DE403996C - Process for the production of potash nitrate from crude potash salts - Google Patents

Description

Process for the production of potash nitrate from crude potash salts. To the Manufacture of potash nitrate from crude potash salts specified in patent specification 335819 by reacting the potassium chloride contained in these with magnesium nitrate the patent 399465 one embodiment. In this case, the - as much as possible MgCl, -free - Potash crude salt in the so-called remaining after the second crystallization Dissolved saltpeter end liquor (. Claim 3). The resulting magnesium chloride-containing Crude salt solution is then mixed with the required amount of magnesium nitrate liquor and brought to cool. Since the added Mg (NO,) z solution is NaCl-free or is very low in sodium chlorine, a completely NaCl-free is achieved in this way Nitrate crystallization despite the use of crude salts containing NaCl.

The lye economy envisaged in patent 399465 now has a disadvantage insofar as the dissolving solution itself already has a very high specific gravity and for this reason requires a fairly long duration of the dissolving operation and subsequently poses great difficulties in clearing the cloudy solution.

It has been found that these disadvantages can be avoided in the following manner can avoid largest parts without the simultaneous excretion of sodium chloride to fear. The crude salt is no longer directly in the final nitric liquor dissolved, but in a lye, which by diluting the same with a part the magnesium nitrate solution required to form the desired amount of potassium nitrate arises. The rest of the NaCl-free Mg (NO3) = lye is used after the dissolving operation added, making the remaining nitric mother liquor unsaturated in sodium chloride remain.

The mode of operation in question is given by the following exemplary embodiment explained in more detail.

61 of a final nitric liquor with a specific gravity of 1.36 (25 ° C.), which contained 270 g of Mg C12 170 9 Mg (NO3) 26o g of KCl 40 g of NaCl per liter, with 1.5 l of a magnesium nitrate liquor of a specific gravity 1.18 mixed. The resulting solution had a volume of 7.5 liters and contained 216 g MgCl2 173 9 Mg (NO3) 2 48 g KCl 32 g NaCl per liter. This amount of lye was heated to 100 ° and then 400 g of 1'Iarfsalz (about 23 percent KCl) were added in one dose. The dissolving operation was continued for 15 minutes with constant stirring and with further supply of heat (caustic temperature about cgo °).

After the crude salt solution had ended, the lye was removed from the residue sucked off a suction filter. The solution residue was washed off with so much hot water that that the crude salt solution had a total volume of 8 liters.

After washing out and suctioning off, the residue contained 0.013 percent N. 1.34 - KCl 36, o7 - Mgn0 ,. The crude salt solution obtained - including washing liquor of the residue - had a specific weight (go °) of 1.37 and had the following composition (per liter of liquor) igi g mgcl =. 1 (16 g Mg (NO ;;) 2 2f> g -, vigSO, 152 g KCl 56 g NaCl. These 8 1 lye were now diluted with -2.5 1 magnesium nitrate solution (i, 18) and then allowed to cool. During the crystallization, 10.5 1 25o g of KCl were stirred into the total amount of liquor, which had been removed from the liquor cycle as a result of the previous double salt precipitation - recovery of the final nitric liquor (cf. Patent 8575a, claim 5 and patent 8 (o.14, claim 3). The potassium chloride stirred in was quickly absorbed. The crystallization of the potassium nitrate began at about 45 ° C.

At i5 z C the remaining mother liquor has the following composition (1.32) i98 g 31gC12 123 g - # lg (NOs) 2 28 g MgSO, 72 g KCl 57 g NaCl per liter.

Suction gave 15 (-) above-mentioned moist potassium nitrate which, uncovered, contained 92.8 percent KNO and 17 percent Cl. After covering with 1 cc of cold water, about 98o g of potassium nitrate were obtained with only 0.08 percent Cl.

The remaining nitric mother liquor is used to the required extent evaporated and then at about 25 to 30 ° C for the second time for crystallization brought. It separates the excess magnesium chloride in the form of artificial Carnallite (double salt). Including the double salt suds she then has the average composition given at the beginning.

Instead of the mixing ratios listed in the previous exemplary embodiment Of course, other mixing conditions can also be used.

You can z. B. the crude salt only in a more or less severe Dissolve magnesium nitrate liquor and then all of the final nitric liquor after completion to mix in the dissolving operation.

To wash out the crude salt solution residue, one can advantageously use the Use detergent solution from the stage salt.

Claims (1)

PATENT CLAIMS: i. Process for the production of potassium nitrate Crude potash salts according to Patent 399465, characterized in that the potash salts dissolves in the potassium nitrate solution mixed with magnesium nitrate solution and the resulting Rob's salt solution diluted with magnesium nitrate lye. a. Method according to claim i, characterized in that the crude salts are dissolved in a magnesium nitrate liquor and the resulting crude salt solution before crystallization with the possibly still with Water or NaCl-unsaturated lye mixed with diluted nitric final lye. 3. A method according to claim i and consisting in doing that in the double salt elimination Potassium chlorine removed from the caustic cycle during the crystallization of potash salt returns to the lye. q. Method according to claims 1 and 2, characterized in that that you use the washing liquor of the stage salt to wash out the crude salt solution residue used.