RU2361844C2 - Method for production of ceramic products - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method for production of ceramic products includes preparation of moulding mass from main group rocks as filler and binder, moulding of products from prepared moulding mass and their thermal treatment. Binder is produced by mixing of 80÷95 wt % of filler from main group rocks with particle size 50÷500 mcm and humidity of not more than 5% with 5÷20 wt % of phosphoric acid with density of 1.50÷1.85 g/cm³. Moulding mass is prepared by soaking of prepared mixture at temperature of 10÷30°C for 24÷72 hours, and thermal treatment is carried out at temperature of 100÷300°C. It is reasonable to mold products by means of hot pressing with force from 10 to 500 kg/cm². Mixing of filler and phosphoric acid is carried out for 30÷90 minutes.

EFFECT: simplification of technology to expand raw materials base and assortment of produced products; performance of thermal treatment process at considerably lower temperatures makes it possible to use inexpensive process equipment with the possibility to use secondary heat, which creates economically less expansive technology for production of ceramic products.

3 cl, 1 tbl, 4 ex

Description

The invention relates to a technology for producing stone-ceramic products from rocks of the main group using a binder. At its core, this technology is based on the traditional technology of heat treatment of powders or preforms at temperatures below the melting temperature of at least one of the components — sintering and the technology for the production of ceramic materials using binders.

The group of main rocks includes two subgroups: the gabbro subgroup and the basalt-diabase subgroup [Zdorik TB, Matias VV Minerals and rocks of the USSR. M, "Thought", 1970, p. 281-287].

A known method of producing basalt ceramics by sintering, the feedstock for which is fused basalt powder with a particle size of 0.5 ÷ 60 microns. The resulting powder is mixed with 3 ÷ 10 wt.% Paraffin, pressed under pressure of 300 ÷ 1800 kg / cm ² , subjected to preliminary firing at 800 ÷ 900 ° C, then the temperature is increased to 1100 ° C, at which the product is kept for 2 hours. The entire period of the sintering process lasts about 24 hours. Sintered basalt is a homogeneous material of red-brown color with a density of 2.83 g / cm ³ [Pelican A. Fused stones. M .: Metallurgizdat, 1959, p.199-200].

The main disadvantage of this technology is multi-stage, which leads to an increase in economic costs.

There is also known a method of producing stone-ceramic products from basalt by the slip method, including operations: grinding of basalt and some components of the slip; preparation of a slip by obtaining a pasty mass from a mixture of finely ground silicate starting materials mixed in water; casting; extraction of castings; their editing; drying and firing [Lipovsky I.E., Dorofeev V.A. The basics of petrurgy. M .: "Metallurgy", 1972, S. 221-223].

Slip according to the above method for various application conditions have the following composition, wt.%: Basalt 60 ÷ 85, clay 0.2 ÷ 15, soda 0.02 ÷ 0.20, water glass 0.02, mineralizer 2.0. The composition of the clay-free slip is also known, wt.%: Basalt 95, glycerin 5, water up to 30 (over 100). The moisture content of these slurries is 33 ÷ 34%. The optimal particle size distribution of basalt is 90 ÷ 100 microns. The grinding of the components of the slip is carried out both by wet joint method, and separate dry. The clay is first ground on the runners, then shut with water and kept for 2–3 days. To dilute the slip, deflocculants are introduced. Chromite, fluorite, zircon are used as mineralizers. The products are cast into the molds where they are from 2 to 17 hours, then removed from the molds, dried in air for 4 ÷ 7 hours, and then dried at a temperature of 100 ÷ 120 ° C to a residual moisture content of 2 ÷ 3% and fired at 1100 ° C with a rate of temperature rise of 30 ÷ 40 ° C per hour. Exposure at the final temperature of 4 hours, the temperature drop rate of 40 ° C per hour, the duration of the complete firing cycle 48 hours.

In these technologies for the production of stone-ceramic products from basalt, the methods of dry (500 ÷ 1000 kg / cm ² ) and wet (30 ÷ 50 kg / cm ² ) pressing are used.

The described methods are quite complex technologically and multi-stage. So, when using slurries containing clay, a separate grinding of the latter, mixing with water and holding for 2–3 days are required. In addition, the introduction of deflocculants is necessary. Expensive mineralizers are introduced into slip compositions. The full firing cycle lasts 2 days, which requires large energy costs and makes it economically intensive.

