FI64755B - SAINT VIDEO RUBBER WITH PHOSPHATHALTIGE MINERAL AND CARBONATE- OR SILICATEHALTIGA SYSTEM GENOM SKUMFLOTATION - Google Patents

Description

[11] {11) NOTICE OF ADVERTISEMENT. , Π cr • ISF® LJ '* utläggni ngsskr, ft 04/00 ^ v (51) ICy.lk.3 / lnt.CI.3 B 03 D l / 02 FINLAND —'FINLAND (21) p * tenttlh *, 'emu * - P «Mnawi6knlng 770690 (22) Hakemhpilvl - An * eknlng * dag 03-03-77 (23) Alkupllvl — Glltighttsdaf 03.03.77 (41) Become Public - Blivlt offentlfj 06, 09. 77

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(32) (33) (31) Privilege claimed — Begird prlorltet 05-03-76

Sweden-Sweden (SE) 760301 + 5-1 (71) KemaNobel AB, Box 11005, S-100 6l Stockholm, Sweden-Sweden (SE) (72) Alexander Meyer, Stockholm, Margita Ingegärd Nilsson, Saltsjö-Boo, Sweden Sverige (SE) (7 ^) Oy Jalo Ant-Wuorinen Ah (5 * 0 A method of enriching phosphate-containing minerals from carbonate and silicate-containing systems by foaming - Sätt vid anrikning av fosfathaltiga Mineral ur carbonat- och silikat-haltiga system genasta kosom skumflotation This invention phosphate-containing minerals from carbonate- and silicate-containing systems by foaming.

In particular, the invention relates to the enrichment of phosphate-containing minerals from mineral mixtures containing alkaline earth metal carbonates, fluorides, silicates, etc., by foaming in an alkaline medium at a pH of more than 6 using amidocarboxylic acid as a collecting reagent. The selectivity of the process is promoted by the presence of excipients known per se, such as dispersants, activators, blowing agents, printers (tryekarreagens, depressor).

Phosphate-containing minerals, such as apatite and phosphorite, are purified and concentrated from the crude minerals, usually by flotation, i.e. by treating the aqueous suspension of refined crushed mineral material from removed as a foam product.

Enrichment of phosphate-containing minerals by flotation is generally accomplished with anionic collecting reagents such as fatty acids, various sulfates or sulfonates and their alkali salts, etc. in an alkaline medium in the pulp using various 64755 excipients such as printers, activators, etc. for selective process conditions. However, common anionic collection reagents are non-selectively chemisorbed on the alkaline earth metal-containing mineral surfaces, which usually results in a highly contaminated co-concentrate. These co-concentrates must be further purified either by repeated treatment in several stages or, after the so-called desorption stage, by additional foaming in the presence of other types of collecting reagents. Purification of the crude concentrate in several repetition steps is not very efficient and often results in a significant loss of phosphorus in the waste.

It is known that in carrying out the selectivity of the process, foaming by means of a collecting reagent of said type can be improved to some extent by carrying out foaming in an acidic medium. SE patent 326,417 describes, for example, the separation of calcite from apatite in an acidic medium using fatty acid-mineral-oil emulsions. One disadvantage of anionic collecting reagents, in addition to their poor selective collecting ability, is their sensitivity to water hardness builders and pulp temperature. In order to be effective, they must be used at a pulp temperature of 25-30 ° C, which often puts a strain on the flotation process economically. Sensitivity to hardness builders in the process water adversely affects the flow of flotation and makes continuous softening of systems using closed process water necessary.

According to the invention, it has been found that phosphate-containing minerals can be enriched from carbonate and silicate-containing systems by foaming at a pH above 6, using a collecting reagent consisting of at least one amidocarboxylic acid, or an alkali salt thereof, and in the presence of a printer.

The amidocarboxylic acids used according to the invention have a very good selective affinity for phosphate minerals and thus give higher yields and purer concentrates in flotation compared to conventional collecting reagents. The presence of a negative substituent on the hydrocarbon chain of acids synergistically emphasizes the dissociation ability of the carboxyl group at the terminal position. This fact promotes the conditions for chemisorption of the collector into the mineral surfaces and allows a high flotation rate. Amido carboxylic acids are less sensitive to hardness builders in process water, are easily dispersed therein and can thus be added to the pulp without prior emulsification. Amidocarboxylic acids are not sensitive to temperature, i.e. they are completely effective even at low mass temperatures.

