# Oil- and Fuel-Resistant Rubber for Pressure Hoses Containing Carbon-Based Technological Waste as a Filler

## TL;DR

This paper explores using carbon-based mining waste as a filler in oil- and fuel-resistant rubber for pressure hoses, showing promising mechanical and thermal properties.

## Contribution

The study introduces a novel use of acid-activated shungite concentrate as a sustainable filler in rubber compounds.

## Key findings

- Shungite fillers increase scorch and cure times due to oxide impurities affecting vulcanization.
- Acid-activated shungite improves tensile strength and thermo-oxidative stability in rubber.
- Rubber with acid-activated shungite retains mechanical properties when exposed to oil.

## Abstract

Carbon-enriched concentrates based on shungite ore from rare-metal mining waste were obtained, and their effect on the properties of oil- and fuel-resistant carbon-black-filled rubber used for the production of pressure hoses was investigated. The shungite concentrates were produced by flotation followed by acid activation. A blend of nitrile butadiene rubber and butadiene–α-methylstyrene rubber was used as the elastomeric base. Carbon black was partially replaced with shungite fillers (5–15 phr). The presence of shungite was found to prolong both the scorch time and the optimum cure time of the rubber compounds, likely due to oxide impurities that interfere with the vulcanization activation process. Replacing carbon black with shungite ore and its flotation concentrate in the rubber formulations resulted in a decrease in Mooney viscosity compared to the samples without shungite fillers. Acid-activated shungite concentrate at contents above 5 phr increases the viscosity of the rubber compound. It was found that acid-activated shungite concentrate provides high tensile strength and excellent thermo-oxidative stability of the rubber, whereas the use of shungite ore above 5 phr reduces the tensile strength and causes significant changes in tensile properties upon thermo-oxidation. When exposed in oil, rubbers containing shungite fillers retain their mechanical properties, with the best resistance in hydrocarbon media observed for the rubber filled with acid-activated shungite concentrate.