The technical problem is determined by the fact that the rocks of the main group are composed mainly of silicate minerals. For example, basalt consists of 50–70 wt.% Plagioclase of a labrador-isomorphic mixture of albite NaAl [Si ₃ O ₈ ] and anorthite CaAl ₂ [Si ₂ O ₈ ]. There are also: pyroxenes, represented mainly by augite (an isomorphic mixture of diopside CaMg [Si ₂ O ₆ ] and hedenbergite CaFe [Si ₂ O ₆ ]); olivine - solid solutions of forsterite Mg ₂ [SiO ₄ ] and fayalite Fe ₂ [SiO ₄ ]; magnetite FeO · Fe ₂ O ₃ and other minerals. When heated to temperatures of 1000 ÷ 1100 ° C, they soften due to the partial melting of low-melting minerals, which play the role of binders that determine the energy-intensive and expensive process of liquid-phase sintering.

The closest in technical essence is a method of manufacturing products based on silica binder using mineral raw materials and various industrial wastes [RU 2283818, 2006] (prototype).

According to the prototype, the method includes preparing a silica-containing binder with a density of 1.1 ÷ 2.1 g / cm ³ from a mixture containing an inorganic binder, a silica-containing component and water when they are intensively mixed in a high-speed mixer at a mixing speed of 1500 ÷ 2500 rpm, the oscillation frequency mixed particles of 2000 ÷ 3500 Hz, heating to 80 ÷ 90 ° C and subsequent cooling with stirring at a speed of 40 to 100 rpm for 10 ÷ 12 hours at 15 ÷ 25 ° C, moreover, as a silica-containing component in the preparation of the bond They use quartz sand with a moisture content of not more than 20%, calcined clay, loam, sandy loam, loess deposits, silica fume obtained from ferroalloy production waste, silica processing waste obtained by sawing or grinding, for example granite, or in the production of crushed granite, hydromica, in particularly used in the production of vermiculite or expanded perlite; preparation of the molding material by mixing 9.0 ÷ 13.5 wt.% silica binder and 86.5 ÷ 91.0 wt.% silica filler, which is used as: river sand, sea sand, quarry sand, granite, basalt, vermiculite , expanded perlite sand, expanded clay, hydromica, metallurgical slag, coal slag and ash, expanded clay, stone and stone processing waste, amorphous silica mixtures. Heat treatment is carried out at temperatures of 400 ÷ 950 ° C.

The disadvantage of this method is primarily its complexity, due to the need to perform an independent stage of preparation of a silica binder, requiring high-speed mixing at a temperature of 80 ÷ 90 ° C, followed by cooling also with stirring for 10 ÷ 12 hours.

The second disadvantage is that heat treatment is carried out at sufficiently high temperatures of 400 ÷ 950 ° C, which, combined with the need to use expensive equipment, makes this technology economically intensive.

The invention is aimed at simplifying the method, expanding the field of application of rocks of the main group and creating an economically less expensive technology for producing stone-ceramic products.

The technical result is achieved by the fact that the proposed method for producing ceramic products, including the preparation of the molding material from rocks of the main group as a filler and binder, molding from the obtained molding material of the products and their heat treatment, characterized in that the preparation of the molding material is carried out by mixing 80 ÷ 95 wt.% filler from the rocks of the main group with particle sizes of 50 ÷ 500 μm and a moisture content of not more than 5%, with 5 ÷ 20 wt.% phosphoric acid with a density of 1.50 ÷ 1.85 g / cm ³ taken as curing, and maintaining the mixture at a temperature of 10 ÷ 30 ° C for 24 ÷ 72 hours, the subsequent heat treatment is carried out at a temperature of 100 ÷ 300 ° C.

It is advisable that the molding of products is carried out by hot pressing with a force of 10 to 500 kg / cm ² .

It is desirable that the mixing of the filler and phosphoric acid is carried out for 30 ÷ 90 minutes

The binding properties of phosphoric acid are determined by its interaction with silica and silicates that make up the main rocks with the formation of orthophosphates, primarily aluminum orthophosphates, which, when mixed with a filler, form a solid monolithic mass.

The claimed density of phosphoric acid is due to the fact that at a density below 1.50 g / cm ^{3 the} acid contains more than 35% moisture, which leads to the formation of highly porous products of limited use, the use of a filler with a moisture content of more than 5% leads to the same results. The density of 1.85 g / cm ³ corresponds to the maximum for industrially produced phosphoric acid.

