# Research on the Preparation of Ultramarine Pigments from Palygorskite

## TL;DR

This study presents a new method to make ultramarine blue pigment using palygorskite, which improves efficiency and reduces sulfur use.

## Contribution

A novel synthesis method using palygorskite that reduces sulfur consumption and enhances pigment properties.

## Key findings

- Optimal pigment chrominance achieved with a 2:6:3 mass ratio of palygorskite, sodium carbonate, and sulfur.
- The new method uses significantly less sulfur than traditional processes, offering environmental benefits.
- Modified pigment shows improved acid resistance and stability in neutral and alkaline conditions.

## Abstract

Ultramarine is a highly favored blue inorganic pigment. It is non-toxic with a deep color and widely used in architecture, plastics, coatings, fine arts and cosmetics. In this study, ultramarine pigment was synthesized using palygorskite, anhydrous sodium carbonate and sulfur as the raw materials through the high-temperature solid-phase method. The incorporation of palygorskite into the synthesis process greatly improves the reaction efficiency and reduces the amount of sulfur. When the mass ratio of palygorskite, anhydrous sodium carbonate and sulfur is 2:6:3, the resulting ultramarine pigment exhibits optimal chrominance. Notably, this sulfur ratio is substantially lower than that used in conventional processes, highlighting the efficiency and potential environmental benefits of this approach. The XRD, FT-IR, UV visible spectroscopy and SEM reveal that the synthetically produced blue pigments possess a sodalite structure, incorporating S3− and S2− radicals. Stability assessments indicated a marked improvement in the acid resistance of the dark blue pigment upon modification with dodecyltrimethoxysilane, with no notable color degradation observed in either neutral or alkaline conditions. The refined formulation and synthesis process not only optimize the production of ultramarine pigment, but also pave the way for enhanced durability and broader application prospects in various industries.