Method of production of modified red iron oxide pigments

FIELD: chemical and paint-and-varnish industries; production of inorganic pigments.

SUBSTANCE: proposed method includes leaching-out of serpentine ore mixture containing magnesium and chromium by sulfuric or hydrochloric acid for obtaining iron-containing solution which is treated with hydrogen peroxide and is neutralized to pH= 7.0-8.0. Suspension thus obtained is filtered and iron hydroxide residue is dissolved with sulfuric or hydrochloric acid, then it is treated with alkaline reagent to pH=2.0-6.0 and is filtered. Then, iron hydroxide residue is washed off water-soluble ions, dried and burnt at temperature of 550-700C.

EFFECT: wide range of tints in processing and decontamination of sulfate and chloride waste obtained at production of periclase and chromite concentrate.

2 cl, 5 tbl, 6 ex

 

The invention relates to chemical technology of production of inorganic pigments and can be used in the chemical and paint industries, as well as in the processing, utilization and neutralization of sulfate and chloride waste generated in the production process magnesia and chromite concentrate.

A method of obtaining micaceous iron pigment from the slurry-jarosite obtained during the purification of zinc solutions from iron. By this method the jarosite (containing, in wt.%: potassium - 8, iron - 30, sulphur - 13, zinc - 0,15) in an amount of 500 g mixed with the stoichiometric amount of potassium hydroxide (157 g) and calcined at t=800°C for two hours. Next, the product is washed with water, dried and milled. The finished product is characterized by a high content of iron oxide (up to 90% Fe2About3). (USSR author's certificate No. 666758, CL SS 1/24, publ. 1976).

The disadvantages of the method are:

low pigment properties of the finished product: high dispersibility is 30 μm and the opacity to 90 g/m2;

- no way to obtain a modified red iron oxide pigments with a wide range of shades;

- the known method cannot be used to produce iron oxide pigments in the processing of magnesium-chromium ores, since the main mineral serpentine, in odasi in the composition of the ore mixtures, does not decompose under the influence of alkalis at t=800°to obtain oxides of iron, magnesium, silicon, etc.

To improve the pigment properties and expansion of the color gamut of hues such pigment can be entered modifying additives in the form of oxides or hydroxides of aluminum and / or zirconium and / or titanium and / or chromium and / or Nickel and / or silicon in the ratio of 100 parts of Fe2About3of 0.01 to 10.0 parts modifying additives (Japan, No. 3055333 B2, IPC SS 1/24, publ. 2000).

The resulting pigments have bright colour characteristics and good pigment properties.

However, these methods cannot be used in the process of getting micaceous iron pigments from sludge - waste production of dead-burned magnesia from serpentine raw materials, as required list of additives and their number is already contained in the feedstock and impractical for them to be part of the sludge and the finished product; you only need to find a way to extract and use.

The closest technical solution is a method for micaceous iron pigment waste from the production of titanium pigments. By this method the solution after leaching is treated with alkali to pH=6,0-7,0. The resulting suspension is filtered, the precipitate is dried, washed from chlorine or sulfate ions, again dried and calcined (procul the offer) at t=500-800° C. the resulting product is characterized by high pigment properties and is used in the production of paints and enamels (USSR Author's certificate No. 1255629, IPC SS 1/24, publ. 1986).

However, the pigment obtained by this method of sludge from the production of magnesium oxide (dead-burned magnesia), will have a significant drawback - low content of basic substance is iron oxide (III) and a high content of impurities.

An object of the invention is to obtain red micaceous iron pigment with a maximum content of the main substance of Fe2O3(not less than 90%) while ensuring a wide range of colors (from red-light brown to dark red purple, raspberry).

The technical result of the use of the invention is to provide a method ensuring receipt of a pigment having a set of performance properties, wide range of shades, the optimal dispersibility, opacity.

This technical result is achieved due to the fact that in a method of producing the modified red micaceous iron pigments, including the neutralization of acidic iron-containing solution to pH=7,0-8,0, filtering the resulting suspension, laundering the hydroxide precipitate iron from water-soluble ions, drying and calcination at a temperature of 550-700� With, acidic iron-containing solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture of sulfuric or hydrochloric acid, treated it with hydrogen peroxide to oxidize the ferrous iron to ferric iron and then serves to neutralize and before laundering precipitate of iron hydroxide additional dissolve these acids are neutralized with an alkaline reagent to pH=2.0 to 6.0 and filtered.

The neutralization of the alkaline exercise, or soda, or ammonia solution.