The ratio of phosphoric acid and filler is determined by the chemical composition of the latter, in particular the content of aluminosilicates.

The dispersion of the filler plays a secondary role in the process of obtaining ceramic products, therefore, its particle size can have a wide range.

The mixing time of the filler and phosphoric acid is determined by the volume of the latter and the dispersion of the filler and is 30 ÷ 90 min to obtain a homogeneous composition of the mixture.

This mixture is aged for 24 ÷ 72 hours at a temperature of 10 ÷ 30 ° C for the reaction between phosphoric acid and the filler

The heat treatment temperature of 100 ÷ 300 ° C of products from the molding material obtained by the claimed method is sufficient to give the products the desired consumer properties.

To implement the method according to the invention, various grinding and mixing devices are used: jaw, cone, roller, rotary, drum crushers; ball mills, rod mills, vibratory mills, planetary mills, etc., as well as mixers: turbine, blade, milling, anchor, frame, screw, etc.

The intensity of interaction during sintering increases significantly when pressing the molding material, especially with simultaneous heating. The molding force is determined by the requirements for the products obtained.

The claimed method is implemented as follows: the feedstock from rocks of the main group is subjected to grinding to obtain fractions with a particle size of 50 ÷ 500 μm, the powder is dried to a residual moisture content of not more than 5%, then mixed for 30 ÷ 90 min with phosphoric acid with a density of 1, 5 ÷ 1.85 g / cm ³ in a ratio of 5 to 20 wt.% Phosphoric acid and from 95 to 80 wt.% Filler from rocks of the main group, withstand the prepared molding mass at a temperature of 10 ÷ 30 ° C for 24 ÷ 72 hours, carry out the molding of products from the resulting molding mass, if necessary, carry out pressing with a force of 10 to 500 kg / cm ² and carry out the heat treatment process at 100 ÷ 300 ° C for 1 ÷ 3 hours.

The following are examples of the implementation of the claimed method for producing ceramic products, which illustrate the method, but do not limit it. Examples of the implementation of the claimed method and the prototype method, as well as the properties of the obtained products are summarized in the Table.

In the examples cited, the following were used as filler:

- gabbro of the Berezovskoye deposit of the Sverdlovsk region, having a chemical composition, wt.%: SiO ₂ - 47.44; Al ₂ O ₃ - 16.56; TiO ₂ 0.35; Fe ₂ O ₃ - 1.55; FeO 4.95; MnO - 0.10; CaO - 12.10; MgO 11.50; SO ₃ 0.40; K ₂ O - 0.15; Na ₂ O - 1.50; p.p.p. - 3.3;

- basalt of the Vasilievskoye deposit of the Kemerovo region, having the following chemical composition, wt.%: SiO ₂ - 50.61; Al ₂ O ₃ - 19.24; TiO ₂ - 1.35; Fe ₂ O ₃ - 4.58; FeO - 2.66; MnO - 0.15; CaO 8.75; MgO - 5.81; Na ₂ O - 3.52; p.p.p. - 3.33;

- diabase deposits "West Kondopoga" of the Republic of Karelia, having a chemical composition, wt.%: SiO ₂ - 49.67; Al ₂ O ₃ - 14.0; (Fe ₂ O ₃ + FeO) - 13.40; CaO - 10.00; MgO 8.53; K ₂ O - 0.36; Na ₂ O - l, 87; p.p.p. - 2.17

Example 1

According to the method according to the invention, the preparation of the molding material is carried out by mixing in a screw mixer 80 wt.% Filler from gabbro deposits "Berezovskoye" Sverdlovsk region with a particle size of 150 ÷ 300 microns and humidity ≤ 5% with 20 wt.% Phosphoric acid with a density of 1.85 g / cm ³ (100 wt.%) for 45 minutes The resulting molding material is kept at a temperature of 10 ÷ 30 ° C for 24 hours, placed in molds and subjected to heat treatment at a temperature of 250 ° C for 1.5 hours. The properties of the products obtained are given in the Table.

Example 2

The molding material is prepared by mixing in an anchor mixer 90 wt.% Filler from basalt of the Vasilievskoye deposit in the Kemerovo region with a particle size of 50 ÷ 100 μm and humidity ≤ 5% with 10 wt.% Phosphoric acid with a density of 1.65 g / cm ³ (80 wt. %) within 75 minutes The resulting molding material is kept at a temperature of 10 ÷ 30 ° C for 56 hours, placed in molds and subjected to heat treatment at a temperature of 200 ° C for 2 hours. The properties of the products obtained are given in the Table.