The collecting reagent used in the process of the invention is a free amidocarboxylic acid, or an alkali metal salt thereof, having the following general gross formula R - X - (CH 2) n COOH, wherein X is a group R 1 R 11 1 - N - C -, or - C - N -

Wherein n is 0 wherein R represents a saturated or unsaturated, normal or branched aliphatic group having 7 to 30 carbon atoms, R 2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and n is 1 to 8.

R represents an alkyl group having at least 7 carbon atoms, for example heptyl, octyl, nonyl, decyl, dodecyl, tri-decyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, and higher alkyl having up to 30 carbon atoms, corresponding unsaturated carbon atoms, , for example, decenyl, tridecenyl, hexadecenyl, heptadecenyl, octadecenyl, eicosenyl, etc., double or polyunsaturated alkyl groups having 7 to 30 carbon atoms, aryl-substituted alkyl groups and alkyl-substituted cycloalkyl, , nonylphenyl, dodecylphenyl, tridecylphenyl, nonylcyclopropyl, dodecylcyclobutyl, etc., wherein any of the above groups may contain oxygen bridges or non-interfering inert substituents.

R is preferably a straight or branched, saturated or unsaturated alkyl group having 11 to 22 carbon atoms, R 1 is a methyl, ethyl, propyl or butyl group, n is 2 to 6 and X is a group R 1 to C to N-, wherein R 1 means the same as above.

n o

The separation of the phosphate-containing mineral is carried out according to the invention by foaming with the above-mentioned collecting reagent at a pH of more than 6, preferably at a natural pH, in the presence of conventional reagents such as dextrin, tannin, sodium silicate, etc. Batch flotation yields the phosphate mineral as a foam product.

The flotation is suitably carried out at the natural pH of the pulp, which is normally in the pH range of 8-10. According to the invention, the pH of the pulp can also be adjusted according to the petrographic phase composition of the material, for example by adding soda, slaked lime or lye.

With the method according to the invention, phosphate-containing minerals can be enriched, for example, from the systems phosphorite-silicate, apatite-hematite-silicate, apatite-dolomite-biotite, etc.

In the processes mentioned in Examples 1 and 2, apatite is removed as a foam product in a highly hydrophobized state. This state is the result of the physical and chemical absorption of the collecting reagents onto the surfaces of the mineral particles. The absorption process follows known physical laws and depends on several parameters and also on the temperature of the pulp, its pH and the negativity and Z-potential of the mineral surfaces. These are different for different minerals, so the collecting reagents are sorted differently and with different intensities and preferably around active centers (cf. e.g. Ney, Zeta-Potentiale und Flotierbarkeit von Mineralen, Springer-Verlag 1973, pp. 108-115, 96-101; Vladimer Ponec et al. Adsorption on Solids, Butterworths, 1074, pp. 435-488).

The phosphate-containing foam product obtained by the process of the invention is subsequently subjected to selective foaming at a pH of 4-5.5, whereby carbonate-containing alkaline earth metal impurities are obtained as a foam product and the phosphate-enriched mineral as a chamber product.

Due to the high reactivity of amidocarboxylic acids and their good selective affinity for phosphate-containing minerals, it is possible from in accordance with. The result of the flotation depends on many factors that normally affect the flotation process such as mineral pretreatment and refining crushing, grain size distribution, pulp concentration, conditioning time, etc., i.e., known parameters. Collecting reagent 5 64755 is used in excess of 40 g per tonne of dry matter. The upper limit is limited by the critical concentration at which double absorption layers are formed. The collecting reagent is suitably added at 50-150 g / ton.

The invention is explained in more detail in the following embodiments, which, however, are not intended to limit the invention. Percentages refer to weight percentages unless otherwise indicated. Example 1:

Separation of apatite concentrate from hematite-pig iron ore.

