SU42067A1 - Alunite processing method - Google Patents

Description

The currently proposed methods of using the Zappecksky alunite are reduced to the production of alumina, potassium sulphate and sulfuric acid from sulfuric acid, associated with alumina with alumina.

The proposed new method of processing Zaglik alunite (K, Na) 2 804 (SOi) in a row with alumina, ammonium sulfate and potassium makes it possible to produce 1.5 tons of high-permeability solution of high-capacity solution per 1 ton of alumina for the oil industry. soda or sodium chloride or sulphate soda.

A new way is as follows. Finely milled ore is intimately mixed with sulfuric acid ammonium, taken in an amount necessary to convert s alumina found in the ore, into a sulfuric acid compound. The mixture is roasted in an oven at an AOO temperature of 500 °. During calcining, ammonia is released, and alumina is converted to soluble sulfuric acid aluminum. The calcined material is leached with water with the addition of ammonium sulphate and potassium chloride. The addition of the latter aims to convert the sulfuric acid sodium in the alunite into sulfuric acid potassium and thus obtain a mixture of ammonium and potassium alum.

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In order to purify alum from iron, which is also in a small amount in alunite and goes into solution together with aluminum, alum is recrystallized after pre-reduction of iron with ammonium bisulfite, in order to avoid the formation of truce soluble, isomorphic with aluminum, iron alum.

Ammonium and potash alum purified in this manner with iron are dissolved in the ox. The heated solution is treated with circulating calcium fluoride with the addition of natural in case of lack of circulating. According to the equation:

(5О4Я12 (5О4) з + 2СаР2 Rl.F.SO, 4- KoSOi (NN4) 3504 + 2CaSOt

hard-to-dissolve gypsum is formed, a soluble fluoride-aluminum compound containing fluorine in the form of a complex, and sulfuric acid ammonium is liberated. The accompanying lead fluoride sprit at all does not go into solution during this operation. as all fluorine is bound to aluminum in a resistant complex. In addition, the main mass of calcium fluoride is a recycled product, therefore, it will be pure with respect to silica. Iron in solution will also not, because the starting material - ammonium alum and circulating calcium fluoride - will not contain it, and a small amount

natural calcium fluoride, introduced to replenish mechanical losses, can be pre-cleaned of a small amount of iron by washing it with weak sulfuric or hydrochloric acid. In addition, if necessary, the solution of the complex compound can easily be purified from iron by adding complex hydrate-aluminum to it, precipitated from the solution of the same compound by adding ammonia. The complex hydrate, dissolved in a sulfuric acid compound, displaces the iron from the solution in the form of a basic salt.

The solution of the complex compound, clear of iron and silica, is treated with ammonia, as a result of which the complex hydrate A12P4 (OM) 2 is precipitated and a solution of ammonium sulphate of ammonium and potassium is formed. Ammonium sulphate is separated by crystallization from potassium sulphate and is partially returned to production, and partly removed from the process along with potassium sulphate, as a by-product.

Complex hydrate calcined in a furnace with continuous transmission of ammonia water vapor at a temperature of 450-550. According to the equation:

А1гР4 (ОМ) 2 + 4N Нз + НгО АЦОд + + 4NH4F

gaseous ammonium fluoride is formed and the final product is alumina, free of iron and silicon. Example. 6250 g Zaglik alunite rock, with a content - 20 ° / o; OO-20.90 / 0, KAO -2.50 / 0, MajO -2.4, mixed with sulfuric acid ammonium in the amount of 3250 g required to convert / 3 alumina enclosed in rock to sulfuric acid aluminum . The mixture is calcined at a temperature of 400-500 °. The following reaction occurs:

(K, I1a) 2SO, Rl2 (S04) 3 2Н120з 6Н2О +

+ 6 (ISH4) 2SO4 KgSOi + NajSOi-tH-3 12 (504) 3 4-12MN3) -f 6H, O. .(one)

The calcined mass is leached with water with the addition of ammonium sulphate to form ammonium alum and potassium chloride to convert sour sulphate leached from the calcined material to sulphate potassium, which with sulphurous aluminum gives an additional amount of potassium alum.

1000 g of alumina was found in the solution, which corresponds to approximately 800/0 - th output of alumina from alumina in the ore.

For the purification of potassium ammonium alum from iron, after preliminary reduction with ammonium bisulfite, it is double recrystallized.

When heated and moved, alum solution is treated with 1530 g of circulating calcium fluoride:

(K, NH4) 2S04hl2 (SO4) 3 + 2CaF A12p4504 + + K2SO4 + (NH4) 2304 + 2CaS04,. . (2)

moreover, soluble fluoride complex and 2660 g of gypsum are formed.

Filtered gypsum is treated with a mixture of ammonia gas and carbon dioxide.

CaSOi + 2MNz + HjO + COj (MH4), ZO4-b + CaCOs. (3)

All sulfuric acid found in the gypsum is recycled as ammonium sulphate.

Solution I 2p4504 is treated with an excess of ammonia:

A12F4SO4 + 2ННз + 2НгО Д12Р4 (ОН), +

+ (HN4) 2S04. (4)

Sulfuric ammonium, which, after evaporation and crystallization, partially returns to the cycle, and part of it, in an amount of 1,500 g, together with 700 g of potassium sulphate, is removed from the cycle as a by-product.

Hydrate Al2P4 (OH) 2 is filtered, washed thoroughly and then calcined at a temperature of 450-550 ° in a stream of water and ammonia vapors:

Al2P4OH2 + 4МНг + Н2О ЯЬОз -Ь

-f4NH4F (5)

1000 g of alumina and 1450 g of ammonium fluoride gas mixed with ammonia are obtained. Ammonium fluoride is introduced into a saturated solution of sodium chloride (or sodium sulfate). According to the reaction: NHiF + NaCl NaF4- a precipitate of 1570 g of sodium fluoride is formed, which is centrifuged and washed from the mother liquor containing ammonium chloride. The ammonium chloride solution is treated with lime when heated to isolate ammonia and return it back to the cycle. Filtered sodium fluoride with approximately 25 / oh moisture is heated with milk of lime containing 180-190 g of CaO per liter. Due to the exchange reaction 2NaF + Ca (OH) 2 2NaOH + CaF. (7) approximately 25 ° / oh alkali solution is obtained in the amount of 1500 g in terms of NaOH and 1450 g of insoluble calcium fluoride returned after centrifuging, washing and neutralizing excess lime with sulfuric acid back into the cycle. It can be seen from the above example that about 1.5 tons of sodium hydroxide (), 1.5 tons of ammonium sulphate and 700 kg of potassium sulphate are produced per ton of alumina. Thus, the proposed method of producing alumina from alunite through complex sulfate containing fluorine and aluminum allows, along with the production of alumina, to obtain a high percentage solution of sodium hydroxide from sodium chloride or sodium sulfate and to use all sulfuric acid of alunite in the form of sulfuric acid ammonium and potassium acid, minus the amounts needed to cover the small losses that accompany the individual operations of the described method. The subject matter of the invention. 1. A process for processing alunite, characterized in that alunite is mixed with ammonium sulfate, taken in an amount sufficient to convert about Vs of alumina present in the rock into sulfuric acid aluminum, the mixture is calcined at a temperature of 400-500 ° and the calcined mass leached with water. 2. A method according to claim 1, characterized in that ammonium sulfate and potassium chloride are introduced into the leaching water to convert sodium sulfate leached from the calcined material to potassium sulfate and form an additional amount of alum with aluminum sulfate.