RU2189867C2 - Method of final concentration of magnetite concentrates - Google Patents

Abstract

FIELD: concentration of minerals; final concentration of magnetite concentrates at high content of sulfur. SUBSTANCE: magnetic concentrate after magnetic concentration or magnetite-containing product of one of stages of magnetic concentration is subjected to attrition re-grinding during three minutes followed by conditioning in presence of sulfuric acid, xanthate of alkali metal and additionally introduced modifier - oxyethylated high-molecular compound followed by flotation according to scheme including rough and control floatations. Sulfides (pyrrthotine) is separated in front product. Used as modifier is oxyethylated alkyl phenol OП-4-4 or ОП- 10 or polyethylene glycol ester alkyl phenol neonol or oxyethylated amine OKC of oxyethylated fatty acid-ОЖК. EFFECT: complete removal of sulfides. 2 tbl, 3 ex

Description

 The invention relates to mineral processing and can be used for the refinement of magnetite concentrates with a high sulfur content.

 There is a method of refining magnetite concentrates that have passed the stage of wet magnetic enrichment of the Taiga deposit [1]. According to this method, the initial magnetite concentrate is crushed to a particle size of 90-93% class - 0.074 mm and floated according to the scheme, including the main and control flotation. Soda, copper sulfate, butyl xanthate and T-80 blowing agent are used as reagents. As a result of flotation of the initial magnetite concentrate containing 1.06% S, a product is obtained in which the mass fraction of sulfur is 0.3% when 74.9% S is recovered in the sulfide product. Loss of iron with a sulfide product is 10.4%. The disadvantages of the method are: a low degree of purification of the magnetite concentrate from grains of sulfide minerals, which is explained by the low bearing capacity of the foam created by the T-80 blowing agent. In addition, the process in an alkaline environment created by soda, leads to the transition of part of the magnetite grains in the foam product and high losses of iron.

 There is also known a method of desulfurization of magnetite concentrates of one of the deposits of South Yakutia [2]. According to this method, the magnetite concentrate after magnetic separation is subjected to enrichment according to the scheme, including the main flotation and four refining of the foam product. As reagents, copper sulfate, butyl xanthate, T-80 blowing agent and liquid glass are used. As a result of flotation according to this method, the sulfur content in magnetite concentrate is reduced from 0.5% S to 0.2-0.17% S. The disadvantage of this method is the low degree of sulfide recovery, which is associated with the lack of special preparation of the oxidized surface of pyrrhotite for flotation (flotation pyrrhotite should be carried out immediately after grinding, when a clean cleaved surface is formed). In addition, the proposed reagent mode is ineffective in the enrichment of fine-grained concentrate, since liquid glass non-selectively coagulates sludges.

The closest in technological essence and the achieved result is a method of flotation separation of iron sulfides from a fine-grained magnetite concentrate at the Marcona concentrator [3], according to which the initial magnetite magnetic separation concentrate is ground to a particle size of 65% class - 0.044 mm, the ground pulp is contacted with CuSO ₄ , amyl xanthate and blowing agent. Flotation is carried out in an acidic environment at pH 4.5. However, this method is not effective enough for flotation of sulfides with their low content (less than 0.5%) in the feedstock, when it is necessary to use a strong collector. Amyl xanthate does not provide high process selection: sulfur decreases from 0.4% S to 0.25% S.

 The purpose of the invention is a more complete removal of sulfides to obtain a magnetite concentrate conditioned by the content of limited impurities of sulfur (S <0.05-0.08%).

 The invention consists in the following. Magnetitic concentrate that has undergone magnetic enrichment, or a magnetate-containing product of one of the stages of magnetic enrichment, is finely grinded for 3 minutes, conditioned in the presence of sulfuric acid, alkali metal xanthate, an additional ethoxylated compound is introduced, and then floated according to the scheme including the main and control flotation. Sulfides (pyrrhotite) are released into foam products. As the modifying reagent, use is made of the ethoxylated alkyl phenol OP-4 or OP-10, or the polyethylene glycol ether of alkyl phenols-neonol, or the ethoxylated amine — ACS, or the ethoxylated fatty acid — OLC.

 It is known that the surface of pyrrhotite is prone to oxidation. During oxidation, its reactivation (reduction) is practically impossible, which significantly reduces the flotation activity of the mineral. Therefore, prior to flotation, an chopping of the starting material should be carried out.

 The dependence of the sulfur content in the concentrate on the influence of pH is shown in the drawing. From these data it follows that sulfides are most effectively floated at a pH of 5.6-6.8. Flotation in more alkaline environments leads to a sharp deterioration in the quality of the concentrate.

 Surfactants based on ethylene oxide enhance the collective action of xanthate, increasing its adsorption on the surface of minerals. This is especially important when the sulphide content is low in the feed, when a strong collector is required.

 In addition, ethoxylated high molecular weight compounds (OVS) peptize sludge while hydrophobizing their surface. This is consistent with the results of experiments on flotation of sulfides from magnetite concentrate of the Kovdorsky GOK. Table 1 presents the comparative values of sulfur contents and distributions by size classes of magnetite concentrates obtained as a result of flotation using xanthate and aeroflot (mode I) and with xanthate and OVS (mode II). An analysis of these data indicates that the OVS provides selective flotation of sulfides from thin classes: in the fraction - 0.063 mm magnetite concentrate after flotation, 29.8% S remains after recovery at a content of 0.03% S. When flotation in mode I, sulfur recovery in class - 0.063 mm magnetite concentrate is 56.1% with a content of 0.181% S.

