Elena Tsiba

Faculty of ecology and chemical technology
Speciality: Chemical technology of refractory non-metal and silicate materials

Theme of master's work:

The use of rejects of zircon ores as basic material for the production of building material

Leader of work: Professor Nikolai Belomerya

e-mail: Lenochka-cyba@mail.ru

ABSTRACT

Introduction

Ceramics, among of all other artificial materials, has being accompanied a man and society in whole over the time of development. Due to its amazing properties, a wide spread of basic raw material as the clays or their mixtures, the ceramic wares and materials have being served to the people as vessels in the everyday life, build material for building dwelling, as standards of spiritual structure.
This dispade the fact the now days concrete and reinforced the main basic build materials the ceramic products for building have not lose their meaning. Especially widely ceramic products are used for the constructions of building of improved architecture and also for individual building. Thus, now days the plans-manufactories of building material are facing a problem to produce high-quality products using cheap raw material.

Actuality of theme. Purposes and tasks

Natural raw materials gradually disappear. The question of use of the second raw materials which is produced as a result of activity of chemical, mining and coal industry, black and colored metallurgy becomes very actual. Given fields of industry along with the enormous issue of the products are instrumental in accumulation of good number of wastes which can contain valuable components for production of the different goods including the build materials.
A purpose of work is research of the possibility of use of the reject of zirconium concentrate as a raw material for production of the building materials. This waste has a chemical composition similar to the composition of the nepheline concentrate therefore it can be used as a flux.
This work is a research of production of a ceramic brick and tile with the use of nepheline- containing waste and clays of different deposits as well as selection of the optimum compositions, conditions and properties of the products.

Experimental part

The object of the research is a waste of zircon production of Donetsk chemical-and-metallurgical plant having a nepheline as the main component. Waste is some million tons and occupies a large territory.
Now this tailing is not used effectively although at chemical analysis it is possible to assume their using for production of the silicate materials and products, for example, for production of the ceramic products – ceramic bricks and tails, pipes, tiling. As it contains a considerable quantity of iron that the colored glasses, undercoat enamels and colored cover enamels and glazes can be produced at using of this waste.
Therefore, the experimental part of the work consists in research of the possibility of using of the zirconium ores reject as a raw material for production of the ceramic bricks and tails.
Chemical composition of the waste stated in the table 1 rather like a composition of the natural raw materials used as a fluxing agent.

Table 1 – Chemical composition of waste

Component	SiO₂	Al₂O₃	Fe₂O₃	TiO₂	MgO	CaO	K₂O	Na₂O	ZrO₂	ignition loss
Containing, %	39,31	32,87	1,01	0,28	0,61	1,53	5,92	16,33	0,10	2,04

Moisture of the nepheline concentrate which ranges 7-15 %, bulk density is 1,36 kg/m3, granulometric composition: fraction from 0 to 0,16 mm -53,46 %, from 0,16 to 0,315 mm – 54,41 %, from 0,315 to 0,63 mm – 39,25 %, from 0,63 to 1,25 mm – 20,77 %, from 1,25 to 2 mm – 5,41 % - are determined.
The tests with the purpose of research of the possibility of the clay brick production using nepheline waste, Chasov-Yar (CY) and Mariupol clay (M) as well as the overburdens of The White Gully kaolin deposits are carried out.
Laboratory samples of the following composition were produced: 50 % of nepheline and 50 % of clay, 40 % of nepheline and 60 % of clay, 30 % of nepheline and 70 % of clay, 20 % of nepheline and 80 % of clay.
For production of samples under the soft technology the clay was crushed carefully and sifted 05. Clay and waste in set mass ratio were weighed and mixed, tempered by water till normal moisture, vacuumed. The samples were produced from received mass. After formation the samples were dried in natural conditions and in drying cabinet at the temperature 105-120 ^оС.
At the production of samples the quantity of waste influenced to forming properties of ceramic mass. On forming stage this waste is a nonplastic material, i.e. it is a framework of ceramic mass. The forming was difficult at its addition in. At addition of nepheline-containing concentrate into the mixture of masses of Mariupol’s and Chasov-Yar’s clay the quantity of waste positively affects formability at its addition in number 20, 30, 40, 50 %. At addition of waste into the mixture of masses with the overburdens of The White Gully deposit the forming was improved at its number 20, 30 %.
With the purpose of determination of the optimal compositions, conditions, properties of the products at addition of different quantity of nepheline-containing waste to the mass the samples were fired at the temperature 1000, 1050, 1070, 1100 ^oС. On firing stage it is a fluxing agent owing to a number of alkalic and alkali-earth oxides which reduce the firing temperature.
Air shrinkage, fire shrinkage and full shrinkage, water absorption ability and mechanical strength were determined on these samples. These specifications of the samples are stated in Table 2 (semiacid kaolin (K), clay loams (CL) and ferruginized kaolin (FK) of The White Gully deposit).