Example 3

The molding material is prepared by mixing in a frame mixer 85 wt.% Filler from basalt of the Vasilievskoye deposit in the Kemerovo region with a particle size of 50 ÷ 100 μm and humidity ≤ 5% with 15 wt.% Phosphoric acid with a density of 1.75 g / cm ³ (90 wt.% ) for 60 minutes The resulting molding material is kept at a temperature of 10 ÷ 30 ° C for 40 hours, placed in molds and subjected to heat treatment at a temperature of 300 ° C for 1 hour. The properties of the products obtained are given in the Table.

Example 4

The molding material is prepared by mixing in a paddle mixer 95 wt.% Filler from diabase of the West Kondopoga deposit of the Republic of Karelia with a particle size of 100-200 μm and humidity ≤ 5% with 5 wt.% Phosphoric acid with a density of 1.53 g / cm ³ ( 70 wt.%) For 90 minutes The obtained molding mass is kept at a temperature of 10 ÷ 30 ° C for 24 hours, placed in molds, subjected to hot pressing with a force of 250 kg / cm ² , after which the heat treatment process is carried out at 100 ° C for 3 hours. The properties of the products obtained are given in the Table.

Process indicators, product properties Example No. Prototype one 2 3 four Filler gabbro basalt Basalt diabase quartz sand The filler content, wt.% 80 90 85 95 91.0 ÷ 86.5 The binder content, wt.% twenty 10 fifteen 5 9.0-15.5 The density of the binder, g / cm ³ 1.85 1.65 1.75 1.53 1.50 Humidity of the filler,% less than 5% less than 6% The particle size of the filler, microns 150 ÷ 300 50 ÷ 100 50 ÷ 100 100 ÷ 200 60 ÷ 120 The mixing time of the molding material, min 45 75 60 90 to obtain a homogeneous composition of the charge The pressing force of the molding material, kg / cm ² 0 0 0 250 200 ÷ 400 The temperature of the heat treatment of the molding material, ° C 250 200 300 one hundred 750 ÷ 950 The heat treatment time of the molding material, hours 1.5 2 one 3 0.2 ÷ 0.5 The density of the obtained products, g / cm ³ 2.4 ÷ 2.6 1.9 ÷ 2.1 0.8 ÷ 1.0 0.6 ÷ 0.8 2.4 ÷ 2.6 Water absorption,% 0.9 ÷ 1.1 1.3 ÷ 2.7 2.4 ÷ 5.6 2.7 ÷ 6.2 2.5 ÷ 14.0 Chemical resistance in sulfuric to-those,% 97.3 ÷ 98.7 89.1 ÷ 90.4 78.3 ÷ 90.7 76.2 ÷ 76.8 Acid Resistance 0.95 Chemical resistance in hydrochloric acid,% 87.1 ÷ 90.2 83.5 ÷ 84.2 76.1 ÷ 78.3 71.6 ÷ 73.8

The proposed method for the manufacture of stone-ceramic products from rocks of the main group allows us to simplify the technology by eliminating the independent stage of preparation of the binder, to expand the raw material base and the range of products. At the same time, carrying out the heat treatment process at significantly lower temperatures allows the use of inexpensive technological equipment with the possibility of using secondary heat, which creates an economically less expensive technology for producing stone-ceramic products.

Claims (3)

1. A method of producing ceramic products, including the preparation of the molding material from rocks of the main group as a filler and a binder, molding from the obtained molding material of the products and their heat treatment, characterized in that the preparation of the molding material is carried out by mixing 80 ÷ 95 wt.% Filler from rocks of the main group with particle sizes of 50 ÷ 500 μm and a moisture content of not more than 5% with 5 ÷ 20 wt.% phosphoric acid with a density of 1.50 ÷ 1.85 g / cm ³ , taken as a binder, and keeping the mixture at a temperature ur 10 ÷ 30 ° C for 24 ÷ 72 hours, the subsequent heat treatment is carried out at a temperature of 100 ÷ 300 ° C. 2. The method according to claim 1, characterized in that the molding of products is carried out by hot pressing with a force of 10 to 500 kg / cm ² . 3. The method according to claim 1, characterized in that the mixture of the filler and phosphoric acid is carried out for 30 ÷ 90 minutes