In continuing the previous studies (This Journal, 58, No. 651, 300-304 (1950); 59, No. 655, 18-21 & No. 665, 533-537 (1951); 60, No. 675, 386-390 (1952)), the results of further studies were reported, as following: (1) Alunite samples were obtained from Shoko-Mountain in Hiroshima Prefecture, and analysed, (2) Alunite sample was heated with powder of limestone to make double decomposition as K
2SO
4⋅Al
2(SO
4)
3⋅4Al(OH)
3+3CaCO
3=K
2SO
4+3Al
2O
3+3CaSO
4+6H
2O+3CO
2, (3) The mixed powder (K
2SO
4+3Al
2O
3+3CaSO
4) obtained by the above double decomposition was mixed with (NH
4)
2CO
3 in water solution or blowed with NH
3 and CO
3 gases, to make the conversion of CaSO
4 to CaCO
3 as K
2SO
4+3Al
2O
3+3CaSO
4+6NH
3+3CO
2 or 3(NH
4)
2CO
3=(K
2SO
4+3(NH
4)
2SO
4)+(3Al
2O
3+3CaCO
3), (4) The filtered mixed sulphate solution (K
2SO
4+3(NH
4)
2SO
4) was evaporated to crystal, which contains about 8-10% K
2O in K
2SO
4 and 19-22% NH
3 in (NH
4)
2SO
4, which will be used as useful fertilizer, (5) The residue (3Al
2O
3+3CaCO
3) was dried and heated at about 1350°C, to make high alumina containing clinker, from which early high strength alumina cement can be specially obtained, (6) The yield of potash-ammonia fertilizer is about 17-19% of the original alunite, and the yield of special alumina cement is about 85-95%.
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