Introduction of titanium dioxide and the production process of titanium dioxide powder with sulphuric acid "dry goods"

Introduction of white powder and the production process of titanium-type titanium dioxide with sulfateforeword:
First titanium dioxide as a white pigment used in coatings, master grains and other color formulations, giving bright color, gloss and strong cover, in addition, it is also used as an ultraviolet shield to protect the paint film, improve weather resistance.
, titanium dioxide introduced the
of titanium dioxide is called titanium dioxide pigment white 6. It has two crystals, Rutile and Anatase, which are
chinese
. Type A titanium dioxide whiteness is better, but the coloring force is only 70 type R, in terms of weather resistance to add type A titanium dioxide test film only after only one year began to crack or fragmented peeling, and added R type titanium dioxide test film, after ten years its appearance only minor changes. Because of the good coloring and weather resistance of type R-type titanium dioxide, plastic coloring uses R-type titanium dioxide as well. According to the manufacturing process of titanium dioxide, there are sulfuric acid and chlorination methods, both methods can produce type A and type R titanium dioxide. The sulphuric acid method began in 1931, and the chlorination method was only started by DuPont in 1975 to produce type A, in which oxidation steps control particle size distribution and
crystal structure
, enabling it to produce titanium dioxide with high masking and base color, and high coloring strength.II, the use of titanium dioxide
titanium dioxide is the main role of both the cover background color and the new color is very good fusion, this cover force is mainly based on titanium dioxide high refractive coefficient (goldstone type 2.71, sharp titanium type 2.52), and it can reflect almost all of the visible light.
Titanium white powder is mainly used in coatings, inks, ceramics, glass and other industries for coloring pigments, the paper industry as fillers and coating materials to improve the appearance of paper, India and opacity, rubber products as colorants and rehydration agents, in plastics It is both a filler and a colorant, chemical fiber, printing and dyeing industry for raw liquid coloring and printing color paste, can also be used for welding rods, the manufacture of sponge titanium and titanium alloy, for fine arts pigments, cosmetics, pharmaceutical fillers, food industry and so on.
1, the paint industry is the largest user of titanium dioxide, especially redstone-type titanium dioxide, most of the paint industry consumed. Paint made of titanium dioxide, bright colors, high cover, strong coloring force, dosage, variety, the stability of the medium can play a protective role, and can enhance the mechanical strength and adhesion of the paint film, prevent cracks, prevent ultraviolet and moisture through, extend the life of the paint film.
2, the plastics industry is the second largest user, in plastics to add titanium dioxide, can improve the heat resistance of plastic products, light resistance, weather resistance, so that the physical and chemical properties of plastic products improved, enhance the mechanical strength of products, extend the service life.3, the paper industry is the third largest user of titanium dioxide, as a paper filler, mainly used in high-end paper and thin paper. In the paper to add titanium dioxide, can make the paper has a better whiteness, good gloss, high strength, thin and smooth, printing without penetration, light quality. Paper with titanium dioxide powder generally uses unsociated sharp titanium-type titanium white powder, can play the role of fluorescent whitening agent, increase the whiteness of the paper. However, lamination paper requires the use of surface-treated redstone titanium dioxide to meet the requirements of light and heat resistance.Three, sulfuric acid sharp titanium titanium dioxide production process
1
, titanium ore crushing
the purchase of titanium ore sand with Raymond machine or wind sweeping and other crushed into titanium powder in line with the requirements of the process.
2
, acid solution
crushed titanium iron ore into the acid solution tank, with the configuration of
sulfuric acid
acid solution, acid solution when air pressure, and then titanium iron The ore and sulfuric acid stirring for about half an hour, the addition of steam to trigger the main reaction, the main reaction of about three hours, after the reaction, continue air pressure for 10-15 minutes, began to invade, will be measured water into the acid solution tank, dissolve the solid phase. This process is also about three hours, after the invasion of the knot speed, plus a certain amount of monomath
FE
, reducing titanium liquid in the tri-price iron ions. When three titaniums appear in the solution, add the flocculant. The titanium ore is broken down by thick sulfuric acid to make the soluble titanium sulfate. The main component of titanium iron ore is iron-biased (FeTiO3), a weak acid and alkali salt that can be broken down with strong acids. This reaction is a heat release reaction with a maximum temperature of 250 degrees C.