The method is as follows:

Acidic iron-containing solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture of mineral acids (sulfuric or hydrochloric), introducing the hydrogen peroxide solution to oxidize the ferrous iron to ferric iron. Then the solution is neutralized alkali, soda or ammonia solution to pH=7,0-8,0. The resulting suspension is filtered. Sediment - slurry containing hydroxides of iron (III), aluminum, chromium, Nickel, colloidal solution of silicon and calcium sulfate (called a precipitate of iron hydroxide), is dissolved by the acid (sulfuric or hydrochloric) and neutralized with an alkaline reagent (alkaline or soda, or ammonia solution) to pH=2,0-6,0. The suspension is filtered, the precipitate of iron hydroxide (FeOOH) repulper (washed from water-soluble IO is s) and again filtered. The purified iron hydroxide dried and calcined at t=550-700°C. Obtained micaceous iron pigment is crushed, passed through sieve No. 0063. The finished product has high pigment properties and meets THE 6-10-602-86.

It should be noted that

- neutralization of the acidic solution after leaching to pH <7.0 and pH>8.0 for inappropriate conduct, since it leads to loss of Fe2About3because of the transition oxidized ferrous iron in the solution of sulfate (or chloride) magnesium at pH <to 7.0 and at pH>8.0 to increase the concentration of MgO in the hydroxide of iron, and consequently, in the finished product;

- neutralization of the solution obtained after dissolving the precipitate of iron hydroxide at pH<2,0, significantly reduces the output of the basic substance - Fe2O3and at pH>6,0 increasing the concentration of the impurities AL3+, Cr3+Mg2+in the finished product above is valid;

- firing the precipitate of iron hydroxide at a temperature below 550°With results in pigment with low content of basic substance of Fe2About3due to the high content of volatile components (the value of loss on ignition - SPT) in the finished product;

- firing the precipitate of iron hydroxide at temperatures above 700°facilitates production of pigments shades darker is and the expense of a transition of Fe 2O3in Fe3About4.

Examples of the complete method.

Example 1 (according to the method of the prototype).The solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture with sulfuric acid, neutralized soda solution (300 g/l Na2CO3in the amount of 34 g per 100 g ore) to pH=7,0. The suspension is filtered, the filtrate is a solution of magnesium sulfate is directed to the obtaining of dead-burned magnesia, and the precipitate of iron hydroxide repulper (washed from ions of Na+, SO42-, CO32-), again filtered, dried and calcined at t=700°C. the color of the pigment - light orange-red.

Example 2.The solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture with sulfuric acid, neutralized soda solution (300 g/l Na2CO3in the amount of 34 g per 100 g ore) to pH=7,0. The suspension is filtered, the filtrate is a solution of magnesium sulfate is directed to the obtaining of dead-burned magnesia, and the precipitate of iron hydroxide is dissolved with sulfuric acid (560 g/l H2SO4consumption 21,0 g H2SO4100 g ore). Acidic sulphate solution is treated with soda solution (300 g/l Na2CO3consumption of 10 g of Na2CO3100 g ore) to a pH of 2.0. The suspension is filtered, the precipitate of iron hydroxide washed again filtered. The mother liquor is sent for recycling, and PTS is placed FeOOH - on firing at t=700°C. the color of the pigment - bright-red-orange, and purple.

Example 3.The solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture with sulfuric acid, is treated in accordance with the method according to example 2 up to obtain an acidic solution of sulphate, which is treated with soda solution (300 g/l Na2CO3consumption of 14 g of Na2CO3100 g ore) to pH=2,8. Further filtering processes and laundering of sediment carried out according to the scheme, analogous to example 2. Firing FeOOH is carried out at t=700°C. the color of the pigment - red-brown.

Example 4.The acidic solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture with hydrochloric acid, treated with hydrogen peroxide solution and neutralize the soda solution (300 g/l Na2CO3consumption of 32 g of Na2CO3100 g ore) to pH=7,0. The suspension is filtered, the filtrate is a solution of magnesium chloride is directed to the obtaining of dead-burned magnesia, and sludge (the precipitate of iron hydroxide) dissolved hydrochloric acid (210 g/l HCl consumption of 12 g of HCl per 100 g ore). The obtained acidic solution of chlorides of Fe3+, AL3+, Cr3+, CA2+and Ni2+treat soda solution (300 g/l Na2CO3consumption of 18 g of Na2CO3100 g ore) to a pH of 2.6. The processes of filtration, washing the precipitate hydroxide glands is carried out according to the scheme, analogous to example 2. Calcination of the precipitate is carried out at t=550°C. the color of the pigment - light-red-brown.

