Crucibles & Babbitt Ingots. Metals - Melting Temperatures. Homemade Refractories. "Masonry cement" (on the left) is not the same as "Portland cement". Portland cement is plain cement powder and specifically says Portland cement. Masonry cement is a mixture of Portland cement and sand. It may also contain other components (admixtures) to provide a certain characteristic such as waterproofing agents, colors etc. In some cases you only need to add water to masonry cement mixtures. Fireclay is usually (at least where I buy it) sold in 50lbs (about 23kg) plain packages and they don't even say "fireclay" on them.
Another type of clay is Bentonite clay. Melting metal in a home foundry, backyard metalcasting, metal casting. Mechanical Charts - Typical Shrinkage Allowances for Important Casting Metals.