3
, sequestration
acid leaching, reduction after containing soluble impurities and insoluble impurities. Sulfates from metals such as iron, vanadium, chromium and manganese are soluble impurities that are removed during crystallization or hydrolyzing and washing. Most of the insoluble impurities (e.g. uncomposed titanium ore, sand grains, etc.) can be naturally subsided and removed by gravity. The other part of insoluble impurities is the colloidal compounds of silicon and aluminum, as well as some early hydrolysed titanium, which is small in quantity but high in stability and requires additional sedatives to strengthen the sequestration clarification process.
4
, slag
by using the plate frame filter machine pressure filter method to recover most of the soluble titanium elements, insoluble titanium and other insoluble impurities as slag discharge. The black titanium liquid is entered into the subsiding pool, after which it is sethered and filtered, and the titanium liquid is entered into the titanium preheat tank.5
, crystallization
divided into cold frozen crystal and vacuum crystallization. The main purpose is to reduce the temperature of titanium liquid.
Cold Frozen Crystals
is the use of evaporation of refrigeration media (liquid ammonia or freon or lithium bromide, etc.) to take away heat, so that the temperature of frozen bridal water is reduced, while taking out part of the crystalline water, and then separated and removed.
sulsion crystallization
is based on the principle of insulation and evaporation of the solution, the use of flash steaming to make the water in the titanium liquid rapid insulation evaporation, absorbing the heat of the titanium liquid so that the temperature of the titanium solution is reduced, while bringing out part of the crystalline water, and then separated and removed.
6
, titanium hydraulic filtration
suspended impurities not visible to the naked eye in titanium liquid must be precisely filtered. Using the plate frame pressure filter machine, and charcoal powder (or diatom soil, pearl rock) as a filter aid for filtration, the use of charcoal powder strong adsorption to further remove insoluble impurities in titanium liquid, to achieve the goal of purification.7
, concentrated
the concentration of titanium liquid to the target required for hydrolysaling. The concentration of titanium liquid must be carried out at a lower temperature. Using the principle of reducing the boiling point of the solution in a vacuum, the titanium solution is boiled at low temperature, the water in the titanium liquid is evaporated, and the concentration of the titanium liquid after fine filtration can be increased to meet the hydrolytic requirements.
8
, hydrolysed
is the process of re-transformation of titanium dioxide from liquid phase (titanium liquid) to solid phase. Titanium liquid has the properties of a common ion solution and is hydrolysed > at a pH of 0.5. By controlling the speed of heating, the titanium solution is hydrolysed at the required hydrolysal speed, resulting in water and titanium dioxide particles. 9
, washing
hydrolyzed titanium dioxide contains sulphuric acid and iron, aluminum, manganese, copper, nickel, vanadium, lead plasma, if with the hydrated titanium dioxide into the kiln, after calcination will generate the corresponding oxides, showing a variety of colors. The impurities were removed by using the difference in the concentration of impurity ions in washing water and hydration titanium dioxide.
10
, bleaching
after the initial washing of partial titanium acid, at a certain concentration, the addition of quantitative thick sulfuric acid, so that part of the partial titanium and sulfuric acid reaction to produce titanium sulfate oxygen, and then add aluminum powder, Titanium sulfate dissolved in water four-price titanium reduced to tri-price titanium, to maintain a certain amount of tri-priced titanium in the liquid after bleaching, the process of washing and oxidized iron ions reduced to low-cost titanium iron ions, so that the partial titanium acid washing more thorough.
11
, salt treatment
partial titanium acid before calcination needs to be added to the different types of additives to make the calcination process, the temperature is appropriate, internal changes are stable, the finished titanium dioxide has a stable crystal type, good color, gloss, better coloring, covering force, low oil absorption and suitable grain size, shape, as well as in the use of medium good dispersion.
12
, calcination
is the hydrated titanium dioxide after dehydration, desulfurization into titanium dioxide. At high temperature, free water, combined water, sulfur trioxide, etc. in hydrated titanium dioxide are removed, and then crystalline finishing and transformation are carried out in the high temperature area to form the particle material of titanium dioxide.
13
, crushed and packaged
material in the Raymond machine, after high-speed rotation of the grinding roller and grinding ring impact, quickly crushed, and then through the grading impel grading, the coarse material returned to the crushing chamber fine material into the bag filter, through the star-shaped feeder into the spiral feeder, sent to the finished material warehouse, packaging is the finished product.