamine, N-decylhexamethylenediamine and beef tallow propylenediamine; and tertiary amines such as condensate of stearic acid with N-oleyl-N', N'-diethylethylenediamine or triethanolamine and N-acylates of alkylenetriamines, with inorganic acids such as hydrochloric acid and phosphoric acid or with organic acids such as acetic acid, propionic acid, tertaric acid and succinic acid.
A higher aliphatic or aromatic sulfonate serves as the other constituent of the flotation reagent in the present invention. These surfactants, often referred to as the alkane sulfonates, have a long chain hydrocarbon group, either saturated, unsaturated or mixtures thereof, connected to a sulfonate radical. The hydrocarbon group should contain at least about eight carbon atoms, and preferably at least about 12, up to the usual limits of the art, with an average of about 22-24 carbons being the normal upper limit as a practical matter, although longer chain compounds would not be excluded where available. Compounds of this type having intermediate linkages, such as ester, amide, or either groups, between the long chain group and the sulfonate radical can also be employed. These higher aliphatic or aromatic sulfonates or alkane sulfonates are used in the form of their salts of an alkali metal, preferably sodium, but also potassium, lithium and the like. Sulfonates obtained by sulfonation of higher aliphatic or aromatic hydrocarbons such as higher paraffinic and higher olefinic hydrocarbons are preferred, particularly sodium salts of petroleum sulfonic acids obtained by treatment of petroleum with concentrated sulfuric acid.
In the flotation reagent, the proportion of the higher aliphatic amine salt to the higher aliphatic or aromatic sulfonate is in the range of 5:95- 60:40 by weight. The flotation reagents are used in the form of a 10-50 wt. percent solution in water.
With a combination of the above-described components are the flotation reagent, resort to hydrofluoric acid as an activating agent is not required. It is sufficient to adjust the pH of the flotation medium to the desired acidity according to the practice of the art by means of sulfuric acid. The acidity will be usually a pH of, at least, about 4.5 and preferably 3.5-2.
GENERAL DESCRIPTION OF PREFERRED EMBODIMENT
A preferred embodiment of the process of the present invention will be illustrated below.
A raw ore is finely divided and then a fraction having a particle size less than about 1 mm is collected and washed thoroughly with water to effect desliming. Thereafter, the water in a flotator is adjusted to pH 2-3.5 with sulfuric acid. Next, there is added a water solution of a mixture of a higher aliphatic amine salt and a higher aliphatic or aromatic sulfonate (5:95- 60:40 ) of a concentration less than 50 percent. Pulp concentration is about 20-30 wt. percent. An impeller is rotated to effect sufficient foaming and the resulting froth is separated from the tailings. Thus, feldspar and quartz, i.e., siliceous sand, are obtained as froth and tailings, respectively. If the amount of the flotation reagent is increased, the resulting feldspar has a reduced content of Al 2 O 3 and Fe 2 O 3 , although the yield of feldspar itself is increased. Therefore, the amount of the flotation reagent should be selected depending upon desired quality of the recovered feldspar and the separation efficiency.
In general, the aggregate amount of the flotation reagents used here, on a dry basis, should not exceed about 0.15-0.2 percent by weight of ore and smaller quantities in the order of 0.05-0.10 may be preferable in accordance with the usual practice of the art regarding weights of foaming agent and collector together.
According to the process of the present invention, safe operation is assured, since hydrofluoric acid is not used and, in addition, an offensive smell peculiar to pine oil is not present since pine oil is not used as the foaming agent.
The process of the present invention will be illustrated by an example which is intended to illustrate but not to limit the scope of the present invention. Unless otherwise stated, all parts and percentages are by weight.
EXAMPLE
A raw ore containing 88.71 percent of SiO 2 , 9.40 percent of Al 2 O 3 and 0.142 percent of Fe 2 O 3 is divided finely and a fraction of a size below 1190μ is collected and washed with water. Separately, 23 parts of 1 percent aqueous beef tallow amine acetate (Diomin T) solution are mixed with 77 parts of 1 percent aqueous sodium petroleum sulfonate (Aeropromotor No. 825, a product of American Cyanamide Co.) solution to obtain flotation reagent.
The ore washed with water is charged in a F-W flotator to obtain a pulp of 25 percent concentration. The pulp is then adjusted to pH 2.5 with sulfuric acid and kept at a temperature of 12.5°-13.5°C. The flotation reagent, as constituted above, is introduced therein in quantities of 10, 20, 30 and 40 cc per Kg of the washed ore. Flotation is carried out in a usual manner. The results thus obtained are shown in the following Table.
________________________________________________________ __________________ Quantity Separa- of re- Composition of Composition of tion agent isolated si- isolated rate of (cc/Kg liceous sand (%) feldspar Feldspar ore) SiO 2 Al 2 O 3 Fe 2 O 3 SiO 2 Al 2 O 3 Fe 2 O 3 (%) ____________________________________________________________ ______________ 10 97.50 1.65 0.096 75.00 19.30 0.24 4 20 98.00 0.95 0.088 77.50 17.50 0.20 13 30 98.50 0.75 0.075 78.50 16.20 0.18 18 40 99.10 0.49 0.067 80.50 13.68 0.15 26 ____________________________________________________________ ______________
As apparent from the above Table, as the quantity of the flotation reagent is increased, the separation rate of the feldspar increases but Al 2 O 3 and Fe 2 O 3 content of the separated feldspar froth are reduced.