Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components

Currently, the main trend of the pulp and paper industry development is bio-refining. It is based on integrated and deep processing of wood raw materials to obtain products with higher value added and reduced amount of waste. One of the high priority tasks of bio-refining is improvement of technology of by-product (sulphate soap) extraction from spent liquor with an increase in the yield and quality of the resulting product and a decrease in the level of environmental pollution. The complexity and energy intensity of sulphate soap extraction from spent liquor depends on many factors, including the species used for wood cooking, composition of extractives, the method of wood preparation for delignification, etc. Sulphate soap is a multicomponent emulsion with a predominant content of resin and fatty acids, small amount of unsaponifiable substances and an admixture of lignin, which is mainly extracted from waste liquior by settling. The low degree of its extraction is associated with the absence of systematical data on the mutual influence of the sulphate soap components. In this work, the patterns of intermolecular interaction of the individual components of the by-product (sulphate soap) are found. For this purposes the critical concentration of micelle formation (CCM) and surface tension depression of surface-active sodium oleate and sodium abietate and their mixtures of varying compositions were determined by the methods of tensiometry and conductometry. A detailed analysis of its mixed micelles and adsorption layers was carried out using the Rubin–Rosen pseudophase model. The interaction mechanisms of components in mixtures are explained. The impact on the composition of micelles and adsorption layers of the more surface-active sodium oleate was detected in mixed solutions. A maximum synergistic effect of micelle formation was observed in mixtures with a predominant content of sodium abietate. Analysis of experimental data and the result of sulphate soap modeling allow substantiating the complexity of its extraction from waste liquor after wood cooking with the presence of hardwood over 30 %, which is explained by the reduced content of resin acids in black liquor. For citation: Yakubova O.S., Demiantseva E.Yu., Smit R.A., Dubovy V.K. Analysis of Micelle Formation and Adsorption Layers of Binary Mixtures of Sulphate Soap Components. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 196–205. DOI: 10.37482/0536-1036-2021-6-196-205

Application of Waste Engine Oil for Improving Ilmenite Flotation Combined with Sodium Oleate Collector

Collectors commonly have synergetic effects in ores flotation. In this work, a waste engine oil (WEO) was introduced as a collector to an ilmenite flotation system with sodium oleate (NaOL). The results show that the floatability of ilmenite was significantly improved by using WEO and NaOL as a combined collector. The recovery of ilmenite was enhanced from 71.26% (only NaOL) to 93.89% (WEO/NaOL combined collector) at the pH of 6.72. The optimum molar ratio of NaOL to WEO was about 2.08 to 1. The WEO and NaOL also have synergetic effects for the collection of ilmenite, because to obtain the ilmenite recovery of 53.96%, the dosage of 45 mg/L NaOL is equal to 38.56 mg/L WEO/NaOL combined collector (30 mg/L NaOL + 8.56 mg/L WEO). In other words, 15 mg/L of NaOL can be replaced by 8.56 mg/L of WEO. It is an effective way to reduce the dosage of the collector and reuse WEO. Therefore, it is a highly valuable and environmentally friendly approach for WEO reuse. WEO mainly consists of oxygen functional groups, aromatics, and long-chain hydrocarbons, especially for the RCONH2 and RCOOH, thereby forming a strong interaction on the ilmenite surface. The adsorption mechanism of waste engine oil and sodium oleate on the ilmenite surface is mainly contributed by chemical adsorption. Therefore, WEO exhibits superior synergistic power with NaOL as a combined collector. Herein, this work provided an effective collector for ilmenite flotation and a feasible approach for reducing NaOL dosage and recycling WEO.

Optimization of Conditions for Processing of Lead–Zinc Ores Enrichment Tailings of East Kazakhstan

This article presents the results of studies of a low-waste technology for processing enrichment tailings using a combined enrichment–hydrometallurgical method. After washing the enrichment tailings from harmful products and reducing their size, multi-stage flotation of the crushed material of the enrichment tailings was carried out. The use of a new reagent in the flotation process was studied in order to ensure the maximum recovery of the main valuable components from the enrichment tailings. A new collector of Aero 7249 (Shenyang Florrea Chemicals Co., Ltd., Shenyang, China) type was used for the flotation. The recovery of valuable components was as follows: Cu, 6.78%; Zn, 91.69%; Pb, 80.81%; Au, 95.90%; Ag, 82.50%; Fe, 78.78%. Tailings of the flotation were re-enriched using a fatty acid collector (sodium oleate). Additional (reverse) flotation resulted in obtaining a product corresponding to the composition of building sand in terms of the content of valuable components of the waste rock. The studies of the conditions for processing the enrichment tailings of lead–zinc ore indicate the possibility of its optimization in order to maximize the involvement of waste in the production.