Table 2 – Specifications of the samples

compositions of ceramic masses, mas. %		firing temperature, ^oС	water absorption ability, %	air shrinkage, %	fire shrinkage, %	full shrinkage, %	mechanical strength, kgs/сm²
clay	nepheline	firing temperature, ^oС	water absorption ability, %	air shrinkage, %	fire shrinkage, %	full shrinkage, %	mechanical strength, kgs/сm²
50 К	50	1070	21,5	5,3	0,3	5,6	33
60 К	40	1070	20,8	4,7	0,1	4,8	59
70 К	30	1070	22,5	4,2	0,2	4,4	48
80 К	20	1070	22,9	5,2	0,4	5,6	51
50 CL	50	1000	20,2	7,7	0,1	7,8	65
60 СL	40	1000	17,4	8,2	0,5	8,7	60
70 СL	30	1000	19,3	10,5	0,4	10,9	63
80 СL	20	1000	17,8	11,8	1,1	12,9	78
50 FK	50	1000	20,4	6,1	0,9	7,0	41
60 FK	40	1000	20,7	8,3	3,3	11,6	45
70 FK	30	1000	22,5	10,5	1,7	12,2	58
80 FK	20	1000	23,6	10,4	1,7	12,1	84
50 K	50	1100	22,1	4,9	0,2	5,1	39
60 К	40	1100	20,6	4,6	0,3	4,9	38
70 К	30	1100	19,9	8,6	0,3	8,9	41
80 К	20	1100	24,5	9,2	0,7	9,9	64
50 CY	50	1000	10,2	-	-	-	135
60 CY	40	1000	6,9	-	-	-	124
70 CY	30	1000	8,5	-	-	-	128
50 CY	50	1100	8,5	3,9	3,5	7,4	298
60 CY	40	1100	4,9	5,1	3,2	8,3	320
50 М	50	1050	12,5	6,5	0,5	7,0	81
60 М	40	1050	14,8	11,2	0,4	11,6	87
70 М	30	1050	15,5	13,2	0,1	13,3	92
80 М	20	1050	10,9	11,2	2,7	13,9	208

In accordance with results we can make the following conclusions:
- introduction of nepheline-containing waste in number of 20-50 % has a positive effect to forming properties of the product depending on used clay raw material;
- at waste using the firing temperature decreases and durability increases;
- received products with using of waste with mixture of Mariupol’s and Chasov-Yar’s clays can be used for construction of bearing structures;
- received products with using of mixture of waste with the overburdens of The White Gully deposit can be used as the heat insulators.
So:
- the reject of zirconium ores can be cheap substitute of the natural raw materials at the production of ceramic bricks and tiles;
- using of waste favour decreasing of anthropogenic loading to the environment. Having analyzed the chemical composition of the waste we can propose to use it for production of different ceramic products.

Further plans

Using of nepheline-containing waste with other clay materials, selection of optimal compositions, conditions and properties of these products. Comparison of properties of received samples under the soft technology and dry compaction. Introduction of different colored agents in ceramic mass for receiving of improved decorative properties of the products.