# Study of Oxidative-Reductive Potential Changes in the Enrichment of Oxidized Polymetallic Ores
###### Abstract
This will enable the efficient use of resources, reduce environmental damage, and ensure the sustainable development of the mining and metallurgical industry [2; 3; 4; 5; 6; 7; 8; 9; 10; 11]. A method for enriching oxidized polymetallic ores is flotation after preliminary sulfidation. Sulfidization of oxidized minerals is a process of chemically modifying the surface of minerals, wherein their oxidized compounds are converted into sulfides. This method is used to enhance the hydrophobicity of minerals, improve their flotation properties, and increase the extraction of non-ferrous metals from ores. The main goal of sulfidization is to convert the oxidized forms of metals (e.g., carbonates, sulfates, and oxides) into sulfide forms, which are more easily floated. This is especially important for difficult-to-enrich oxidized and mixed ores containing metals such as copper, lead, or zinc. Sulfidization occurs in several stages [12; 13]:  
1. Treatment of minerals with sulfur-containing reagents:
2. Minerals are treated with sulfidizing agents such as sodium sulfide (Na\({}_{2}\)S), sodium or ammonium polysulfides, hydrogen sulfide (H\({}_{2}\)S), or other compounds that can interact with the oxidized surfaces. 3. Sulfidization reaction:
4. The reagent interacts with the surface of oxidized minerals, forming a sulfide film on the surface. For example: \[\text{PbO}+\text{Na}_{2}\text{S}\rightarrow\text{PbS}\downarrow+\text{Na}_{2} \text{O}\] \[\text{PbCO}_{3}+\text{Na}_{2}\text{S}\rightarrow\text{PbS}\downarrow+\text{ Na}_{2}\text{CO}_{3}\]
5. As a result, the oxide and carbonate compounds of lead are converted into lead sulfide. 6. Fixation of the sulfide film:* The sulfide film formed on the surface of the minerals improves their hydrophobicity, which facilitates the attachment of flotation reagents and air bubbles during flotation. * Flotation:
* The modified sulfide minerals are extracted by flotation using xanthates or other collector reagents that effectively interact with the sulfide surface. It has also been proven that the stabilization of the electrochemical state of the dispersed system before flotation is necessary, controlled by measuring the oxidative-reductive potential (ORP) of the pulp. The oxidation-reduction potential (ORP) is a critical indicator reflecting the ratio between oxidized and reduced species in the pulp's liquid phase. This parameter characterizes the prevailing direction of chemical processes in the system, whether oxidation or reduction. ORP significantly influences the ion-molecular composition of the liquid phase, altering it due to the occurrence of oxidation; reduction reactions. The ORP value is measured in volts or millivolts and serves as an indicator of the oxidative or reductive activity of the medium. A positive value indicates a tendency toward oxidation, while a negative value signals the predominance of reduction processes. Thus, ORP serves as an important additional factor determining the chemical behavior of the liquid phase of the pulp and the direction of the reactions occurring [8; 9; 10]. The regulation of oxidation-reduction potential (ORP) is a key factor in the enrichment of oxidized polymetallic ones. A comprehensive study of ORP changes during flotation, leaching, and precipitation processes allows the development of effective enrichment technologies and enhances the extraction of valuable metals. Proper understanding and control of ORP help optimize the selectivity of separation and increase the efficiency of extracting target components [13; 14; 15; 16; 17]. According to the studies by [PERSON], [PERSON], and others, sulfidization primarily occurs on the surface layer of the mineral, forming a thin sulfide film. The formation of this sulfide film significantly increases the hydrophobicity of the mineral. However, excessive use of the Na\({}_{2}\)S reagent leads to the formation of a loose colloidal sulfide film, which easily breaks down and reduces the effectiveness of the sulfidization process.