METHOD OF PRODUCING CARBONATED BONDED PRESS-MOULDED ARTICLE Russian patent published in 2019 - IPC B28B11/24 C04B40/02 C04B18/00 

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a method of producing a carbonate pressed molded article. Method comprises steps of producing a particulate material which is carbonisable and which contains water, pressing in a mold of a disperse material to produce a sealed workpiece and carbonate the dispersed material in said compacted workpiece to obtain carbonates when converting the sealed workpiece into said carbonate molded bonded mold in the mold. Particulate material is carbonised by contacting the compacted workpiece with a gas which contains at least 1 vol. % of carbon dioxide. At that, according to the first embodiment of the method, before pressing in the mold of the disperse material to produce the said densified workpiece, a number of tests are performed, on which at least one sample of disperse material is pressed in mold for each sealing pressure from row of increasing sealing pressures in range from least to maximum pressure of seal at use of said sealing pressure. After compression of sealing pressure parameter is determined, which characterizes density of sample pressed in mold. Dispersed material is pressed in mold to produce said compacted workpiece using sealing pressure, which is selected from range limited by lower and upper limit values of seal pressure. At the same time the lower boundary value of the sealing pressure is more than 5 MPa, and the upper limit value of the sealing pressure is equal to or less than the specified maximum seal pressure. And, in case density decreases with increase in seal pressure in the said range of tests from smaller seal pressure from said row of sealing pressures to higher seal pressure from said row, said upper boundary pressure value of the seal is smaller than said higher seal pressure, and preferably equal to or less than said lower seal pressure. According to the second embodiment, prior to pressing in the mold of disperse material to produce said compacted workpiece, at least one of its sample is subjected to testing, where sample is pressed at increasing compaction pressure until achieving predetermined sealing pressure or in case, if the disperse material has such a high water content that when the sample is pressed, water begins to be forced out of the said sample, starting from the low seal pressure, which is smaller than said predetermined seal pressure at least until achieving said reduced seal pressure. Dispersed material is pressed in mold to produce said compacted workpiece using sealing pressure, which is selected in range limited by lower and upper limit values of sealing pressure, wherein the lower boundary value of the seal pressure is greater than 5 MPa, and the upper boundary pressure value of the seal is at least 7 MPa less than said predetermined seal pressure and at least 7 MPa less than said reduced seal pressure in case disperse material has said high water content.

EFFECT: technical result is to obtain optimal tensile strengths in compression of pressed in the mold and carbonized sealed billets and reduce the negative impact on the tensile strength in compression of the workpiece.

19 cl, 13 dwg, 2 tbl