titanium oxide and 2 per cent' sulphuric acidand 63 per cent water, are slowly added to a solution containing 1050 pounds of barium sulphide, held in a large cylindrical tank, provided with a rotary agitation :capable of producing rapid agitation. The mass isthus v rapidly agitated, and the 2 per cent of sulphuric acid contained in the titanium acid cake reacts with a small portion of the barium sulphide. This reaction may be represented by the following equation TiO H 80 The free sulphuric acid of the titanium acid cake is neutralized by thebarium sul-' phide solution, forming barium sulphate and hydrogen sulphide, as indicated by the above equation. As the sulphuric acid is present only in a small percentage, the major porltiion of the barium sulphide remains as suc very fine colloidal suspension. The barium sulphate produced is also very fine, and the presence of this. very fine barium sulphate in suspension, and also of the very fine colloidal titanium oxide, is believed to be the explanation of the great improvement in the properties of the finished lithopone.
Having thus described the origin and uses of the pigment, we now come to the question, what is lithopone? It is, in short, a chemical compound usually consisting of 30.5 per cent zinc sulphide, 1.5 per cent zinc oxide and 68 per cent barium sulphate, but these proportions vary slightly in the different makes. Lithopone of this composition is sold as the highest grade, either as red seal or green seal, as it best suits the idea of the manufacturer. Many manufacturers, especially in Europe, sell and also export other brands under other seals, containing 24, 20, 18 and as little as 12 per cent of zinc sulphide with very small percentages of zinc oxide, the balance being usually barium sulphate, but sometimes certain portions of China clay or gypsum (calcium sulphate) or whiting (calcium carbonate). Such brands are not a chemical compound, but mechanical mixtures of the chemically compounded lithopone and the admixtures referred to.
“Unlike some other chemicals used in food, titanium dioxide has no nutritive, preservative, or food safety function—its use is purely cosmetic,” said CSPI principal scientist for additives and supplements, Thomas Galligan. “The prospect of titanium dioxide nanoparticles damaging DNA is concerning enough for us to recommend consumers avoid foods that have it.”
However, the market could not sustain these high prices and strived for equilibrium, causing the prices to fall. Further, after the complete removal of restrictions, the factories churned out products at a much faster pace than the market offtakes. Hence, the manufacturers reduced their quotations to maintain positive product movement in the market. The spot prices of titanium dioxide averaged around 2264 USD/MT in June’23 in the Chinese market.
Another important property of Chinese anatase titanium dioxide is its photocatalytic activity, which enables it to break down organic pollutants and harmful chemicals when exposed to light. This makes it an attractive choice for applications in environmental remediation, such as air and water purification systems. Additionally, its photocatalytic properties have also been studied for use in self-cleaning surfaces, such as windows and building facades, where it can help to reduce maintenance costs and keep surfaces looking clean.
Others are looking into recycling waste streams from the manufacturing process to recover titanium compounds, thus closing the loop on material use Others are looking into recycling waste streams from the manufacturing process to recover titanium compounds, thus closing the loop on material use
Preparation of the titanium solution This involves dissolving titanium ore or other titanium-containing compounds in a suitable solvent to form a concentrated solution Preparation of the titanium solution This involves dissolving titanium ore or other titanium-containing compounds in a suitable solvent to form a concentrated solution