These factors determine the feasibility of using OVS as a reagent modifier of complex action. In this case, the following oxyethylated compounds can be used as ODS: oxyethylated alcohols (reagents OC _18-26 and OC _18-40 ), ethoxylated fatty acids (OFA), ethoxylated alkyl phenols (OP-4, OP-10), polyethylene glycol ether of alkyl phenols ( neonol grade AF-9-10), ethoxylated palmitic acids (OPK), ethoxylated amine ACS (reagent oxamine).

 Table 2 presents the results of flotation of sulfides in the presence of OVS of various composition, as well as in prototype mode.

 The use of organic compounds in combination with xanthate can reduce the sulfur content in magnetite concentrates of Kovdor GOK from 0.32-0.34% to 0.035-0.093% (examples 1-10), in magnetite concentrates of Olenegorsk GOK from 0.22-0.23 % S to 0.0094-0.012% S (examples 12, 13). As the starting material, not only magnetite concentrates can be used, but also magnetite-containing products of the magnetic enrichment cycle. As a result of flotation of sulfides from a ball mill sand sample (Example 14), the sulfur content was reduced from 0.26 to 0.03%, from a sample of a concentrate of stage I wet magnetic separation (Example 15), from 0.35% S to 0.051% S.

Sulfur recovery in foam products of sulfide flotation (1000-ε $\genfrac{}{}{0ex}{}{\text{S}}{\text{Magnet}}$ ) amounts to 74.6-89.7% during the doflotation of the magnetite concentrate of the Kovdor GOK and 96.4-95.1% of the Olenegorsk GOK. The extraction of iron into chamber products (magnetite concentrates) is 88.2-97.8% Fe and 82.5-87.2% Fe, respectively. When flotation in prototype mode, it was not possible to obtain a magnetite concentrate, conditioned by sulfur content (example 11).

 The method is as follows.

Example 1 (table. 2). The flotation of sulfide minerals was carried out from magnetite concentrate obtained at the Kovdorsky enrichment plant by the method of post-adial wet magnetic enrichment. Magnetite concentrate is represented by the following mineral composition, wt.%: Magnetite 95.0; apatite 0.6; forsterite 1.8; sulfides 1.0; phlogopite 0.5; others - 0.6. The size of the floated product is less than 0.3 mm. The experiments were carried out in flotation laboratory machines with a chamber volume of 1 liter. The pulp was pre-treated with sulfuric acid at a flow rate of 1500 g / t for 3 min (pH 5.9-6.1), then 10 min the pulp was treated with butyl xanthate 500 g / t and for 2 min OC _18-40 in an amount of 150 g / t After this, the main sulfide flotation was carried out. Flotation time 10 min. The main flotation chamber product was subjected to control flotation. Xanthate consumption 250 g / t, OC _18-40 50 g / t. Sulfide minerals float in a foam product. The sulfur recovery in the foam product was 88.0%. In the chamber product remains desulfurized magnetite concentrate. The content in it S _total 0.04%.

Example 2 (table. 2). Flotation of sulphides from the sands of a ball mill at a magnet processing plant at the Kovdor GOK. The experiments showed the possibility of sulfur flotation from intermediate products of the magnetic concentration cycle. The product contains F _total 59.18%; S 0.26%. This material has a larger sieve characteristic (grade content +0.063 mm - 35.2%). The original product, crushed in a laboratory ball mill, was treated with sulfuric acid (pH 6.0), then xanthate and reagent modifier OC _18-26 . Flotation is carried out immediately after grinding, therefore, a special grinding milling regrinding is not required.

 The prepared flotation material has a slightly oxidized surface, unlike magnetite concentrate, which positively affects the process of separation of minerals. Technological laboratory flotation scheme includes the main and control operation. Main flotation time 10 min. The residual S content in the magnetite product was 0.03% when the sulfur was recovered in the foam product - 88.9%.

Example 3 (table. 2). Sulfide flotation was carried out from Olenegorsk iron concentrate obtained after post-adial enrichment by wet magnetic separation. The chemical composition of the concentrate,%: Fe _total 70.6; SiO ₂ 6.0; CaO 0.24; MgO 0.43; Al ₂ O ₃ 0.23; S 0.22. The experiments were carried out in laboratory flotation machines with a chamber volume of 1 liter. The pulp was preliminarily, as in example 1, treated with H ₂ SO ₄ at a flow rate of 1.5 kg / t (pH 6.0-6.3), then after agitation with xanthate and reagent OC _18-40 , the main flotation was carried out and sequentially 2 control operations. The total flotation time was 15 minutes The sulfur recovery in the foam product was 95.1-96.6%. The residual S content in the magnetite concentrate was 0.0094-0.012% with an initial sulfur content of 0.23-0.22%.

Sources of information
1. The practice of obtaining low-sulfur magnetite concentrates by flotation / D. I. Suvorova, L. G. Tyuryukhanov, L. P. Pekhova // Ways to improve the quality of iron ore concentrates. - M .: Nedra, 1988.- S. 31-38.

 2. Technology for the integrated use of sulfide magnetite ore / D. I. Suvorova, P. V. Shulgin, L. M. Bondarev, and others // Chemical, combined enrichment and analysis of ferrous ores. - M .: Nedra, 1989 .-- S. 31-38.

 3. ClineW.A., Rosas Rene C. How Marcona floats iron sulphides from magnetite pellet feed concentrate // Wold mining. - 1975. - N 3. - 28. - P. 38-52.

Claims (1)

 The method of flotation separation of sulfides from magnetite concentrate and magnetite-containing intermediate products, including grinding, conditioning with acid, alkali metal xanthate and a modifying reagent and flotation with the release of sulfides into a foam product, characterized in that an ethoxylated high molecular weight compound is used as a modifying reagent: oxyethylated -OP-4 or OP-10, or alkylphenol polyethylene glycol ether — neonol, or ethoxylated amine-ACS, or ethoxylated fatty acid - OZHK.

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