Example 5.The acidic solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture with hydrochloric acid, treated with hydrogen peroxide solution and neutralize the soda solution (300 g/l Na2CO3consumption of 32 g of Na2CO3100 g ore) to pH=8,0. The suspension is filtered, the filtrate is a solution of magnesium chloride is directed to the obtaining of dead-burned magnesia, and the precipitate of iron hydroxide is dissolved with hydrochloric acid (210 g/l HCl consumption of 12 g of HCl per 100 g ore). The acid solution is treated with ammonia water (200 g/l NH4OH, consumption - 18 g NN4OH per 100 g ore) to pH=4,0. Further filtering processes and laundering the hydroxide precipitate iron is carried out by a scheme analogous to example 2. The firing is carried out at t=700°C. the color of the pigment - red-purple, crimson.

Example 6.The precipitate of iron hydroxide (method of preparation, see example 4) is dissolved with sulfuric acid (560 g/l H2SO4consumption 21,0 g H2SO4100 g ore). Acidic sulphate solution is treated with sodium hydroxide solution (200 g/l NaON consumption of 15 g NaON 100 g ore) to pH=6,0. Further filtering processes laundering precipitate of iron hydroxide and firing scheme, similar to example 4. Shade pigment - red-purple, lighter than the other 5.

Micaceous iron pigments obtained by the proposed method, the main properties correspond to THE 6-10-602-86 red micaceous iron pigment and are characterized by the following properties:

- mass fraction,% :

iron content in terms of Fe2About3- not less than 90.0%;

volatile substances is not more than 0.5;

water-soluble substances not more than 0.2;

- spreading rate, g/m2- 5,0-7,0;

- dispersible in the oil, min - 20-30;

the oil absorption, g/100 g pigment - 20-30;

the residue after wet sieving sieve 0063, % - 0,2-0,3.

The hue of the pigments depends on

- type of mineral acid (sulfuric or hydrochloric), used for leaching, the original ore and dissolving hydrated iron rest,

- the pH of the neutralization of the acid solution and receive hydroxide FeOOH,

concentration of the modifying additive (Al2About3, Cr2About3, SiO2and others,

- temperature firing (calcination).

In tables 1-2 shows the chemical and mineralogical composition of the original ore.

In table 3-4 summarizes the properties of the original solution and the obtained pigments.

Table 5 shows the obtained color shades pigments.

SiO2
Table 1. The chemical composition of ore
Name of the componentAl2O3MgOCaOFe2O3totalCr2O3Na2ONivolatile
Content, %37,21,5234,630,557,806,00,410,2311,66

Table 2. The mineralogical composition of the original ore
The name of the mineralSerpentineOlivineChromiteQuartzChloritePyroxeneSPT
Content, %65,08,010,02,06,01,08,0

Table 3. The content of components in solution
Acid leachingThe content of the components in solution, g/l
Fe2O3FeOCaOCr2O3Na2ONi
H2SO413.23.30 1.161.060.870.49
HCl15.20.551.211.210.900.51

Table 4. The content of components in the pigment
No. op. p/pAlkaline reagentthe pH of the formation of FeOOHt°C calcinationThe content of the pigment, %
Fe2O3Al2O3MgOCaONiCr2O3SiO2volatile
1--70058.314.2614.634.860.164.701.250.48
2Na2CO32.070098.50.230.190.120.030.210.180.34
3Na2CO33.170097.30.860.260.150.020.740.29 0.38
4Na2CO33.855095.31.210.950.230.031.490.340.50
5NH4OH4.070095.50.191.210.310.022.050.320.41
6NaOH6.070092.62.041.750.410.032.380.310.49

Table 5. The shades of color pigments depending on the content of the main substance of Fe2O3and the method of their derivation
No. op. p/pthe pH of precipitationt°C calcinationThe content of the pigment, %Color shades
Fe2O3volatile
1-70058,30.48Light orange-red
22,070098,50.34the RCO-red-orange, Magenta
33,170097,30.38Red-brown
4the 3.8550for 95.30.50Red-light brown
54,070095,50.41Red-purple, raspberry
66,070092,60.49Red-purple, lighter than op

1. A method of obtaining a modified red micaceous iron pigments, including the neutralization of acidic iron-containing solution to a pH of 7.0 to 8.0, filtering the resulting suspension, laundering the hydroxide precipitate iron from water-soluble ions, drying and calcination at a temperature of 550-700°, characterized in that the acidic iron-containing solution obtained after leaching serpentinous magnesium-hromsoderzhashchej ore mixture of sulfuric or hydrochloric acid, treated it with hydrogen peroxide to oxidize the ferrous iron to ferric iron and then serves to neutralize and before laundering precipitate of iron hydroxide additional dissolve these acids are neutralized with an alkaline reagent to a pH of 2.0 to 6.0 and filter.

2. The method according to claim 1, characterized in that the neutral is the implementation of the alkaline exercise, or soda, or ammonia solution.



 

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