1.6 kg phosphate-rich hematite ore with a type composition of: hematite 35.9%, magnetite 14.4%, fluoroapatite 15.1%, quartz 7.1%, muscovite 2.2%, calcite 0.7%, feldspar and mica 18 .4% and water 6.2% are measured in a rod mill and ground to a flotation fineness of K80 = 0.075 mm so that the required cleaning crushing and the optimal grain distribution curve are achieved. 0.35 g of dextrin prepared by partial hydrolysis of corn starch is added as a printer.

For a foaming test in a Fagergren-type laboratory apparatus with a cell volume of 2,5 l, measure 1,5 kg of a freshly prepared mineral suspension, the volume of which is diluted to 2.3 l with water. To a pulp with a natural pH of 8.2 and a dry matter content of 44% are added 0.5 g of a 40% solution of Na 2 Si 2 O 5 as a slurry dispersant and 0.15 g of octadeceneamidoacetic acid as a collecting reagent. After conditioning for 5 minutes at 15 ° C, air is introduced and the foam layer formed is wiped off manually over a period of 6 minutes.

The water is removed from the foam product and dried to give a residue as a crude apatite concentrate. The results of the chemical analyzes obtained for the raw apatite in three parallel experiments are shown in the following table:

Fe% P% concentration distribution concentration distribution Experiment 1 3.1 3.7 14.5 92.4

Experiment 2 4.1 5.4 13.5 91.4

Experiment 3 2.9 3.2 15.0 96.0

After the raw flotation step, the air inlet is closed and the water level in the cell is adjusted by adding about 150 ml more water. The air inlet is then opened and scavenger-foamed (de-icing) for 5 min using a very large air supply. The main product, iron ore, which has a very low phosphorus content, leaves the process as a chamber product. The foam cake obtained from the residue removal can be returned to the raw flotation step if the process is carried out continuously or, after inspection, is combined with the raw flotation concentrate. The crude apatite concentrate is reprocessed in two steps to isolate the apatite concentrate without the addition of additional collecting reagent. Type analysis of fluoroapatite concentrate after reprocessing and drying at 120 ° C:

Fe CaCO 3 MgCO 3 CaF 2 Ca 5 (PO 4) 3 F P yield Experiment 1 0.1 2.5 1.0 2.0 94.5 96

Experiment 2 0.41 2.0 0.8 1.8 95.0 96.5

Experiment 3 0.36 1.4 0.7 1.6 96.0 94.0

The phosphorus-poor iron concentrate remaining as a chamber product is subjected to flotation using a cationic collector reagent to purify the iron concentrate of the acidic components present, such as quartz, silicic acid, silicates and their alkali salts. The flotation is carried out in a manner known per se using methods commonly used in enrichment techniques.

The chamber product leaving the silicate flotation step to remove water therefrom with a drum filter is a very pure concentrate which is well suited for reduction into iron sponge or spherical sintering.

Type analysis of iron concentrate Fe P SiO 2 S NaO + K 2 O Fe yield Experiment 1 70.2 0.011 1.2 0.001 0.1 94.4

Experiment 2 69.3 0.010 1.8 0.004 0.12 96.0

Experiment 3 69.4 0.017 3.2 0.004 0.11 95.9

Example 2:

Isolation of apatite concentrate by direct flotation.

Coarse primary waste obtained from the purification of phosphorus from crude magnetite by a continuous magnetic separator with a phosphorus content of 2.5% is further crushed to Kqq = 0.110 mm in the wet state in an autogenous grinding circuit.

After thickening, a mineral suspension is obtained in water with a dry content of about 45%, which is unsorted and transferred directly to the apatite separation by flotation. According to Example 1, 1.5 kg of a crushed cleaning crushed suspension with a dry matter content of about 45% are weighed into a Fagergren-type laboratory flotation cell. Dilute the volume to 2.3 l with water. To a pulp with a natural pH of about 8.0-8.1 is added 0.5 g of Na 2 Si 2 O 3 to peptize the slurry and depressurize the silicates and 0.125 g of octadecenylamidopropionic acid to the apatite collecting reagent.

