Lithopone or sulphide of zinc white has been in general use for twenty years or more in many industries where a white pigment of considerable body or hiding power is required that is not subject to change like lead carbonate and has not the brittle character of zinc oxide, besides being sold at a lower figure than either of these. Nevertheless it is still comparatively new to the general painting trade. Because of our tariff protection its manufacture in this country has made great progress. Yet in spite of this and the duty imposed on it, the imports are still in excess of the quantity manufactured here. A short history of its origin will no doubt prove of interest to our readers.

Production[edit]

2: Clarification mechanism of coagulant

Chemical coagulation is a process in which chemical agents (coagulants) are added to water treatment to make colloidal dispersion system destabilize and agglomerate. In the coagulation process, small suspended particles and colloidal impurities are aggregated into larger solid particles to separate particulate impurities from water, which is called coagulation clarification.

After adding coagulant into water, colloidal particles and other small particles can be polymerized into larger flocs through the comprehensive action of mixing, coagulation and flocculation. The whole process of coagulation and flocculation is called coagulation.

(1) Destabilization and condensation of colloids

Adding electrolyte to water can compress the electric double layer and destabilize the colloid. The main mechanism is that the electric double layer of colloidal particles in water is compressed or neutralized by adding aluminum salt or iron salt coagulant. The coagulant and raw water are mixed rapidly and evenly, and a series of chemical reactions are produced to destabilize. This process takes a short time, generally about 1 min. Some cationic polymers can also play a role in the destabilization and condensation of colloids in water. These polymers have a long chain structure and positive charge in water. Their destabilization and condensation of colloids in water is due to the interaction of van der Waals force adsorption and electrostatic attraction.

(2) Flocculation and formation of floc (alum)

The particle size of the initial flocculate formed by colloid destabilization and coagulation in water is generally more than 1 m. at this time, Brownian motion can no longer push them to collide and form larger particles. In order to make the initial flocs collide with each other to form large flocs, it is necessary to input additional energy into the water to produce a velocity gradient. Sometimes it is necessary to add organic polymer flocculant into water, and the adsorption bridging effect of long chain molecules of flocculant is used to improve the probability of collision and adhesion. Flocculation efficiency usually increases with the increase of flocculate concentration and flocculation time.

Compared with polyaluminum chloride, polyaluminum chloride has the advantages of high density, fast settling speed and wide pH adaptability; the coagulation effect is less affected by temperature than that of polyaluminum sulfate; however, when adding ferric salt, it should be noted that when the equipment is not in normal operation, the iron ions will make the effluent color, and may pollute the subsequent desalination equipment.

In recent years, there has been a growing focus on sustainability and environmental responsibility in the manufacturing industry. Titanium dioxide manufacturers are no exception, with many companies implementing eco-friendly practices to minimize their impact on the environment. This includes reducing energy consumption, implementing recycling programs, and exploring alternative production methods that are more environmentally friendly.

It is an anatase titanium dioxide pigment produced by a special process from sulfuric acid. Widely used in PVC pipes, interior coatings, industrial pigments, rubber, leather, polyolefins, Printing ink, plastic, paper, etc.

It’s also used in food products to provide a white color. Candies, cakes and creamers are examples of foods that may contain titanium dioxide for its color enhancing and bleaching properties.

What is the FDA limit for titanium dioxide?

Both P25TiO₂NPs (with or without vitamin B2) were not found beyond the epidermis in 99% of the analyzed TEM images (Fig. 8). This is coherent with previous findings showing that nanoparticles greater than 50 nm can not penetrate the skin, even in vivo models with movement, stretching, and friction [54]. However, in one of the zones, a few nanoparticles were observed inside a hair follicle. This could be due to the follicle exposure after the localized rupture of this physical barrier when rats were shaved in order to clean the area for cream topical administration. This finding suggests that nanoparticle-based sunscreen should not be applied on recently shaved or harmed skin, in order to avoid nanoparticle skin penetration.

Challenges and Innovations

Technical Specifications：(Standard：Q/SNBJ1-2012)  

Dongfang Titanium Industry R-5568 titanium dioxide with zinc salt stabilizer, zirconium, aluminum, silicon coating. It has the characteristics of high blue phase, easy dispersion, high weather resistance, high hiding power, low oil absorption, good system compatibility, and excellent processing rheology. It is a high-quality titanium dioxide for plastics. Dongfang Titanium R-5568 titanium dioxide is recommended to be widely used in polyolefin, PVC, ABS, PS and other color masterbatches, profiles, plates and pipes, and can also be used in leather color paste, oily paint and other industries.

The company has a wide variety of products, mainly including rutile titanium dioxide R818, R838, R868, R878, covering profiles, also have anatase TiO2 A1. Soft plastics and masterbatches, flat coatings, high-gloss coatings, water-based coatings, oil-based coatings, rubber, powder coatings, papermaking and other special fields, its products have been known in the market for their excellent whiteness and brightness, good hiding power and tinting power, stable application performance, and stable product quality and supply capacity.

4.3 g/Cm3

Lithopone, a white pigment composed of a mixture of barium sulfate and zinc sulfide, is commonly used in the leather industry as a coloring agent. Leather suppliers around the world rely on lithopone to achieve the desired color and finish on their products.

Lithopone in plastics and masterbatch

The most common foods containing titanium dioxide are chewing gum, candies, pastries, chocolates, coffee creamers, and cake decorations (1Trusted Source, 3Trusted Source).

Assessment of biocompatibility in prokaryotic cells

6. What happens next?