The mass is conditioned for 5 minutes at normal temperature, after which air is allowed to enter and the foam cover formed is wiped off manually for 5 minutes. Flotation takes place according to the following schedule:

Step Product Weight% P content Yield Fe Concentration pH

mouth%%% time 4 Apatite- 12.8 17.4 88.9 0.2 4 7.9 concentrate 3 Pre-concentrate 13.8 16.6 91.3 4 7.9 repetition 2 Scavenger 3.8 2.7 2.2 3 8.6 product 1 Raw 17.8 13.1 93.4 5 8.6 concentrate 0 Conditioning 5 8.7

Entered 100 2.5 100.0 substance

Amidocarboxylic acid scavenger reagents have excellent selectivity in separating silicate-iron oxide-apatite mineral systems. With a continuous process, higher phosphorus yields can be obtained because in this case the scavenger product can be taken back to flotation.

Example 3i

Separation of apatite concentrate from low-value complex carbonate materials consisting of the apatite-calcite-dolomite-biotite system with a distribution of 8:15: 10: 67.

Selective separation of the above system by flotation with conventional collection reagents is a technically difficult and economically poor process. Common anionic build-up reagents such as normal fatty acids, sulfonates, phosphoric acid esters, etc. are non-selectively chemororbed into alkaline earth minerals and provide highly contaminated co-concentrates in flotation. Purification in several repetition steps is not very efficient and often results in significant phosphorus loss.

Other results are obtained using the two-step method and the Na salt of octadecenyl-β-amidocaproic acid as a collection reagent.

1.5 kg of fresh, crushed mineral suspension is weighed into a flotation cell, type Fagergren, cell volume 2.5 l, and the pulp is diluted with water to 2.3 liters to a pulp density of about 40% dry matter. To a mass having a natural pH of about 8.6 to 8.8 is added 1 g of a 40% solution of Na 2 Si 2 Og and 0.4 g of the above-mentioned collecting reagent. After conditioning for 6 minutes, the pH is adjusted to 9-9.2, and air is introduced and flotation is carried out according to the method mentioned in Example 1. As a foam product, a co-concentrate is obtained which contains all the alkaline earth-containing minerals contained in the pulp. Since only the apatite fraction is a value mineral, care is taken to ensure that the residue removal step is carried out quantitatively so that the p2 ° 5_P * content in the chamber product does not exceed 0.1%. The foam product and scavenger concentrate from the pre-foaming are reprocessed so that most of the biotite remains as a chamber product and is removed as waste. The apatite-calcite-dolomite concentrate is conditioned with phosphoric acid at pH 4-4.5 and then subjected to selective flotation. The calcite-dolomite fraction separates as a foam product and the apatite concentrate is obtained as a chamber product.

The material balance of the above-mentioned flotation process, using alkylaminocapronate as a collecting reagent, is shown in the following summary:

Product in co-enrichment Weight% p2®5 Distribution Feed rate 100.0 3.88 100.0

Total concentrate 30.8 12.03 97.72 Waste (silicates) 69.14 0.1 2.28

Selektiivivaahdotustuote

Calcite-dolomite fraction 25.6 0.1

Claims (3)

9 64755 A method of enriching phosphate-containing minerals from carbonate and silicate-containing systems by foaming, characterized in that the foaming is first carried out at a pH above 6 with a collecting reagent consisting of at least one amidocarboxylic acid or its alkali metal salt of the general formula R - X00 (CH2) wherein X is a group R1 »1 f I - C - N - or - N - C - 'n 0 0 wherein R represents a saturated or unsaturated aliphatic group having 7 to 30 carbon atoms, R 1 represents hydrogen or a group containing 1 to 4 carbon atoms alkyl group, and n is 1 to 8 and in the presence of a printer, to obtain a phosphate-containing mineral as a foam product, and that the resulting foam product is then subjected to selective post-flotation at pH 4-5.5 to obtain carbonate-containing alkaline earth metal impurities as a foam product and phosphorus product. kammiotuotteena. Process according to Claim 1, characterized in that the collecting reagent consists of at least one amidocarboxylic acid of the above formula, or an alkali metal salt thereof, wherein R represents a saturated or unsaturated aliphatic group having 7 to 22 carbon atoms, R 1 represents 1 to 4 carbon atoms n is 2 to 6 and X is a group R 1 «- C - N -, which has the same meaning as above. It O Method according to one of the preceding claims, characterized in that the flotation is carried out in the presence of known flotation agents and activators.